Previous cesarean section as a risk factor for abruptio placentae - Revista Brasileira de Ginecologia e Obstetrícia

Previous cesarean section as a risk factor for abruptio placentae |

PURPOSE: to study the relationship between previous cesarean section and abruptio placentae. METHODS: a retrospective study reviewed 6495 deliveries between April 2001 and January 2004. The adopted inclusion criteria were: clinical diagnosis of abruptio placentae confirmed by placental examination after delivery, single pregnancy, birth weight >500 g, gestational age >22 weeks and no history of abdominal trauma. Five controls were selected for each abruptio placentae case and were matched for the following parameters: parity, gestational age (< or > 30 weeks), maternal arterial hypertension during pregnancy, presence of nonobstetrical uterine scar, premature rupture of membranes and polyhydramnios. Statistical analysis of continuous variables was perfomed by Student's t test. Statistical significance of the comparisons of categorical variables was evaluated by the chi2 test or by the Fisher exact test. p values <0.05 were considered to be significant. RESULTS: thirty-four cases of abruptio placentae were included (incidence 0.52%). The control group included 170 cases that fulfilled the matching criteria. The incidence of previous cesarean section in the abruptio placentae group was 26.5% (9 cases) and in the control group it was 21.2% (36 cases). No significant difference was found between the groups (p=0.65, OR=1.34, CI 95%=0.53-3.34). CONCLUSION: the present study was not able to demonstrate association between abruptio placentae and previous cesarean section.