Effect of mild preoperative thrombocytopenia on postpartum hemorrhage after cesarean deliveries

BACKGROUND: Thrombocytopenia at the time of delivery is considered as a risk factor for postpartum hemorrhage. However, platelet count thresholds for postpartum hemorrhage are variable and not extensively studied. OBJECTIVE: This study aimed to examine whether mild thrombocytopenia is associated with an increased risk of postpartum hemorrhage among women undergoing cesarean delivery. STUDY DESIGN: This was a retrospective cohort study of all women who underwent cesarean delivery at a tertiary care hospital labor and delivery unit from September 2015 to June 2018. Women with normal platelet counts (>= 150,000/mu L) were compared with women with mild thrombocytopenia (100,000-149,000/AL). Women were excluded if they had moderate to severe thrombocytopenia (platelet count of <100,000/mu L) or had received a platelet transfusion. The primary outcome was postpartum hemorrhage (quantitative blood loss of >= 1000 mL). Secondary outcomes included frequencies of red blood cell transfusion, wound complications (surgical site infections, dehiscence, or hematoma), and postpartum emergency department visits. Adjusted odds ratios with 95% confidence intervals were calculated, controlling for maternal age, gestational age, body mass index, scheduled cesarean delivery, hypertension, and preoperative hemoglobin level. RESULTS: Of 3133 women, 2799 (89.3%) had normal platelet levels, 298 (9.5%) had mild thrombocytopenia, and 36 (1.2%) had moderate to severe thrombocytopenia. There were no differences in the risks of postpartum hemorrhage, need for a red blood cell transfusion, wound complications, or postpartum emergency department visit comparing women with normal platelet counts with those with mild thrombocytopenia (24.6% vs 25.8% [adjusted odds ratio, 1.16; 95% confidence interval, 0.88-1.54]; 6.5% vs 6.7% [adjusted odds ratio, 1.34; 95% confidence interval, 0.80-2.24]; 4.5% vs 5.4% [adjusted odds ratio, 1.53; 95% confidence interval, 0.88-2.64]; 9.0% vs 10.7% [adjusted odds ratio, 1.37; 95% confidence interval, 0.92-2.03], respectively). CONCLUSION: Preoperative mild thrombocytopenia was not associated with postpartum hemorrhage, red blood cell transfusion, wound complications, or postpartum emergency department visits in women undergoing cesarean delivery.

Automated summary

In women undergoing cesarean delivery, preoperative mild thrombocytopenia was not significantly associated with postpartum hemorrhage, red blood cell transfusion, wound complications, or postpartum emergency department visits.