If you are a coffee lover like me, then this question may have stopped you dead in your tracks. Does coffee cause infertility? The idea that your beloved morning latte or dirty chai may cause you to be infertile is a serious matter, and one that we are going to thoroughly explore. Because let’s be honest, it will take a lot of convincing to overpower our love, and possible addiction to coffee.
Caffeine is probably the most frequently ingested pharmacologically active substance in the world. It is found in common beverages (coffee, tea, soft drinks, energy drinks), in products containing cocoa or chocolate, and in medications. For most of us, drinking coffee is one of our favorite rituals and essential components to surviving our oh-so-busy lives. Because of this, it is one of the most researched substances. The problem is that the studies on caffeine, and more specifically coffee, are contradictory. One day drinking coffee prevents dementia and heart disease, and the next it causes miscarriages and anxiety. So what are we to think?
If you are pregnant, or are considering getting pregnant in the next year, then this debate is quite relevant for you and your spouse. That is because it has been estimated that 7.4% of women and their husbands in the United States are infertile and that the number of infertile people in the world may be as high as 15%. Therefore, we should do everything in our power to increase our chances of getting pregnant by supporting our reproductive system and fertility. Coffee and its active component caffeine may have an affect on your ability to get pregnant and to have a healthy child, so let’s learn more so we can make the best decision for ourselves. Does coffee cause infertility and is it safe to drink while pregnant?
The Connection with Caffeine and Fertility
When preparing to get pregnant, it’s time to start looking at our lifestyle choices and our diet. That’s because our food and lifestyle practices influence our fertility.
This is where coffee comes in. There have been many research studies focusing on caffeine in relation to pregnancy. Some say caffeine has no effect, and others say it can negatively influence your ability to get pregnant. Given the contradictory results on the reproductive effects of caffeine and the fact that caffeine is so widely consumed, its health benefits and consequences have been, and still are being studied extensively.
How does Coffee or Caffeine influence Fertility?
Scientists are still trying to nail down the exact mechanism, but it is thought that caffeine has several different effects on the functioning and regulation of our sex hormones. Here are a few of those mechanisms:
- Blood Sugar Balance – caffeine stimulates the adrenal glands, which causes the release of adrenalin hormones and glucose. This is where the buzz comes from. The regular ingestion of caffeine may cause a higher sensitivity to insulin levels increasing insulin resistance in the body. This can interrupt normal hormone function thus impacting reproductive health. It is believed that insulin resistance can reduce sperm production in men and hinder ovulation in women.*this is especially important for women who suffer from PCOS, low blood sugar or diabetes
- Fallopian Tubes – A women’s fallopian tubes carry the eggs from your ovaries to your uterus (womb). Typically the muscles in your fallopian tubes contract in smooth, rhythmic waves to move the egg to the uterus. It is believed that caffeine disrupts this rhythmic pattern of movement, preventing the egg from successfully reaching the uterus.
- Mineral loss – Coffee is a diuretic and increases the frequency of urine elimination. The more we urinate, the higher the chance of eliminating vital minerals. Minerals are essential for fertility in numerous ways. It is postulated that mineral deficiency caused by excessive coffee intake may be a reason why drinking coffee can cause infertility.
- Prevents Oocyte Maturation – oocytes are immature egg cells that are produced in the ovaries. Once fertilized by the sperm they go on to create a baby. Preliminary studies in mice and monkeys suggest caffeine inhibits oocyte maturation. An immature oocyte does not fertilize and therefore is unable to produce a pregnancy.
- Sperm Quality – countless studies show that caffeine may harm sperm at a molecular level. From sperm quality to sperm count, the consumption of caffeine (coffee) can inhibit healthy sperm and thus promote infertility in men.
Where is the Research?
The good news is that the scientific community wants to know the answer to whether coffee and caffeine causes infertility as much as we do. This is evidenced by the countless research studies performed on the matter. In fact, there are so many I could not even come close to going through them all. But this is a really good start. The following is a snippet of what you will find in terms of research on the subject. Some studies are specifically about coffee and fertility, and some expand more into the affects of caffeine once pregnant. If you want to delve in further, head down to the bottom of the page for references.
Study #1. The authors conclude that high levels of caffeine intake may delay conception among fertile women.
