Risk factors for complications during pregnancy include
Preexisting maternal medical conditions and characteristics
Modifiable risk factors (eg, smoking, substance use)
Previous obstetric complications (eg, a previous history of preeclampsia)
Some major risk factors are discussed here. For additional medical conditions that may complicate pregnancy, see Pregnancy Complicated by Disease Pregnancy Complicated by Disease .
Diabetes
Preexisting diabetes mellitus Diabetes Mellitus in Pregnancy Pregnancy makes glycemic control more difficult in preexisting type 1 (insulin-dependent) and type 2 (non–insulin-dependent) diabetes but does not appear to exacerbate diabetic retinopathy,... read more is present in approximately 1% of pregnancies (1 Diabetes references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more , 2 Diabetes references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ), and gestational diabetes occurs in approximately 8% of pregnancies (3 Diabetes references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ). Incidence is increasing as the incidence of obesity increases.
Preexisting insulin-dependent diabetes increases the risk of the following:
Fetal death
Major fetal malformations
The incidence of fetal macrosomia is approximately 50% higher in pregnant women with preexisting diabetes than in pregnant women in the general population. The incidence of perinatal fetal or neonatal mortality is also higher.
Women with preexisting diabetes are more likely to require preterm delivery for obstetric or medical indications. Exercise during pregnancy (with judicious changes in diet) reduces the need for cesarean and operative deliveries in these women (4 Diabetes references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more , 5 Diabetes references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ).
Tight glucose control before conception and during early pregnancy is essential to prevent fetal malformations.
Insulin requirements usually increase during pregnancy.
Gestational diabetes increases the risk of the following:
Hypertensive disorders of pregnancy
Gestational diabetes is routinely screened for at 24 to 28 weeks and, if women have risk factors, during the first trimester. Risk factors include the following:
Previous gestational diabetes
A macrosomic infant in a previous pregnancy
Unexplained fetal losses
Prepregnancy body mass index (BMI) > 30 kg/m2
Maternal age > 40 years
Family history of diabetes
Non-Hispanic Asian/Pacific Islander and Hispanic/Latina ethnicity
Screening and confirmation of the diagnosis of gestational diabetes can be done in 1 or 2 steps (6 Diabetes references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more , 7 Diabetes references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ):
1-step test: A fasting, 75-g glucose, 2-hour oral glucose tolerance test (GTT). Abnormal results are any of the following: fasting (≥ 92 mg/dL [5.1 mmol/L]); 1 hour (≥ 180 mg/dL [10 mmol/L]); or 2 hour (≥ 153 mg/dL [8.5 mmol/L).
2-step test: A non-fasting, 50-g glucose, 1-hour GTT; if abnormal (≥ 130 mg/dL [7.5 mmol/L] to 140 mg/dL [7.8 mmol/L]), then a fasting, 100-g, 3-hour GTT. For interpretation of results , see table .
The American College of Obstetricians and Gynecologists (ACOG) recommends the 2-step test to diagnosis gestational diabetes. The 1-step approach has been used and promoted by other organizations, including the International Association of Diabetes and Pregnancy Study Group (IADPSG) (6 Diabetes references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ).
Optimal treatment of gestational diabetes Treatment Pregnancy makes glycemic control more difficult in preexisting type 1 (insulin-dependent) and type 2 (non–insulin-dependent) diabetes but does not appear to exacerbate diabetic retinopathy,... read more (with dietary modification, exercise, and close monitoring of blood glucose levels and insulin when necessary) reduces risk of adverse maternal, fetal, and neonatal outcomes. Women with gestational diabetes are at a higher lifetime risk of cardiovascular events and, after delivery, should be referred for appropriate cardiovascular risk assessment and follow-up.
Women with gestational diabetes mellitus may have had undiagnosed diabetes mellitus before pregnancy. Thus, they should be screened for diabetes mellitus Screening Diabetes mellitus is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia... read more 6 to 12 weeks postpartum, using the same testing and criteria used for patients who are not pregnant.
See Diabetes Mellitus in Pregnancy Diabetes Mellitus in Pregnancy Pregnancy makes glycemic control more difficult in preexisting type 1 (insulin-dependent) and type 2 (non–insulin-dependent) diabetes but does not appear to exacerbate diabetic retinopathy,... read more for details regarding management of diabetes in pregnancy.
Diabetes references
1. Deputy NP, Kim SY, Conrey EJ, Bullard KM: Prevalence and Changes in Preexisting Diabetes and Gestational Diabetes Among Women Who Had a Live Birth - United States, 2012-2016. MMWR Morb Mortal Wkly Rep 67(43):1201-1207, 2018. Published 2018 Nov 2. doi:10.15585/mmwr.mm6743a2
2. Goya M, Codina M: Diabetes mellitus and pregnancy. Updated clinical practice guideline 2021. Executive summary. Endocrinol Diabetes Nutr (Engl Ed) 70 Suppl 1:1-6, 2023. doi:10.1016/j.endien.2021.12.006
3. Gregory EC, Ely DM: Trends and Characteristics in Gestational Diabetes: United States, 2016-2020. Natl Vital Stat Rep 71(3):1-15, 2022.
