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A man’s age and smoking habits around the time of conception can affect his chance of a healthy baby, new research suggests. It’s long been known that women should try to stay as healthy as possible during pregnancy to give her baby the best start in life. But in recent years there’s been increasing evidence that the health of both parents before conception is important for their future baby’s health.

Two recently published research papers have added to this. The first looked at 10 studies estimating the effect of a man’s age on the risk of miscarriage. Overall, the results showed that the older the father is, the higher the risk of miscarriage. Compared to men aged under 30, men aged 40 to 44 have a 23 per cent higher risk of their partner suffering miscarriage. And for men aged over 44, the risk increased by 43 per cent. So, although the woman’s age is the biggest factor in the risk of miscarriage, this research shows that the male partner’s age also makes a difference.

The second paper looked at the connection between a man smoking before conception and the risk of his baby having a birth defect. For this study researchers used data from 566,439 couples in China who had completed questionnaires on pre-conception paternal smoking behaviour and the outcomes of pregnancy.

In all, 29 per cent of the men smoked before conception. Of these nine per cent stopped, 13 per cent decreased, and seven per cent continued smoking during early pregnancy. Babies whose fathers had stopped, or decreased smoking had a lower risk of being born with neural tube defects such as spina bifida, and abnormalities in their heart, limbs, and digestive tract than those whose fathers continued smoking.

The take-home message is that men’s age and health behaviours matter for the health of their children. So, when there is a choice about timing, sooner is better, and when it comes to smoking, quitting as soon as possible will benefit the health of fathers and their babies.  



du Fosse NA, van der Hoorn MP, van Lith JMM, le Cessie S, Lashley E. Advanced paternal age is associated with an increased risk of spontaneous miscarriage: a systematic review and meta-analysis. Hum Reprod Update 2020.

Zhou Q, Zhang S, Wang Q, Shen H, Zhang Y, Tian W, Li X. Association between preconception paternal smoking and birth defects in offspring: Evidence from the database of the National Free Preconception Health Examination Project in China. BJOG 2020.