Effects of maternal undernutrition and heavy physical work during pregnancy on birth weight.

The study attempted to determine if heavy physical labour by mothers during pregnancy affected fetal growth when such mothers had calorie intakes which were below 70 per cent of WHO/FAO recommended standards. Full term infants of such mothers had a mean birth weight of 3060 +/- 355 (SD) g compared to 3270 +/- 368 SD g for the newborn of less physically active mothers on similar low calorie diets (P less than 0.01). The mothers who engaged in heavy labour had a mean pregnancy weight gain of 3.3 +/- 2.4 (SD) kg, independent of the birth weight of their offspring, compared with 5.9 +/- 3.3 kg for the less active mothers (P less than 0.001). The mothers' weight in early pregnancy had an insignificant influence on birth weights when mothers were on low calorie intakes.