Obstetric outcomes in pregnant women with congenital heart disease

Abstract

Background

Predictors of adverse maternal and neonatal outcomes in pregnant women with congenital heart disease (CHD) have been described, but not for obstetrical outcomes. The primary aim of this study was to determine what risk factors predict sustaining adverse obstetric events in pregnant women with CHD. In addition, a secondary aim was to assess the impact of avoiding Valsalva on obstetrical outcomes, an intervention commonly recommended, but never studied.

Methods

A retrospective cohort study examined outcomes in women with CHD who delivered between 1998 and 2005. We examined baseline cardiac characteristics in a multivariate logistic regression model to assess which were associated with adverse obstetric events. We also compared outcomes of women who avoided Valsalva versus those who were allowed to Valsalva.

Results

The study included 65 women with 112 pregnancies. An adverse obstetric event occurred in 32.6% (n = 32) of ongoing pregnancies, the most common being preterm delivery (n = 19), post-partum hemorrhage (n = 13), and preterm premature rupture of membranes (n = 9). There were no independent predictors for sustaining an adverse obstetric event. Women who avoided Valsalva had increased rates of post-partum hemorrhage and 3rd/4th degree lacerations.

Conclusions

Although one-third of pregnancies were associated with an adverse obstetric outcome, these events could not be predicted by baseline hemodynamic characteristics. The routine practice of avoiding Valsalva may be associated with high rates of post-partum hemorrhage and 3rd/4th degree lacerations.

Introduction

Increasing numbers of women with congenital heart disease (CHD) are surviving into their childbearing years. Prior studies evaluating pregnancy outcomes in these women have focused on adverse maternal cardiac events [1], [2], [3] with few studies evaluating obstetric outcomes [4]. In addition, the majority of these studies assess the relationship between pregnancy outcomes and diagnostic categories of CHD rather than baseline hemodynamic characteristics [5], [6], [7], [8]. Multiple studies have suggested that actual hemodynamics are more important than congenital diagnoses in predicting outcome, likely due to the variable outcomes of corrective cardiac surgery [1], [3].

We have previously published data on adverse maternal cardiac events and neonatal outcomes in women with CHD and evaluated predictors of those adverse outcomes [1]. The focus of the current study is to provide a detailed analysis of obstetric outcomes and further investigate what baseline hemodynamic risk factors predict sustaining an adverse obstetric outcome. A secondary goal was to assess the impact of routinely avoiding Valsalva in the second stage of labor and assisting expulsion with forceps or vacuum. The cardiovascular changes of pregnancy place women with CHD at unique risk for adverse cardiac events, particularly during the active phase of labor through the immediate post-partum period when significant fluid shifts and increased myocardial demand occur [9], [10]. Many authorities recommend a passive second stage of labor and assisted delivery to avoid the reduction in preload and increase in cardiac oxygen requirements that occur with maternal Valsalva and exertion [11], [12]. It is unclear how this practice impacts obstetric outcomes such as chorioamnionitis, rate of cesarean delivery and post-partum hemorrhage (PPH).