• Contact us
• About us
• A-Z topics
• Symptom Checker
• Service Finder
• Linking to us
• Information partners
• Terms of use
• Privacy

Pregnancy, Birth and Baby is funded by the Australian Government and operated by Healthdirect Australia.

Pregnancy, Birth and Baby is provided on behalf of the Department of Health

Pregnancy, Birth and Baby’s information and advice are developed and managed within a rigorous clinical governance framework. This website is certified by the Health On The Net (HON) foundation, the standard for trustworthy health information.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

This information is for your general information and use only and is not intended to be used as medical advice and should not be used to diagnose, treat, cure or prevent any medical condition, nor should it be used for therapeutic purposes.

The information is not a substitute for independent professional advice and should not be used as an alternative to professional health care. If you have a particular medical problem, please consult a healthcare professional.

Except as permitted under the Copyright Act 1968, this publication or any part of it may not be reproduced, altered, adapted, stored and/or distributed in any form or by any means without the prior written permission of Healthdirect Australia.

Support this browser is being discontinued for Pregnancy, Birth and Baby

Support for this browser is being discontinued for this site

• Internet Explorer 11 and lower

We currently support Microsoft Edge, Chrome, Firefox and Safari. For more information, please visit the links below:

• Chrome by Google
• Firefox by Mozilla
• Microsoft Edge
• Safari by Apple

You are welcome to continue browsing this site with this browser. Some features, tools or interaction may not work correctly.

Moderate daily caffeine intake during pregnancy may lead to smaller birth size

You are here

Home » News & Events » News Releases

News Release

Thursday, March 25, 2021

Pregnant women who consumed the caffeine equivalent of as little as half a cup of coffee a day on average had slightly smaller babies than pregnant women who did not consume caffeinated beverages, according to a study by researchers at the National Institutes of Health. The researchers found corresponding reductions in size and lean body mass for infants whose mothers consumed below the 200 milligrams of caffeine per day — about two cups of coffee — believed to increase risks to the fetus. Smaller birth size can place infants at higher risk of obesity, heart disease and diabetes later in life.

The researchers were led by Katherine L. Grantz, M.D., M.S., of the Division of Intramural Population Health Research at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development. The study appears in JAMA Network Open.

“Until we learn more, our results suggest it might be prudent to limit or forego caffeine-containing beverages during pregnancy,” Dr. Grantz said. “It’s also a good idea for women to consult their physicians about caffeine consumption during pregnancy.”

Previous studies have linked high caffeine consumption (more than 200 milligrams of caffeine per day) during pregnancy to infants being small for their gestational age (stage of pregnancy) or at risk for intrauterine growth restriction—being in the lowest 10th percentile for infants of the same gestational age. However, studies on moderate daily caffeine consumption (200 milligrams or less) during pregnancy have produced mixed results. Some have found similar elevated risks  for low birth weight and other poor birth outcomes, while others have found no such links. The current study authors noted that many of the earlier studies did not account for other factors that could influence infant birth size, such as variation in caffeine content of different beverages and maternal smoking during pregnancy.

For their study, the authors analyzed data on more than 2,000 racially and ethnically diverse women at 12 clinical sites who were enrolled from 8 to 13 weeks of pregnancy. The women were non-smokers and did not have any health problems before pregnancy. From weeks 10 to 13 of pregnancy, the women provided a blood sample that was later analyzed for caffeine and paraxanthine, a compound produced when caffeine is broken down in the body. The women also reported their daily consumption of caffeinated beverages (coffee, tea, soda and energy drinks) for the past week—once when they enrolled and periodically throughout their pregnancies.

Compared to infants born to women with no or minimal blood levels of caffeine, infants born to women who had the highest blood levels of caffeine at enrollment were an average of 84 grams lighter at birth (about 3 ounces), were .44 centimeters shorter (about .17 inches), and had head circumferences .28 centimeters smaller (about .11 inches).

Based on the women’s own estimates of the beverages they drank, women who consumed about 50 milligrams of caffeine a day (equivalent to a half cup of coffee) had infants 66 grams (about 2.3 ounces) lighter than infants born to non-caffeine consumers. Similarly, infants born to the caffeine consumers also had thigh circumferences .32 centimeters smaller (about .13 inches).

The researchers noted that caffeine is believed to cause blood vessels in the uterus and placenta to constrict, which could reduce the blood supply to the fetus and inhibit growth. Similarly, researchers believe caffeine could potentially disrupt fetal stress hormones, putting infants at risk for rapid weight gain after birth and for later life obesity, heart disease and diabetes.

The authors concluded that their findings suggest that even moderate caffeine consumption may be associated with decreased growth of the fetus.

About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): NICHD leads research and training to understand human development, improve reproductive health, enhance the lives of children and adolescents, and optimize abilities for all. For more information, visit https://www.nichd.nih.gov.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih. gov.

