- According to an observational study in 529,090 couples, there was a 35 percent increase in the chance of birth defects in newborns if the father regularly drank alcohol in the 6 months leading to conception.
- The types of birth defects tracked in the study included congenital heart disease, limb anomalies, clefts, digestive tract anomalies, gastroschisis, and neural tube defects.
- Experts note several limitations to the study, including the fact that it did not track the amount of alcohol consumed before conception.
New evidence suggests a link between paternal alcohol consumption before conception and the chances of fetal birth defects.
The study, published in JAMA Pediatrics on April 19, found that paternal drinking is associated with an increased risk of sperm abnormalities, which could lead to defects like congenital heart disease, limb anomalies, clefts, and digestive tract anomalies.
The association between alcohol consumption and birth defects has been most closely studied in mothers, but researchers have recently started taking a closer look at how paternal drinking affects babies.
The study adds to a growing pile of evidence that paternal alcohol consumption can potentially negatively affect the health of the baby.
It’s unclear why paternal drinking may lead to birth defects, but early evidence suggests alcohol changes the shape, size, and motility of sperm and could also alter the DNA that’s passed down to children.
Overall, the chances of birth defects remain low, regardless of alcohol consumption.
“This study raises questions that maybe both partners should be equally responsible in terms of when they are planning to create the new life,” said Dr. Lubna Pal, a Yale Medicine reproductive endocrinologist and professor of obstetrics, gynecology, and reproductive services at Yale School of Medicine.
Birth defects more commonly reported by fathers who drink alcohol
The researchers recruited 529,090 couples who were planning to become pregnant within 6 months.
Of the participating couples, 364,939 fathers did not drink alcohol before conception (defined as at least one time drinking a week) and 164,151 did.
The research team then tracked the rate of birth defects reported by parents 42 days after the baby was born.
Overall, 609 total birth defects were reported, including congenital heart disease, limb anomalies, clefts, digestive tract anomalies, gastroschisis, and neural tube defects.
Among the fathers who consumed alcohol, there were 363 birth defects. Among the fathers who did not consume alcohol, there were 246 birth defects.
The research team found that babies had a 35 percent greater chance of having a birth defect if their father regularly drank once a week or more in the 6 months leading up to conception.
In addition, babies had a 55 percent greater chance of developing clefts if their father drank regularly before conception.
According to the researchers, the epidemiological evidence suggests paternal drinking before conception can damage the sperm cells and increase the chances of birth defects.
The researchers also suggest the findings should inform guidance on paternal drinking to help reduce the chances of defects.
The study does not confirm a direct link, but it does raise questions that there may be preventable strategies that both partners can take to improve the health of the baby, according to Pal.
Why might paternal drinking have this impact?
Research on paternal drinking has historically focused on the effects of maternal alcohol consumption.
Mothers have historically been advised against drinking before conception, but guidance for paternal drinking before conception has been scarce.
“Fertility is a team sport. There are two players involved, but the burden has disproportionately fallen on women for [the] longest time,” Pal said.
A 2020 review of 55 studies also found a strong correlation between paternal drinking and babies being born with a birth defect like congenital heart disease (CHD).
According to that study, drinking alcohol within 3 months of conception was linked to a 44 percent higher chance of CHD. Furthermore, the risk appeared to be greatest in fathers who drank heavily.
It’s unclear why paternal drinking may be linked to a higher rate of birth defects.
Past evidence suggests alcohol affects the size, motility, and shape of sperm cells. Other research suggests exposure to alcohol can alter the father’s DNA and be inherited by the offspring.
Early evidence suggests the effects are not permanent, and it might only take 3 months for the sperm to become healthy again once the alcohol consumption stops.
More research is needed to understand the link
This new observational study raises questions that there might be a link between the father’s lifestyle choices before conception and the health of the baby.
But much more research is needed to explore the potential mechanisms at play along with other contributing factors.
Dr. Boback Berookhim, the director of male fertility and microsurgery at Lenox Hill Hospital, would like to see more data on how much alcohol the fathers consumed before conception.
“It would be very important to know how much is too much — a question which is not answered here,” Berookhim said.
Given the overall low rate of birth defects, even in fathers who consumed alcohol, more data is needed to determine whether alcohol abstinence before conception is beneficial, according to Berookhim.
“I tell potential fathers to moderate the alcohol intake but do not suggest complete abstinence,” Berookhim said.
The bottom line
New evidence has found a link between paternal alcohol consumption before conception and the chances of fetal birth defects.
Fathers who drink alcohol regularly before conception are associated with greater chances of birth defects like congenital heart disease, limb anomalies, clefts, and digestive tract anomalies.
It’s unclear why alcohol may cause birth defects, but early evidence suggests alcohol changes the shape, size, and motility of sperm and could also alter the DNA.
More research is needed to understand the link between paternal drinking and birth defects.
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