Small-for-gestational age, ponderal index and neonatal polycythaemia: a study of their association with maternal hypertension among Nigerian women
AbstractBackground/Objective: To examine the influence of maternal hypertension on rate of delivery of small-for-gestation age (SGA) infants, incidence of neonatal polycythaemia and mean ponderal indices of the resultant newborn infants.
Methods:From the birth weights and lengths, the ponderal indices of SGA infants born to mothers with chronic hypertension were compared with those of their counterparts born to mothers with pregnancy-induced hypertension. In addition, the spun venous haematocrit values of 265 infants born to mothers whose pregnancies were complicated by hypertension were compared with those of 804 infants born to control mothers.
Results: The rates of delivery of SGA infants were 82.0 and 54.7 per 1000 live births among hypertensive and normotensive mothers respectively (p>0.05). The prevalence of neonatal polycythaemia was 8.2% and 2.2% for infants of hypertensive and control mothers respectively (p<0.001). The rate of delivery of SGA infants was 18.6 times higher in mothers with chronic hypertension than in mothers with pregnancy-induced hypertension (p<0.001). SGA infants born to mothers with chronic hypertension had normal mean ponderal index (≥ 2.3) while their counterparts born to mothers with pregnancy-induced hypertension had low mean ponderal index (<2.3). The prevalence of neonatal polycythaemia was 52.9% and 5.0% in infants born to mothers with chronic hypertension and infant of mothers with pregnancy-induced hypertension respectively (p<0.001).
Conclusion: Maternal hypertension is associated with an increased incidence of neonatal polycythaemia and delivery of SGA infants. This risk is dramatically higher in women with chronic hypertension. Chronic maternal hypertension causes proportionate foetal growth retardation while pregnancy-induced hypertension causes disproportionate foetal growth retardation.
Keywords: maternal hypertension, small for gestational age, ponderal index, neonatal polycythaemia
Annals of African Medicine Vol. 4(4) 2005: 154-159