Malnutrition and pathogenic colonization of the vagina are two major contributors to preterm labour, newborn survival and low birth babies at high risk of long term poor quality of life. It was hypothesized that use of probiotics as a food supplement would improve the appetite and health of the mother and newborn babies. Two probiotic strains, Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 were tested in a Sprague-Dawley albino rat model. The probiotic preparations (1X109cfu/ml) were administered to rats in group A, as supplementation in drinking water for 30 days. Feed intake and the birth weight of the newborns were measured. There was a significant improvement in appetite for the lactobacilli treated animals with a mean weight of 31.16g of feed, compared with 27.16g for the controls, P<0.01. The mortality rate for the control animals was 6% while no death occurred in the probiotic group. There was significantly increased birth weight among 37 newborns whose mothers had been fed probiotics (6.5g), compared to controls (4.5g) (P<0.01). There was a two log increase in total lactobacilli recovered from the stool of the probiotic treated animals with significant presence of the two lactobacilli treatment strains. No adverse effects were noted in the animals. This is the first report of nutritional appetite benefits of probiotics during pregnancy and of improvements in weight of newborn babies. Considering well nourished babies born within the normal weight range have a considerably better long term prognosis, if the present findings were to be duplicated in pregnant women, the implications for health especially of mothers and babies in developing countries could be very significant.