Abortion rate in assisted reproduction--true increase?

Pregnancies achieved by assisted reproduction were considered to carry an increased risk for spontaneous abortion, and ectopic and heterotopic pregnancies. In order to examine the validity of this hypothesis we compared the outcomes of spontaneous pregnancies and assisted reproduction pregnancies using the published reports in the world literature during the last decade. We also studied the outcome of 53,928 in vitro fertilization (IVF) pregnancies reported during the years 1985-91. The reported loss rates in spontaneous pregnancies (abortions and ectopic pregnancies) compared to pregnancies achieved by assisted reproduction were 19% and 30%, respectively. The differences in loss rates between spontaneous and assisted reproduction pregnancies are not completely understood and may originate from predisposing factors such as tubal disease, uterine disorders, corpus luteum dysfunction, and endometriosis that are more frequent in patients suffering from infertility. Increasing maternal age correlates with a higher risk of fetal chromosomal anomalies which results in an increased rate of abortions.