An analysis of intra-uterine growth retardation in rural Malawi

(1) To describe the sex-specific, birth weight distribution by gestational age of babies born in a malaria endemic, rural area with high maternal HIV prevalence; (2) to assess the contribution of maternal health, nutritional status and obstetric history on intra-uterine growth retardation (IUGR) and prematurity.

Information was collected on all women attending antenatal services in two hospitals in Chikwawa District, Malawi, and at delivery if at the hospital facilities. Newborns were weighed and gestational age was assessed through post-natal examination (modified Ballard). Sex-specific growth curves were calculated using the LMS method and compared with international reference curves.

A total of 1423 live-born singleton babies were enrolled; 14.9% had a birth weight <2500 g, 17.3% were premature (<37 weeks) and 20.3% had IUGR. A fall-off in Malawian growth percentile values occurred between 34 and 37 weeks gestation. Significantly associated with increased IUGR risk were primiparity relative risk (RR) 1.9; 95% CI 1.4--2.6), short maternal stature (RR 1.6; 95% CI 1.0--2.4), anaemia (Hb<8 g/dl) at first antenatal visit (RR 1.6; 95% CI 1.2--2.2) and malaria at delivery (RR 1.4; 95% CI 1.0--1.9). Prematurity risk was associated with primiparity (RR 1.7; 95% CI 1.3--2.4), number of antenatal visits (RR 2.2; 95% CI 1.6--2.9) and arm circumference <23 cm (RR 1.9; 95% CI 1.4--2.5). HIV infection was not associated with IUGR or prematurity.

The birth-weight-for-gestational-age, sex-specific growth curves should facilitate improved growth monitoring of newborns in African areas where low birth weight and IUGR are common. The prevention of IUGR requires improved malaria control, possibly until late in pregnancy, and reduction of anaemia.