Preterm delivery, low birthweight and small-for-gestational-age in liveborn singleton babies resulting from in-vitro fertilization.

The Medical Research Council In-Vitro Fertilization (IVF) Register report on births resulting from assisted conception in Great Britain demonstrated a high incidence of preterm and low birthweight babies. This incidence remained high even when the analysis was restricted to singleton babies. The present paper investigates possible risk factors for prematurity, low birthweight and small-for-gestational-age (SGA) in singleton IVF births. Thirteen per cent of singleton IVF babies were preterm, 11% low birthweight and 17% small-for-gestational-age. Analysis by multiple regression indicated that hypertension during pregnancy was an independent risk for preterm delivery, low birthweight and SGA, bleeding during pregnancy for preterm delivery, and the number of embryos transferred and the type of infertility for low birthweight.