Paternal Preconception Alcohol Consumption Tied To Fetal Birth Defect Risk

Preconception paternal alcohol consumption is associated with an increased risk of fetal birth defects, driven by an elevated risk of clefts in particular, a Chinese study suggests.

Researchers examined data on 529,090 couples participating in the National Free Preconception Health Examination Project in mainland China from April 2010 to December 2012 who had data available on both paternal preconception alcohol consumption and pregnancy outcomes. Overall, 155,151 couples (31.2%) reported preconception alcohol consumption among fathers and 17,491 (3.3%) reported preconception alcohol consumption among mothers.

A total of 609 infants were born with birth defects. The risk of birth defects was significantly higher for couples that reported paternal preconception alcohol consumption (odds ratio 1.35), with the strongest association for clefts (OR 1.55), according to the results in JAMA Pediatrics.

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"Our take-home message for both clinicians and couples is that future fathers should be encouraged to modify their alcohol intake before conceiving to reduce fetal risk," said senior study author Dr. Xiaotian Li of the department of obstetrics and gynecology at the Hospital of Fudan University in Shanghai.

For the study, researchers defined preconception alcohol consumption as drinking at least once per week, without identifying a specific amount of alcohol.

"It is expected that a different risk of birth defects exists with light, moderate, and heavy alcohol consumption since alcohol may influence sperm in genetics and epigenetics," Dr. Li said by email. "Further study including detailed information of paternal drinking is necessary."

In the current study, parents reported any birth defects at 42 days after delivery.

Couples with and without paternal preconception alcohol consumption were matched based on maternal province of origin, maternal alcohol consumption, folic acid supplementation, and paternal smoking.

Several other types of birth defects including congenital heart disease, digestive tract abnormalities, and neural tube defects were more likely when couples reported paternal alcohol consumption, but these differences were not statistically significant.

"Although the link between maternal alcohol consumption and birth defects has been thoroughly investigated, the puzzle behind the association of preconception paternal alcohol consumption and offspring remain unsolved," said Dr. Thomas Zegkos, a cardiologist at AHEPA University Hospital in Thessaloniki, Greece, who wasn't involved in the study.

The most plausible explanation is the ethanol-induced disruption of the sperm-inherited epigenetic mechanisms, Dr. Zegkos said by email. These mechanisms consist of abnormalities in the translational processes of the DNA.

"Simply, there is an inherited problematic deciphering of the genetic code, caused by alcohol, which leads to deficient organ development," Dr. Zegkos said. "However, the exact pathophysiological mechanism warrants further investigation."

In the meantime, clinicians should consider giving the same advice to both men and women who are trying to conceive - abstain from alcohol consumption, Dr. Zegkos said. The exact period of preconception abstinence isn't yet clear, however.

"This should be at least six months in order to minimize the risk attributed to the alcohol," Dr. Zegkos said. "If complete abstinence is not feasible, a 'lower the better' strategy should be adopted."

—Lisa Rapaport

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