The modified WHO class is associated with maternal complications in women with congenital heart disease

Aims: With a growing population of women with congenital heart disease (CHD), pregnancies in this group are expected to increase. However, pregnancy in women with CHD is associated with increased adverse outcomes for both mother and child. The aim of this study was to evaluate pregnancy and foetal complications in women with CHD and to test their association with the modified WHO (mWHO) classification. Methods and Using logistic regression, there was an association between high mWHO class (mWHO III, IV) and caesarean section [odds ratio (OR) 3.4, 95% confidence interval (CI) 1.8-6.7], preterm birth (<37 weeks) (OR 8.3, 95% CI 4.1-17.1), and preeclampsia (OR 3.8, 95% CI 1.5-9.9). Conclusion: Pregnancy complications are more common in women with CHD. In women with CHD, the mWHO classification is associated with maternal complications and preterm birth. Thus, large national register data corroborate the advice provided in current guidelines, and the mWHO class is deemed a valuable risk stratification tool in women with CHD.