Invited commentary: an assessment of maternal intergenerational factors in pregnancy outcome.

Abstract

Further support for the greater importance of maternal factors comes from studies showing that fetal growth is most strongly related to the birth weights of relatives in the maternal line (10-13). Furthermore, the association of maternal grandmother's stature to grandchild's fetal growth in two studies (9, 14) indicates a multigenerational process. Lumey and Stein (2) report the latest findings from the Dutch Famine Birth Cohort Study, which takes advantage of an unfortunate natural experiment. In this paper, they identify the mother's own early gestational growth as a critical period for her future reproductive success. The expected between-sibling parity relations of birth weight were disrupted in infants born to mothers who had experienced intrauterine exposure to the famine during the first trimester of pregnancy. Because adequate nutrition was reestablished during the third trimester—the time of large body mass accumulation—these mothers had higher birth weights than those mothers exposed in the second and third trimesters. This finding of low correlations between birth weights of mothers and infants is consistent with studies of mothers who are twins. As a group, these mothers have babies as large as those of singleton mothers, even though twins are markedly small at birth (15, 16). The growth pattern of twins is similar to that of singletons until late in gestation. Thus, as in the Lumey and Stein study (2), it is the mother's early gestational growth retardation which seems to be related to later suboptimal reproductive outcomes.