In vitro fertilization and preterm delivery, low birth weight, and admission to the neonatal intensive care unit: a prospective follow-up study.
To compare the risk of preterm delivery, low birth weight, and admission of the newborn to a neonatal intensive care unit (NICU) in women pregnant after fertility treatment and subfertile women with the risk in fertile women. Prospective follow-up study. Aarhus University Hospital, Skejby, Denmark, 1989-2006. A total of 20,080 liveborn singletons. None. Preterm delivery, low birth weight, and admission of the newborn to a NICU. After adjustment we found a statistically significantly increased risk of preterm delivery and very preterm delivery in women who conceived after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) compared with fertile women. Compared with fertile women, the risk of preterm delivery and very preterm delivery was not statistically significantly different in women pregnant after non-IVF assisted reproductive treatment (non-IVF ART) or subfertile women. We found no association between IVF/ICSI and the risk of low birth weight at term or admittance to the NICU. The increased risk of preterm delivery after IVF/ICSI may be due to the fertility treatment or unknown characteristics in the couples who undergo IVF/ICSI.