Background: It has been suggested that a history of subfertility is associated with increased obstetric and perinatal risks. It is unclear if the cause is inherent characteristics in the women or the fertility treatment.
Objectives: To compare the obstetric and perinatal risks of singleton pregnancies in women with a history of subfertility in comparison with the general population.
Design: Population cohort.
Setting: Aberdeen, Scotland.
Population: Cases were women attending the Fertility Clinic between 1989 and 1999 who subsequently went on to have singleton pregnancies. Controls included the general population of women who delivered singletons over the same period.
Methods: We performed a retrospective cohort study to investigate the obstetric outcome of singleton pregnancies in women with subfertility. The general population of women who delivered singletons over the same period served as controls.
Main outcome measures: Obstetric and perinatal complications in singleton pregnancies.
Results: Maternity records were available for a total of 1437 subfertile women and 21,688 controls. Subfertile women were older [mean (SD) age: 31 (4.7) years vs 27 (5.4) years, P < 0.01] and more likely to be primiparous (70% vs 65%, P < 0.001). After adjusting for age and parity, subfertile women were at increased risk of pre-eclampsia (OR 1.9, 95% CI 1.5-2.5), placenta praevia (OR 3.9, 95% CI 2.2-7.0) and placental abruption (OR 1.8, 95% CI 1.1-3.0), and more likely to undergo induction of labour (OR 1.5, 95% CI 1.3-1.6), caesarean section (OR 2.1, 95% CI 1.8-2.4) and instrumental delivery (OR 2.2, 95% CI 1.8-2.6), and deliver low birthweight (OR 1.4, 95% CI 1.3-1.7) and preterm (OR 1.7, 95% CI 1.2-2.2) infants. There were no differences between treatment-related and treatment-independent pregnancies.
Conclusion: Subfertile women are at higher risk of obstetric complications, which persist after adjusting for age and parity.