Study #2. According to the results obtained from this study, maternal caffeine consumption can disrupt male reproductive development and impair fertility at later stages of life. Our findings demonstrate that gestational and lactational exposure to caffeine has adverse effects on body and reproductive organ weight, testicular structure, epididymal sperm parameters including sperm motility, sperm count and sperm morphology, serum testosterone levels, and fertility of male offspring rats. Maternal caffeine consumption affects development of the reproductive system and has deleterious long-term effects on reproductive efficiency and fertility of male offspring in the peripubertal, postpubertal, and adulthood periods.
Study #3. In their subsequent cycles, women who consumed more than the equivalent of one cup of coffee per day were half as likely to become pregnant, per cycle, as women who drank less.
Study #4. In all, 28% of pregnant women consumed greater than or equal to 151 mg of caffeine daily, and these “moderate-to-heavy” caffeine users were significantly more likely to experience late first- or second-trimester spontaneous abortion when compared with nonusers and light users (0 to 150 mg).
Study #5. Taken together with studies reporting similar findings, these results suggest that heavy caffeine consumption increases the risk for fetal growth retardation.
Study #6. The risk of dyspermia (abnormality of sperm) increased with the number of cups of coffee drunk per day compared with men drinking no or one cup per day.
Study #7. Our results demonstrated that high doses of caffeine intake during pregnancy increase the risk of miscarriage, independent of pregnancy-related symptoms.
Study #8. Utero and lactational exposure to caffeine affects the reproductive function of the offspring of rats and found significant (caffeine) dose-related decreases in the body and reproductive organ weight, seminiferous tubule diameter, and germinal epithelium height of the offspring. The damage on testicles of the experimental animals was also demonstrated. Even the hormone level and semen quality would be affected by caffeine exposure which also induces adverse outcomes.
Study #9. Caffeine has been associated with an increase in the time to pregnancy of over 9.5 months, particularly if the amount is over 500 mg per day. The negative effects that are emphasized in recent research are miscarriage, spontaneous abortion, fetal death and still birth.
Study #10. High levels of caffeine intake (>500 mg per day; approximately >5 cups per day) may increase time to pregnancy, as reported by a 45% increased risk of subfecundity (≥9.5 months to conception) in first pregnancies in the European Study of Infertility and Subfecundity.
Study #11. Couples in which the man consumed the most caffeine (equivalent to three or more 8-ounce cups of coffee a day) were half as likely to have a pregnancy as couples where the male consumed the least caffeine (less than a cup of coffee daily), the researchers said.
What are the Proposed Risks of Caffeine for getting Pregnant and Pregnancy?
If you do not have the desire, or the capacity to read science talk, then here is the overview of how caffeine may prevent you from getting pregnant. Furthermore, it is very important to mention that caffeine not only affects fertility, but can also affect the fetus once pregnant. It has been confirmed that caffeine crosses the placenta.
- Decreases blood flow to uterus
- Interferes with implantation
- Increases time to pregnancy
- Increases risk of clotting
- Lowers sperm count
- Causes fetal growth impairment
- Leads to poor sperm quality
- Can cause a miscarriage, spontaneous abortion, fetal death and still birth
- Damage to testes, hormone levels and semen quality in male fetuses
- Long-term effects on reproductive efficiency and fertility of male offspring
As you can see there are many ways in which drinking caffeinated beverages like coffee can prevent you from getting pregnant. This is true not only for women, but for men as well. Also, it is very important to realize that there is a lot of research suggesting that drinking coffee WHILE pregnant is dangerous as well. From causing spontaneous abortions to negatively affecting the reproductive system of the fetus, the research indicates that drinking coffee while pregnant may not be the safest choice.
What about the Positive Side? No harm at all!
Now that we’ve reviewed all the ways in which caffeine and drinking coffee DOES affect pregnancy, let’s take a look at how it may NOT hurt after all. You will notice that the research for this position is far less abundant, and I will say that this is not a reflection of a personal bias.
Study #1. Though no association was seen between coffee or tea consumption and pregnancy rate, this study is the first to report that caffeine can reach the follicular fluid and there is a suggestive evidence of its possible harmful role on the consequences of reproductive process.
