While the vast majority of babies are born in the hospital, with a medical doctor handling the delivery, there has been a steady rise in the number of midwife deliveries, from 3.7 percent of all births in 1989 to 7 percent in 1997, the report says.
Sally C. Curtin of the National Center for Health Statistics, who co-authored Thursday's report, says the two-way trend is not completely understood.
Midwifery is much less medically invasive, focusing on the woman as a future mother, not just as a patient, said Judith Rooks, a midwife in Portland, Ore., who published a book on midwifery in 1997.
"The women who are choosing midwives don't want such a medical approach," she said. "It's not just 'how are we going to get this baby out of your uterus,' but how are we going to make this transition into being a mother?"
At the same time, use of modern techniques is up.
The number of induced births doubled from 9 percent in 1989 to 18 percent in 1997. Some are medically necessary, but many are simply for the convenience of the patient or the doctor, said Dr. Fredric Frigoletto, chief of obstetrics at Massachusetts General Hospital in Boston.
"Most often, women are tired of being pregnant at the end of their pregnancy," he said.
The report also found an increase in use of ultrasounds, from 48 percent of births in 1989 to 64 percent in 1997. During that period, the use of electronic fetal monitoring went from 68 percent to 83 percent.
That does not mean that all those women need these procedures, Frigoletto said. More are done partly because more doctors were trained with the technology and because fewer are uncomfortable with it.
The monitors screen for respiratory distress in the fetus, though they often wrongly suggest distress when it is not there and contribute to unnecessary Caesarean sections, he said.
Frigoletto also said ultrasounds probably are overused. They can detect birth defects, he explained, and should be used when there is cause for concern. If serious defects are detected, a woman can choose to abort the pregnancy, but short of that, there is little that can be done.
Still, most pregnant women now want ultrasounds.
"I actually do tell them they don't need it, but it's whistling Dixie," he said.
The report also found that the percent of C-sections fell from 22.8 percent in 1989 to 20.7 percent in 1996. That drop followed national concern too many C-sections being performed, especially for mothers giving birth to another child following an earlier C-section.
But the number of C-sections edged up in 1997 following recent research about the risk to mothers of delivering vaginally after a previous C-section.
Other findings from the report:
- Mothers should not induce labor on Jan. 1, 2000, if their only motivation is trying to hav a Y2K baby
- While midwifery may conjure images of delivery at home, 96 percent of these births are now in hospitals. The vast majority of midwives are highly trained certified nurse midwives.
- More induced labors have meant more deliveries during the week, as few doctors schedule a birth for the weekend. Tuesday continues to be the most popular day for delivery, Sunday the least likely.
- The most common months for delivery are July and August.