Women who drink heavily are significantly more likely to experience unintended pregnancies.
For the study published in the journal Addiction, researchers analysed data from 2,015 non-pregnant women aged 15 to 34, focusing on a subgroup of 936 women who expressed a strong desire to avoid pregnancy. Among this group, 429 reported heavy alcohol use, and 362 reported cannabis use.
Over a 13.5-month follow-up period, 71 of these women became pregnant. More than half of those pregnancies occurred among heavy drinkers. In fact, women who drank heavily had a 50 per cent higher risk of becoming pregnant compared to those who drank moderately or not at all. Surprisingly, cannabis use was not associated with an increased risk of unwanted pregnancy.
While the study doesn’t explain why alcohol use leads to higher pregnancy risk, factors like impaired judgement, reduced contraception use and riskier sexual behaviour could be possible contributors. “Given the potentially life-altering effects of foetal alcohol spectrum disorders (FASD, which occur when a foetus is exposed to alcohol through the mother's drinking) and the fact that the risk of the condition increases with the amount and duration of the mother's drinking, it is important for doctors and clinicians to support women who drink heavily to stop drinking as soon as they suspect an unintentional pregnancy," the author emphasised.