Study #2. No significant association was found for any of the caffeinated beverages except tea. Drinking one-half cup or more of tea daily approximately doubled the odds of conception per cycle.
Study #3. The evidence for an effect of caffeine on reproductive health and fetal development is limited by the inability to rule out plausible alternative explanations for the observed associations, namely confounding by pregnancy symptoms and smoking, and by exposure measurement error. Because of these limitations, the weight of evidence does not support a positive relationship between caffeine consumption and adverse reproductive or perinatal outcomes.
Study #4. Two large studies have been performed to assess the relationship between caffeine intake and preterm birth. A randomized double-blind controlled trial of caffeine reduction in 1,207 women evaluated birth data for 1,153 singleton live births (6). An average intake of 182 mg per day of caffeine did not affect length of gestation. Additionally, a prospective, population-based cohort study conducted by Clausson et al evaluated the effect of caffeine consumption on gestational age at delivery in 873 singleton births (7). Again, no association was found between caffeine and preterm birth. Consequently, it does not appear that moderate caffeine intake is a contributor to preterm birth.
What Should we Do? Coffee or No Coffee?
Although studies have come up with very mixed results, most come to the conclusion that there’s a negative link between caffeine and fertility on some level. So the answer to the question of “does coffee cause infertility” is yes, most likely. Caffeine has been found to affect the ability to both conceive and to nurture an embryo. Based on that information, I would take the stance that it is best to avoid coffee and caffeine when pregnant and trying to conceive. With most studies indicating that the effects of caffeine are related to amount of caffeine consumed, it would be wise for women contemplating pregnancy to limit caffeine consumption all together.
An important thing to note is that the amount of caffeine that causes negative effects is not clear. In some studies over 2 cups a day of coffee is damaging, and in others it is 3-5 cups. Therefore, there cannot be a clear recommendation to whether 1 cup a day of coffee is safe. In my opinion, if you are not sensitive to caffeine and do not have any issues with hormone imbalance or blood sugar balance then 1 cup a day while trying to conceive is safe. While I say that, I am a person that loves to err on the side of caution, so I would rather ditch the coffee and not take risk. But that is not to say that countless women have both conceived and birthed healthy babies while drinking coffee.
Why is it not Conclusive Then?
I know it seems like all the evidence points in the direction that coffee causes infertility and negatively impacts pregnancy, but there can be flaws in the research. This is why the question is still being studied.
That’s in part because there are so many factors at play in these kinds of observational studies. People often make choices that are paired together and can be difficult to separate, even with the help of statistics. That makes it hard to prove that one particular choice is causing one particular outcome. To make this concept more clear, here is an example: Let’s say we are studying a group of people who drink green smoothies but also do yoga regularly and take supplements. So if you were studying how yoga relates to cancer risk, you would be likely to determine that yoga prevents cancer. But it’s far more plausible that the green smoothie-drinkers’ supplement use is the main driver that prevents cancer, and that doing yoga may have nothing to do with cancer prevention at all. But then again, we cannot be sure. This is how these studies end up having different conclusions to the same question.
As for the connection between caffeine and pregnancy, the demographics studied usually have certain behaviors in common. For example, a number of studies have shown that women who consume a lot of caffeine while pregnant are also more likely to drink alcohol and to smoke. And it has been concluded that smoking and drinking alcohol are, of course, also tied to miscarriage risk. Therefore, what is actually causing the miscarriage? The coffee, the alcohol or the smoking?
I want to quit coffee but how?
I get you. I tried quitting coffee about five or six times, and it wasn’t until this last time did it really stick. And by I mean stick, I mean that I no longer drink it everyday in the morning, but sometimes on occasion have a small cup. To me this is success (no one said we had to be PERFECT).
The best way to get off coffee is to taper off, and then to replace it with a different warm beverage. For most of us the addiction is more about the experience of drinking the coffee than the coffee itself. That is why finding a good replacement is the key to quitting.
The first thing to do is to drink less. Each day, or every few days, back off by a quarter cup. You can add extra milk, or even a coffee replacement to the coffee. This way you are getting used to less caffeine. The following are my favorite coffee replacements. Remember the goal is to drink less caffeine, but that does not mean you cannot have any at all. For example, green tea matcha has caffeine, but not nearly as much as a cup of coffee. Research indicates that a small amount may be safe, so strive for less. To figure out how much caffeine is in energy drinks, sodas, coffee and caffeinated foods go HERE, but on average, a cup of coffee (8 oz.) contains 135 mg.