4. Artal R: Exercise: The alternative therapeutic intervention for gestational diabetes. Clinical Obstetrics and Gynecology 46 (2):479–487, 2003.
5. Artal R: The role of exercise in reducing the risks of gestational diabetes mellitus in obese women. Best Pract Res Clin Obstet Gynaecol 29 (1):123–4132, 2015.
6. American College of Obstetrics and Gynecology (ACOG): ACOG Practice Bulletin No. 190: Gestational Diabetes Mellitus. Obstet Gynecol. 2018;131(2):e49-e64. doi:10.1097/AOG.0000000000002501
7. American Diabetes Association Professional Practice Committee: 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024. Diabetes Care. 2024;47(Suppl 1):S20-S42. doi:10.2337/dc24-S002
Hypertension
Hypertensive disorders Hypertension in Pregnancy Recommendations regarding classification, diagnosis, and management of hypertensive disorders (including preeclampsia) are available from the American College of Obstetricians and Gynecologists... read more of pregnancy are classified as (1 Hypertension references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more )
Chronic hypertension: Present before the pregnancy or developing before 20 weeks of pregnancy
Gestational hypertension: New onset of systolic and/or diastolic blood pressure (BP) ≥ 140/≥ 90 mm Hg on 2 occasions at least 4 hours apart after 20 weeks of gestation
Preeclampsia Preeclampsia and Eclampsia Preeclampsia is new onset or worsening of existing hypertension with proteinuria after 20 weeks gestation. Eclampsia is unexplained generalized seizures in patients with preeclampsia. Diagnosis... read more : New onset after 20 weeks of gestation of persistent (2 episodes within 4 hours) systolic and/or diastolic BP ≥ 140/≥ 90 mm Hg OR at least 1 measurement of systolic and/or diastolic BP ≥ 160/≥ 110 mm Hg PLUS new unexplained proteinuria (> 300 mg/24 hours or urine protein/creatinine ratio ≥ 0.3 or dipstick reading of 2+; in the absence of proteinuria, new-onset hypertension with new onset of other signs of end-organ damage (eg, thrombocytopenia [platelets < 100,000/mcL], impaired liver function, renal insufficiency, pulmonary edema, new-onset headache [unresponsive to medication and not accounted for by alternative diagnoses], visual symptoms).
Preeclampsia with severe features: Preeclampsia with persistent (2 episodes within 4 hours) systolic and/or diastolic BP ≥ 160/≥ 110 mm Hg and/or other signs of end-organ damage
HELLP syndrome: A form of severe preeclampsia with hemolysis, elevated liver enzymes, and low platelet count
Chronic hypertension plus superimposed preeclampsia: Worsening hypertension and new or worsening proteinuria or other signs of end-organ damage after 20 weeks in a woman with preexisting hypertension
Eclampsia: New-onset tonic-clonic, focal, or multifocal seizures not accounted for by other causes
Chronic hypertension increases risk of the following:
Fetal growth restriction Small-for-Gestational-Age (SGA) Infant Infants whose weight is < the 10th percentile for gestational age are classified as small for gestational age. Complications include perinatal asphyxia, meconium aspiration, polycythemia... read more (by decreasing uteroplacental blood flow)
Adverse fetal and maternal outcomes
Before attempting to become pregnant, women with hypertension should be counseled about risks. Prenatal care should begin as early in pregnancy as possible. Pregnant women with chronic hypertension who require antihypertensive therapy should be started or continued on appropriate medications and referred to a maternal-fetal medicine specialist (2 Hypertension references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ).
Management of chronic hypertension during pregnancy Treatment Recommendations regarding classification, diagnosis, and management of hypertensive disorders (including preeclampsia) are available from the American College of Obstetricians and Gynecologists... read more includes measurements of baseline renal function (eg, serum creatinine, blood urea nitrogen [BUN]), funduscopic examination, and directed cardiovascular evaluation (auscultation and sometimes ECG, echocardiography, or both). Each trimester, 24-hour urine protein, serum uric acid, serum creatinine, and hematocrit are measured.
Ultrasonography to monitor fetal growth is done at 28 weeks and every 4 weeks thereafter. Delayed growth is evaluated with multivessel Doppler testing by a maternal-fetal medicine specialist.
If women are at high risk of preeclampsia, clinicians may prescribe low-dose aspirin (81 to 162 mg orally once a day) to be taken daily starting at 12 to 28 weeks of gestation and taken until delivery (3 Hypertension references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more , 4 Hypertension references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ).
Women with a history of preeclampsia or gestational hypertension are at a higher lifetime risk of cardiovascular events and, after delivery, should be referred for appropriate cardiovascular risk assessment and follow-up.
