Caesarean section and tubal infertility: is there an association?

Abstract

To explore the association between exposure to caesarean section and subsequent tubal infertility. A case control study. Cases for this study included all women attending the Aberdeen Fertility Clinic between 1989 and 2005 with secondary infertility caused by tubal factor (presence of one or both blocked tubes diagnosed by either hysterosalpingography or laparoscopy and dye test). Women with history of previous tubal surgery or sterilization were excluded. The cases were matched with controls from the Aberdeen Maternity and Neonatal Databank by year of their first delivery. The controls included all women who had one previous live-birth (index delivery) followed by another and hence proven fertility. The incidence of caesarean section in the index delivery was noted in both the cases and controls. The Statistical Package for Social Scientists (SPSS version 14) for Windows was used to facilitate data analysis. Cases and controls were first compared in terms of age, smoking habits, history of appendectomy, ovarian surgery, PID, ectopic pregnancy, miscarriage, termination and previous caesarean section by univariate analysis and crude Odds Ratios with 95% confidence intervals calculated. Normally distributed continuous variables were expressed as mean with standard deviation and compared by independent samples t test. Categorical variables were compared using the Chi-square test. A probability value of ≤0.05 was considered statistically significant. Statistically significant variables on univariate analysis were entered into a binary logistic regression model to generate adjusted odds ratios with 95% confidence intervals. A total of 220 women with secondary infertility due to a tubal factor problem were compared with 18,376 fertile women (experienced a previous viable pregnancy followed by another live-birth during the same time period when the infertile women were trying to conceive) in terms of exposure to caesarean section. After adjusting for confounding factors, there was no difference in the incidence of exposure to caesarean section between the two groups (adjusted odd's ratio 1.27 (95% CI 0.90, 1.78) and P=0.16). However age (adjusted OR 1.2, 95% CI 1.2, 1.3), history of PID (adjusted OR 17.3, 95% CI 10.9, 27.6) and previous ectopic pregnancy (adjusted OR 12.8, 95% CI 7.1, 23.1) were found to be predictive of future tubal infertility. The risk of secondary infertility due to tubal disease is not increased in women with previous caesarean section.