IntroductionHuman breast milk is particularly adapted to our biological needs and remains the best source of nutrition for the human infant (Kunz et al, 1999). It provides the necessary support for the development of the immune system (Goldman et al., 1994; Garofalo and Goldman, 1999). The powerful anti-infection qualities of breast milk are measured by the reduction in infant mortality in developing countries where exclusive breastfeeding is the norm (Scariati et al, 1997; Ball and Wright, 1999). Breast milk is about 6% carbohydrates, about 4% fat, about 1% protein, and about 89% water. The composition of breast milk is very different from that of artificial milk or “formula”. Most artificial breast milk products use cow's milk as a substrate. The latter contains more protein and less lactose than breast milk (Kunz et al, 1999). Lactose levels correlate well with brain size across species. Given the large size of its brain, it is not surprising that humans have a higher concentration of lactose in their milk than any other species (Newton, 2004). From the perspective of the Islamic religion, although it is recommended to prolong adequate lactation until two years later, the Prophet Mohammed pointed out that milk from pregnant women is harmful to infants and strongly advised mothers pregnant women never breastfeed their infants. The aim of this study was to compare milk composition in pregnant and non-pregnant lactating mothers in order to learn to what extent pregnancy might affect milk composition and how this might reflect on both development and health. of the child.Subjects and methodsI- SubjectsThis study was carried out on 64 healthy urban lactating women attending the outpatient department...... middle of paper ......urs in the brain and 60% of this tissue is lipidic (Newton, 2004). Stopping breastfeeding, in the event of pregnancy, to avoid its harmful effects on breastfed infants can expose them to many dangers such as gastroenteritis. and diseases linked to malnutrition. It is therefore our responsibility to strongly advise against pregnancy while breastfeeding so that the newborn receives the best nutritional support to ensure its full physical and neurological development. This is exactly what the Islamic religion recommends to prolong adequate lactation, up to two years, to meet the demands of the infant and at the same time to avoid pregnancy in addition to breastfeeding with its harmful effects both on the breastfed infant than on the fetus. It is hoped that further work will be carried out to study the effect of pregnancy on other constituents of milk which could also affect the breastfed infant..