Hemodynamic changes in underweight pregnant women.
Twelve normal-weight and 12 underweight women were compared to test whether fetal growth retardation in underweight gravidas is related to inadequate maternal hemodynamic adjustments. Plasma volume (+/- standard error) was 3227 +/- 103 mL in normal-weight and 2731 +/- 84 mL in underweight women (P less than .002). Cardiac output was 6340 +/- 167 mL/minute in controls and 5689 +/- 213 mL/minute in underweight women (P less than .03). Total peripheral vascular resistance was lower in controls than in underweight subjects (1025 +/- 31 versus 1198 +/- 58 dyne/second/cm5). Mean birth weight was 2837 +/- 125 g in underweight women and 3362 +/- 106 g in controls (P less than .005). Similarly, placental weight was reduced in the underweight group. All infants delivered by control mothers had a normal birth weight, whereas six infants from underweight gravidas were growth-retarded. In all cases combined, maternal plasma volume correlated significantly with both birth weight (r = 0.6, P less than .002) and placental weight (r = 0.56, P less than .01); total peripheral vascular resistance also correlated significantly and inversely with newborn weight and placental weight. Cardiac output correlated only with placental weight (r = 0.54, P less than .02). These results are consistent with the hypothesis that underweight mothers are at higher risk of fetal growth retardation because of a smaller plasma volume and lower cardiac output.
Rosso
P
P
Department of Pediatrics, School of Medicine, Pontificia Universidad Católica de Chile, Santiago.
Donoso
E
E
Braun
S
S
Espinoza
R
R
Salas
S P
SP
D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D001835:Body Weight / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology*; D005260:Female; D006801:Humans; D010953:Plasma Volume / Q000502:physiology*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third