Plasma volume in normal pregnant Nigerian primigravidae.

Plasma volume was measured in 10 non-pregnant, healthy nulliparous Nigerian and 30 normal primigravid Nigerians at various times of gestation by the Evans blue dye dilution technique. The mean plasma volume of 2098 ml for the non-pregnant Nigerians was statistically different (P less than 0.001) from values in non-pregnant caucasian primigravidae of comparable status. A mean maximum plasma volume increase of 1387 ml above non-pregnant value was found. Essentially, pregnancy imposed a much higher physiological load on Nigerian primigravidae compared to caucasian primigravidae. There was a significant negative correlation between plasma volume and packed cell volume (PCV) in pregnancy (r = -0.51, P less than 0.001), which may be related to excessive hemodilution in the primigravid Nigerian. Differences found may be due to geographical and/or racial factors.