Hypertension references
1. American College of Obstetrics and Gynecology (ACOG): ACOG Practice Bulletin, Number 222: Gestational hypertension and preeclampsia. Obstet Gynecol 133 (1):1, 2019. doi: 10.1097/AOG.0000000000003018
2. Tita AT, Szychowski JM, Boggess K, et al: Treatment for Mild Chronic Hypertension during Pregnancy. N Engl J Med 386(19):1781-1792, 2022. doi:10.1056/NEJMoa2201295
3. American College of Obstetrics and Gynecology (ACOG) ACOG Committee Opinion No. 743: Low-dose aspirin use during pregnancy. Obstet Gynecol 132 (1):e44–e52, 2018. doi: 10.1097/AOG.0000000000002708
4. Ayyash M, Goyert G, Garcia R, et al: Efficacy and Safety of Aspirin 162 mg for Preeclampsia Prophylaxis in High-Risk Patients. Am J Perinatol. Published online July 29, 2023. doi:10.1055/s-0043-1771260
Thyroid Disorders
Thyroid disorders Overview of Thyroid Function The thyroid gland, located in the anterior neck just below the cricoid cartilage, consists of 2 lobes connected by an isthmus. Follicular cells in the gland produce the 2 main thyroid hormones... read more may predate or develop during pregnancy. Pregnancy does not change the symptoms of hypothyroidism and hyperthyroidism.
Fetal effects vary with the disorder and the medications used for treatment. But generally, untreated or inadequately treated hyperthyroidism can result in
Untreated hypothyroidism can cause
Intellectual deficits in children
The most common causes of maternal hypothyroidism are Hashimoto thyroiditis Hashimoto Thyroiditis Hashimoto thyroiditis is chronic autoimmune inflammation of the thyroid with lymphocytic infiltration. Findings include painless thyroid enlargement and symptoms of hypothyroidism. Diagnosis... read more and treatment of Graves disease Etiology Hyperthyroidism is characterized by hypermetabolism and elevated serum levels of free thyroid hormones. Symptoms include palpitations, fatigue, weight loss, heat intolerance, anxiety, and tremor... read more .
If women have or have had a thyroid disorder, thyroid status should be closely monitored during and after pregnancy in the women and after delivery in infants. Goiters and thyroid nodules discovered during pregnancy should be evaluated as they are in nonpregnant patients (see Approach to the Patient With a Thyroid Nodule Approach to the Patient With a Thyroid Nodule Thyroid nodules are benign or malignant growths within the thyroid gland. They are common, increasingly so with increasing age. (See also Overview of Thyroid Function.) The reported incidence... read more and Diagnosis of Simple Nontoxic Goiter Diagnosis Simple nontoxic goiter, which may be diffuse or nodular, is noncancerous hypertrophy of the thyroid gland without hyperthyroidism, hypothyroidism, or inflammation. Except in severe iodine deficiency... read more ).
Sexually Transmitted Infections (STIs)
(See also Sexually Transmitted Infections Overview of Sexually Transmitted Infections Sexually transmitted infection (STI) refers to infection with a pathogen that is transmitted through blood, semen, vaginal fluids, or other body fluids during oral, anal, or genital sex with... read more and Infectious Disease in Pregnancy Infectious Disease in Pregnancy Most common maternal infections (eg, UTIs, skin and respiratory tract infections) are usually not serious problems during pregnancy, although some genital infections (bacterial vaginosis and... read more .)
Screening for sexually transmitted infections should be done during pregnancy to make treatment possible and to prevent adverse effects of intrauterine or perinatal transmitted infections to the fetus or neonate. The rate of congenital syphilis Congenital Syphilis Congenital syphilis is a multisystem infection caused by Treponema pallidum and transmitted to the fetus via the placenta. Early signs are characteristic skin lesions, lymphadenopathy... read more in the United States consistently rises (see CDC: National Overview of STDs, 2021).
Routine prenatal care includes screening tests for HIV infection, hepatitis B, hepatitis C (1 STIs references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ), and syphilis and, if < 25 years, for chlamydial infection and gonorrhea at the first prenatal visit. Syphilis testing is repeated during pregnancy and at delivery if risk continues or if the patient resides in an endemic area (2 STIs references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ). Pregnant women who have any of these infections are treated with antimicrobials.
Fetal syphilis Congenital Syphilis Congenital syphilis is a multisystem infection caused by Treponema pallidum and transmitted to the fetus via the placenta. Early signs are characteristic skin lesions, lymphadenopathy... read more in utero can cause fetal death, congenital malformations, and severe disability.
