Why daughters of older mothers are less likely to have children

WOMEN who leave it late to start a family could be condemning their daughters to childlessness, according to a major new study.

The older the mother is when she gives birth, the more likely it is that her daughter will not have a family, it is claimed.

Women whose mothers were 35 or older when they gave birth are 40 per cent more likely to remain childless, compared to those whose mothers were pregnant with them in their early 20s.

An older mother’s reproductive system might negatively affect her unborn daughter’s potential fertility, said researchers.

But the findings could also reflect the fact that daughters tend to copy their mothers’ behaviour. In the journal Human Reproduction, scientists reported ‘a strong positive correlation between maternal age at birth and a daughter’s childlessness’.

‘Women born to older mothers were substantially more likely to be childless,’ they concluded.

The study examined 43,000 women aged 44 or older.

More educated daughters were less likely to have children. But comparing women with a similar level of education, the link between childlessness and their mothers’ age at birth remained strong.

The researchers, based at McGill University in Montreal, said animal studies suggested the biology of the older womb could negatively affect the reproductive success of the offspring. Older female mice, for example, had a higher risk of placenta problems.

But the team conceded there was limited evidence over whether the daughters of older mothers were less fertile.

They concluded: ‘Whether our results are due to biology, behaviour or socioeconomic factors – or a combination of these – the possible influence of maternal age on offspring fertility deserves further study.’