Study finds lower late-pregnancy placental protein levels linked with ADHD.
A new study from University of Iowa Health Care researchers has found a possible link between placental health during late pregnancy and a child’s later diagnosis of attention deficit/hyperactivity disorder, or ADHD. The findings suggest that changes in the placenta may be connected to how a child’s brain develops before birth.
ADHD is a common condition among children. It can involve trouble paying attention, hyperactivity and impulsive behavior. The condition can affect school, work and other parts of daily life. Researchers have been studying for years how ADHD develops, including whether some of the factors involved may begin during pregnancy.
The Iowa research team looked at placental growth factor, known as PlGF, which is a protein made by the placenta. PlGF can also provide information about the health of the placenta during pregnancy. Low levels have already been linked with pregnancy problems such as preeclampsia. For the study, researchers examined stored blood samples from 176 pregnancies. The samples came from the University of Iowa Department of Obstetrics and Gynecology’s Perinatal Family Tissue Bank. Blood samples had been collected during all three stages of pregnancy. Researchers later connected the samples with health records for the children born from those pregnancies.
The results showed a difference during the third trimester. Pregnancies that later resulted in children diagnosed with ADHD had lower PlGF levels than pregnancies that did not result in an ADHD diagnosis. Researchers found that each standard-deviation drop in PlGF was linked with 2.6 times higher odds of a later ADHD diagnosis. The difference was not seen during the first or second trimester. Researchers also looked at endothelin-1, another protein tied to blood vessel health during pregnancy but did not find a meaningful difference between the two groups.
The connection between lower third-trimester PlGF levels and ADHD remained after researchers took several pregnancy conditions into account. Those conditions included preeclampsia, restricted growth before birth and early premature birth. Each of those conditions has already been linked with ADHD and can also be linked with lower PlGF levels.
Researchers said the findings may point to smaller changes in placental health that can occur without an obvious pregnancy problem. The placenta supplies blood and nutrients to the developing baby, removes waste and helps protect the baby from harmful exposures. Because of its role during pregnancy, changes in placental function may affect development before birth. Still, the study does not show that low PlGF causes ADHD. The research involved a relatively small number of pregnancies from one medical center, so larger studies will be needed to see whether the same pattern appears in other groups.
Serena Gumuslogu, PhD, an assistant professor at the University of Iowa, said the findings raise questions about whether placental health may play a role in brain development. Future research will examine the possible connection in greater detail. One planned area of study involves testing whether lowering PlGF levels in pregnant mice can change brain development in their offspring. If future studies confirm the finding and show a cause-and-effect link, PlGF levels during pregnancy could eventually help researchers understand which children may need closer developmental follow-up. At this stage, however, the finding remains an early research result rather than a test that can predict whether a child will develop ADHD.
The study was published in JAMA Psychiatry under the title “Placental Growth Factor Trajectories During Pregnancy and Child ADHD.” The research adds another area for scientists to study as they work to understand how conditions affecting pregnancy may relate to brain development years later.
Sources:
Placental health in late pregnancy linked to childhood ADHD
Placental Growth Factor Trajectories During Pregnancy and Child ADHD
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