Congenital heart disease in twins: The contribution of type of conception and chorionicity

Increased incidence of congenital heart disease (CHD) has been reported in the offspring of monochorionic twin gestations. Assisted reproductive technology (ART), which is related to increased rates of twinning, has also been associated with higher risk of birth defects. We studied the incidence of CHD in a cohort of twins to clarify the contribution of type of conception and chorionicity.Data concerning 874 live-born twins of which at least one was admitted in our Neonatal Unit during 1995-2012 were analysed. Forty-five % (N=197) of the gestations resulted from ART (in vitro fertilisation or intracytoplasmic sperm insertion).In the ART group 32/389 (8.2%) had CHD compared to 21/485 (4.3%) infants conceived naturally (OR 1.90, 95%CI 1.08-3.34, p=0.024). Spontaneous-conception gestations had higher incidence of monochorionic placentation (47/245 versus 4/197, p0.001), and included younger mothers (29.1±5.2 versus 33.9±5.5years, p0.001) who had higher parity (median 2 [range 1-7] versus 1 Pinborg (2005), Blondel and Kaminski (2002), Knopman et al. (2014), Kyvik and Derom (2006) ; p0.001). Multivariable logistic regression analysis showed that ART (OR 2.60, 95% CI 1.24-5.45) and monochorionicity (OR 3.49, 95% CI 1.57-7.77) were significant determinants of CHD, independently of maternal age, parity, and the gender of the offspring.We confirmed that monochorionic twins have increased risk of CHD and we documented a higher incidence of CHD in ART twins independently of chorionicity. We suggest improvement of echocardiographic skills of health care professionals involved in prenatal screening and foetal cardiology referral of ART dichorionic twins with suspicious findings at screening, in addition to all monochorionic gestations.