Smoking during pregnancy 'may impact on grandchildren's growth': Effects of the habit can span generations, study finds Smoking in pregnancy can affect growth of future grandchildren, study finds. Teenager boys heavier when maternal grandmother smoked while pregnant. But they may also have better cardiovascular fitness, researchers claim Girls whose mother and maternal grandmother smoke had reduced height and weight, British scientists found. Smoking during pregnancy can affect the growth of a woman’s future grandchildren, a new study has warned. Researchers have found that if a maternal grandmother smoked during pregnancy, her grandsons became heavier than expected during adolescence, But the study also found those grandsons had better cardiovascular fitness. However when both the maternal grandmother and the mother had smoked, girls had reduced height and weight compared with girls whose mothers, but not grandmothers, smoked. In non-smoking mothers whose paternal grandmothers smoked during pregnancy, granddaughters tended to be taller, the report claims. And both granddaughters and grandsons tended to have greater bone mass and lean muscle mass. The study was carried out in Britain and published in the American Journal of Human Biology and suggests the effects of smoking during pregnancy can span generations. Senior author Professor Marcus Pembrey said: ‘These likely transgenerational effects from the grandmothers' smoking in pregnancy need to be taken into account in future studies of the effects of maternal smoking on child growth and development. ‘If replicated, such studies could be a useful model for the molecular analysis of human transgenerational responses.’ NHS guidelines warn that smoking during pregnancy can increase the risk of a baby being stillborn, make it more likely that it will be born early and make it less able to cope with any birth complications. In nonsmoking mothers whose paternal grandmothers smoked during pregnancy, granddaughters tended to be taller, the report claims.