Early prenatal diagnosis of acardiac anomaly: A triplet case report

Abstract

In early pregnancy, ultrasound is vital to confirm heart activity, check gestational age, determine the number of fetuses and assess chorionicity and amnionicity for multiple pregnancy. The scan between 11 and 13 + 6 weeks for nuchal translucency is used to screen for chromosomal abnormalities and major structural malformations. The incidence of multiple gestation pregnancy has increased in recent years due to in-vitro fertilization treatment. In 2016, China reported 0.3 million in vitro fertilization babies through assisted reproductive technology, which accounted for 1.6% of the total live births; the number of in vitro fertilization cycles performed increased from 360 in 2013 to 657 in 2016 per million inhabitants, and the proportion of twins among IVF deliveries was 27.9%. Acardiac anomaly, also called Twin Reversed Arterial Perfusion (TRAP) sequence, is a rare complication of monochorionic multiple pregnancies diagnosed in the first trimester by ultrasound. It is caused by an abnormal vascular anastomoses between the fetuses and is characterized by the presence of a twin embryo with an absent or nonfunctioning heart (“acardiac twin”) and a twin providing perfusion (“pump twin”) with normal appearance. In a series of 24 acardiac anomalies diagnosed between 11 and 13 weeks 6 days, there was spontaneous demise of the pump twin in 9 and obvious abnormalities in 2 between the first and second trimester. In another series of 15 acardiac anomalies diagnosed before 14 weeks, all fetuses which were managed expectantly, died. However survival in fetuses with intrauterine intervention was better. Early diagnosis allows for closer surveillance of the pregnancy and determine the best time for intrauterine intervention to improve the survival rate of the pump fetus.