Tag: does vaping affect egg count

A new Hertility study of more than 16,000 women has found that current vaping is associated with lower levels of anti-Müllerian hormone (AMH), a commonly used marker of ovarian reserve. Vaping is often positioned as a less harmful alternative to cigarette smoking. And when it comes to overall health, evidence suggests vaping exposes people to fewer harmful substances than smoking. But less harmful does not mean risk-free. Until now, we have known surprisingly little about how vaping could affect female reproductive health. Most previous research has come from animal studies, small fertility-clinic populations or studies looking at pregnancy rather than ovarian function. New research from Hertility, published in the peer-reviewed journal BMC Women’s Health, looked at vaping, cigarette smoking and ovarian reserve markers in 16,087 women aged 18-45. The main finding? Women who currently vaped had 5.6% lower AMH levels, on average, than women who had never vaped, even after accounting for cigarette smoking and other factors such as age, BMI and ethnicity. That does not mean vaping has been proven to reduce fertility or that someone who vapes will struggle to get pregnant. But it is an important novel signal that deserves further investigation. Does vaping affect fertility? We don’t yet know whether vaping directly reduces female fertility. However, Hertility’s new study found that current vaping was associated with lower AMH, a hormone used as a marker of ovarian reserve. The study did not measure whether women became pregnant, how long it took them to conceive, egg quality, IVF success or live birth rates. Because it was cross-sectional, it also cannot prove that vaping itself caused the difference in AMH. Instead, the findings suggest there may be an association between current vaping and one aspect of ovarian biology. This distinction matters. Fertility is influenced by many different factors, including age, egg quality, ovulation, sperm health, the fallopian tubes and uterus. AMH is one piece of that puzzle. What did the study find? Researchers analysed reproductive health and hormone data from 16,087 women aged 18-45 across the UK. The main findings were: The association between vaping and AMH was relatively small. It represented an estimated absolute difference of around 0.71 pmol/L, which the researchers emphasise should not be interpreted as a clinically meaningful reduction in ovarian reserve for an individual woman. Instead, it is better thought of as a population-level signal that now needs to be investigated in studies that follow women over time. About the research The study used anonymised data collected through Hertility’s reproductive health service between November 2022 and February 2025. Women with reproductive health conditions that could independently influence ovarian reserve or hormone levels – including PMOS, previously known as PCOS, endometriosis, primary ovarian insufficiency and hypothalamic amenorrhoea — were excluded. Women using hormonal contraception were also excluded. Participants reported whether they had never, previously, occasionally or currently vaped and smoked. AMH and follicle-stimulating hormone (FSH) were measured from at-home capillary blood samples. Where applicable, samples were collected on day three of the menstrual cycle, and the researchers accounted statistically for age, BMI, ethnicity and cigarette-smoking behaviour. Importantly, vaping and cigarette smoking were included in the same statistical model. This allowed the researchers to examine the association with vaping independently of smoking, rather than assuming everyone who vapes has never smoked cigarettes. What is AMH and what does it have to do with fertility? Anti-Müllerian hormone, or AMH, is produced by cells within developing follicles in the ovaries. It is commonly used as a marker of ovarian reserve – broadly, the pool of eggs remaining in the ovaries. In general, AMH tends to decline as ovarian reserve decreases with age. AMH testing can therefore be useful when assessing ovarian reserve and estimating how the ovaries might respond to stimulation during fertility treatment. But there is an important caveat. AMH does not measure egg quality and it cannot tell you whether you can or cannot get pregnant naturally. Someone can have low AMH and conceive naturally, while someone with a high AMH can still experience fertility difficulties for completely unrelated reasons. So, when this study reports lower AMH among current vapers, it does not mean that current vapers were 5.6% less fertile or had a 5.6% lower chance of pregnancy. Those are different outcomes. Does vaping reduce your egg count? This study cannot tell us that vaping reduces someone’s egg count. AMH is associated with the number of developing follicles in the ovaries, but it does not directly count how many eggs someone has. The researchers also did not perform antral follicle counts (AFCs) using ultrasound, which would provide another measure of ovarian reserve. For that reason, the finding should be described as an association between vaping and lower AMH, rather than evidence that vaping directly destroys eggs or causes diminished ovarian reserve. Future studies combining repeated AMH measurements with AFC, detailed vaping exposure and long-term reproductive outcomes will be needed to answer this properly. How could vaping affect the ovaries? At the moment, we don’t know. There are several biologically plausible explanations, but most of the evidence comes from cigarette smoking, laboratory studies or animal research rather than large human vaping studies. Nicotine is one possibility. Experimental research suggests nicotine can influence follicular development, cell death and the normal production of reproductive hormones. Nicotine’s major metabolite, cotinine, has also been detected in follicular fluid — the fluid surrounding a developing egg — in people who smoke and vape. But nicotine may not be the whole story. E-cigarette aerosol can contain a complex mixture of substances depending on the device and liquid used, including metals, aldehydes and flavouring chemicals. Some laboratory and animal studies have suggested that certain components may affect ovarian follicles or endocrine function. That does not mean these substances have been shown to damage human fertility at the levels produced by normal vaping. It does mean there is enough biological uncertainty to justify much better research – particularly as vaping becomes more common among younger people. Is vaping worse for fertility than smoking? […]