Babies in the womb who are smaller than they should be have higher rates of breathing problems when delivered early by C-section vs. similar babies who are born vaginally, a new study shows.
In the past, obstetricians have often chosen to deliver a baby by C-section if a baby is not growing at the rate it should be. This was believed to be better for these infants. But this study casts that notion into doubt.
The new study was presented today at the 32nd Annual Society for Maternal-Fetal Medicine Meeting in Dallas.
It is not always clear why a fetus may be small, but common reasons for this include maternal high blood pressure during pregnancy, placenta problems, poor nutrition during pregnancy, and maternal smoking or alcohol use while pregnant.
Researchers reviewed birth certificate and hospital discharge data for 2,560 small-for-gestational-age babies who were delivered early. Those babies who were delivered by a C-section before 34 weeks of pregnancy had a 30% higher risk of developing respiratory distress syndrome than babies born vaginally at a similar gestational age, the study shows.
"C-section delivery doesn't offer any protection for these babies," says Diane Ashton, MD, MPH. She is the medical director of the March of Dimes. "It actually increases the risk of respiratory distress." The March of Dimes will be honoring the new study at the meeting.
There are some valid reasons to deliver a baby via C-section, she says. For example, if the baby is in distress or the heart rate is dropping, a C-section may be appropriate.
This study did not include babies with complications such as birth defects, delivery requiring use of forceps or vacuum assistance, or in women with a past history of C-sections. Ashton says she hopes the new study will change practice. C-section is a major surgery. There are risks to the mother as well as the baby.
James Ducey, MD, agrees. He is the director of maternal-fetal medicine at Staten Island University Hospital in New York. "You shouldn't have a C-section unless there is a good reason," he says. Some reasons pertain to moms and others to the baby.
"Being small, in and of itself, is not a reason to do a C-section," Ducey tells WebMD. "It is more risky for mom and there is no benefit for baby, so why should we do it?"