ORLANDO, FLA. — Women receiving prostaglandin-assisted induction of labor were less likely to receive a cesarean delivery than were women in spontaneous labor, according to a study presented by James M. Nicholson, M.D., at the annual meeting of the American Academy of Family Physicians.

“Active Management of Risk in Pregnancy at Term basically involves applying preventive technology to the field of obstetrics in terms of improving outcomes,” said Dr. Nicholson of the department of family practice at the University of Pennsylvania, Philadelphia.

While in private practice at a small New England hospital, Dr. Nicholson noted that the cesarean rates at the facility fell to around 10%, at a time when the national cesarean delivery rate never dropped below 20%. The number of deliveries at the small hospital remained the same, with a stable cadre of providers. Seven family physicians, five obstetricians, and one certified nurse-midwife practiced at the facility.

“What did change was our induction of labor rates per year. As the induction rates seemed to go up, the C-section rates seemed to go down,” said Dr. Nicholson, adding that the physicians also began using prostaglandin E2 (PGE2).

Dr. Nicholson conducted a retrospective, 4-year cohort study. From 1993 to 1997, the hospital had 2,199 deliveries. He included women who had at least one prenatal visit, were at 38 weeks' gestation, had no maternal or fetal health reasons mandating a cesarean delivery, and were carrying a single fetus, for a total of 1,871 deliveries.

Dr. Nicholson analyzed provider labor induction and PGE2 usage rates. Four family physicians and one obstetrician used both induction and PGE2 at a high rate, equal to or greater than 21%. Dr. Nicholson classified the 791 women cared for by these five physicians as “highly exposed.”

Three family physicians, four obstetricians and one midwife used labor induction and PGE2 in less than 21% of their deliveries. The group of 1,080 women that they cared for were classified as “somewhat exposed.”

Anemia and single status were more common in the highly exposed group. In the less exposed group, there was a greater number of women with short stature, excess weight gain, and epidurals.

In the highly exposed group, more women had an unripe cervix at time of admission, so physicians used more PGE2 and more often induced labor. The gestational age was significantly lower, 39.1 weeks vs. 40 weeks, in the less-exposed group.

The elective induction rate was 21.2% in the highly exposed group and 8.1% in the less exposed group. The rate for impending cephalopelvic disproportion was 6.2% in the highly exposed and 2.8% in the less exposed cohorts. The rate for impending uteroplacental insufficiency was 3.8% in the highly exposed and 1.8% in the less exposed groups. Gestational age between 41 weeks and 42 weeks was 9% in the highly exposed and 5.9% in the less exposed cohorts.

The cesarean rate was 5.3% in the highly exposed group and 11.8% in the less exposed group. There were also lower rates of fetal intolerance, cephalopelvic disproportion, and malpresentation in the highly exposed cohort.

Second stage labor was shorter in the highly exposed group. The rate of babies requiring neonatal intensive care was 2.3% in the highly exposed group vs. 4.2% in the less exposed group.

“The babies came out healthier,” Dr. Nicholson said.

The percentage of nulliparous women requiring a cesarean section was 7.5% in the highly exposed group and 26% in the less exposed group. No multiparous women in the highly exposed group received a cesarean section, but 10.4% of the women in the less exposed group did. In women who had had a prior cesarean delivery, the rate was 7.4% in the highly exposed cohort and 32.7% in the less exposed cohort.

“We were able to show there was an association between higher provider usage of preventive care by induction and a lower cesarean rate,” Dr. Nicholson said.

He also completed two retrospective studies using Active Management of Risk in Pregnancy at Term in an urban population and presented those results at the World Conference of Family Doctors, which met at the same time and in the same Orlando convention center. Both of those studies compared the outcomes of 100 women exposed to induction and PGE1 or PGE2 to 300 randomly selected controls who received the current obstetric standard of care.

Again, the women in the highly exposed cohorts delivered an average of 1 week earlier than the standard-of-care group. Exposure to Active Management of Risk in Pregnancy at Term was associated with a higher labor induction rate and lower cesarean delivery rate in both urban studies.

It also was associated with lower rates of neonatal intensive care unit admission, major perineal trauma, and passage of thick meconium.

Higher Induction Rate May Decrease Cesareans