Heterotopic pregnancy is a rare complication in which both extra-uterine and intra-uterine pregnancies occur simultaneously. Factors associated with the occurrence of a heterotopic pregnancy are still unclear. The purpose of our study was to identify potential maternal and IVF related factors of heterotopic pregnancy.METHODS:
Around 188,770 IVF cycles were identified from the SART national database including all in vitro fertilization (IVF) cycles conducted in the US between 2008 and 2011. Maternal factors, IVF treatment including the use of gonadotropin releasing hormone (GnRH) agonist or antagonist, and embryogenic factors and their relation to heterotopic implantation were evaluated in bivariate analyses. A logistic regression was also performed to assess the independent relationship of these factors with heterotopic pregnancy.RESULTS:
There were 188,624 intrauterine and 141 heterotopic pregnancies. Race (P=.04), smoking status (P=.02), endometriosis (P=.01), type of embryo implanted (P=.04), and GnRH antagonist use (P=.003) were found to be related to heterotopic pregnancy. Results from the multivariate analysis showed higher odds of heterotopic pregnancy among women with endometriosis (OR=1.72, 95% CI: 1.11–2.68, P=.02). Likewise, the odds of heterotopic pregnancy, were elevated among women receiving GnRH antagonist (OR=1.55, 95% CI: 1.07–2.23, P=.02).CONCLUSION:
Endometriosis and the use of GnRH antagonist are risk factors for IVF-heterotopic pregnancies. This could be related to impair tubal motility and decreased receptivity of the endometrium.