Drinking alcohol is linked to reduced chances of pregnancy
A study of the associations between drinking alcohol and the chances of becoming pregnant suggests that women who want to conceive should avoid heavy drinking. In the second half of the menstrual cycle, even moderate drinking is linked to reduced chances of pregnancy.

Participants were recruited and followed, and completed daily diaries reporting their alcohol intake (type and number of drinks) for a maximum of 19 months of follow-up (N=413).

Participants were between 19 and 41 years of age. After completion of baseline surveys, they were asked to record their alcoholic beverage intake as the number of drinks of beer, wine, and liquor per day, in addition to other exposures such as caffeine and smoking. Furthermore, they submitted urine samples each month to assess pregnancy. Menstrual cycle phases were calculated using the Knaus–Ognio approach. Discrete survival analysis methods were employed to estimate the association between categories of alcohol intake in each phase of the menstrual cycle and fecundability.

--In the luteal phase, both moderate drinking and heavy drinking were associated with a reduction in fecundability, compared to non-drinkers.

--For the follicular phase, heavy drinking in the ovulatory sub-phase was similarly associated with reduced fecundability, compared to non-drinkers.

--For the pre-ovulatory sub-phase, heavy drinking was associated with a reduction in fecundability, but this association was inconsistent when subjected to sensitivity tests.

--Each extra day of binge drinking was associated with a 19%, and 41% reduction in fecundability for the luteal phase and ovulatory sub-phase respectively, but no association was observed in the pre-ovulatory sub-phase.

--No meaningful differences in fecundability between beverages were observed in any menstrual phase.

Results suggest an inverse association between alcohol and fecundability and support the relevance of menstrual cycle phases in this link. More specifically, moderate to heavy drinking during the luteal phase, and heavy drinking in the ovulatory window could disturb the delicate sequence of hormonal events, affecting chances of a successful conception.

Human Reproduction
Source: https://doi.org/10.1093/humrep/deab121
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