Transactions of The Twenty-Second Annual Meeting of The Society for Maternal-Fetal MedicineReassessing the labor curve in nulliparous women☆
Section snippets
Material and methods
We used data from a previous study in which detailed labor and delivery information was collected.8 In brief, we systematically selected 1329 subjects from 1992 to 1996 on the basis of the following inclusion criteria: nulliparous, singleton pregnancy, maternal age between 18 and 34 years, gestational age between 37 weeks 0 days and 41 weeks 6 days, birth weight between 2500 and 4000 g, spontaneous onset of labor, vertex presentation at admission, cervical dilation <7 cm at admission, and
Results
Our study population consisted of women with a mixed race/ethnicity: 65% non-Hispanic white, 12% non-Hispanic black, 7% Hispanic, 11% Asian, and 5% other. Mean maternal age was 23 years; mean maternal height and weight at delivery were 64 inches and 169 pounds, respectively; mean gestational age was 39.3 weeks. At admission, the median cervical dilation was 3.5 cm (10th and 90th percentiles: 1.5 and 5.0 cm, respectively). Thirty-eight percent had complete effacement and 35% had ruptured
Comment
Our study indicates that the pattern of labor progression in contemporary practice is markedly different from what was observed in the 1950s. Labor appears to progress more slowly now than the Friedman curve indicates. This finding is consistent with previous studies. For example, Friedman2 showed that his study population who were delivered in the 1950s had a mean duration of active phase of 4.6 hours, which was similar to the observation by Hendricks et al11 in the 1960s. However, data from
Acknowledgements
We thank Dr Watson A. Bowes, Jr, for his valuable comments on the manuscript.
References (20)
- et al.
The effect of the increasing prevalence of maternal obesity on perinatal morbidity
Am J Obstet Gynecol
(2001) - et al.
Lack of utility of standard labor curves in the prediction of progression during labor induction
Am J Obstet Gynecol
(2000) - et al.
Graphic analysis of actively managed labor: prospective computation of labor progression in 500 consecutive nulliparous women in spontaneous labor at term
Am J Obstet Gynecol
(2000) - et al.
Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment
Am J Obstet Gynecol
(2001) - et al.
The length of active labor in normal pregnancies
Obstet Gynecol
(1996) Factors related to the increasing cesarean section rates for cephalopelvic disproportion
Am J Obstet Gynecol
(1986)- et al.
Active-phase labor arrest: oxytocin augmentation for at least 4 hours
Obstet Gynecol
(1999) - et al.
Active phase labor arrest: revisiting the 2-hour minimum
Obstet Gynecol
(2001) - et al.
Perinatal outcome in relation to second-stage duration
Am J Obstet Gynecol
(1995) Primigravid labor: a graphicostastistical analysis
Obstet Gynecol
(1955)
Cited by (294)
Descent of the presenting part assessed with ultrasound
2024, American Journal of Obstetrics and GynecologyThe evolution of the labor curve and its implications for clinical practice: the relationship between cervical dilation, station, and time during labor
2023, American Journal of Obstetrics and GynecologyThe latent phase of labor
2023, American Journal of Obstetrics and GynecologyNew insights on labor progression: a systematic review
2023, American Journal of Obstetrics and GynecologyThe active phase of labor
2023, American Journal of Obstetrics and Gynecology
- ☆
Reprint requests: Jun Zhang, PhD, MD, Epidemiology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Building 6100, Room 7B03, Bethesda, MD 20892. E-mail: [email protected]
- b
†Deceased.