Health knowledge and news provided by doctors.

Caffeine May Be a Cause of Small Babies, Says Study

Tim Boyer's picture
Fetus Life

According to a recent study published in the open access online journal BMC Medicine, researchers have uncovered a link between caffeine consumption and small babies that is leading health experts to reconsider just how much coffee is safe for a woman’s fetus during pregnancy.


According to the study’s authors, growing epidemiological evidence demonstrates that what a pregnant mother eats and drinks during a pregnancy can have significant impact on growth and development in-utero as well as affect the risk of disease later in the newborn’s life.

One common myth of pregnancy is that the placenta is likened to a very selective barrier that protects the developing fetus from harmful substances, while at the same time ensuring that needed and necessary nutrients make it past the placental barrier to nourish the fetus.

However, according to an article published by Fit Pregnancy, this is not necessarily always true and that in fact, many noxious substances that mom either ingests or is exposed to make it to the fetus as well:

“When researchers examined the umbilical cord blood of 10 U.S. babies born in August and September 2004, they found a total of 287 industrial chemicals. Of those, 180 were carcinogens; 217 were toxic to the brain. ‘Numerous environmental contaminants can cross the placental barrier,’ a National Institutes of Health report noted. ‘To a disturbing extent, babies are born pre-polluted.’”

The authors of the study report that caffeine is a xanthine alkaloid found primarily in coffee, tea, cocoa, energy drinks and some soft drinks that can pass through the placental barrier freely. Furthermore, we are told that because the fetus does not express the enzymes needed to inactivate caffeine, that it and its metabolites have been found to accumulate in the fetal brain and that some officials believe that this bathing of a fetal brain in caffeine may be more harmful than previously believed.

Currently, the World Health Organization (WHO) guidelines recommend keeping caffeine consumption down to below 300 milligrams per day during pregnancy, while the American College of Obstetricians and Gynecologists recommends a maximum caffeine intake of 200 milligrams per day.

Depending on how you get your caffeine, the number of cups of coffee, tea or soda allowable by those standards can vary. The following is a listing of how much caffeine is present in 7 and 12 ounces of various preparations of coffee and tea respectively:

• Coffee, drip 115-175 mg
• Coffee, brewed 80-135 mg
• Coffee, instant 65-100 mg
• Coffee, decaf, brewed 3-4 mg
• Coffee, decaf, instant 2-3 mg
• Coffee, espresso 100 mg of caffeine 1 serving (1.5-2oz)
• Tea, iced 70 mg
• Tea, brewed, imported 60 mg
• Tea, brewed, U.S. 40 mg
• Tea, instant 30 mg

Follow eMaxHealth on YouTube, Twitter and Facebook.
Please, click to subscribe to our Youtube Channel to be notified about upcoming health and food tips.

Therefore, in some cases as little as 1-2 cups per day can meet or exceed the recommended dose allowed per day during a pregnancy.

With a focus on prenatal development, the authors of the paper designed a study with the aim of examining the relationship between maternal caffeine intake and affected prenatal growth from different sources of caffeine such as coffee, tea and chocolate using the parameters of:

1. Gestational length with emphasis on the risk toward spontaneous preterm delivery (PTD)
2. Birth weight (BW)
3. Baby being small for gestational age (SGA).

In the study, data gleaned from a total of 59,123 women with uncomplicated pregnancies giving birth to a live infant was utilized that included fetal measurements throughout the pregnancy using ultrasound and final physical measurements upon birth. Questionnaires given to the mothers during their pregnancies provided self-reported data regarding the amount of caffeine intake from all potential sources of caffeine including coffee, tea, sodas, cocoa-containing cakes, deserts and chocolate.

Using population-based and customized growth curve charts to rank the prenatal and birth development, what the researchers found was that caffeine from coffee (but not other sources) was associated with a prolonged gestation rather than preterm delivery (PTD). And, that caffeine from all sources during pregnancy is associated with a lower birth weight (BW) during development, which places a fetus at risk of being small for gestational age (SGA) at birth.

The clinical implications of these results is that because SGA babies are at higher risk for both short term and lifelong health problems and that their data shows that caffeine intake is associated with lower birth weight, that even the previously recommended 200-300mg caffeine per day of caffeine during pregnancy may need to be reevaluated by health officials to reduce the risk of small babies being born.

Image Source: Courtesy of Wikipedia


“Maternal caffeine intake during pregnancy is associated with birth weight but not with gestational length: results from a large prospective observational cohort study” BMC Medicine 2013, 11:42; Published: 19 February 2013; Verena Sengpiel, Elisabeth Elind, Jonas Bacelis, Staffan Nilsson, Jakob Grove, Ronny Myhre, Margaretha Haugen, Helle M Meltzer, Jan Alexander, Bo Jacobsson and Anne-Lise Brantsaeter.

Fit Pregnancy: “The Myth of the Placental Barrier”