fertility and vices

How Do Your Vices Impact Your Fertility? 

vices and fertility

by Dr. Lora Shahine

My patients ask me every day about ways to improve their fertility. We talk about nutrition, exercise, sleep, stress management, and especially limiting exposures to things that may harm egg and sperm function and chances of a healthy pregnancy, like alcohol, marijuana, and caffeine. There are so many different recommendations on these ‘vices’ – how much is ok, when to stop them when you’re trying to conceive or pregnant, all or nothing – it’s easy to get confused. Let’s review.  

Alcohol in pregnancy should be avoided due to its association with fetal alcohol syndrome (physical and developmental issues with the baby), but what about alcohol and fertility? Honestly, the research varies from a little bit of alcohol may actually improve chances of conceiving. A Danish study published in 2003 showing shorter time to pregnancy in couples trying to conceive (1) to many studies showing longer time to conception, poor outcomes with fertility care options, and increased miscarriage with moderate to heavy alcohol use (2,3). So what’s okay? Since no one knows how much is too much – the most conservative recommendation is no alcohol when trying to conceive. The worst outcomes are seen with daily alcohol use and binge drinking (more than 5 drinks in one day), so it’s recommended to avoid that. Enjoying a drink or two occasionally while trying to conceive is likely okay, but with all the different recommendations, it’s best to talk to your doctor about your personal situation.  

Marijuana is often thought of as a safe, ‘natural’ way to unwind and relax. My patients often point out that since it’s prescribed by doctors for pain and nausea in cancer patients and comes from plants, it must be okay to use while trying to conceive, right? Unfortunately, the research indicates poor fertility with regular marijuana/cannabis/THC use. This chemical has been associated with poor sperm parameters, male factor fertility issues, decreased success rates with assisted reproductive treatment, and poor pregnancy outcomes like miscarriage, low birth weight, and more (4-6). No study suggests a safe amount or usage for marijuana while trying to conceive. Therefore, I do not recommend my patients use it. If you are using marijuana for a medical purpose – talk to your doctor about your personal situation while trying to conceive.  

Caffeine is controversial in fertility, but strong evidence supports limiting or even stopping in pregnancy. Many people love their cup of coffee in the morning or sodas throughout the day. They get conflicting recommendations from loved ones, Dr. Google, and healthcare providers about caffeine intake while trying to conceive. The majority of research does not show an impact of caffeine on sperm parameters, success with fertility care, or time to pregnancy. Research does show a high intake of caffeine (more than 250 mg a day) in early pregnancy can be associated with increased miscarriage risk (7). Talk to your doctor about your options, but many will recommend limiting to one cup of coffee in the morning or switching to a lower caffeine option like green tea in pregnancy. Plus, once you do conceive, shifting to less caffeine won’t be as tough!

Growing your family is already stressful enough without worrying about all the little things that can change outcomes. I talk to my patients about focusing on overall health and well-being since optimizing your mental and physical health will improve your reproductive health. When it comes to vices like alcohol, marijuana, and caffeine - less is more for reproductive health, so choose wisely and talk to your doctor about your personal situation. See my YouTube videos on these topics for an in-depth discussion and research references.

Dr. Lora Shahine

Changemakers - ShahineDr. Lora Shahine, reproductive endocrinologist at Pacific NW Fertility and clinical faculty at the University of Washington in Seattle, completed her fellowship in reproductive endocrinology at Stanford University and residency in obstetrics and gynecology at the University of California in San Francisco. She is dedicated to educating and advocating for increased awareness of infertility, miscarriage, and the impact on environmental toxins on health through an active social media presence, teaching, clinical research, her books including best-selling, Not Broken: An Approachable Guide to Miscarriage and Recurrent Pregnancy Loss, and her podcast, Baby or Bust. Find her at drlorashahine.com and on Instagram, YouTube, TikTok, and Twitter.


  1. Tolstrup JS, et al. Alcohol use as predictor for infertility in a representative population of Danish women. Acta Obstet Gynecol Scand; 2003;82(8):744-9.
  2. Anwar, MY, etc. al. The association between alcohol intake and fecundability during menstrual cycle phases. Human Reproduction, Volume 36, Issue 9, September 2021, Pages 2538–2548.
  3. The association between alcohol intake and fecundability during menstrual cycle phases.
  4. Eggert, J et al. Effects of alcohol consumption on female fertility during an 18-year period. Fertile Steril 2004; 81:379-383.
  5. Gundersen TD, et al. Association Between Use of Marijuana and Male Reproductive Hormones and Semen Quality: A Study Among 1,215 Healthy Young Men. Am J Epidemiol. 2015 Sep 15;182(6):473-81.
  6. Pacey AA, et al. Modifiable and non-modifiable risk factors for poor sperm morphology. Hum Reprod 2014 Aug;29(8):1629-36.
  7. Mumford SL. Cannabis use while trying to conceive: a prospective cohort study evaluating associations with fecundability, live birth and pregnancy loss. Hum Reprod 2021; 20;36(5):1405-1415.
  8. Lyngso J, et al. Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose–response meta-analysis. Clin Epidem 2017; 9:699-719.

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