How does smoking affect fertility?

We’ve been getting more questions about smoking and vaping from Ovally patients and therefore decided to add to our series on lifestyle factors and fertility. Unlike for other factors, the evidence for an effect of smoking on natural conception and the success of fertility treatments is pretty clear cut: It significantly lowers chances of success. While there’s been research on smoking, the effects of vaping are just starting to be investigated.

A range of observational studies have examined the relationship between smoking and the chances of natural conception, all showing a much lower likelihood of natural conception in women who smoke. Across studies, researchers identified 60% lower odds of success for smokers vs. non-smokers in conceiving naturally. Even though these comparative studies couldn’t rule out all other variables that potentially distinguish smokers from non-smokers having, this is a drastic difference between groups.

The research on fertility treatments and smoking looks very similar: Women undergoing IVF treatment who smoke were 50% less likely to conceive than women who did not. While smokers’ eggs fertilized at a similar rate as non-smokers’, IVF patients who smoked had much higher rates of ectopic pregnancies and spontaneous miscarriage, and significantly lower rates of pregnancy and live birth.

If the male partner smokes, IVF success rates are also affected negatively: In a study of 300 couples undergoing IVF, pregnancy rates were significantly lower if the man smoked. This effect held true even if the woman did not smoke and if the sperm selection method ICSI was used for IVF. The authors suggested that smoking may alter DNA in spermatozoa that could hinder embryo development.

Without even going into the negative effects of smoking on the baby during pregnancy, the negative effects on conception and fertility treatment outcomes are clear: Smoking drastically decreases outcomes, not just if the woman is a smoker, but if the man is as well.

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