Without treatment, risk of transmission of HIV Transmission Human immunodeficiency virus (HIV) infection results from 1 of 2 similar retroviruses (HIV-1 and HIV-2) that destroy CD4+ lymphocytes and impair cell-mediated immunity, increasing risk of certain... read more from mother to child is approximately 30% prepartum and approximately 25% intrapartum. Antiretroviral treatment of the pregnant woman before and during pregnancy and of the neonate within 6 to 12 hours of birth reduces risk of HIV transmission to the fetus Prevention Human immunodeficiency virus (HIV) infection is caused by the retrovirus HIV-1 (and less commonly by the related retrovirus HIV-2). Infection leads to progressive immunologic deterioration and... read more by two thirds; risk is lower (< 2%) with a combination of 2 or 3 highly active antiretrovirals. Highly active antiretrovirals are given to the mother during pregnancy and intrapartum to prevent mother-to-child transmission.
During pregnancy, hepatitis, bacterial vaginosis, gonorrhea, and genital chlamydial infection increase risk of preterm labor Preterm Labor Labor (regular uterine contractions resulting in cervical change) that begins before 37 weeks gestation is considered preterm. Risk factors include prelabor rupture of membranes, uterine abnormalities... read more and prelabor rupture of the membranes Prelabor Rupture of Membranes (PROM) Prelabor rupture of membranes is leakage of amniotic fluid before onset of labor. Diagnosis is clinical. Delivery is recommended when gestational age is ≥ 34 weeks and is generally indicated... read more .
Treatment of bacterial vaginosis, gonorrhea, or chlamydial infection may prolong the interval from rupture of the membranes to delivery and may improve fetal outcome by decreasing fetal inflammation.
STIs references
1. American College of Obstetrics and Gynecology (ACOG): ACOG Clinical Practice Guideline No. 6.: Viral Hepatitis in Pregnancy, Obstet Gynecol 2023;142(3):745-759. doi:10.1097/AOG.0000000000005300
2. Workowski KA. , Laura H. Bachmann LH, Chan PA: Sexually transmitted infections treatment guidelines, 2021. MMWR Recomm Rep 70 (4):1–187, 2021. doi: http://dx.doi.org/10.15585/mmwr.rr7004a1external icon
Female Genital Tract Abnormalities
Structural abnormalities of the uterus and cervix (eg, uterine septum, bicornuate uterus) make the following more likely:
Fetal malpresentation Fetal Presentation, Position, and Lie (Including Breech Presentation) Abnormal fetal lie or presentation may occur due to fetal size, fetal anomalies, uterine structural abnormalities, multiple gestation, or other factors. Diagnosis is by examination or ultrasonography... read more
Dysfunctional labor
Uterine fibroids Uterine Fibroids Uterine fibroids (leiomyomas) are benign smooth muscle tumors of the uterus. Fibroids frequently cause abnormal uterine bleeding and pelvic pressure and sometimes urinary or intestinal symptoms... read more uncommonly cause placental abnormalities (eg, placenta previa Placenta Previa Placenta previa is implantation of the placenta over or near the internal os of the cervix. It typically manifests as painless vaginal bleeding after 20 weeks gestation; the source of bleeding... read more ), preterm labor Preterm Labor Labor (regular uterine contractions resulting in cervical change) that begins before 37 weeks gestation is considered preterm. Risk factors include prelabor rupture of membranes, uterine abnormalities... read more , and recurrent spontaneous abortion Recurrent Pregnancy Loss Recurrent pregnancy loss is usually defined as the loss of ≥ 2 pregnancies. Each pregnancy loss merits careful review to determine if evaluation of the woman or the couple may be appropriate... read more . Fibroids may grow rapidly or degenerate during pregnancy; degeneration often causes severe pain and peritoneal signs and may also cause preterm labor.
Cervical insufficiency Cervical Insufficiency Cervical insufficiency (formerly called cervical incompetence) is painless cervical dilation resulting in second-trimester pregnancy loss. Transvaginal cervical ultrasonography during the second... read more (incompetence) makes preterm delivery more likely. The risk of cervical insufficiency is higher in women who have had lacerations or injury of the cervix during a previous procedure (eg, therapeutic abortion, instrumental vaginal deliveries). Cervical insufficiency is treated with surgical intervention (cerclage).
If, before pregnancy, women have had a myomectomy in which the uterine cavity was entered, cesarean delivery is required because uterine rupture Uterine Rupture Uterine rupture is rupture of the myometrium in late pregnancy before labor or during labor, which usually occurs in patients with prior uterine surgery (eg, cesarean delivery or myomectomy)... read more is a risk during subsequent vaginal delivery.
Uterine abnormalities that lead to poor obstetric outcomes often require surgical correction, which is done after delivery.
