Older Moms Have More C-Sections
Study Shows 40% of First-Time Moms Aged 40-44 Had Cesarean Sections
March 12, 2007 -- Older moms are far more likely to have their babies
delivered by cesarean section than younger moms, even when they have no obvious
risk factors for a high-risk birth, new research shows.
The chance of delivering by C-section was greatest among older, first-time
mothers. Half of first-time moms aged 45 and over had surgical births, as did
roughly 40% of first-time moms aged 40 to 44.
Researchers reviewed 8 million U.S. single-child births occurring between
1995 and 2000 by examining birth certificate data.
After adjusting for known risk factors for surgical delivery, they found
little difference in cesarean delivery rates among low-risk, first-time moms
aged 35 and older and all women 35 and older who gave birth.
"It was really shocking that we didn’t see a difference between the
low-risk women and all comers," researcher Barbara Luke, ScD, MPH, RN,
The study was funded by the National Institute of Child Health and Human
In a statement, NICHD Director Duane Alexander, MD, calls for more research
into why C-section rates are so high for older women.
"Until we learn why older mothers with low-risk pregnancies have a
disproportionately high rate of cesarean delivery, the utmost caution is needed
in evaluating older mothers as candidates for the procedure," he notes.
"Although older mothers share certain risk factors in common, each woman
is a unique individual and the potential benefits and risks of cesarean
delivery should be evaluated for her specific case."
More Older Moms
It is no surprise that more and more women are giving birth later in life.
In just over two decades, first births increased threefold among women aged 30
and over, while they jumped sixfold in women 35 and older and 15-fold in women
40 and over.
It is also well known that older women tend to have more risk factors for
cesarean delivery, and this was confirmed in the new study, published in the
latest online issue of the journal Human Reproduction.
Using birth data from the National Center for Health Statistics, the
researchers evaluated factors such as the mothers’ medical risk factors,
pregnancy complications, and mode of delivery by age.
Compared to women under 35, older women were at much higher risk for
complications during pregnancy and delivery. First-time mothers, regardless of
age, were also more likely to deliver by C-section, even when their pregnancies
were considered low risk.
Not surprisingly, women 45 and older were most likely to have high blood
pressure and diabetes while pregnant, two big risk factors for C-section
delivery. They were also at the greatest risk for experiencing excessive
bleeding during labor and premature delivery.
But these and other known risk factors for problem births did not explain
the excess of cesarean deliveries among older moms.
"This is a disturbing trend," Luke says. "C-sections are
increasing, and women need to understand that there are risks involved. I am an
old neonatal nurse, and I know the process of passing through the birth canal
is beneficial for the baby. These babies tend to breathe better because they
have less mucus."