NUTRITIONAL STRESS OF REPRODUCTION - A COHORT STUDY OVER 2 CONSECUTIVE PREGNANCIES

Background. The evaluation of nutritional stresses of reproduction is far more complex than perceived in the literature so far. The use of i nappropriate outcome measures, the lack of adjustment for the complex inter-relationships among confounding variables, and the poverty of an alytical models, has led to conflicting results. Our objective was to evaluate, using a new analytical framework, the maternal and fetal eff ects of the nutritional stress imposed by reproduction in a cohort of 278 women followed over two consecutive pregnancies. Methods. The anal ytical framework evaluated nutritional stress over successive pregnanc ies. The effect of birth interval on change in maternal weight, body m ass index and hemoglobin over two consecutive pregnancies was evaluate d using multiple linear regression accounting for the effects of mater nal age, parity and weight or body mass index or hemoglobin in the fir st of the two pregnancies. For change in fetal birth weight correction was made for the confounding effect of maternal age, parity and weigh t, and fetal gestational age, sex and birth weight. Results. Birth int erval was associated with change in maternal weight (p=0.001); change in body mass index (p=0.002); and change in birth weight (p=0.048). No association was found between birth interval and change in hemoglobin . Conclusions. The nutritional stress imposed by reproduction affects maternal and fetal outcomes. Maternal nutrient stores can be depleted and fetal growth can be restricted in association with shorter birth i ntervals. Perinatal nutrition may be improved by adequate spacing of p regnancies with appropriate birth control.