Does Caffeine Really Affect Fertility When Trying to Conceive?

Written by: Lauren Manaker, MS, RDN, LD

Edited by: Dr. Will Haas, MD, MBA

Last updated: September 27th, 2020

Reproductive-age woman with a cup of caffeinated coffee

From coffee to tea to kombucha, caffeine is found in many popular drinks…. And if you’re anything like us, it would be a huge sacrifice to give up that morning cup of Joe (#coffeeislife).  

However, the important question is – do you actually need to cut the caffeine when trying to conceive? 

Luckily, when we dug into the available data, you may be pleasantly surprised to learn that caffeine might not be as detrimental to your fertility as one would imagine.

But before you reach for your third cup of coffee or your second soda of the day, there are some important things you should know.

Why Caffeine Causes Reason for Concern

One of the biggest reasons the American College of Obstetrics and Gynecology suggests limiting caffeine intake to < 200 mg/day is the associated risk of higher levels of intake with an increased risk for miscarriage. 

Data from pulled together from over 25 studies suggest that caffeine consumption of 300 mg/day is associated with a 37% increased risk for spontaneous abortion. When this amount increases to 600 mg/day, the risk increases 2.5 fold compared to no caffeine intake. 

When looking into the matter more closely, it appears that some women may be more susceptible to the impacts of caffeine when it comes to maintaining a pregnancy.

Based on the results of a case-control study (the study that compares 2 different groups to one another), it appears that women with a certain genetic polymorphism (CYP1A2) are more likely to experience recurrent pregnancy loss (RPL) than those without this gene mutation. 

Now for those of you wondering about caffeine before pregnancy, a study published in Lancet back in 1998 initially created a lot of negative buzz over caffeine’s impact on fertility. In that study, women who consumed more than one cup of coffee per day were half as likely to conceive as those who drank less. 

Of course, as you know, the results from one study should not lead us to a definitive conclusion.

Bottom line: caffeine can have a negative impact on your reproductive efforts once pregnant, but there’s more to consider surrounding its effect on your initial efforts to conceive.

What the Current Fertility Research Reveals

When reviewing the evidence surrounding caffeine and fertility, it’s helpful to break things down according to the impact on couples trying to conceive naturally versus couples undergoing fertility treatment. 

Trying to conceive naturally 

In the same meta-analysis we referenced regarding spontaneous abortion risk, researchers failed to find an association between caffeine consumption and fertility outcomes. Additionally, no clear connection was found between caffeine and time to pregnancy.

In a separate prospective study of over 7000 women, neither the consumption of caffeine nor the relative amount consumed affect those who were diagnosed with primary infertility.  

Similar findings were also noted in another prospective study of over 18,000 women without a prior history of infertility. In this study, researchers noted that caffeine consumption “did not impair ovulation to the point of decreasing fertility.”  

Trying to conceive with fertility treatments 

During the past decade, the use of assisted reproductive technologies (ART) has increased worldwide. Luckily for us, the research investigating modifiable lifestyle factors (such as caffeine intake) and ART outcomes has grown too. 

A recent review article summarized the impact of caffeine intake on reproductive outcomes from women undergoing ART.  Of the five epidemiologic studies that focused on caffeine intake and ART outcomes, only one study found a significant negative effect of caffeine intake on live birth following ART. The other studies in the review did not identify any negative effects that caffeine places on fertility outcomes among women undergoing ART. 

Additional data echoes the conclusion that moderate caffeine intake by women in the year prior to ART has not been associated with negative outcomes. 

There is one study that’s somewhat interesting and stands out. When researchers looked at a group of 1,708 women undergoing various fertility treatments (IVF/ICSI/IUI), coffee consumption did not seem to affect the chance of achieving a clinical pregnancy or live birth. Surprisingly, women treated with IUI who consumed coffee on a daily basis were more likely to achieve a clinical pregnancy and live birth compared to coffee abstainers. 

Important considerations about the research

Before you go off and change your caffeine consumption, it’s important to keep in mind that researching the impact of lifestyle choices is a little complicated. 

Why? 

Well, most of these studies are performed on data gathered from real-life situations. And as we know, real life is not black and white. Meaning, researchers could not control for everything women ate or drank or the accuracy of the information reported. 

Nevermind the fact that one person’s cup of coffee may look quite different from someone else’s and that the strength of the cup might vary as well. 

Bottom line: the current evidence regarding caffeine intake and fertility outcomes may not be as alarming as they were initially thought.

