Ventriculomegaly is defined as dilation of the fetal cerebral ventricles and is a relatively common finding on prenatal ultrasound. The purpose of this document is to review the diagnosis, evaluation, and management of mild fetal ventriculomegaly. When enlargement of the lateral ventricles (≥10 mm) is identified, a thorough evaluation should be performed, including detailed sonographic evaluation of fetal anatomy, amniocentesis for karyotype and chromosomal microarray analysis, and a workup for fetal infection. In some cases, fetal magnetic resonance imaging may identify other central nervous system abnormalities and should be considered when this technology as well as expert interpretation is available. Follow-up ultrasound examination should be performed to assess for progression of the ventricular dilation. In the setting of isolated ventriculomegaly of 10-12 mm, the likelihood of survival with normal neurodevelopment is >90%. With moderate ventriculomegaly (13-15 mm), the likelihood of normal neurodevelopment is 75-93%. The following are Society for Maternal-Fetal Medicine recommendations: We suggest that ventriculomegaly be characterized as mild (10-12 mm), moderate (13-15 mm), or severe (>15 mm) for the purposes of patient counseling, given that the chance of an adverse outcome and potential for other abnormalities are higher when the ventricles measure 13-15 mm vs 10-12 mm (GRADE 2B); we recommend that diagnostic testing (amniocentesis) with chromosomal microarray analysis should be offered when ventriculomegaly is detected (GRADE 1B); we recommend testing for cytomegalovirus and toxoplasmosis when ventriculomegaly is detected, regardless of known exposure or symptoms (GRADE 1B); we suggest that magnetic resonance imaging be considered in cases of mild or moderate fetal ventriculomegaly when this modality and expert radiologic interpretation are available; magnetic resonance imaging is likely to be of less value if the patient has had a detailed ultrasound performed by an individual with specific experience and expertise in sonographic imaging of the fetal brain (GRADE 2B); we recommend that timing and mode of delivery be based on standard obstetric indications (GRADE 1C); we recommend that with isolated mild ventriculomegaly of 10-12 mm, after a complete evaluation, women be counseled that the outcome is favorable, and the infant is likely to be normal (GRADE 1B); we recommend that with isolated moderate ventriculomegaly of 13-15 mm, after a complete evaluation, women be counseled that the outcome is likely to be favorable but that there is an increased risk of neurodevelopmental disabilities (GRADE 1B).

In the United States, 1-2.5% of pregnant women are infected with hepatitis C virus, which carries an approximately 5% risk of transmission from mother to infant. Hepatitis C virus can be transmitted to the infant in utero or during the peripartum period, and infection during pregnancy is associated with increased risk of adverse fetal outcomes, including fetal growth restriction and low birthweight. The purpose of this document is to discuss the current evidence regarding hepatitis C virus in pregnancy and to provide recommendations on screening, treatment, and management of this disease during pregnancy. The following are Society for Maternal-Fetal Medicine recommendations: (1) We recommend that obstetric care providers screen women who are at increased risk for hepatitis C infection by testing for anti-hepatitis C virus antibodies at their first prenatal visit. If initial results are negative, hepatitis C screening should be repeated later in pregnancy in women with persistent or new risk factors for hepatitis C infection (eg, new or ongoing use of injected or intranasal illicit drugs) (GRADE 1B). (2) We recommend that obstetric care providers screen hepatitis C virus-positive pregnant women for other sexually transmitted diseases, including HIV, syphilis, gonorrhea, chlamydia, and hepatitis B virus (GRADE 1B). (3) We suggest that patients with hepatitis C virus, including pregnant women, be counseled to abstain from alcohol (Best Practice). (4) We recommend that direct-acting antiviral regimens only be used in the setting of a clinical trial or that antiviral treatment be deferred to the postpartum period as direct-acting antiviral regimens are not currently approved for use in pregnancy (GRADE 1C). (5) We suggest that if invasive prenatal diagnostic testing is requested, women be counseled that data on the risk of vertical transmission are reassuring but limited; amniocentesis is recommended over chorionic villus sampling given the lack of data on the latter (GRADE 2C). (6) We recommend against cesarean delivery solely for the indication of hepatitis C virus (GRADE 1B). (7) We recommend that obstetric care providers avoid internal fetal monitoring, prolonged rupture of membranes, and episiotomy in managing labor in hepatitis C virus-positive women (GRADE 1B). (8) We recommend that providers not discourage breast-feeding based on a positive hepatitis C virus infection status (GRADE 1A).

Chromosomal microarray analysis is a high-resolution, whole-genome technique used to identify chromosomal abnormalities, including those detected by conventional cytogenetic techniques, as well as small submicroscopic deletions and duplications referred to as copy number variants. Because chromosomal microarray analysis has a greater resolution than conventional karyotyping, it can detect deletions and duplications down to a 50- to 100-kb level. The purpose of this document is to discuss the technique, advantages, and disadvantages of chromosomal microarray analysis and its indications and limitations. We recommend the following: (1) that chromosomal microarray analysis be offered when genetic analysis is performed in cases with fetal structural anomalies and/or stillbirth and replaces the need for fetal karyotype in these cases (GRADE 1A); (2) that providers discuss the benefits and limitations of chromosomal microarray analysis and conventional karyotype with patients who are considering amniocentesis and chorionic villus sampling (CVS), and that both options should be available to women who choose to undergo diagnostic testing (GRADE 1B); (3) that pre- and posttest counseling should be performed by trained genetic counselors, geneticists, or other providers with expertise in the complexities of interpreting chromosomal microarray analysis results (Best Practice); (4) that patients be informed that chromosomal microarray analysis does not detect every genetic disease or syndrome and specifically does not detect autosomal-recessive disorders associated with single gene point mutations, as well as that chromosomal microarray analysis can detect consanguinity and nonpaternity in some cases (Best Practice); (5) that patients in whom a fetal variant of uncertain significance is detected by prenatal diagnosis receive counseling from experts who have access to databases that provide updated information concerning genotype-phenotype correlations (Best Practice).

Providers should be aware of the signs and symptoms of ICP and provide accurate diagnosis and management of affected women. Women with a diagnosis of ICP should be treated with ursodeoxycholic acid to improve maternal symptoms. Given the increased risk of stillbirth in the setting of ICP, delivery may be considered at 37 weeks' gestation.

Birth defects are associated with multiple modifiable and nonmodifiable risk factors. Obstetrics providers should work with patients to minimize their risk of birth defects if modifiable risk factors are present and to appropriately counsel patients when nonmodifiable risk factors are present.