NIH…Turning Discovery Into Health^®

References

Gleason, JL et al. Maternal caffeine consumption and metabolism and neonatal anthropometry in the NICHD Fetal Growth Studies. JAMA Network Open. 2021. doi:10.1001/jamanetworkopen.2021.3238

###

Connect with Us

• Contact Us
• Twitter
• Facebook
• Instagram
• YouTube
• Flickr

Effects of restricted maternal caffeine intake on pregnancy, fetal and newborn outcomes

Caffeine is a stimulant found in tea, coffee, cola, chocolate and some over-the-counter drugs. Conflicting literature has made it difficult for health professionals to advise pregnant women on whether caffeine intake should be avoided during pregnancy. The clearance of caffeine from the mother's blood (clearance of caffeine from the blood) is slowed down during pregnancy. Some authors of observational studies have concluded that caffeine intake is harmful to the fetus, causing growth restriction, low birth weight, preterm labor, or stillbirth. The newborn may also experience withdrawal symptoms if the mother consumes large amounts of caffeine during pregnancy (more than eight cups of coffee per day). nine0003

Two studies met the inclusion criteria, but only one contributed data to the outcomes of interest for the review. The study was conducted in Denmark. Women less than 20 weeks pregnant were randomized to either caffeinated instant coffee (568 women after elimination) or decaffeinated instant coffee (629 women). Three cups of coffee per day in early pregnancy had no effect on birth weight, preterm birth, or growth restriction. nine0003

Both included studies were randomized controlled trials. In one study, pregnant women were randomly assigned to caffeinated or non-caffeinated groups. In another clinical trial, it was not clear if the allocation to study groups was blinded [hidden]. The blinding of study staff and participants was satisfactory in both studies, while blinding of investigators evaluating outcomes was not clearly stated. One study also unclearly explained the presence of attrition bias (dropouts, loss of patients from follow-up). Results from one trial that provided data for analysis showed no evidence of an effect of caffeine withdrawal on outcomes such as birth weight, preterm birth, and small-for-gestational age [gestational age]. nine0003

Two outcomes were assessed and assigned a quality rating using the GRADE methodology. The quality of the evidence for these two outcomes, namely birth weight and preterm birth rate, was rated as low, with downward decisions due in part to the relatively small sample sizes and wide confidence intervals of the single included trial that contributed data to this review.

There is insufficient evidence to confirm or refute the effectiveness of avoiding caffeine intake on birth weight and other pregnancy outcomes. nine0003

Translation notes:

Translation: Yudina Ekaterina Viktorovna. Editing: Ziganshina Lilia Evgenievna. Russian translation project coordination: Kazan Federal University - an affiliated center in Tatarstan of the Northern Cochrane Center. For questions related to this translation, please contact us at: [email protected]

Coffee during pregnancy: a complete guide to all the do's and don'ts

When a woman sees "two lines" on her test, her life begins to change that same day. In this life, there are more good habits (timely sleep, proper nutrition, moderate exercise) and less bad habits (alcohol, smoking, sedentary lifestyle, unhealthy food). Coffee as a potentially dangerous product, around which there is a lot of controversy, often falls under the barrier of prohibitions. nine0003

Even without any pregnancy, coffee often raises a number of questions and concerns in people, so the debate around this drink is quite understandable and justified. But our task is to separate myth from reality and figure out when restrictions make sense and when they are a pointless obstacle to a fulfilling joyful lifestyle.

How does coffee affect the body of a pregnant woman?

Before talking about some special effect of coffee on a pregnant woman, let's refresh our memory of what actually happens to us when we drink coffee:

• After caffeine enters the blood, dopamine is released, which, as we remember, is responsible for a good mood. This hormone of joy very willingly “jumps out” in response to a shot of espresso or cappuccino and makes us feel good.
• Under the influence of dopamine, it is easier for us to play sports, we become more enduring and notice less pain in the muscles. It also improves overall performance.
• If there is too much caffeine (read - dopamine), the suppression of serotonin production begins. This leads to increased anxiety and can provoke depression. nine0028
• In parallel, under the influence of caffeine, adrenaline is released, another hormone that is responsible for our good mood and cheerfulness.
• Increased concentration.
• In most cases, coffee stimulates our heart to beat faster. The rhythm of the heartbeat accelerates and at the same time the pressure rises.
• The theophylline contained in coffee acts on the intercostal muscles and muscles of the diaphragm, as a result of which our breathing becomes more relaxed and easy. nine0028
• The excretory systems (diuretic and intestines) are stimulated – under the influence of caffeine, we feel the desire to visit the restroom faster.
• Caffeine also stimulates the nervous system. The peak of this action occurs in the first hour or two after drinking coffee, then for an average of 3-4 hours the breakdown of caffeine in the blood occurs, at which time many people have difficulty falling asleep.

What changes when a pregnant woman drinks coffee? In addition to the above phenomena, the following important parameters should be additionally indicated:

• slows down the process of removing caffeine from a woman's body;
• increased fetal heart rate;
• increased fetal activity;
• Excessive use creates possible risks for the child.

It is the last item on this list that is cause for concern and doubt about the admissibility of coffee in the diet of a pregnant woman. Below we describe in detail what these risks are and in what cases concerns can be justified. nine0003

Can pregnant women drink coffee?

Let's start with a high-profile peer-reviewed study published in the BMJ Evidence-Based Medicine. Professor Jack James from Reykjavik University in Iceland conducted a series of studies in 2020 and concluded that there is no safe level of caffeine intake for pregnant women: even the smallest amount can negatively affect the development of the fetus. However, Mr. James' colleagues from other countries categorically disagree with him. The National Health Service, the European Food Safety Authority, and the American and British Colleges of Obstetricians and Gynecologists recommend limit but not eliminate caffeine intake during pregnancy . The research paper was deemed "too panicky" and inconsistent with the accepted evidence.

“There are so many do's and don'ts associated with pregnancy, and the last thing we want to do is cause unnecessary worry. After all, women need to be sure that caffeine can be consumed in moderation during pregnancy,” says Dr. Luc Grzeskowiak, a pharmacist at the University of Adelaide in Australia. nine0068