Pre-pregnancy low body mass index, micronutrient deficiency and short stature are known risk factors for adverse pregnancy outcomes. The benefit of pre-conception folate on prevention of congenital anomalies has been established in randomized trials; however, the role of other nutrients needs to be examined further.
Improving nutritional status may be important to cover the period of placental formation and growth which is key for laying the foundation for improved placental immunity, and preventing placental malaria (and other infections), a major cause of adverse maternal and fetal outcomes. Second, anemia is strongly associated with adverse perinatal outcomes including maternal mortality and low birth weight. Conventionally, iron supplements are provided to women when they are pregnant. However, many women enter pregnancy with little or no iron reserves due to poor diet, closely spaced pregnancies, blood loss by postpartum hemorrhage, and prolonged periods of lactation.
Therefore, it is very difficult to replenish iron stores once the pregnancy is in progress. Additionally, iron deficiency is responsible for only about half of the anemia burden in pregnancy, with other micronutrient deficiencies playing a major role. Third, pre-conception vitamin A supplementation may be important for maternal and fetal survival as well. Supplementation of women during childbearing years reduced pregnancy-related mortality by about 50% in undernourished women in a large trial from rural Nepal (n~45,000); however, the effects of vitamin A supplementation need to be confirmed in African settings with high burden of malaria and HIV infection. Fourth, free radicals generated during conception, fertilization, and early pregnancy lead to oxidative stress, degeneration of the syncytiotrophoblasts and early pregnancy failure. Therefore pre-pregnancy supplementation will be a practical population intervention to tackle poor pregnancy outcomes especially early in pregnancy.
