The breadth of the placental surface but not the length is associated with body size at birth

The associations between a larger breadth of the placental surface and a larger baby are consistent with the hypothesis that tissue along the breadth plays a key role in nutrient transfer from mother to baby. Mothers who are short in stature are known to have lower rates of protein turnover in pregnancy. In these circumstances the ability of the placenta to transfer amino acids to the fetus may be critical.