Evidence for effects of weight on reproduction in women.

Body weight, and its constituent components of fat mass and lean tissue, plays an important role modulating reproductive development and functioning. Body weight influences the timing of menarche and the capacity to achieve a pregnancy. The nature of this relationship appears to be some variant on a 'U' shape. Extremes in body weight are associated with infertility and a range of adverse outcomes for both mother and baby across the course of pregnancy and perinatal period. Whereas underweight is associated with poor fetal growth and elevated pregnancy loss, overweight is more strongly associated with diseases in pregnancy, pregnancy loss and stillbirth and high birth weight. An emerging area of interest is the role of obesity on fertility, and the intergenerational 'tracking' of high maternal body weight into the second and subsequent generations, resulting not only in an increased risk of metabolic disease, but also perturbed reproductive functioning in the offspring.