OC09.05: Adverse obstetric outcomes in pregnancies with major fetal congenital heart defects: a cohort study

To investigate the risk of placenta-related adverse obstetric outcomes in pregnancies with major fetal congenital heart defects (mCHDs). A cohort study of all singleton pregnancies with a live-born child after gestational week 24+0 in Denmark (2008-2018). Children with chromosomal aberrations were excluded. Data were retrieved from the Danish Fetal Medicine Database. The mCHDs included 11 subtypes. Adverse obstetric outcomes included pre-eclampsia, preterm birth < 37+0 weeks, fetal growth restriction (Z-score<-2 SD), placental abruption, and a composite outcome including all of these outcomes. Outcomes were compared between pregnancies with mCHD and the unselected background population. Odds ratios (OR) were calculated with logistic regression models adjusted for maternal BMI, age, and year of delivery. The study included 534,170 pregnancies (mCHD: n = 745). Adverse obstetric outcomes were more frequent in pregnancies with mCHD: pre-eclampsia (6.2% vs. 3.1%), preterm birth (15.7% vs. 4.6%), and fetal growth restriction (6.7% vs. 2.3%). A total of 22.8% of pregnancies with mCHD had an adverse obstetric outcome versus 9.0% in the background population (OR 2.93 (95% CI 2.46, 3.49). All subtypes of mCHD were associated with a higher risk (OR > 2.5) of adverse obstetric outcomes except for pregnancies with fetal TGA, which had a risk profile that did not differ from the background population (see figure 1). Almost one in four pregnancies with mCHD were complicated further by adverse obstetric outcomes which was significantly more than in the background population. Pregnancies with fetal TGA did not have an increased odds of adverse pregnancy outcomes. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.