The effects of arterial hypertension during pregnancy on birth weight, intrauterine growth retardation and neonatal evolution. A matched case-control study

Objective: To determine the impact of hypertensive disorders in pregnancy on birth weight, small-for-gestational age births (SGA) and neonatal outcome.

Methods: Matched case-control study. Methods: A Tertiary Neonatal Intensive Care Unit. Methods: The effects of maternal hypertension were analyzed in 11,358 infants born between January 1990 and December 1996 at the Italian Hospital of Buenos Aires. Infants born to mothers with pregnancy-induced hypertension, preeclampsia or eclampsia were included. Each infant was matched for gestational age to 1 control infant born to normotensive mothers. Exclusion criteria were: twins, intrauterine infections, chronic hypertension and major malformations. Methods: Birth weight, incidence of SGA infants, neonatal outcome.

Results: 279 infants of hypertensive mothers and 279 controls met the inclusion/exclusion criteria and were enrolled. Maternal hypertension was significantly associated with a higher rate of C-section (OR = 3.80; 95% CI: 2.64-5.50); SGA infants (OR = 7.08; 95% CI: 3.07-18.6), low birth weight (LBW) (OR = 1.8, 95% CI: 1.24-2.60) and very low birth weight infants (VLBW) (OR = 2.14; 95% CI: 1.13-4.19). The frequency of low Apgar score at 5 minutes (OR = 3.63; 95% CI: 1.12-15.3), necrotizing enterocolitis (OR = 3.33; 95% CI: 1.23-10.30) and polycythemia (OR = 3.63; 95% CI: 1.12-15.3) was significantly increased in infants born to hypertensive mothers. There were no significant differences regarding other causes of neonatal morbidity and mortality rate.

Conclusions: Hypertension in pregnancy mainly increased the risk of SGA infants. Furthermore, infants of hypertensive mothers had a higher incidence of LBW, VLBW, low Apgar score at 5 minutes, necrotizing enterocolitis and polycythemia.