Screening
Prenatal screening
Prenatal screening is routine, but extra vigilance may be required if there is a family history of birth defects, the mother is aged >35 years, harmful medications have been used during pregnancy, or there has been exposure to radiation. First-trimester ultrasonography is performed to estimate gestational age, to confirm the pregnancy or determine the presence of a multiple pregnancy, and to rule out the presence of abnormal gestation or molar pregnancy. Second-trimester ultrasonography is employed to assess fetal developmental abnormalities, evaluate fetal wellbeing, and identify potential causes of oligo- or polyhydramnios.
Routine maternal serum testing, known as the triple screen, is performed at 16 to 18 weeks' gestation to screen for the presence of alpha-fetoprotein, human chorionic gonadotropin, and estriol.[21] Screening for abdominal wall defects routinely occurs when maternal serum alpha-fetoprotein levels are elevated due to proteins lost from the intestine floating in the amniotic fluid in gastroschisis. Ultrasonography performed in the second trimester can detect abdominal wall defects by visualization of a mass outside of the abdominal wall and confirm the presence of other associated structural abnormalities.
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