Preemies and Risk of Blood Clots Into Adulthood
Odds are small, but family, doctors should keep possibility in mind, researchers say
For the study, Dr. Bengt Zoller, of the Center for Primary Health Care Research at Lund University in Malmo, Sweden, and colleagues used records from the Swedish Birth Registry to track the babies' health. The researchers found that premature babies had an increased risk of blood clots in their veins in infancy, but also from ages 1 to 5 and from 18 to 38.
Very preterm births -- before 34 weeks of gestation -- also had a risk of blood clot-related illness in adolescence, from age 13 to 17.
Boys had an increased risk of blood clots in infancy, while girls were more likely to carry the risk into adolescence and adulthood, the study authors reported.
No one knows why this increased risk exists, but it could be due to genetic factors that caused the mother to deliver prematurely in the first place, Watterberg and McCabe said.
Diseases such as diabetes, thyroid problems and obesity are genetic in nature and can cause preterm delivery, McCabe said.
Also, some mothers who suffer a genetic deficiency in a key protein that controls blood clotting may be predisposed to give birth prematurely, Watterberg said.
"It may be that maternal genetics are a setup for preterm delivery, and those problems are passed along to the infant," she said.
The mother's wellness and lifestyle also play a role in a baby's lifelong health, and could influence their risk of blood clots, McCabe said.
Finally, this link might arise because the babies are born prematurely, and are robbed of maternal hormones and nutrition in the womb that could have decreased their future risk of blood clots.
"We are not as good at getting nutrition into those babies as the mother and placenta are, and we do know that hormones have something to do with the predisposition to clotting," Watterberg said. "It makes sense to me you'd have changes in those long-term outcomes as well."
In any case, it is something for the family and doctor of a person born prematurely to keep in mind, McCabe said.
"If a patient has a history of preterm birth, and the more preterm, the more attention it needs to have," he said. "It helps us be better prepared. If a patient comes in with unusual findings, this provides us some clue."