To assess outcome in twin pregnancies according to chorionicity.
A cohort was retrieved from local ultrasound databases at 14 obstetric departments in Denmark, comprising all twin pregnancies with two live fetuses scanned between weeks 11 to 14 in the period 1 January 2004 to 31 December 2006. Outcome data were retrieved from the National Board of Health.
Among 2038 twin pregnancies, 1757 (86.2%) were dichorionic (DC) and 281 (13.8%) were monochorionic diamniotic (MC). MC pregnancies had a more than three-fold higher rate of spontaneous fetal loss in both second and third trimester compared to DC pregnancies; 6.0% versus 1.9% for at least one fetus in second trimester (p<0.001) and 2.1% versus 0.7% in third trimester (p=0.03). At least one infant was liveborn in 98.4% of DC and in 91.1% of MC pregnancies. Amongst pregnancies with two live fetuses at 24 weeks, the proportion with two live infants at 28 days after delivery was 97.5% and 95.1%, respectively.
The increased incidence of fetal loss and neonatal death in MC compared to DC pregnancies predominantly occurs before 24 weeks’ gestation. Although risk of IUFD is slightly higher in MC than DC after 24 weeks’ gestation, women’s chance of having two live infants one month after delivery levels out between MC and DC, if both fetuses are alive at 24 weeks.
|Number of pages||6|
|Publication status||Published - Jan 2012|