Men should quit alcohol six months before trying for a baby to protect them from congenital heart diseases, scientists warn.
A study of 340,000 births found fathers who drank before pregnancy put their child at significant risk of the potentially deadly conditions.
Men who regularly consumed high amounts of alcohol in the three months before pregnancy had a 42 per cent greater risk of their child having a defect, compared to those who didn’t.
For women who had consumed alcohol in that time period, the risk was increased by 16 per cent.
Frequent binge drinking, defined as five or more drinks per sitting, was related to a 52 per cent higher likelihood of the birth defects for men and 16 per cent for women.
Researchers at the Central South University in Changsha, China, have now advised men not to drink any alcohol for six months before conception.
They added that women should stop drinking alcohol one year before, and avoid it completely while pregnant.
Congenital heart diseases are the most common birth defects, affecting around eight per cent of all births every year.
These conditions are the main cause of death for babies in their first week of life and can increase the likelihood of cardiovascular disease later life.
Alcohol is a known teratogen – substance that may cause birth defects by having a toxic effect on an embryo or foetus.
When women drink during pregnancy it can cause foetal alcohol spectrum disorder (FASD).
This can result in mental and physical problems in the baby including poor growth, cerebral palsy and learning difficulties.
Around one in four children with FASD have congenital heart disease, indicating that alcohol may also be implicated in these disorders.
Previous studies investigating the link between alcohol and congenital heart disease have focused on prospective mothers, with inconclusive results.
This is the first study to examine the role of paternal alcohol drinking on the baby’s heart health.
The researchers compiled the best data published between 1991 and 2019, which amounted to 55 studies.
They included 41,747 babies born with congenital heart disease and 297,587 without.
The analysis showed a relationship between paternal alcohol drinking and congenital heart diseases.
Researchers said the chance of the birth defects rose as alcohol consumption increased.
They added there was not significant at lower quantities of alcohol consumption, but did not specify the amount.
The study also found that, compared to abstinence, maternal drinking was linked to a 20 per cent greater risk of tetralogy of Fallot.
The condition is a combination of four abnormalities in the heart’s structure and strikes five out of every 10,000 births.
Academics noted that this was an observational study and does not prove an effect.
They reiterated that it doesn’t prove that paternal drinking is more harmful to the foetal heart than maternal drinking.
The data also cannot be used to define a cut-off of alcohol consumption that might be considered safe.
Dr Jiabi Qin, of Xiangya School of Public Health at Central South University, said: ‘We observed a gradually rising risk of congenital heart diseases as parental alcohol consumption increased. The relationship was not statistically significant at the lower quantities.
‘The underlying mechanisms connecting parental alcohol and congenital heart diseases are uncertain and warrant further research.
‘Although our analysis has limitations – for example the type of alcohol was not recorded – it does indicate that men and women planning a family should give up alcohol.’