The effect of epidural anesthesia on the length of labor

Journal of Family Practice, March, 1995 by Sigrid Johnson, Jo Ann Rosenfeld

Background. Epidural anesthesia, although effective, has been associated with changing the course of labor. Previous studies have been criticized for not pinpointing the factors determining the use of epidural anesthesia. The purpose of this study was to determine the effect of epidural anesthesia use on the course of labor.

Methods. A retrospective chart review of 224 women who gave birth from July 1, 1993, to June 30, 1994, was completed in a small-town family practice. The time frame included 6 months before and after the initiation of Tenncare, a state-funded health insurance plan designed to serve the uninsured and those previously served by Medicaid in Tennessee.

Results. The rate of epidural anesthesia use in this study population fell sharply after January 1, 1994, the start date for Tenncare. Epidural anesthesia by women in this study was found to increase the average length of the second stage of labor by 38 minutes for primiparas and 23 minutes for multiparas.

Conclusions. The average length of the second stage of labor is significantly longer for women who receive epidural anesthesia. The rate of epidural anesthesia use in this study population was strongly influenced by a change in health-care financing.

Key words. Anesthesia, labor stage, second; insurance, health, reimbursement. (J Fam Pract 1995; 40:244-247)

Epidural anesthesia is a common choice of analgesia during both the first and second stages of labor. Although considered safe, it affects the course, speed, and consequences of labor. Several European and Canadian studies have shown that the use of epidural anesthesia can lengthen the second stage of labor.[1-6] In one study of nulliparous women, the average length of the second stage of labor was more than 1 hour longer among women receiving epidural, compared with those who received narcotic, analgesia.[2] Criticisms of these studies have suggested, however, that the epidural analgesia rate is confounded by the particular physician's or hospital's standard of care or the patient's inherent need for epidural anesthesia.[7] These evaluations have suggested that women who have cephalopelvic disproportion, and thus long labors, are the ones most likely to need epidural anesthesia and subsequently to require forceps delivery or cesarean section.[8,9] These studies have been criticized for the lack of comparability among the populations studied and, therefore, the inability to isolate epidural anesthesia use as the cause of observed differences in labor.[7,10,11]

The introduction on January 1, 1994, of Tenncare, a state-funded health care insurance plan designed to serve uninsured and Medicaid patients in Tennessee, caused an immediate and significant decrease in the epidural anesthesia rate among the population of this study. Ninety-five percent of all these patients were immediately covered by Tenncare insurance. A patient's type of insurance coverage (Tenncare, Virginia Medicaid, or private) had a significant impact on whether she received epidural anesthesia during labor. There were no other changes in physician care, nursing staff, hospital, physicians involved, or demographics of the population. The purpose of this study was to examine the effect of epidural anesthesia on the length of labor.

Methods

The labor and delivery records of all patients who gave birth from July 1, 1993, to June 30, 1994, and who were in the care of the residents and faculty of the Bristol Family Practice Residency were examined retrospectively. Demographic and labor and delivery data were recorded, including date of delivery, maternal age, parity, gestational age, race, insurance, type of anesthesia, type of delivery, birthweight, and length of the second stage of labor.

In January 1994, the State of Tennessee initiated a new health insurance system called Tenncare. After January 1, 1994, most Tenncare patients did not routinely receive epidural anesthesia for childbirth.

Of 224 women who gave birth during the year of this study, 38 had cesarean sections for reasons such as previous section, maternal genital herpes, primigravida breech, cephalopelvic disproportion, and fetal distress; these women were excluded from the study. Six precipitate deliveries were also excluded because the length of the second stage of labor could not be determined. After these exclusions, 180 women were eligible for the study. There were no maternal or fetal intrapartum deaths.

Statistical significance was determined by chi-square analysis and t test.

Results

Of the 224 women who gave birth during the year of the study, 98% were white and 2% were African American; 20% were under the age of 20 years, 66% were aged 20 to 29, and 14% were older than 29 years.

There were expected differences in age by parity: 35% of the primiparous women were under 20 years of age, 57% were aged 20 to 29, and 8% were over the age of 30 years. Only 8% of the multiparous women were younger than 20 years; 72% were aged 20 to 29, and 20% were over the age of 30 years.

In the first half of the study year, 67% of the women were insured by Tennessee Medicaid, 26% by Virginia Medicaid, 3% by private insurance, and 4% had no insurance. In the second half of the study year, 53% were covered by Tennessee Tenncare, 32% by Virginia Medicaid, 10% by private insurance, and 5% had no insurance.