- Matcha Chai by Onnit (has the caffeine equivalent of 1/4 c of coffee)
- Herbal Coffee by Teeccino
- Herbal Tea
- Warm lemon water with honey
- Superfood Lattes by The First Mess
I hope that this gives you some inspiration and motivation to make the switch. To be honest, I actually love drinking my Matcha Chai even more than I did coffee. Overall I feel that my energy is better (more sustained throughout the day), I sleep more soundly, and my head is clearer. Plus, the Matcha Chai has so many health benefits including antioxidants from matcha tea to protect against toxins, and turmeric to lower inflammation and fight disease. Even more to feel happy about!
Med Sci Monit. 2010 Dec;16(12):CR598-605. The effect of caffeine consumption on the success rate of pregnancy as well various performance parameters of in-vitro fertilization treatment. Al-Saleh I1, El-Doush I, Grisellhi B, Coskun S.
Am J Epidemiol. 1997 Feb 15;145(4):324-34. Caffeine intake and delayed conception: a European multicenter study on infertility and subfecundity. European Study Group on Infertility Subfecundity. Bolúmar F1, Olsen J, Rebagliato M, Bisanti L.
Clin Exp Reprod Med. 2012 Dec; 39(4): 144–152. Published online 2012 Dec 31. doi: 10.5653/cerm.2012.39.4.144 Maternal caffeine consumption has irreversible effects on reproductive parameters and fertility in male offspring rats Mehran Dorostghoal, 1 Naeem Erfani Majd,2 and Parvaneh Nooraei1
Lancet. 1988 Dec 24-31;2(8626-8627):1453-6. Caffeinated beverages and decreased fertility. Wilcox A1, Weinberg C, Baird D.
Am J Obstet Gynecol. 1986 Jan;154(1):14-20. Caffeine consumption during pregnancy and association with late spontaneous abortion. Srisuphan W, Bracken MB.
Am J Public Health. 1991 Apr;81(4):458-61. Caffeine consumption during pregnancy and fetal growth. Fenster L1, Eskenazi B, Windham GC, Swan SH.
Arch Androl. 1993 Sep-Oct;31(2):105-13. Risk factors for unexplained dyspermia in infertile men: a case-control study. Parazzini F1, Marchini M, Tozzi L, Mezzopane R, Fedele L.\Am J Public Health. 1998 February; 88(2): 270–274. Differences in fertility associated with caffeinated beverage consumption. B Caan, C P Quesenberry, Jr, and A O Coates
Am J Obstet Gynecol. 2008 Mar;198(3):279.e1-8. doi: 10.1016/j.ajog.2007.10.803. Epub 2008 Jan 25. Maternal caffeine consumption during pregnancy and the risk of miscarriage: a prospective cohort study. Weng X1, Odouli R, Li DK.
Cao H, Ren J, Feng X, Yang G, Liu J. Is caffeine intake a risk factor leading to infertility? A protocol of an epidemiological systematic review of controlled clinical studies. Systematic Reviews. 2016;5:45. doi:10.1186/s13643-016-0221-9.
Sharma R, Biedenharn KR, Fedor JM, Agarwal A. Lifestyle factors and reproductive health: taking control of your fertility. Reproductive Biology and Endocrinology : RB&E. 2013;11:66. doi:10.1186/1477-7827-11-66.
Ruder EH, Hartman TJ, Goldman MB. Impact of oxidative stress on female fertility. Current opinion in obstetrics & gynecology. 2009;21(3):219-222.
Food Chem Toxicol. 2010 Oct;48(10):2549-76. doi: 10.1016/j.fct.2010.06.019. Epub 2010 Jun 15. A review of the epidemiologic evidence concerning the reproductive health effects of caffeine consumption: a 2000-2009 update. Peck JD1, Leviton A, Cowan LD.
American College of Obstetricians and Gynocologists. Number 462. August 2010. Moderate Caffeine Consumption During Pregnancy.