Choosing Your Caffeine Source Carefully

Although caffeine may not impact fertility outcomes as much as once thought, sugar-filled caffeinated beverages still pose reason for concern. 

Data suggests that higher intake of sugary soda is associated with lower total, mature, and fertilized oocytes and top-quality embryos after ovarian stimulation. 

Outcomes from one study found that when compared to women who those who abstained, women who consumed sugar-containing caffeinated beverages had on average:

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    1.1 fewer oocytes retrieved

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    1.2 fewer mature oocytes retrieved

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    0.6 fewer fertilized oocytes

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    0.6 fewer top-quality embryos

In the end, the authors conclude that sugary beverages, independent of their caffeine content, maybe a bigger threat to reproductive success than caffeine and caffeinated beverages without added sugar. 

If you’re reluctant to switch your soft drinks to another caffeine source, here’s another potentially motivating find for you… Researchers have found that women who drank ≥ 2 servings of tea per day were more likely to conceive than those who did not.

Caffeine and The Male Factor

For those of you willing to cut the caffeine, you might be wondering to yourself… “What about the man in this equation? Should he be cutting back on caffeine too?

Well, caffeine and male fertility appear to have an even bigger question mark. 

Since coffee is often lumped into the category of other bad habits like cigarette smoking and recreational drug use, it’s often recommended that men simply abstain from caffeine intake when trying to conceive.

However, data suggests that this sort of recommendation is not as clear cut as many would believe. Based on the results from a systematic review of 28 papers that included almost 20,000 men, here are some findings to consider:

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    Caffeine intake is associated with sperm DNA breaks, but not with other markers of DNA damage. 

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    Most semen parameters are not affected by caffeine intake, at least not from caffeine in coffee, tea and cocoa-containing drinks.

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    Caffeine of sugar-sweetened soda negatively impacts semen volume, sperm count, and sperm concentration.

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    Coffee drinking among men has been associated with prolonged time to pregnancy in some, but not all, studies.

The take-home message should be that blanket statements regarding caffeine and male fertility are not feasible at this time. Caffeine may play a role in some fertility parameters, but not all.

When it comes to caffeine consumption among men, what they should likely focus their attention on is reducing sugar-containing caffeinated beverages like soda or energy drinks. Similar to the data for women, caffeinated soda and energy drink intake are associated with reduced fecundability among males.

How to Spot Your Caffeine Consumption

When deciding whether or not to reduce your caffeine consumption, it’s first important to determine how much caffeine you’re actually consuming. 

Just how much caffeine is in a standard cup of coffee? How about that 12-ounce can of soda? 

Here are some basic estimates regarding the caffeine content of various beverages:

Coffee:

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    Brewed (8 oz.) = 95 – 200 mg

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    Regular instant (8 oz.) = 27 – 173 mg

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    Expresso (1 -2 oz.) = 45 – 75 mg

Tea:

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    Black tea, brewed (8 oz.) = 40 – 60 mg

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    Green tea, brewed (8 oz.) = 25 – 45 mg

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    Bottled ready-to-drink (8 oz.) = 5 – 65 mg

Soft drinks:

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    Coke (16 oz.) = 45 mg

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    Pepsi (16 oz.) = 45 mg

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    Dr. Pepper (12 oz.) = 41 mg

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    Mountain Dew, regular (12 oz.) = 54 mg

Examples of 200 mg of caffeine when trying to conceive

Make sure to take a close look at the caffeine content in your favorite beverages and tally up the total amount you consume throughout the day!

Final Thoughts

Regardless of all the buzz around the topic, caffeine intake while trying to conceive does not appear to be a bad culprit when trying to conceive. 

Hopefully, you picked up that the exception to caffeine consumption is sugary caffeinated beverages – those should most definitely be avoided. 

Otherwise, recommendations for caffeine intake should be made on a case-by-case basis. Women at-risk for miscarriage should definitely limit or avoid caffeine altogether. And once a confirmed pregnancy is established, following the expert guidelines keeping caffeine intake under 200 mg/day should be followed to limit any negative risk. 

And if you simply can’t kick your caffeine habit, try a half-caffeinated cup of coffee or a warm cup of herbal tea. These options may satisfy your craving without loading your body up with the stimulant you may be wanting to limit.

With Love & Empowerment,
Lauren Manaker, MS, RDN, LD
Whenever you’re ready... learn how to remove fertility-threatening foods from your diet so you too can increase your chances of getting pregnant without the confusion about what really matters.

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