Nutritional aspects of preconceptional period as related to pregnancy and early infancy.

The maternal nutritional status is considered as one of the most important factors influencing the pregnancy and the state of the offspring. There are limited data available on inadequate intake, especially before conception. A variety of nutritional and non-nutritional factors can act during the preconceptional period. Prepregnancy body weight and gestational weight gain have an independent but cumulative influence on the birth weight. The vitamin deficiency in preconceptional period, especially of folates, seems to be associated with neural tube defects. The infants of women with total gestational weight gain below 9 kg have the mean birth weight always lower than those of women with weight gain more than 9 kg in all three categories of preconceptional relative weight (i.e. less than 95%, from 95% to 105% and greater than 105%). Also the proportion of infants with birth-weight greater than 2500 g is higher in average (6.2%) and under-weight (4.4%) groups than in those over-weight (1.8%). Several other maternal nutritional as well as non nutritional variables are related with the pregnancy outcome. Among those with harmful effect on pregnancy outcome since preconceptional period, are alcohol drinking and smoking. Work outside the home can be associated with preterm deliveries and low-birth-weight infants, but the results are not consistent. Nutritional intervention, energy and/or protein supplementation also contribute to an increase of the birth-weight. As far as the antenatal care is concerned, only few studies investigated, with a scientific rigour the relation if any between prenatal care and pregnancy outcome. We concluded that the available evidence confirms a significant impact of preconceptional nutrition on pregnancy outcome. A sensitive evaluation of nutritional status in preconceptional period seems to be a positive strategy for prevention of at risk pregnancies. There is a clear need of prospective human studies with aim to relate the nutrient status of future mother to the evolution of her pregnancy.