RED-CELL DISTRIBUTION WIDTH (RDW) CHANGES IN PREGNANCY

Objective: As part of an exercise in establishing normograms of hemato logical parameters in pregnancy, we studied the red cell distribution width (RDW) in healthy pregnant women. Methods: A longitudinal study o f RDW measurements in 121 pregnant women at 16 and 34 weeks gestation and during labor and at Days 3 and 7 postpartum. All the women had unc omplicated pregnancies, minimum hemoglobin (Kb) of 11.0 g/dl at recrui tment and took iron supplements from 16 weeks of gestation and until 7 days after delivery. All subjects went into spontaneous labor, 110 ac hieving a normal vaginal delivery while the remaining 11 were delivere d by cesarean section. Two-way analysis of variance was used to study the changes in RDW between any given gestations to test the variabilit y between and within subjects. Results: RDW increased significantly (P < 0.0001) between 34 weeks of gestation and the onset of labor. No si gnificant changes occurred between 16 and 34 weeks gestation, or durin g the 7 days postpartum Conclusion: This is the first longitudinal stu dy analyzing the between and within women changes in RDW with progress ion of pregnancy. The unexpected rise in the RDW during the last 4-6 w eeks leading up to the onset of labor suggests increased bone marrow a ctivity. The stimulus is unknown, but as RDW changes are highly signif icant there may well be a useful indicator of impending parturition. ( C) 1998 International Federation of Gynecology and Obstetrics.