Uterine sutures at prior caesarean section and placenta accreta in subsequent pregnancy: a case-control study.

ABSTRACT

OBJECTIVE: To clarify the effects of uterine myometrial suture techniques at prior caesarean section on the incidence of pathologically diagnosed placenta accreta in placenta praevia with prior caesarean section (PPPC). DESIGN: Case-control study. SETTING: Eleven tertiary referral hospitals in central Japan. POPULATION A total of 98 cases of placenta praevia, a history of one or more prior caesarean sections, and a history of uterine transverse incision and usage of only absorbable thread for myometrial sutures at the prior caesarean section. Exclusions were a history of myomectomy or Strassmann's operation. METHODS: Cases were grouped into a pathologically diagnosed placenta accreta group (38 cases) and a no accreta group (60 cases). Clinical characteristics including uterine suture methods at prior caesarean section were compared (single-layer versus double-layer closure; continuous versus interrupted sutures in the inner myometrial layer). MAIN OUTCOME MEASURE: The incidence of placenta accreta. RESULTS: No difference was found comparing single-layer with double-layer closure in the incidence of placenta accreta (37.1 versus 39.7%, P = 0.805); however, a significant difference was found comparing continuous with interrupted sutures (58.1 versus 29.9%, P = 0.008). Multivariable logistic regression analysis with stepwise selection for the eight factors meeting the criterion of P < 0.10 in univariate analysis was used, and four independent factors were selected, as follows gravidity ≥ 3 (adjusted odds ratio, aOR, 3.4, 95% confidence interval, 95% CI, 0.99-11.6, P = 0.050); total praevia (versus non-total, aOR 18.4, 95% CI 3.2-107.0, P = 0.001); anterior/centre placenta (versus posterior, aOR 16.4, 95% CI 3.7-72.2, P < 0.001); and continuous sutures (versus interrupted, aOR 6.0, 95% CI 1.4-25.2, P = 0.015). CONCLUSIONS: In this limited study, a history of continuous sutures on the inner side of the uterine wall showed potential to influence the development of placenta accreta in PPPC patients.