**3.8. Spinal dysraphism and the Arnold-Chiari malformation**

#### *3.8.1. Pregnancy management*

Assessment for other abnormalities should be performed by the detailed sonography. Associated brain abnormalities include hydrocephaly, relative microcephaly, agenesis of the corpus callosum, and diastematomyelia. Non-CNS anomalies consist of congenital scoliosis or kyphosis and hip deformities [20]. There is a high prevalence of genetic abnormalities among fetuses with NTDs, especially in the presence of other congenital anomalies so microarray should be offered. The diagnostic sensitivity of prenatal sonography for detection of myelomeningocele in a high risk population is about 97–98% with 100% specificity [27]. Determining the site and extent of the spinal lesion is important because these features correlate with neurologic outcome; more severe neurologic dysfunction is associated with higher and larger lesions. Sonographic diagnosis of open spina bifida typically occurs during the second trimester of the pregnancy.

When the diagnosis of NTD is confirmed, the parents should be offered the opportunity to discuss the long-term prognosis for a child with multidisciplinary team (neonatologist, medical geneticist, pediatric neurologist, pediatric neurosurgeon, pediatric urologist, pediatric orthopedic surgeon). Long-term prognosis is related to the location of the NTD—the lower the defect, the better the prognosis [16]. In fetuses with myelomeningoceles, higher and larger lesions on MRI were significantly associated with full-time wheelchair use. High lesion level was associated with dysphagia. The absence of a covering membrane was associated with scoliosis and high-risk bladder dysfunction [28]. If the diagnosis is at less than 22–24 weeks of gestation, the opportunity of pregnancy termination can be offered to the parents. During prenatal counseling, discussion with the parents includes the natural history of myelomeningocele and the prenatal management decisions, including termination of the pregnancy, pursuit of additional prenatal testing, choice of delivery setting, and, when applicable, the possibility of fetal surgery. The postnatal management choices are also discussed, including surgical closure of the defect and possible need for ventriculoperitoneal shunt placement. Longitudinal follow-up after prenatal diagnosis of myelomeningocele suggests that approximately 60–70% of pregnancies end in termination or fetal demise [29, 30].

typically delivered by cesarean section. The optimal route of delivery of a fetus presenting in the vertex position is controversial. Vaginal delivery is reasonable if the head is normal size, the meningocele is unlikely to cause dystocia, and there are no obstetrical indications for

Management of Pregnancy and Delivery in Prenatally Diagnosed Congenital Anomalies

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Fetal cerebral ventriculomegaly is a relatively common finding on second trimester obstetrical ultrasound examination. Many cases are associated with other abnormal findings, but in some fetuses, ventriculomegaly is the only abnormality [36]. Most children with isolated, mild ventriculomegaly have a normal outcome. The risk of abnormal outcome increases with the severity of ventriculomegaly, progression of ventriculomegaly, and presence of other anomalies. After ventriculomegaly is identified, further management involves identifying whether additional abnormalities (CNS and non-CNS) are present, diagnostic evaluation for the most common causes of ventriculomegaly, and counseling patients about the prognosis and potential pregnancy interventions. If the etiology of ventriculomegaly has been determined (e.g., trisomy, CMV) or associated malformations are identified, the parents can be given more specific information. Before viability, pregnancy termination is an option and

• Assessment for associated CNS and extra-CNS anomalies. Associated abnormalities have been reported in 10–76% of cases [36, 37]. Identification of these abnormalities helps in determining the cause of ventriculomegaly and the prognosis. Fetal MRI can be used to identify underlying CNS abnormalities not detected by sonography. Because CNS infection can result in ventriculomegaly, it is important to look for characteristic sonographic findings of fetal infection, such as intracerebral and periventricular calcifications, hepatic

• Evaluation for infection. Tests for CMV infection, toxoplasmosis, Zika virus infection, and lymphocytic choriomeningitis virus infection should be recommended. Sporadic cases of ventriculomegaly associated with other viruses have also been reported (mumps enterovirus 71 (EV71), parainfluenza virus type 3, parvovirus B19) [36]. PCR for CMV and toxoplasmosis should also be obtained when amniocentesis is performed. If the patient declines amniocentesis or karyotyping has been done previously, maternal serology is used to identify an infectious etiology. However, serology is neither as sensitive nor as specific as PCR on amniotic fluid, thus amniotic fluid PCR is the preferred method of evaluation

• Genetic assessment. Fetuses with apparently isolated mild ventriculomegaly in 4.7% were found to have an abnormal karyotype [38]. The risk is higher with severe ventriculomegaly

• Follow-up evaluation. Follow-up ultrasound examinations are obtained to look for regression or progression of ventriculomegaly and to re-evaluate for anomalies. Early isolated

calcifications, hepatosplenomegaly, ascites, and polyhydramnios.

cesarean [35].

should be offered.

for infection [36].

or associated abnormalities.

**3.9. Fetal cerebral ventriculomegaly**

*3.9.1. Pregnancy management*

• Fetal intervention. Fetal surgery for myelomeningocele can arrest leakage of spinal fluid from the back and might therefore prevent or reverse herniation of the hindbrain (Chiari II malformation) and hydrocephalus [31]. Prenatal surgery for myelomeningocele reduced the need for shunting and improved motor outcomes at 30 months but was associated with maternal and fetal risks [32]. These benefits occurred despite a higher risk of preterm delivery and pulmonary complications among infants undergoing fetal surgery and of obstetrical complications, including placental abruption, dehiscence of the hysterotomy site, and maternal transfusion at delivery [32, 33]. Because fetal surgery is associated with risks of fetal and maternal complications, the family should be informed about the option of prenatal surgery, including the uncertainty regarding whether the risks of the procedure are outweighed by the potential benefits, particularly since longterm outcomes are not clearly known. Women with pregnancies complicated by fetal myelomeningocele who meet established criteria for in utero repair should be counseled in a nondirective fashion regarding all management options, including the possibility of open maternal-fetal surgery. Maternal-fetal surgery for myelomeningocele repair should be offered only to carefully selected patients at facilities with an appropriate level of personnel and resources [34].

#### *3.8.2. Delivery management*

For infants with a prenatal diagnosis of myelomeningocele who do not undergo fetal intervention, delivery should occur at a center with a level III NICU, pediatric neurosurgery services, and other personnel experienced in the neonatal management of these infants. Latex-free gloves and equipment should be used during delivery and subsequent care of the infant because patients with myelomeningocele are at risk for developing life-threatening latex allergy.

Term delivery is preferable, but increasing ventriculomegaly with macrocephaly on prenatal ultrasound may necessitate preterm delivery. Fetuses presenting in the breech position are typically delivered by cesarean section. The optimal route of delivery of a fetus presenting in the vertex position is controversial. Vaginal delivery is reasonable if the head is normal size, the meningocele is unlikely to cause dystocia, and there are no obstetrical indications for cesarean [35].
