Effects of in vitro fertilization on low birth weight, preterm delivery, and multiple birth

To quantify the contribution of in vitro fertilization (IVF) on changes in the rates of low birth weight (LBW), preterm delivery, very low birth weight, and multiple births during the past 3 years.

Data on IVF pregnancies from 1994 to 1996 within Alberta were reviewed. Population data were obtained from the Provincial notice of a live or stillbirth.

The IVF component of increased LBW rate in the province was 17.8% for infants <2500 g and 43.5% for those born <1500 g. IVF accounted for 10.5% of the provincial rate increase in deliveries <37 weeks' gestation and 66.2% of those <30 weeks' gestation. IVF accounted for 21.4% of the twins and all of the sets of triplets in the province.

During a 3-year period IVF has affected the incidence of LBW, preterm delivery, and multiple birth. IVF is a substantial contributor to changes in very low birth weight and delivery before 30 weeks, which is partly related to multiple births.