How Low Is Too Low? Postpartum Hemorrhage Risk among Women with Thrombocytopenia
02 June 2017
08 June 2017
06 July 2017 (eFirst)
Objective To estimate the association between severity of thrombocytopenia and postpartum hemorrhage.
Study Design We performed a secondary analysis of a prospective cohort of women delivering by cesarean or vaginal birth after cesarean conducted by the National Institute of Child Health and Human Development (NICHD) Maternal–Fetal Medicine Unit. Women delivering ≥ 20 weeks with platelets < 400,000/mL were included. Thrombocytopenia was defined as predelivery platelets of < 150,000/mL. Primary outcomes were (1) laboratory evidence of hemorrhage, defined as a decrease in hemoglobin ≥ 4 mg/dL and (2) clinical evidence of hemorrhage, a composite of atony, transfusion, coagulopathy, hysterectomy, laparotomy, or intensive care unit admission. Odds ratios were calculated for primary outcomes using thrombocytopenia as a dichotomous and ordinal variable.
Results A total of 54,597 women were included; 5,611 (10.3%) had antepartum thrombocytopenia, 1,976 (3.6%) women had laboratory evidence of hemorrhage, and 3,862 (7.1%) had clinical evidence of hemorrhage. Thrombocytopenia was associated with both laboratory evidence of hemorrhage (adjusted odds ratio [aOR]: 1.60, 95% CI: 1.38–1.86) and clinical evidence of hemorrhage (aOR: 1.68, 95% CI: 1.52–1.83). The odds of laboratory and clinical evidence of hemorrhage increased incrementally with severity of thrombocytopenia.
Conclusion Thrombocytopenia is associated with both laboratory and clinical evidence of hemorrhage; risk increases dramatically as platelet count decreases.
The risk of postpartum hemorrhage is directly proportional to the severity of thrombocytopenia.
This study was presented, in part, as a poster at the 37th Annual Pregnancy Meeting of the Society for Maternal–Fetal Medicine from January 22 to 28, 2017 at Las Vegas, NV (final abstract no. 644).