Substance Use
Substance use during pregnancy Social and Illicit Drugs During Pregnancy Cigarette smoking is the most common addiction among pregnant women. Carbon monoxide and nicotine in cigarettes cause hypoxia and vasoconstriction, increasing risk of the following: Spontaneous... read more , including caffeine, alcohol, tobacco, and illicit drug use, is associated with adverse outcomes. Depending on the particular substance, misuse in pregnancy may lead to a range of complications, including preterm labor Preterm Labor Labor (regular uterine contractions resulting in cervical change) that begins before 37 weeks gestation is considered preterm. Risk factors include prelabor rupture of membranes, uterine abnormalities... read more , low birth weight, congenital anomalies, developmental delays, and long-term behavioral and cognitive problems in the child.
Maternal substance use, especially with opioids, can also result in neonatal withdrawal symptoms Prenatal Drug Exposure Alcohol and illicit drugs are toxic to the placenta and developing fetus and can cause congenital syndromes and withdrawal symptoms. Prescription drugs also may have adverse effects on the fetus... read more requiring specialized care.
Alcohol Alcohol Toxicity and Withdrawal Alcohol (ethanol) is a central nervous system depressant. Large amounts consumed rapidly can cause respiratory depression, coma, and death. Large amounts chronically consumed damage the liver... read more is the most commonly used teratogen. Risk is probably related to amount of alcohol consumed, but no amount is known to be risk-free. Binge drinking in particular, possibly as little as 45 mL of pure alcohol (equivalent to about 3 drinks) a day, can cause fetal alcohol syndrome Fetal Alcohol Syndrome Alcohol exposure in utero increases the risk of spontaneous abortion, decreases birth weight, and can cause fetal alcohol syndrome, a constellation of variable physical and cognitive abnormalities... read more , which may result in fetal growth restriction, facial and cardiovascular defects, and neurologic dysfunction.
Clinicians should ask pregnant patients about substance misuse, utilize validated screening tools, and refer to addiction specialists when necessary.
Exposure to Teratogens
Common teratogens (agents that cause fetal malformation) include infections, drugs, and physical agents. Malformations are most likely to result if exposure occurs between the second and eighth week after conception (the fourth to tenth week after the last menstrual period), when organs are forming. Other adverse pregnancy outcomes are also more likely. Pregnant women exposed to teratogens are counseled about increased risks and referred for detailed ultrasound evaluation to detect malformations.
Common infections that may be teratogenic include
Commonly used drugs that may be teratogenic include
Bath salts (cathinones)
Some prescription drugs (see table )
Hyperthermia or exposure to temperatures > 39° C (eg, in a sauna) during the first trimester has been associated with spina bifida Spina Bifida Spina bifida is defective closure of the vertebral column. Although the cause is often unknown, low folate levels during pregnancy increase risk. Some children are asymptomatic, and others have... read more .
Exposure to Mercury
Mercury in seafood can be toxic to the fetus. The FDA (see Advice about Eating Fish For Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1–11 Years) recommends the following:
Avoiding tilefish from the Gulf of Mexico, shark, swordfish, big-eye tuna, marlin, orange roughy, and king mackerel
Limiting albacore tuna to 4 ounces (one average meal)/week
Before eating fish caught in local lakes, rivers, and coastal areas, checking local advisories about the safety of such fish and, if levels of mercury are not known to be low, limiting consumption to 4 ounces/week while avoiding other seafood that week
Tilefish from the Gulf of Mexico have the highest levels of mercury of all fish (as tested by the U.S. Food and Drug Administration (FDA); tilefish from the Atlantic Ocean can be safely eaten.
Experts recommend that women who are pregnant or breastfeeding eat 8 to 12 ounces (2 or 3 average meals) per week of a variety of seafood that is lower in mercury. Such seafood includes flounder, shrimp, canned light tuna, salmon, pollock, tilapia, cod, and catfish. Fish has nutrients that are important for fetal growth and development.
Maternal Age
Adolescents, who account for 13% of all pregnancies, have an increased incidence of preeclampsia Preeclampsia and Eclampsia Preeclampsia is new onset or worsening of existing hypertension with proteinuria after 20 weeks gestation. Eclampsia is unexplained generalized seizures in patients with preeclampsia. Diagnosis... read more , preterm labor Preeclampsia and Eclampsia Preeclampsia is new onset or worsening of existing hypertension with proteinuria after 20 weeks gestation. Eclampsia is unexplained generalized seizures in patients with preeclampsia. Diagnosis... read more , and anemia Etiology of Anemia Anemia is a decrease in the number of red blood cells (RBCs), which leads to a decrease in hematocrit and hemoglobin content. (See also Red Blood Cell Production.) The RBC mass represents the... read more , which often leads to fetal growth restriction. The cause, at least in part, is that adolescents tend to neglect prenatal care, frequently smoke cigarettes or use other substances, and have higher rates of sexually transmitted infections.
