Can drinking coffee during pregnancy really affect the child? A new study found that children who were exposed to caffeine in the womb tend to be shorter than their non-exposed peers.

Caffeine has been one of those no-nos during pregnancy. Even if it's just in "modest amounts," consuming it while pregnant has been associated with lower birth rates, the researchers noted in their study, published Monday in JAMA Network Open.

"Given that approximately 8 in 10 US pregnant women consume caffeine, it is important to determine whether in utero caffeine exposure has long-term growth implications in offspring," they wrote.

To look into the possible impact of caffeine consumption on child growth, the researchers analyzed two previous studies that involved 2,400 pregnant women, the National Institutes of Health (NIH) noted in a news release.

Indeed, they found that the children who were born to women "with low measured caffeine and paraxanthine during pregnancy" were a little shorter than their peers whose mothers had no caffeine consumption. Paraxanthine is a caffeine breakdown product, noted the NIH.

The gaps even increased from age four to age eight. The association with decreases in child height was observed "even with maternal consumption below current recommendations of 200 mg day," noted the researchers.

In other words, the height difference was observed even if the caffeine consumption was in small amounts.

"Although the clinical implications are unclear for relatively small observed differences, these findings suggest that small amounts of daily maternal caffeine consumption are associated with shorter stature in their offspring that persist into childhood," they wrote.

Consumption of less than 200 mg is about the amount of caffeine in one 12-ounce cup of coffee, noted The American College of Obstetricians and Gynecologists (ACOG). For instance, a mug of instant coffee has about 100 mg of caffeine, while a mug of filtered coffee has 140 mg, according to the Cleveland Clinic.

It's also worth noting that other foods and beverages such as chocolate, tea and soda may also contain caffeine.

The researchers clarified that these height differences they found were "small." It also remains to be seen whether it has an impact on the child's health, or if it persists into adulthood.

"To be clear, these are not huge differences in height, but there are these small differences in height among the children of people who consumed caffeine during pregnancy," one of the leads of the study, Jessica Gleason of the NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development, said as per CNN.

Gleason clarified that there is no reason for families to panic over these results.

"(F)urther research is needed to determine if these differences have any effects on child health," said the other study lead, Katherine Grantz, as per NIH. "Pregnant people should discuss caffeine consumption with their healthcare providers."

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