Complete placenta previa in the second trimester: clinical and sonographic factors associated with its resolution

This study was carried out to evaluate outcomes of pregnancies with complete placenta previa diagnosedin mid-pregnancy, and evaluate whether a history of caesarean section and placenta location effect the resolution ofplacenta previa.

A prospective observational study was conducted on patients diagnosed with complete placentaprevia by ultrasound examination between 20+0 weeks and 25+6 weeks of gestation. Patients were grouped in terms ofplacenta location (anteriorly or posteriorly located) and presence/absence of prior caesarean section. Maternal demographics,ultrasound findings and pregnancy outcomes were subsequently compared between these groups. Statistical analysiswas performed by using SPSS version 16.0.

70 patients with the above characteristics were recruited in our study. Of the 70 patients, 21 (30%) had prior caesareansection, and 41 (58.6%) had an anteriorly located placenta. Patients with prior cesarean delivery delivered earlier(36.9 ± 2.2 weeks versus 38.0 ± 1.8 weeks, P = 0.039). Furthermore, 74.3% of the placenta previa resolved by delivery. Priorcaesarean section (RR 2.941, 95% CI 0.938-9.216, P 0.024) and anterior placenta (RR 3.805, 95% CI 1.126-12.855, P 0.031)were related to greater risk of persistence of placenta previa to term.

Prior caesarean section and anteriorly located placenta are important factors that modify the risk that previawill complicate delivery. Our findings may be useful for patient counselling and future management of the condition.