We see a lot of questions about what people need to do to optimize their odds for each cycle, and, fortunately, there's actually a reasonable amount of evidence-based advice out there.
This information is primarily coming from the American Society for Reproductive Medicine’s committee opinion Optimizing Natural Fertility, though I am also drawing from the physician reference UpToDate’s article Optimizing Natural Fertility in Couples Planning Pregnancy. These are consensus recommendations that come from a review of the literature broadly, not from any single study.
Alcohol intake
Moderate alcohol consumption (less than about 10-14 drinks per week) does not affect time to pregnancy in most studies, and is generally assumed to be fine while TTC. Heavier drinking can increase time to pregnancy, the measure most often used to decide if something is harmful to your prospects while TTC.
Most medical sources will recommend against any drinking during pregnancy. This essentially leaves a gray area of about a week to 10 days during the cycle — prior to ovulation, you are most emphatically not pregnant, and after implantation/a positive test, you are most emphatically pregnant. During the early TWW, you’re not pregnant, but there is potentially an embryo finding its way to the uterus. It is unlikely that moderate drinking does damage at this point (otherwise the time-to-pregnancy statistics would presumably reflect this), but there is no way to say definitively that alcohol does or does not affect the probability of implantation.
UpToDate says:
This information is primarily coming from the American Society for Reproductive Medicine’s committee opinion Optimizing Natural Fertility, though I am also drawing from the physician reference UpToDate’s article Optimizing Natural Fertility in Couples Planning Pregnancy. These are consensus recommendations that come from a review of the literature broadly, not from any single study.
Lifestyle factors
Alcohol intake
Moderate alcohol consumption (less than about 10-14 drinks per week) does not affect time to pregnancy in most studies, and is generally assumed to be fine while TTC. Heavier drinking can increase time to pregnancy, the measure most often used to decide if something is harmful to your prospects while TTC.
Most medical sources will recommend against any drinking during pregnancy. This essentially leaves a gray area of about a week to 10 days during the cycle — prior to ovulation, you are most emphatically not pregnant, and after implantation/a positive test, you are most emphatically pregnant. During the early TWW, you’re not pregnant, but there is potentially an embryo finding its way to the uterus. It is unlikely that moderate drinking does damage at this point (otherwise the time-to-pregnancy statistics would presumably reflect this), but there is no way to say definitively that alcohol does or does not affect the probability of implantation.
UpToDate says:
Moderate alcohol consumption