Risk Factors and Pregnancy Outcomes: Complete versus Incomplete Placenta Previa in Mid-pregnancy.

This prospective study was conducted to compare risk factors and pregnancy outcomes between women with complete placenta previa and those with incomplete placenta previa diagnosed in mid-pregnancy. The study was carried out from April 2014 to December 2015, during which 70 patients with complete previa and 113 with incomplete previa between 20 weeks and 25 weeks of gestation were included. Maternal demographics and pregnancy outcomes were compared between the two groups. Comparisons between categorical variables were tested by chi-squared test and those between continuous variables by Student t test. Resolution of previa occurred in 87.43% of the studied women. The mean gestational age at resolution was 32.1±4.4 weeks. Incidence of maternal age ≥35 years and incidence of prior uterine operation ≥3 were high in women with complete previa (28.6% vs 8.8%, P=0.003; 28.6% vs. 8.8%, P=0.003). Resolution of previa occurred less often in complete previa group (74.3% vs. 95.6%, P=0.001). Women with complete previa admitted earlier (37.3±2.0 weeks 38.1±1.4 weeks, P=0.011) and delivered earlier (37.7±1.2 weeks vs. 38.3±1.4 weeks, P=0.025). Maternal age ≥35 years and prior uterine operation ≥3 increase the risk of complete previa in mid-pregnancy. Placenta previa is more likely to persist in women with complete previa than those with incomplete previa diagnosed in midpregnancy. What is more, women with complete previa in mid-pregnancy delivers earlier.