Abstract Grandmothers play a crucial role in families enhancing grandchild wellbeing and survival but their effects can be context-dependent, and the children born in poor conditions are most likely to benefit from the investments made by helping grandmothers. In this study, we examined, for the first time, whether grandmothers' presence modified associations between adverse birth status and survival up to 5 years of age. In detail, we verified, whether (i) firstborns, (ii) twins, (iii) children born within 24 months after their sibling, and (iv) children followed by short interval (i.e. their younger sibling was born within 24 months) survived better when either their maternal, paternal, or both grandmothers were present. Moreover, we evaluated whether illegitimate children survived better when the maternal grandmother was present. We used an extensive and largely pre-industrial demographic dataset collected from parish population registers kept by the Lutheran Church of Finland from years 1730–1895. We show that although grandmother presence cannot mitigate adverse effects of many poorer birth conditions, grandchildren whose next sibling was born after a short interval survived better when the maternal grandmother was present. Taken together, these findings highlight an important role of grandmothers in compensating the mother's investment in the new baby, thus enabling overall faster successful reproductive rate of mothers. Whilst the opportunity for grandmothers to mitigate the risks of adverse birth statuses is limited, this study does show - through the beneficial effect on survival for those with a short subsequent birth interval - that grandmothers can increase their daughters' and their own reproductive success.

中文翻译：

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奶奶会救我吗？历史芬兰的出生状况、生存和祖母的角色

摘要 祖母在促进孙辈幸福和生存的家庭中发挥着至关重要的作用，但其影响可能因环境而异，而在贫困条件下出生的孩子最有可能从帮助祖母所做的投资中受益。在这项研究中，我们首次检查了祖母的存在是否会改变不良出生状态与 5 岁以下存活率之间的关联。详细地，我们验证了，(i) 长子，(ii) 双胞胎，(iii) 其兄弟姐妹之后 24 个月内出生的孩子，以及 (iv) 间隔较短的孩子（即他们的弟弟妹妹在 24 个月内出生）是否存活当他们的母亲、父亲或两个祖母都在场时会更好。此外，我们评估了当外祖母在场时，私生子是否能更好地存活下来。我们使用了从 1730 年至 1895 年芬兰路德教会保存的教区人口登记册中收集的广泛且主要是前工业化人口数据集。我们表明，虽然祖母的存在不能减轻许多较差出生条件的不利影响，但当外祖母在场时，下一个兄弟姐妹在短时间内出生的孙子存活得更好。综上所述，这些发现突出了祖母在补偿母亲对新生儿的投资方面的重要作用，从而使母亲的整体成功繁殖率提高。虽然祖母减轻不良出生状态风险的机会有限，