Early Pregnancy Loss Rate in In Vitro Fertilization Versus Non-IVF Pregnancies.

Objectives: Compare early pregnancy loss (EPL) rates in in vitro fertilization (IVF) versus non-IVF pregnancies to determine whether IVF has an independent effect on first trimester outcome.

Methods: Our study set consisted of all obstetrical ultrasounds at our institution over a 30-year period demonstrating a singleton intrauterine pregnancy (confirmed by either yolk sac but no embryo, or embryo <10 mm with cardiac activity), with known first trimester outcome. We assessed EPL rates based on mode of conception, maternal age, vaginal bleeding, and initial ultrasound finding (yolk sac only or embryo). We compared IVF versus non-IVF pregnancies with respect to EPL rate, maternal age, and vaginal bleeding. Most importantly, we used logistic regression analysis to determine whether IVF has an independent effect on loss rate, after controlling for age and bleeding.

Results: Our study set consisted of 16,458 pregnancies, 1394 (8.5%) resulting from IVF and 15,064 (91.5%) non-IVF. Overall EPL rate was 3348/16,458 (20.3%) and was higher in IVF pregnancies, in women aged ≥35 years, and with vaginal bleeding (P < .001, all comparisons). IVF pregnancies had higher maternal ages and were less likely to have vaginal bleeding as an indication for sonography. Logistic regression of mode of conception, maternal age, and bleeding as predictors of outcome demonstrated that mode of conception had no independent effect on outcome (P = .33 for cases with yolk sac only, P = .30 for cases with embryo).

Conclusions: IVF has no impact on first trimester outcome. A woman pregnant via IVF has the same likelihood of miscarriage as a comparable woman with a non-IVF pregnancy.