Breech Birth May Be Determined by Genes

FRIDAY, March 28 (HealthDay News) -- If one or both parents were born
bottom first or feet first -- called a breech delivery -- their children
are twice as likely to be born the same way, Norwegian researchers
report.

Most babies are born head first, but about one in 20 is born bottom
first. Breech deliveries increase the risk that the baby will die or
suffer from health problems, the study authors noted.

"Both men and women delivered in breech presentation at term contribute
to increased risk of breech delivery in their offspring," said lead
researcher Tone Nordtveit, a research fellow at the University of Bergen.
"Recurrence through the father is as strong as recurrence through the
mother. Genes passed on from the father or the mother seem to be closely
related to breech delivery," she added.

The findings were published in the March 28 online edition of the
British Medical Journal.

For the study, Nordtveit%26#39;s team collected data on all births in Norway
between 1967 in 2004. Specifically, they looked at information on
first-born children.

"Men and women who themselves were delivered in breech presentation had
more than twice the risk of breech delivery in their own first pregnancies
compared with men and women who had been cephalic presentations,"
Nordtveit said.

The strongest risks for breech delivery were found for vaginally
delivered babies and were equally strong for men and women. Increased risk
of recurrence of breech delivery in offspring occurred only for parents
delivered at term, Nordtveit said.

When the researchers looked at 35,056 men who had children with two
different women, they found the same risk for breech delivery, indicating
that the increased risk appears to have a genetic component.

Predicting a breech delivery is important, Nordtveit said, because
these deliveries are associated with increased mortality and morbidity.

"A considerable number of breech presentations are not detected before
labor, despite careful antenatal surveillance," Nordtveit said. "To avoid
undiagnosed breech deliveries, information about the mother%26#39;s and the
father%26#39;s own presentation at birth will be valuable in the evaluation of
fetal presentation in the third trimester."

Janet Hardy, an assistant professor of obstetrics/gynecology and
pediatrics at the University of Massachusetts Medical School, agrees that
knowing the parents%26#39; history of breech delivery may help predict the risk
of their child having a breech presentation.

"Little is known about risk factors for breech presentation, and the
idea that birth position might be inherited from either or both parents is
novel," said Hardy, who authored an accompanying editorial in the
journal.

"If these results hold true, further research may help us understand
what trait is being passed from parent to child," she added. "Assessing
the presence or absence of all potential risk factors for breech
presentation, including the parents%26#39; own birth positions, may alert the
clinician and patient to prepare for a possible breech delivery."

More information

For more on breech births, visit the American Academy of Family Physicians.