Perinatologist Corner - C.E.U/C.M.E. Modules
Prenatal Genetic Screening – Serum and Ultrasound
Sponsored by The Indian Health Service Clinical Support Center
5. Neural Tube Defects: Maternal serum alpha fetoprotein
Case Scenario
AJ is a 40 y/o G1P0 at 9 weeks gestation who was surprised and pleased to discover she is pregnant. She has read about her age-related risks for Down syndrome and the possibility of first trimester pregnancy risk assessment. How would you counsel her?
Ultrasound
With currently available equipment, high resolution ultrasound should be able to identify over 90% of neural tube defects and ventral wall defects, and only a minority of these patients may need an invasive diagnostic procedure. A significant number of patients will have no obvious reason for their elevated AFP, even after a full evaluation. About 1% of these patients may be at risk of later adverse perinatal events in the third trimester such as fetal demise, preterm labor, fetal growth restriction, or preeclampsia. Intensive fetal surveillance in the third trimester has not been shown to improve perinatal outcomes in this situation, and is not indicated for these patients. Nevertheless, these women should be followed clinically for the above disorders, and a growth scan at about 28-32 weeks may be prudent.