In women ≥ 35 years, the incidence of preeclampsia is increased, as is that of gestational diabetes Diabetes Mellitus in Pregnancy , dysfunctional labor, abruptio placentae Placental Abruption (Abruptio Placentae) Placental abruption (abruptio placentae) is premature separation of the placenta from the uterus, usually after 20 weeks gestation. It can be an obstetric emergency. Manifestations may include... read more , stillbirth Stillbirth Stillbirth is fetal death (fetal demise) at ≥ 20 weeks gestation (> 28 weeks in some definitions). Management is delivery and postpartum care. Maternal and fetal testing is done to determine... read more , and placenta previa Placenta Previa Placenta previa is implantation of the placenta over or near the internal os of the cervix. It typically manifests as painless vaginal bleeding after 20 weeks gestation; the source of bleeding... read more . These women are also more likely to have preexisting disorders (eg, chronic hypertension Hypertension Hypertension is sustained elevation of resting systolic blood pressure (≥ 130 mm Hg), diastolic blood pressure (≥ 80 mm Hg), or both. Hypertension with no known cause (primary; formerly, essential... read more , diabetes Diabetes Mellitus (DM) Diabetes mellitus is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia... read more ). Because risk of fetal chromosomal abnormalities Overview of Chromosomal Abnormalities Chromosomal abnormalities cause various disorders. Abnormalities that affect autosomes (the 22 paired chromosomes that are alike in males and females) are more common than those that affect... read more increases as maternal age increases, genetic screening and testing Preconception or Prenatal Carrier Testing of Parents Carrier testing is part of routine prenatal care and is ideally done before conception. The extent of carrier testing is related to how the woman and her partner weigh factors such as The probability... read more and detailed ultrasound screening for fetal malformations should be offered.
The most common chromosomal abnormality is autosomal trisomy Overview of Chromosomal Abnormalities Chromosomal abnormalities cause various disorders. Abnormalities that affect autosomes (the 22 paired chromosomes that are alike in males and females) are more common than those that affect... read more . The United States National Birth Defects Prevention Study (NBDPS) found that children of women > 40 years are at increased risk of cardiac abnormalities Overview of Congenital Cardiovascular Anomalies Congenital heart disease is the most common congenital anomaly, occurring in almost 1% of live births ( 1). Among birth defects, congenital heart disease is the leading cause of infant mortality... read more , esophageal atresia Overview of Congenital Cardiovascular Anomalies Congenital heart disease is the most common congenital anomaly, occurring in almost 1% of live births ( 1). Among birth defects, congenital heart disease is the leading cause of infant mortality... read more , hypospadias Hypospadias Congenital anomalies of the urethra in boys usually involve anatomic abnormalities of the penis and vice versa. In girls, urethral anomalies may exist without other external genital abnormalities... read more , and craniosynostosis Craniosynostosis Craniosynostosis is premature fusion of one or more calvarial sutures. (See also Introduction to Congenital Craniofacial and Musculoskeletal Disorders and Overview of Congenital Craniofacial... read more (1 Maternal age reference Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ).
Maternal age reference
1. Gill SK, Broussard C, Devine O, et al: Association between maternal age and birth defects of unknown etiology: United States, 1997-2007. Birth Defects Res A Clin Mol Teratol 94 (12):1010–1018, 2012. doi: 10.1002/bdra.23049
Maternal Weight
Pregnant women whose body mass index (BMI) was < 18.5 kg/m2 before pregnancy are considered underweight, which predisposes to low birth weight (< 2.5 kg) in neonates. Such women are encouraged to gain at least 12.5 kg during pregnancy.
Pregnant women whose BMI was 25 to 29.9 kg/m2 (overweight) or ≥ 30 kg/m2 (obese) before pregnancy are at risk of maternal hypertension Hypertension in Pregnancy Recommendations regarding classification, diagnosis, and management of hypertensive disorders (including preeclampsia) are available from the American College of Obstetricians and Gynecologists... read more and diabetes Diabetes Mellitus in Pregnancy Pregnancy makes glycemic control more difficult in preexisting type 1 (insulin-dependent) and type 2 (non–insulin-dependent) diabetes but does not appear to exacerbate diabetic retinopathy,... read more , postterm pregnancy Postterm Pregnancy Postterm pregnancy refers to gestation that lasts ≥ 42 (> 41 6/7) weeks. Late-term pregnancy is defined as 41 0/7 to 41 6/7 weeks. Antenatal surveillance should be considered at 41 weeks. Induction... read more , pregnancy loss Spontaneous Abortion Spontaneous abortion is pregnancy loss before 20 weeks gestation. Diagnosis is by pelvic examination, measurement of beta subunit of human chorionic gonadotropin, and ultrasonography. Treatment... read more , fetal macrosomia Large-for-Gestational-Age (LGA) Infant Infants whose weight is > the 90th percentile for gestational age are classified as large for gestational age. Macrosomia is birthweight > 4000 g in a term infant. The predominant cause is... read more , congenital malformations, intrauterine growth restriction Small-for-Gestational-Age (SGA) Infant Infants whose weight is < the 10th percentile for gestational age are classified as small for gestational age. Complications include perinatal asphyxia, meconium aspiration, polycythemia... read more , preeclampsia Preeclampsia and Eclampsia Preeclampsia is new onset or worsening of existing hypertension with proteinuria after 20 weeks gestation. Eclampsia is unexplained generalized seizures in patients with preeclampsia. Diagnosis... read more , and the need for cesarean delivery Cesarean Delivery Cesarean delivery is surgical delivery by incision into the uterus. The rate of cesarean delivery was 32% in the United States in 2021 (see March of Dimes: Delivery Method). The rate has fluctuated... read more . Ideally, weight loss should begin before pregnancy, first by trying lifestyle modifications (eg, increased physical activity, dietary changes). Women with overweight or obesity are encouraged to limit weight gain during pregnancy, ideally by modifying their lifestyle. The Institute of Medicine (IOM) uses the following guidelines:
Overweight: Weight gain limited to 6.8 to 11.3 kg (15 to 25 lb)
Obese: Weight gain limited to < 5 to 9 kg (11 to 20 lb)
However, not all experts agree with IOM recommendations. Many experts recommend an individualized approach that can include more limited weight gain plus lifestyle modifications (eg, increased physical activity, dietary changes), particularly for women with obesity (1 Maternal weight references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ). During pregnancy, most women should be encouraged to exercise at least 3 times a week for a total of 150 minutes each week (2 Maternal weight references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ).
