Labor therapeutics and BMI as risk factors for postpartum preeclampsia: A case-control study

•New mechanisms leading to postpartum preeclampsia are proposed.•As shown before, we identified pre-pregnancy/first trimester BMI as risk factor.•We also identified rate of fluids during labor as a new risk factor. This study aims at identifying associations between therapeutics used during labor and the occurrence of postpartum preeclampsia (PPPE), a poorly understood entity. This is a case-control study of women who received an ICD-9 code for PPPE (cases) during the years 2009–2011, compared to women with a normotensive term pregnancy, delivery and postpartum period until discharge (controls), matched on age (±1year) and delivery date (±3months). Cases were defined as women having a normotensive term pregnancy, delivery and initial postpartum period (48h post-delivery) but developing hypertension between 48h and 6weeks postpartum. Single variable and multiple variable models were used to determine significant risk factors. Forty-three women with PPPE were compared to 86 controls. Use of vasopressors and oxytocin did not differ between cases and controls, but rate of fluids administered during labor (OR=1.68 per 100cc/h; 95% CI: 1.09–2.59, p=0.02) and an elevated pre-pregnancy/first trimester BMI (OR=1.18 per kg/m2, 95% CI: 1.07–1.3, p=0.001) were identified as significant risk factors in multivariate analysis. We identified two potentially modifiable risk factors for PPPE; further studies are needed to better define the role of these two variables in the development of PPPE.