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

Abstract

Objectives: This study was carried out to evaluate outcomes of pregnancies with complete placenta previa diagnosed in mid-pregnancy, and evaluate whether a history of caesarean section and placenta location effect the resolution of placenta previa. Material and methods: A prospective observational study was conducted on patients diagnosed with complete placenta previa by ultrasound examination between 20+0 weeks and 25+6 weeks of gestation. Patients were grouped in terms of placenta 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 analysis was performed by using SPSS version 16.0. Results: 70 patients with the above characteristics were recruited in our study. Of the 70 patients, 21 (30%) had prior caesarean section, 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. Prior caesarean 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. Conclusions: Prior caesarean section and anteriorly located placenta are important factors that modify the risk that previa will complicate delivery. Our findings may be useful for patient counselling and future management of the condition.