Is routine hemoglobin and hematocrit testing on admission to labor and delivery needed?

Testing hemoglobin and hematocrit values in labor and delivery at term is a routine practice at many centers. This necessity was evaluated by comparing values obtained at 26-28 weeks versus those obtained at term.

This is a prospective, observational study. All patients at least 37 weeks presenting to labor and delivery were evaluated during the study period. Enrollment criteria included having either a hemoglobin or hematocrit between 26 and 28 weeks and again on admission with term labor. Deliveries at less than 37 weeks and pregnancies complicated by multiple gestations, hemoglobinopathies, and hypertensive disorders were excluded. The World Health Organization (WHO) definition of anemia was used as well as an operationally defined threshold, below which local practitioners would change management (hemoglobin 8 g/dL, hematocrit 25%). The compliance of patients to any form of iron therapy was evaluated by questioning patients on admission.

One hundred and one patients met enrollment criteria. At 26-28 weeks, 20 patients were anemic by WHO criteria. On admission to labor and delivery at term, relative to 26-28-week values, hemoglobin had increased from 11.1 g/dL to 11.6 g/dL (P <.01), and hematocrit increased from 31.5-34.3% (P <.01). Eleven patients had term values that were lower than 26-28-week values. Of these, five patients met WHO criteria at 26-28 weeks. However, no value at term was below the operationally defined value.

The frequency of anemia fell from 20% at 26-28 weeks to 11% at term. The mild anemia at term did not change local management in any patient. Thus, if the value obtained at 26-28 weeks is acceptable (non-anemic by WHO criteria), the routine testing of these values at term can be avoided, resulting in significant cost savings.