Gastroschisis is detected in one of three ways: most often, via elevated levels of a routine blood test called an Alpha Fetoprotein test (or AFP); it can also be detected via routine ultrasound, which is typically the 20 week ultrasound;1 and rarely, gastroschisis is unknown during the pregnancy and is then diagnosed only at birth. Infrequently, mothers have reported a sense of “something being wrong” which was later confirmed via medical tests showing gastroschisis. Early detection is an important factor in the health of a baby with gastroschisis, and as such, routine pregnancy visits should begin as soon as a woman realizes she is pregnant.
1. http://www.chop.edu/service/fetal-diagnosis-and-treatment/fetal-diagnoses/gastroschisis.html