Smoking poses significant risks to both maternal and fetal health during pregnancy and is a major public health concern. It is associated with various complications, such as preterm delivery, restricted fetal growth, placental abruption, placenta previa, premature rupture of membranes, and increased risk of perinatal mortality. In addition to these well-known risks, there is growing awareness of the detrimental effects of cigarette smoke on fertility and reproduction, although these effects are not widely recognized.
Smoking has a significant negative impact on fertility for both men and women. This impact is dose-dependent and as result, if you cannot fully quit smoking then it is better to try to cut back significantly than do nothing. It’s important to note that the negative effects of smoking on fertility are not limited to active smoking. Second hand smoke and exposure to environmental toxins can also have similar adverse effects.
Women:
- Ovarian Function: Smoking can accelerate the loss of eggs (ovarian reserve) and reduce the quality of eggs, making it more difficult to conceive.
- Hormonal Imbalances: Smoking can disrupt the hormonal balance in women, affecting the menstrual cycle and ovulation.
- Increased Risk of Tubal and Ectopic Pregnancy: Smoking increases the risk of tubal and ectopic pregnancies, where the fertilized egg implants outside the uterus.
- Increased Risk of Miscarriage: Smoking raises the risk of miscarriage
- Early Menopause: Smoking can bring on menopause at an earlier age, further reducing fertility. Menopause occurs 1-4 years earlier on average for smoking women versus non-smoking women.
- Uterine Receptivity: Research on donor-oocyte cycles indicates that moderate to heavy smokers who receive donor eggs are less likely to become pregnant compared to light or non-smoking recipients. The pregnancy success rates were 34.1% for smokers versus 52.2% for non-smokers. These findings imply that smoking may affect the receptivity of the uterus, leading to reduced success rates in assisted reproductive technology for smokers.
Men:
- Sperm Quality: Smoking can lower sperm count, reduce sperm motility (movement), and increase the number of abnormal sperm. This reduces the chances of successful fertilization.
- DNA Damage: Smoking increases the likelihood of DNA damage in sperm, which can impact embryo development and increase the risk of birth defects.
- Erectile Dysfunction: Smoking contributes to erectile dysfunction, making it more difficult to achieve and maintain an erection.
Overall, smokers undergoing fertility treatments such as in vitro fertilization (IVF) have lower success rates compared to non-smokers. The chances of conceiving and achieving a successful pregnancy are significantly reduced. Smoking has been found to have diverse negative effects on reproductive processes, although the exact impacts may vary across studies. Some reported outcomes include an increased need for ovarian stimulation, lower levels of peak estrogen, higher testosterone levels, a reduced number of retrieved eggs, more canceled cycles, a thicker outer layer of the egg, lower rates of successful embryo implantation, and a higher number of cycles with failed fertilization among smokers when compared to non-smokers. Smokers therefore require about twice the number of IVF attempts to conceive versus non-smokers.
Fortunately, quitting smoking can help improve fertility outcomes. The negative effects on fertility can be partially reversible after quitting smoking. It’s recommended for both partners to quit smoking and adopt a smoke-free environment to maximize their chances of conceiving and having a healthy pregnancy.
Dr Ashley von Martels ND is a naturopath in Toronto focusing on Women’s Health. Her areas of interest include: PCOS, irregular periods, acne, interstitial cystitis, UTI’s, yeast infections, PMS, endometriosis, menopause, fertility, pregnancy and preconception (amongst others). She offers virtual consultations to patients across Ontario.