For pregnant women with overweight or obesity, lifestyle modifications during pregnancy reduce the risk of gestational diabetes and preeclampsia.
Discussing appropriate weight gain, diet, and exercise at the initial visit and periodically throughout the pregnancy is important.
Maternal weight references
1. Artal R, Lockwood CJ, Brown HL: Weight gain recommendations in pregnancy and the obesity epidemic. Obstet Gynecol 115 (1):152–155, 2010. doi: 10.1097/AOG.0b013e3181c51908
2. Mottola MF, Davenport MH, Ruchat SM, et al: 2019 Canadian guideline for physical activity throughout pregnancy. Br J Sports Med 52 (21):1339–1346, 2018. doi: 10.1136/bjsports-2018-100056
Multiple Gestation
Multiple gestation Multifetal Pregnancy Multifetal pregnancy is presence of > 1 fetus in the uterus. Multifetal (multiple) pregnancy occurs in up to 1 of 30 deliveries. Risk factors for multiple pregnancy include Ovarian stimulation... read more increases risk of the following:
Congenital malformations
Perinatal morbidity and mortality
Multiple gestation is usually detected with ultrasonography in the first trimester. Incidence of multiple gestations has been increasing; use of assisted reproductive techniques Assisted Reproductive Technologies Assisted reproductive technologies (ARTs) involve manipulation of sperm and ova or embryos in vitro with the goal of producing a pregnancy. For assisted reproductive technologies, oocytes and... read more have contributed substantially to this increase (1 Multiple gestation reference Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ).
Multiple gestation reference
1. American College of Obstetricians and Gynecologists (ACOG): ACOG Practice Bulletin No. 231: Multifetal gestations: Twin, triplet, and higher-order multifetal pregnancies. Obstet Gynecol 137 (6):e145–e162, 2021. doi: 10.1097/AOG.0000000000004397
Prior Neonate With a Genetic or Congenital Disorder
Risk of having a fetus with a chromosomal disorder Risk Factors for Genetic Disorders or Congenital Anomalies Prenatal genetic counseling is provided for all prospective parents, ideally before conception, to assess risk factors for genetic disorders. In addition, prenatal counseling provides information... read more is increased for most couples who have had a fetus or neonate with a chromosomal disorder (recognized or missed). Recurrence risk for most genetic disorders is unknown. Most congenital malformations are multifactorial; risk of having a subsequent fetus with malformations varies based on the defect itself.
If couples have had a neonate with a genetic or chromosomal disorder, genetic consultation and screening Preconception or Prenatal Carrier Testing of Parents Carrier testing is part of routine prenatal care and is ideally done before conception. The extent of carrier testing is related to how the woman and her partner weigh factors such as The probability... read more is recommended. If couples have had a neonate with a congenital malformation, genetic screening, high-resolution ultrasonography, and evaluation by a maternal-fetal medicine specialist is recommended.
Prior Stillbirth
Stillbirth Stillbirth Stillbirth is fetal death (fetal demise) at ≥ 20 weeks gestation (> 28 weeks in some definitions). Management is delivery and postpartum care. Maternal and fetal testing is done to determine... read more is death of a fetus at ≥ 20 weeks gestation before or during delivery, as defined by the Centers for Disease Control and Prevention (CDC [ 1 Prior stillbirth references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ]), or at > 28 weeks, as defined by the World Health Organization (2 Prior stillbirth references Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more ). Fetal death during late pregnancy may have maternal, placental, or fetal anatomic or genetic causes (see table ). Having had a stillbirth or late abortion (ie, at 16 to 20 weeks) increases risk of fetal death in subsequent pregnancies. Degree of risk varies depending on the cause of a previous stillbirth. Fetal surveillance using antepartum testing (eg, nonstress testing, biophysical profile) is recommended.
