///2017 Abstract Details
2017 Abstract Details2019-08-02T15:54:53-06:00

The Epidemiology of Placenta Previa in California, 2008-2012

Abstract Number: F-06
Abstract Type: Original Research

Alexander Butwick MBBS, FRCA, MS1 ; Anisha Abreo MPH2; Deirdre Lyell MD3; Henry Lee MD, MS4

Introduction:Since the mid-1990s, the rate of cesarean delivery has increased > 50%. As a result, the incidence of placental pathologies, such as placenta previa, may have increased. The main study objectives were to determine contemporary trends and risk factors for previa in a large delivery cohort in California.

Methods:Linked California birth certificate and discharge data were used to identify women who delivered at ≥20 weeks’ gestation in California between 2008-2012. Within this cohort, women with a previa diagnosis were identified with ICD-9 codes 641.x. Temporal trends and risk factors for previa were analyzed. Candidate variables considered as potential risk factors included: maternal age, race/ethnicity, insurance, history of smoking, prior cesarean, diabetes, chronic hypertension, history of abortion, cocaine use, single vs multiple gestation, hypertensive disorders of pregnancy and timing of prenatal care. We performed univariable and multivariable logistic regression to determine odds ratios and 95% CIs for determinants of previa.

Results:Our cohort comprised 2,176,673 women who delivered at ≥20 weeks’ gestation, of whom 14,274 had a previa for a cumulative prevalence of 0.6%. Cases of previa increased slightly from 2872 (0.64%) in 2008 to 2819 (0.66%) in 2012. In our multivariable model, clinical factors independently associated with previa were: maternal age ≥35y (aOR=2.2; 95% CI=2.1-2.3), Asian (aOR=1.5; 95% CI=1.4-1.6), African-American (aOR=1.1; 95% CI=1.0-1.2), Other race (aOR=1.8; 95% CI=1.6-1.9), non/uninsured (aOR=1.1; 95% CI=1.0-1.2), history of abortion (aOR=2.0; 95% CI=1.8-2.3), cocaine use (aOR=2.0; 95% CI=1.1-3.2), smoking (aOR=1.2; 95% CI=1.1-1.4), prior cesarean (aOR=1.4; 95% CI=1.4-1.5), multiparity (aOR=1.05; 95% CI=1.0-1.1), and multiple gestation (aOR=1.7; 95% CI=1.5-1.9). Compared to starting prenatal care in the 1st trimester, prenatal care commenced in the 2nd or 3rd trimester had a 6% and 26% decreased odds of previa, respectively.

Conclusion:The prevalence of previa in California increased modestly from 2008 to 2012. Clinical risk factors for previa (advancing maternal age, prior CD, history of abortion, and cocaine use) are consistent with those reported in prior studies. Further research is needed to examine the complex interactions of biology and health services to explain how socioeconomic factors, such as insurance type, race/ethnicity, and timing of prenatal care influence the likelihood of incurring previa.

SOAP 2017