Prenatal Exposure to Antinausea Drug Associated with Increased Risk of Colorectal Cancer

Prenatal exposure to the combination of doxylamine/dicyclomine/pyridoxine (marketed as Bendectin) an antiemetic prescribed during pregnancy in the 1960s, may be linked to an increased risk of colorectal cancer (CRC) in adulthood, according to the results of a new study published in JNCI Cancer Spectrum.

“Rates of CRC have increased successively by birth cohort starting with persons born in the 1960s, therefore renewing interest in identifying risk factors,” the authors explained. “Birth cohort effects implicate exposures in early life as risk factors: pregnancy-related exposures introduced in the 1960s may contribute to higher rates of CRC among offspring exposed in utero.”

The investigators collected data from Child Health and Development Studies from more than 14,500 pregnant women in Oakland, California, between 1959 and 1967. The data included 18,751 offspring. They found that 5% of the offspring (n=1014), were exposed in utero to Bendectin. These offspring were found to be a higher risk of developing adult-onset CRC than the offspring not exposed to the drug combination (adjusted HR = 3.38; 95% CI, 1.69-6.77).

“Our findings suggest that events in the earliest periods of life – including the womb – can affect risk of cancer many decades later. As many as 25% of pregnant women received Bendectin through the mid-1970s, and there may be long-lasting consequences for offspring that continue today,” the researchers concluded.

Reference:
Murphy C, Cirillo P, Krigbaum N, Singal A and Cohn B. In utero exposure to antiemetic and risk of adult-onset colorectal cancer. JNCI Cancer Spectrum. 2023: 7(2). DOI: https://doi.org/10.1093/jncics/pkad021