Preterm delivery in IVF versus ICSI singleton pregnancies: a national population-based cohort

ObjectivesTo assess the risk of spontaneous and iatrogenic preterm delivery in singleton pregnancies when comparing in vitro fertilization (IVF) pregnancies with intracytoplasmic sperm injection (ICSI) pregnancies.Study designA national population-based cohort study using Norwegian Medical Birth Register data during 1999 through 2006 was designed. The cohort included 5824 singleton pregnancies after IVF and ICSI treatment. Multinomial logistic regression analyses were used to calculate risk estimates.ResultsThere were no differences in maternal complicating factors such as pre-eclampsia, hypertension and diabetes between the IVF and ICSI pregnancies. However, IVF pregnancies had a 60% increased risk of moderately (32+0days–36+6days gestational weeks) iatrogenic preterm delivery (OR: 1.6, 95%CI: 1.1–2.2) and a 40% increased risk of iatrogenic preterm delivery <37 weeks (OR: 1.4, 95%CI: 1.02–1.9) compared to ICSI pregnancies.ConclusionIVF pregnancies were at increased risk of moderately iatrogenic preterm delivery when compared to ICSI pregnancies.