Smoking vs IVF: How tobacco use directly lowers success rates

Lucknow : When couples begin preparing for IVF, most of their attention goes toward medication protocols, hormone injections, embryo quality, and clinic success rates, says Dr Shreya Gupta, Fertility Specialist, Birla Fertility & IVF, Lucknow. Tobacco use tends to receive less focus, partly because its effects on reproductive health are not immediately visible. A person can feel physically well, have no obvious symptoms, and still carry a measurably reduced reproductive potential because of smoking. Research has consistently found that smokers require more cycles of fertility treatment to conceive and have lower success rates per cycle than non-smokers.
 
The mechanisms through which tobacco affects fertility are well documented in both partners. In women, the harmful compounds in cigarette smoke accelerate the loss of ovarian reserve and increase oxidative stress within the reproductive system. This can interfere with hormonal function in ways that affect how the ovaries respond to stimulation medications during an IVF cycle, often resulting in fewer eggs retrieved and lower egg quality. In men, smoking is associated with reduced sperm count, lower motility, abnormal morphology, and elevated DNA fragmentation. A 2024 review published in the Journal of Clinical Medicine confirmed that sperm DNA damage from tobacco exposure can affect embryo development and implantation even when fertilisation is achieved through IVF or ICSI.
 
A common assumption is that stopping smoking a few days before a cycle begins is sufficient. Sperm production takes approximately 70 to 90 days to complete, and egg quality is shaped by cumulative health and environmental exposures over a similar period. Changes made close to a cycle start do not meaningfully affect the eggs and sperm that will be used in that cycle. Fertility specialists generally advise both partners to stop smoking at least three months before beginning treatment for this reason.
 
The biological effects of cessation are measurable. Oxidative stress reduces, blood circulation to the reproductive organs improves, and sperm parameters show documented improvement across the months following cessation. These are changes that translate into better starting conditions for IVF, not changes that require years to manifest.
 
IVF is among the most advanced interventions available in reproductive medicine. Its outcomes are shaped by both the clinical team managing the treatment and by the biological environment in which that treatment is being attempted. Tobacco use creates conditions that work against what IVF is designed to achieve, and removing it from that environment is one of the more direct improvements a couple can make before beginning a cycle.