Bacterial colonization at caesarean section defects in women of secondary infertility: an observational study

Abstract Background Delayed childbearing has been noted in a high percentage of women with a previous Caesarean section (CS). Many women with CS scar defects (CSDs) present with clinical symptoms of irregular vaginal bleeding. The present study aimed to investigate bacterial colonies at CSDs in women suffering from secondary infertility. Methods This observational study included 363 women with secondary infertility who visited the Assisted Reproduction Unit between 2008 and 2013. Among them, 172 women with a previous CS and 191 women with no previous CS were approached. The women with a previous CS had their CS operations in the past 1 to 14 years, with a mean of 3.5 years. The presence of CSDs was detected by vaginal ultrasonography. Bacteriology cultures of specimens taken from the uterine niches in those with CSDs were collected during Day 7 to Day 10 of the follicular phase. Specimens were obtained from the endocervical canal for bacterial culture in those without CSDs. The main outcome measure was the detection of the growth of bacterial colonies. Results CSDs were found in 60.4% (96 of 159) of women with a previous CS. In women with a previous CS, bacterial colonies were identified in 89.6% (86 of 96) and 69.8% (44 of 63) of women with and without CSDs, respectively. In women with no previous CS, 49.7% (88 out of 177) of bacterial cultures of endocervical samples showed bacterial colony growth. Gram-positive cocci (P = 0.0017, odds ratio (OR) = 1.576, 95% confidence intervals (CI) -22.5 to − 5.4) and Gram-negative rods (P = 0.0016, OR = 1.74, CI − 20.8 to − 5.0) were the most commonly isolated bacteria and contributed to approximately 90% of all microorganisms found in those with a previous CS. In women with a previous CS, more Gram-negative rods were isolated (P = 0.01, OR = 1.765, CI − 27.2 to − 3.8), especially Pseudomonas species (P = 0.02, OR = 1.97, CI − 16.7 to − 1.0), in those with visible CSDs than in those without CSDs. Conclusions Bacterial colonization at CSDs was found in a high percentage of women with secondary infertility.