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The second half of the 20th century saw a steep rise in the number of cesarean deliveries, but many experts contend that obstetricians are too hasty in abandoning possible vaginal deliveries either for profit or for their own convenience. However, analysis reveals a global trend, suggesting that multiple, convergent factors are responsible, such as changes in patients and their pregnancies, in options and recommendations for delivery, as well as in patients' and providers' evaluations of the risks.

Two newer prenatal care indexes show that the use of prenatal care services increased substantially between 1981 and 1995, but this was not paralleled by a decrease in premature births or low birth weight. A review of 54 million live births between 1981 and 1995 showed that prenatal care use increased from 32.7% to 47% according to the R-GINDEX and from 18.4% to 28.8% according to the Adequacy of Prenatal Care Utilization Index. Older indexes showed no change in use. Older mothers and those with multiple pregnancies were likely to use prenatal care services intensively., Context.--Two measures traditionally used to examine adequacy of prenatal care indicate that prenatal care utilization remained unchanged through the 1980s and only began to rise slightly in the 1990s. In recent years, new measures have been developed that include a category for women who receive more than the recommended amount of care (intensive utilization). Objective.--To compare the older and newer indices in the monitoring of prenatal care trends in the United States from 1981 to 1995, for the overall population and for selected subpopulations. Second, to examine factors associated with receiving intensive utilization. Design.--Cross-sectional and trend analysis of national birth records. Setting.--The United States. Subjects.--All live births between 1981 and 1995 (N=54 million). Main Outcome Measures.--Trends in prenatal care utilization, according to 4 indices (the older indices: the Institute of Medicine Index and the trimester that care began, and the newer indices: the R-GINDEX and the Adequacy of Prenatal Care Utilization Index). Multiple logistic regression was used to assess the risk of intensive prenatal care use in 1981 and 1995. Results.--The newer indices showed a steadily increasing trend toward more prenatal care use throughout the study period (R-GINDEX, intensive or adequate use, 32.7% in 1981 to 47.1% in 1995; the Adequacy of Prenatal Care Utilization Index, intensive use, 18.4% in 1981 to 28.8% in 1995), especially for intensive utilization. Women having a multiple birth were much more likely to have had intensive utilization in 1995 compared with 1981 (R-GINDEX, 22.8% vs 8.5%). Teenagers were more likely to begin care later than adults, but similar proportions of teens and adults had intensive utilization. Intensive use among low-risk women also increased steadily each year. Factors associated with a greater likelihood of receiving intensive use in 1981 and 1995 were having a multiple birth, primiparity, being married, and maternal age of 35 years or older. Conclusions.--The proportion of women who began care early and received at least the recommended number of visits increased between 1981 and 1995. This change was undetected by more traditional prenatal care indices. These increases have cost and practice implications and suggest a paradox since previous studies have shown that rates of preterm delivery and low birth weight did not improve during this time. JAMA. 1998;279:1623-1628

Active management of labor may not reduce the likelihood of cesarean section, but may lead to briefer labor and decrease the risk of fever in the mother. Active management of labor involves definitive diagnosis of labor and early rupture of membranes, administration of high doses of oxytocin if the uterus contracts inefficiently, and continuous attention to the mother during labor. Researchers compared the deliveries of 1,017 women with actively managed labor to those of 917 women who received usual care during labor. Cesarean deliveries occurred in approximately 19% of deliveries in both groups. Among women who had a low risk of cesarean delivery, the median time of labor was 6.2 hours in the actively managed group and 8.9 hours in the usual care group. In comparison to the usual care group, the actively managed group were less likely to develop a fever.

Routine ultrasound screening during pregnancy does not appear to be necessary. Of 15,151 pregnant women who had a low risk for perinatal problems, 7,812 received one ultrasound screening at 15 to 22 weeks and another at 31 to 35 weeks. The 7,718 women in the control group only got an ultrasound test if their obstetrician thought it was necessary. The incidence of severe neonatal outcomes such as fetal death or serious morbidity was similar in both groups. This was true even for women who delivered late, were pregnant with more than one fetus or delivered a small-for-gestational-age infant. At $200 per scan, routine ultrasound screening could increase cost by $1 billion or more. This cost would result in no significant improvement in perinatal outcome.

The blood of pregnant woman is routinely tested for the presence of alpha-fetoproteins, proteins produced by the fetus that are associated with various birth defects, particularly those involving the developing nervous system (neural tube), the digestive system and the abdominal wall. Expectant mothers also receive ultrasonic (US) examinations to detect fetal defects. A probe is placed on the abdomen which transmits high-energy sound and then measures its reflection to produce an accurate image of the fetus. In the presence of elevated levels of maternal blood alpha-fetoproteins and the absence of fetal abnormalities detectable by ultrasound, amniocentesis is usually performed. In this procedure, a needle is placed through the mother's abdominal wall into the uterus, where fluids inside the amniotic sac are withdrawn for a more sensitive analysis of the presence of alpha-fetoproteins. Normal levels of alpha-fetoprotein in the amniotic fluid, even in the presence of elevated levels in the mother's blood, are highly indicative of a fetus that is free of neural tube and abdominal wall defects. Amniocentesis, being an invasive procedure, is associated with a low but definite risk of lethal injury to the fetus, and it would therefore be useful to have a reliable diagnostic method that posed no risk. This study examines the ability to detect severe fetal abnormalities by means of ultrasound and maternal blood sampling only. From a large group pregnant woman, 51 cases of fetal abnormalities involving either the neural tube or abdominal body wall were reviewed; four different classes of abnormalities were examined. All cases of fetal abnormalities were successfully identified by maternal screening and ultrasound examination. The risk of missing a diagnosis of fetal abnormality was seen to be lower than the risk of abortion following amniocentesis. Some patients in consultation with their physicians may decide to rely on ultrasound data for the confirmation of abnormalities in the presence of elevated maternal levels of alpha-fetoproteins, rather than risk a chance of fetal death due to amniocentesis. (Consumer Summary produced by Reliance Medical Information, Inc.)

To the Editor.-- We read with great interest the article by Lieberman et al[1] regarding intrapartum maternal fever related to epidural analgesia and neonatal outcome. The authors' data indicate that [...]

Determines whether certain maternal and fetal characteristics influenced the risk of maternal- and fetal-indicated cesarean sections in pregnant women at low risk for adverse perinatal outcomes. Models of risk factors; Rates of cesarean sections; Odds of cesarean section as a function of risk factors.