Evaluation of routine antepartum and postpartum blood counts

To evaluate routine screening 28-week, admission and postpartum complete blood counts (CBCs) during a six-month period on the labor and delivery service and to correlate the laboratory data with clinical characteristics of the patients, to determine if routine CBCs are necessary in evaluating blood loss in low-risk patients and to determine whether routine admission screening for thrombocytopenia is necessary prior to epidural placement is necessary in low-risk patients.

Laboratory data form all patients were obtained from a centralized computer system. Clinical characteristics were obtained from the medical record.

Blood loss was determined by a change in hematocrit on admission and postpartum, and the mean of this data was used for analysis. First, the data reflected common clinical assumptions about delivery blood loss. The mean change in hematocrit for operative deliveries (7.93 +/- 5.10, 6.19 +/- 4.42; forceps and cesarean, respectively) was higher than that of spontaneous vaginal deliveries (4.31 +/- 3.78). Forcep deliveries had a larger decrease in hematocrit than repeat or primary cesarean sections combined, although it was not statistically significant (P = .04). More extensive vaginal lacerations were associated with larger decreases in hematocrit. There was a low percentage of patients requiring transfusion (1.3%) during the study period. All these patients had an estimated blood loss of > 1500 mL and delivery circumstances that would alert the clinician to the possibility of transfusion. Second, our data showed that the 28-week platelet count is predictive of the admission platelet count, with a regression coefficient of. 71.

Often clinical assessment of blood loss, including history and physical examination, will predict the results of routine screening CBCs, and we question the need for routine screening of blood loss in uncomplicated deliveries. Our data on the 28-week and admission platelet counts support other authors' data showing that this screen is not necessary prior to epidural placement in low-risk patients.