Treatment of maternal disorders (eg, chronic hypertension, diabetes, infections) may lower risk of stillbirth in a current pregnancy.
Prior stillbirth references
1. CDC: What is stillbirth? Accessed March 2024.
2. World Health Organization: Stillbirth. Accessed March 2024.
Prior Preterm Delivery
Preterm delivery Preterm Labor Labor (regular uterine contractions resulting in cervical change) that begins before 37 weeks gestation is considered preterm. Risk factors include prelabor rupture of membranes, uterine abnormalities... read more is delivery before 37 weeks. Previous preterm delivery due to preterm labor is associated with an increased risk of future preterm deliveries. Preterm delivery is also sometimes medically indicated due to certain pregnancy complications (eg, severe preeclampsia or symptomatic placenta previa). These diseases are not independent risk factors for preterm delivery, but they may recur, and appropriate monitoring or preventive measures should be done.
Women with prior preterm delivery due to unexplained preterm labor should be closely monitored at 2-week intervals beginning at 15 to 16 weeks gestation, up to 23 to 24 weeks. Evaluation may include (1 Prior preterm delivery reference Risk factors for complications during pregnancy include Preexisting maternal medical conditions and characteristics Modifiable risk factors (eg, smoking, substance use) Previous obstetric complications... read more )
Ultrasound evaluation, including measurement of cervical length, beginning at 15 to 16 weeks
Measurement of fetal fibronectin for women with symptoms concerning for preterm labor
Prior preterm delivery reference
1. Prediction and Prevention of Spontaneous Preterm Birth: ACOG Practice Bulletin, Number 234. Obstet Gynecol. 2021;138(2):e65-e90. doi:10.1097/AOG.0000000000004479
Prior Birth Injury
Most cerebral palsy Cerebral Palsy (CP) Cerebral palsy refers to a group of nonprogressive conditions characterized by impaired voluntary movement or posture and resulting from prenatal developmental malformations or perinatal or... read more and neurodevelopmental disorders are caused by factors unrelated to a birth injury. Injuries such as brachial plexus damage can result from procedures such as forceps or vacuum extractor delivery but often result from intrauterine forces during labor or malposition during the last weeks of pregnancy.
Previous shoulder dystocia Shoulder Dystocia Shoulder dystocia occurs during an attempted vaginal delivery (in the second stage of labor [pushing]) when the fetal head delivers but delivery does not progress because the anterior shoulder... read more is a risk factor for future dystocia, and the delivery records should be reviewed for potentially modifiable risk factors (eg, fetal macrosomia, operative vaginal delivery) that may have predisposed to the injury.
Drugs Mentioned In This Article
Drug Name | Select Trade |
---|---|
urea |
Aluvea , BP-50% Urea , BP-K50, Carmol, CEM-Urea, Cerovel, DermacinRx Urea, Epimide-50, Gord Urea, Gordons Urea, Hydro 35 , Hydro 40, Kerafoam, Kerafoam 42, Keralac, Keralac Nailstik, Keratol, Keratol Plus, Kerol, Kerol AD, Kerol ZX, Latrix, Mectalyte, Nutraplus, RE Urea 40, RE Urea 50 , Rea Lo, Remeven, RE-U40, RYNODERM , U40, U-Kera, Ultra Mide 25, Ultralytic-2, Umecta, Umecta Nail Film, URALISS, Uramaxin , Uramaxin GT, Urea, Ureacin-10, Ureacin-20, Urealac , Ureaphil, Uredeb, URE-K , Uremez-40, Ure-Na, Uresol, Utopic, Vanamide, Xurea, X-VIATE |
aspirin |
Anacin Adult Low Strength, Aspergum, Aspir-Low, Aspirtab , Aspir-Trin , Bayer Advanced Aspirin, Bayer Aspirin, Bayer Aspirin Extra Strength, Bayer Aspirin Plus, Bayer Aspirin Regimen, Bayer Children's Aspirin, Bayer Extra Strength, Bayer Extra Strength Plus, Bayer Genuine Aspirin, Bayer Low Dose Aspirin Regimen, Bayer Womens Aspirin , BeneHealth Aspirin, Bufferin, Bufferin Extra Strength, Bufferin Low Dose, DURLAZA, Easprin , Ecotrin, Ecotrin Low Strength, Genacote, Halfprin, MiniPrin, St. Joseph Adult Low Strength, St. Joseph Aspirin, VAZALORE, Zero Order Release Aspirin, ZORprin |
caffeine |
Cafcit, NoDoz, Stay Awake, Vivarin |
cocaine |
GOPRELTO, NUMBRINO |