In vitro fertilization and preterm delivery, low birth weight, and admission to the neonatal intensive care unit: a prospective follow-up study.

Objective 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. Design Prospective follow-up study. Setting Aarhus University Hospital, Skejby, Denmark, 1989–2006. Patient(s) A total of 20,080 liveborn singletons. Intervention(s) None. Main Outcome Measure(s) Preterm delivery, low birth weight, and admission of the newborn to a NICU. Result(s) 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. Conclusion(s) 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.