Caffeine and posted an article today entitled Caffeine Linked to Miscarriage and Dad’s Habits Matter Too. The headline: “New Warning for Couples Trying to Conceive: Caffeine Linked to Miscarriage.” The headline alone will make anyone stop and take a look, especially those trying to conceive. This article can be frightening and I don’t think it has to be. Of course, it is always recommended to reduce caffeine consumption while trying to conceive as well as smoking and other habits but there seems to be some flaws in the study and the cause of alarm might not be as bad as is making it.

Noted in the the study conducted by the Longitudinal Investigation of Fertility and the Environment (LIFE), 501 couples from two states were enrolled in this study. From that group, 344 couples with singleton pregnancies were studied checking their smoking use, caffeine consumption, and multivitamin use from the weeks before they conceived (how many weeks was not listed) through the seventh week of pregnancy.

The study notes they performed a “hazard ratio;” which estimates that chances of a particular outcome during the study time frame. In this instance, caffeinated beverages were evaluated for the likelihood of pregnancy loss. The study states “a score greater than 1 indicates an increased risk for pregnancy loss each day following conception, and a score less than 1 indicates a reduced daily risk.

The results of the study? 98 of the 344 pregnancies ended in miscarriage. That’s a rate of 28%. Yet the normal miscarriage rate is 10-25%. After reading those differences, one might think that the statement “caffeine use leads to miscarriage” is actually correct but there was something else performed in the study which makes a difference.

Women were advised to take regular pregnancy tests. This indicates that women would know they were pregnant sooner than the normal population. Because the gestational ages of the embryo/baby were not listed, we have no idea of knowing if the majority were chemical pregnancies or pregnancies after seeing a heartbeat. So statistically, women and their partners who drink more than three caffeinated beverages per day are at the same risk of miscarriage as couples who don’t. 

I will be the first to say that I am not a statistician or a doctor. I am not trained to analyze studies but the statements implied within can be very damaging to couples, especially women who already tend to hold immense guilt over not being able to sustain a pregnancy. Is the media jumping onto something else to scare women?

But wait! The study found a hazard ratio of 1.98. “For the preconception period, miscarriage was associated with female age of 35 or above, for a hazard ratio of 1.96 (nearly twice the miscarriage risk of younger women).” Yet the authors of the study and the media are reporting that caffeine consumption increases miscarriage risk. Is this for the entire childbearing population or just for women over 35?

A dangerous statement lies within this study. “The study was not designed to conclusively prove cause and effect.” Wait, so more than three caffeinated beverages may NOT cause pregnancy loss after all?


UltrasoundThe study then states, “The study authors cited possible explanations for the higher risk, including advanced age of sperm and egg in older couples or cumulative exposure to substances in the environment, which could be expected to increase as people age.” The study discusses that women over 35 are at a greater risk of miscarriage.

This might bring you to wonder, what were the age groups of the study participants? Those were not listed. Were partners close in age or was one significantly older than the other? What other environmental factors could be present? The above statement sounds like the authors are referring to “advanced maternal age” which has already been studied and women in this category are at an increased risk of miscarriage.

Furthermore, the type of caffeinated beverage was not listed nor the amount of caffeine in those beverages. This can make a significant difference. Someone who drinks green tea (25mg) for instance, will not consume as much caffeine as someone who drinks Monster energy drinks (160mg); 75mg vs. 480mg respectively. A comprehensive list of caffeine content can be listed here.

Two earlier studies had different outcomes. One study in the American Journal of Obstetrics and Gynecology found that women who consumed 200mg or more daily were twice as likely to miscarry and those who didn’t and a study in Epidemiology, found there was no increase in miscarriage of women who consumed between 200-350mg of caffeine daily.

When trying to find a “causative” factor for miscarriage and actually link caffeine to miscarriage, it is important to know if any of the embryos/babies/products of conception were tested? The part of the study I was able to access did not state that. So how many of these miscarriages were due to genetic/chromosomal abnormalities?

Were these healthy babies that were spontaneously aborted because of caffeine consumption? Could caffeine have caused the genetic/chromosomal abnormality? What about the placenta? Did caffeine directly affect growth of the placenta or blood flow to the embryo/baby? These are all valid questions and there are many more that I know others would want answers to. 

So what are couples to do? It’s best to avoid caffeine…to be on the safe side. Caffeine consumption doesn’t cause miscarriage, it may increase the risk and it may not but by no means does it cause miscarriage.

My final question and concern is about the couples in the study, especially the women. Were they counseled? What kind of support did they receive during and after their miscarriage? That’s 98 women and their partners who were affected. How might they feel after the study results came out indicating that pregnancy loss may have occurred due to their and/or their partners caffeine consumption?

This is a very concerning study and the way the media is portraying this can be extremely harmful. Talk with your care providers. Estimate the risks and the benefits. Make a decision that is best for you and your family. If you are addicted to caffeine, meaning, you will have severe headaches if you stop cold turkey, there are other options. Reduce your caffeine intake every few days. The medications you take to combat the headache can be more risky than the caffeine consumption.

NOTE: The study concludes with information on how to reduce risk of miscarriage by taking a multivitamin with folic acid. The B vitamin can help reduce miscarriage. When researching multivitamins, be sure to research folic acid vs. folate. There is a difference and one may make a significant difference in your risk of miscarriage, especially if you have a blood disorder such as MTHFR.

Only those with professional medical subscriptions can access the full details of the study but with the limited information released and the media jumping on the scare-tactic bandwagon, we can only be left to believe that the study is flawed.