Smoking, Fertility & Egg Freezing: What the Science Says
One of the most colossal changes you can make for your short and long-term fertility is to quit smoking. Doctors have told us that the ovaries of women who smoke can look more like those of women up to five years older.
The scientific evidence is also clear. Smoking can reduce your overall fertility by 60%. It’s linked with everything from irregular periods to a diminished ovarian reserve, which makes sense why smokers are more likely to go through menopause one to four years earlier than women who don’t. Every year of smoking has been shown to increase the risk of unsuccessful IVF by up to nine percent and the risk of miscarriage increases by one percent per cigarette smoked per day.
In ovarian stimulation cycles, smokers’ egg quality appears to be lower than that of non-smokers. This is evidenced by the fact that smokers undergoing IVF have more canceled cycles (usually due to poor egg development), lower implantation rates and more cycles with failed fertilization compared to non-smokers.
This is also supported by research showing that women who smoke are more likely to conceive a chromosomally unhealthy pregnancy (such as a pregnancy affected by Down syndrome) than non-smoking mothers.
One culprit is a group of chemicals called polycyclic aromatic hydrocarbons (PAHs) found in cigarette smoke. They are known to accelerate the destruction of eggs by causing DNA damage to the ovarian follicles, where the eggs normally develop to maturity.
It’s unclear how much of the damage is reversible but one large study showed that when women stopped smoking, the risk of earlier menopause decreased.
What is clear is that the sooner you quit, the better it is for your fertility.
What about electronic cigarettes, vaping, or twisps?
There’s no doubt that without the thousands of carcinogens found in cigarette smoke (e.g. lead, arsenic, hydrogen cyanide, formaldehyde, and uranium(!?), to name a few), e-cigarettes are less bad than cigarettes. On the other hand, the aerosols produced by e-cigs can contain nicotine, flavorings, and a variety of other chemicals, some of which are known to be toxic. At this moment, the specific short and long-term effects on fertility are not known, but it’s still concerning enough for at least 16 authorities in the UK to introduce a policy refusing couples access to state-sponsored IVF treatment if they use e-cigarettes or nicotine patches!
Does secondhand smoke matter?
Signs point to yes. While the evidence is limited, one study found that patients exposed to secondhand smoke (“passive smokers”) had the same lower pregnancy rates as smokers, though this could be due to effects on the womb, rather than egg quality. Further evidence comes from a study in which 84% of women who reported themselves as nonsmokers with smoking partners had detectable levels of cotinine (a major metabolite of nicotine that can have a negative impact on fertilization rates) in the follicular fluid surrounding their eggs upon retrieval during IVF. If you often find yourself in the company of smokers, try asking them to smoke outdoors, avoiding enclosed spaces where you’re more likely to get secondhand exposure. Your doctor can suggest a range of resources and support to help you quit smoking in a manageable way.
For more information on smoking and fertility, please download the book, Everything Egg Freezing: the Essential Step-by-Step Guide to Doing it Right or join the digital Fertility Fit™ program (beta).
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