How long before pregnancy should you quit smoking?

What does the evidence say about quitting smoking before trying to conceive while trying to conceive?

1. Cigarette smoke exposure can make it harder to get pregnant, women smoking more than 10 cigarettes a day face a higher infertility risk, and smoking may affect uterine receptiveness in a way that impacts implantation. 1
2. Miscarriage risk is higher among women exposed to cigarette smoke, and some studies link greater smoke exposure to a higher chance of cleft lip or palate, heart defects, and respiratory or digestive problems in the baby. 2
3. In a prospective fecundability study, current regular smokers had roughly a 10 percent lower chance of conceiving each cycle than never-smokers, and that gap widened to about 23 percent lower among women smoking 10 or more cigarettes a day for 10 or more years. Former smokers still showed slightly reduced fecundability, with little difference based on how long ago they had quit. 3
4. Smoking affects fertility in a dose-dependent way: cadmium and a nicotine byproduct that accumulate in ovarian follicular fluid are linked to lower egg quality, and in a pooled analysis of 7 studies, women who smoked needed about twice as many IVF cycles to conceive as nonsmokers. 4
5. In men, smoking is linked to reduced sperm concentration and movement, and fecundity is described as returning to normal with smoking cessation, which is why cessation counseling is considered an important part of an infertility evaluation even though an exact recovery timeline hasn't been established. 4

What to know about quitting smoking before trying to conceive while trying to conceive

• There's no proven safe countdown, so the practical move is to quit as soon as pregnancy enters the picture rather than waiting for a specific number of months. Smoking is linked to lower uterine receptiveness, which may affect how well an embryo implants.
• A partner who smokes matters too. Male smoking is linked to lower sperm concentration and movement, and animal research suggests it can reduce sperm's ability to bind to and fertilize an egg, so quitting works best as a shared plan.
• If conception is taking longer than expected, know that smokers undergoing IVF have needed about twice as many cycles to conceive compared with nonsmokers in pooled research. Fecundity is described as returning to normal with cessation, so quitting still helps even if you're already several months into trying.