Assisted reproductive technology and pregnancy-related hypertensive complications: a systematic review

Hypertensive complications in pregnancy are the leading cause of maternal morbidity, at least in the developed countries. In recent years, infertility issues are managed with ever growing therapeutic options namely assisted reproductive technologies (ART), which improve the ratio of successful induction of pregnancy. It is still debated whether various ART modalities are associated with adverse pregnancy outcomes, including hypertensive complications, particularly with higher incidence of preeclampsia. The main source of controversy stems from the diversity of effect modifiers modulating the association between ART-oriented pregnancy and hypertensive disorders. Indeed, women undergoing an ART procedure are affected by diverse causes of infertility, are frequently characterized by different genetic patterns with respect to their artificially conceived embryo and experienced multiple gestations. In order to investigate whether ART modalities are associated with increased incidence of hypertensive complications in pregnancy, we reviewed all published studies carried out before the end of 2010 and identified in the PubMed database. Among the 47 studies finally selected and by acknowledging the potential of shortcomings related to the different study design and populations, the overall evidence suggests that ART-oriented pregnancies---especially the in-vitro fertilization techniques---are accompanied by increased risk for gestational hypertension and preeclampsia as compared with non-ART pregnancies, even after adjustment for confounders. Multiple gestations, advanced age and underlying polycystic ovary syndrome resulted in constant confounders of the questioned association. Reducing multiple gestations by implementing single embryo techniques might be the therapeutic limiting step to lower the rate of hypertensive complications in assisted pregnancies. Journal of Human Hypertension (2013) 27, 148--157; doi: 10.1038/jhh.2012.13; published online 12 April 2012