Evidence is building that caffeine should be avoided during pregnancy because it harms the developing baby. A recent study found when caffeine (coffee!) is consumed during pregnancy, then structural changes occur in the brain of the developing baby. These changes can be seen years later in brain scans, and these appear to result in behavioral changes in the children. The minimal, but noticeable behavioral changes were behavioral issues, attention difficulties, and hyperactivity.
The Univ. of Rochester School of Medicine and Dentistry researchers found subtle changes in brain pathways ("alteration of the microstructure of critical fiber tracts") between brain regions that could be seen in the children at age 9 to 10 years. They analyzed brain scans (from MRIs) of 9157 children, of which 4,135 had mothers that reported consuming caffeine more than once a week.
Other studies find that health problems associated with caffeine (coffee) intake during pregnancy are miscarriage, stillbirth, low birth weight and/or small for gestational age, and childhood leukemia. There is a dose-response effect - the more caffeine is ingested, the more negative health effects.
Other human studies looking at this issue are observational, but negative health effects are supported by animal research going back more than four decades. Caffeine crosses the placenta and goes to the baby. Negative health effects occur because the fetus can not clear the caffeine well because it lacks an enzyme that metabolizes caffeine.
Unfortunately, medical guidelines in both the US and Europe are that moderate (up to 200 mg) ingestion of caffeine during pregnancy is OK, which means about 2 cups of regular coffee a day. Since studies show it's not OK, it's time to revise the guidelines!
From Science Daily: Brain changed by caffeine in utero
New research finds caffeine consumed during pregnancy can change important brain pathways that could lead to behavioral problems later in life. Researchers in the Del Monte Institute for Neuroscience at the University of Rochester Medical Center (URMC) analyzed thousands of brain scans of nine and ten-year-olds, and revealed changes in the brain structure in children who were exposed to caffeine in utero.
"These are sort of small effects and it's not causing horrendous psychiatric conditions, but it is causing minimal but noticeable behavioral issues that should make us consider long term effects of caffeine intake during pregnancy," said John Foxe, Ph.D., director of the Del Monte Institute for Neuroscience, and principal investigator of the Adolescent Brain Cognitive Development or ABCD Study at the University of Rochester. "I suppose the outcome of this study will be a recommendation that any caffeine during pregnancy is probably not such a good idea."
Elevated behavioral issues, attention difficulties, and hyperactivity are all symptoms that researchers observed in these children. "What makes this unique is that we have a biological pathway that looks different when you consume caffeine through pregnancy," said Zachary Christensen, a M.D/Ph.D. candidate in the Medical Science Training Program and first author on the paper published in the journal Neuropharmacology.
Investigators analyzed brain scans of more than 9,000 nine and ten-year-old participants in the ABCD study. They found clear changes in how the white matter tracks -- which form connections between brain regions -- were organized in children whose mothers reported they consumed caffeine during pregnancy.
"It is important to point out this is a retrospective study," said Foxe. "We are relying on mothers to remember how much caffeine they took in while they were pregnant."
Previous studies have found caffeine can have a negative effect on pregnancy. It is also known that a fetus does not have the enzyme necessary to breakdown caffeine when it crosses the placenta. This new study reveals that caffeine could also leave a lasting impact on neurodevelopment.
The researchers point out that it is unclear if the impact of the caffeine on the fetal brain varies from one trimester to the next, or when during gestation these structural changes occur.