Obstetric consequences of subfertility: a retrospective cohort study

To compare the risk of adverse pregnancy outcomes in women with and without subfertility and to investigate whether fertility treatment contributes to the adverse outcomes.

Register-based retrospective cohort study.

Aberdeen, Scotland

The exposed group included women with subfertility attending Aberdeen Fertility Clinic between 1989 and 2008 and delivering a singleton (n = 3188) or twin (n = 350) at Aberdeen Maternity Hospital between 1992 and 2009. The unexposed cohort included the remainder of women (singleton n = 52443, twin n = 1125) delivering at Aberdeen Maternity Hospital between 1992 and 2009.

The Aberdeen Fertility Centre database and Aberdeen Maternity and Neonatal Databank were linked using Community Health Index numbers. Regression models were used to calculate risk ratios and 95% confidence intervals adjusting for potential confounders.

Maternal outcomes including pre-eclampsia, antepartum haemorrhage, preterm birth, induction of labour; delivery outcomes including operative vaginal delivery, caesarean section; and offspring outcomes including low birthweight, stillbirth and neonatal death.

Women with a history of subfertility who delivered a singleton were at a higher risk of pre-eclampsia [adjusted risk ratios (aRR) 1.18, 95% confidence intervals (CI) 1.02-1.37], antepartum haemorrhage (aRR 1.32, 95% CI 1.18-1.47), induction of labour (aRR 1.21, 95% CI 1.11-1.31) and very preterm delivery (<32 weeks) (aRR 1.96, 95% CI 1.53-2.49). Subfertile women delivering twins were at a higher risk of being delivered by emergency caesarean section (aRR 2.14, 95% CI 1.26-3.66). There were no significant differences in adverse outcomes for singleton pregnancies between the treated and untreated subfertile couples.

Subfertility per se, rather than fertility treatment, was associated with increased risk of adverse outcomes in singleton pregnancies.

Large cohort study found higher incidence of adverse outcome in subfertile women having singletons or twins.