A recent epigenetic hypothesis postulates that ‘a sex-specific male-line transgenerational effect exists in humans’, which can be triggered by childhood trauma during ‘the slow growth period’ just before puberty. The evidence is based on a few rather small epidemiological studies. We examine what response childhood trauma predicts, if any, in the birth size and prematurity risk of almost 800 000 offspring.Methods:
Children of parity 1, 2 or 3, born 1976-2002 in Sweden, for whom we could trace both parents and all four grandparents, constituted generation 3 (G3, n = 764 569). Around 5% of their parents, G2, suffered parental (G1) death during their own childhood. The association of such trauma in G2 with G3 prematurity and birthweight was analysed, while controlling for confounders in G1 and G2. We examined whether the slow growth period was extra sensitive to parental loss.Results:
Parental (G1) death during (G2) childhood predicts premature birth and lower birthweight in the offspring generation (G3). This response is dependent on G2 gender, G2 age at exposure and G3 parity, but not G3 gender.Conclusions:
The results are compatible with the Pembrey-Bygren hypothesis that trauma exposure during boys' slow growth period may trigger a transgenerational response; age at trauma exposure among girls seems less important, suggesting a different set of pathways for any transgenerational response. Finally, parental death during childhood was not important for the reproduction of social inequalities in birthweight and premature birth.