New research was published in the American Journal of Obstetrics and Gynecology. Katherine Laughon, MD, and her colleagues, D. Ware Branch, M.D., Julie Beaver, M.S, and Jun Zhang, Ph.D., M.D., (2012) examined differences in childbirth labor patterns over the past fifty years, comparing data from a large study in the 1960's with data from a large study in the 2000's.

The researchers found differences both in maternal characteristics and obstetric practice patterns. In the contemporary cohort, the authors found an increase in first stage labor of over two hours and a cesarean section rate four times as high as in the past cohort. In the cohort from the 1960's, a higher operative vaginal delivery rate was found as compared to the contemporary cohort. The authors link these differences to changes in obstetric practice patterns. The authors state that even after controlling for maternal and obstetrician characteristics, the increased length of labor result for the contemporary cohort persists (Laughon, Branch, Beaver and Zhang, 2012).

Positive Action Items for Moms and Childbirth Educators

The National Institute of Child Health and Human Development (NICHD)ran a conference call on March 31, 2012, where Katherine Laughon, MD, the lead researcher on the study, gavea brief overview of the study and answered questions. Robin Elise Weiss, LCCE, was on the call and summarized Dr. Laughon's positive steps to take by women and childbirth educators who are interested in natural childbirth. Dr. Laughon's suggestions fall into Lamaze's Six Healthy Birth Practices.

• These women might be comfortable waiting longer to get pitocin and other interventions, including cesareans.
• Choose your practitioner carefully. Dr. Laughon suggests a practitioner should be able to think about the differences in labor patterns in modern times, not from textbooks.
• Remember there is not an ideal length of labor, long or short. It is based on the individual, woman to woman and baby to baby.

As a Lamaze childbirth educator, do the results of this study surprise you?

What does this mean to you and the families you serve?

Below is a synopsis of the study methods, statistics and conclusions.

Study Design: Comparing Data from the 1960's to Data from 2000's

The researchers compared the data from the National Collaborative Perinatal Project (CPP) dating from 1959 - 1966 to the data from the Consortium on Safe Labor (CSL), dating from 2002- 2008. Data from a combined total of 137,850 women from the two studies were included in the 2012 study.

National Collaborative Perinatal Project (CPP) 1959-1966

The CPP (1959-1966) was a prospective study following 54,000 births to 44,000 women. Twelve university centers across the country enrolled pregnant women and collected data such as demographics, medical history, socioeconomic status, behaviors, blood samples, and information from regular physical exams, did interviews and gathered information from the senior obstetrician. The children were followed for seven years after birth. Laughon and her colleagues (2012) limited the use of the CPP data to only women known to be birthing for the first time. Thus, the 2012 study included data from 39,491 women from the CPP study.

Consortium on Safe Labor (CSL) 2002-2008

The CSL (2002 - 2008) was a retrospective cohort study of 228,668 births, with the majority of births (87%) occurring between 2005 and 2007. Information was examined from 12 clinical centers and 19 hospitals in 9 American College of Obstetrics and Gynecology (ACOG) districts. Data was extracted from both the electronically held maternal medical files and neonatal intensive care units. Data on demographics, medical history, maternal and neonatal outcome, and discharge disposition were extracted from the electronic files. Investigators at delivery sites collected information on obstetrician characteristics. Laughon and her colleagues (2012) limited their use of the CSL data to only those women in spontaneous labor with a single gestation. Thus, the 2012 study examined 98,359 women from the CSL study, inclusive of a total of 137,850 women from both the CPP and CSL dataset.

Results: Differences in Characteristics of the Women

Characteristics of the women, of their labors and of their newborns differed significantly between the earlier CPP and the contemporary CSL study.

Women in the CSL were older than in the CPP (26.8 years vs. 24.1), had a higher average BMI both pre-pregnancy (26.3 vs 24.1) and at delivery (29.9 vs 26.3), were more racially diverse, and delivered an average of 4.9 days earlier. Their babies weighed an average of 99 grams (3.48 ounces) more and Apgar scores were higher in the CLS than the CPP.

Results: Differences in Practice Patterns

Use of epidurals (55% vs. 12%), oxytocin (44% vs. 12%); and cesarean delivery (12% vs. 3%) was higher in the contemporary CSL cohort than the CPP. Cesarean delivery in the contemporary cohort is four times as high as in the 1960's cohort.

Episiotomy (68% vs. 17%) and operative vaginal delivery (40% vs. 6%) were higher in the 1960's CPP cohort than the contemporary CSL.

Results: First Stage - Differences in Length of Labor

For nulliparas, the first stage of labor (from 4 cm to completely dilated) was 2.6 hours longer in the contemporary cohort (CSL) than the former cohort (CPP).

For secundagravidas and multigravidas, the length of labor was, on average, 2.0 hours longer for the CSL cohort than the CPP cohort.

Results: Second Stage - Differences in Length of Labor

For nulliparas, in the second stage of labor, in the CLS cohort, there was a 10% operative vaginal delivery rate compared to 66% of the CPP cohort. Among women who spontaneously delivered, there was an increase of 27 minutes in the CSL group as compared to 13 minutes in the (CPP group.

Operative vaginal delivery, in secundagravidas and multigravidas, occurred in the CSL 4% and 2.5 % compared to 36% and 18% in the CPP. In secunagravidas and multigravidas, second stage labor did not have a clinically relevant difference in length of labor between the two groups.

Conclusion

The authors state firm conclusions merit further study.

In summary:

'...for women who presented in spontaneous labor at term, the duration of labor from 4 cm to 5 cm in multiparas to complete dilation and the 2nd stages of labor were longer in the contemporary population than a cohort from the 1960s. The overall median differences in the first stage of labor persisted after controlling for maternal and obstetric characteristics, indicating that modern labor differs from the older cohort largely due to changes in obstetric practices. Since labor times are longer today than in the past,the benefit of extensive interventions such as oxytocin and cesarean delivery in modern labor management needs further evaluation.'(Laughon, Branch, Beaver and Zhang, p. 14).

Hopefully this study will generate increased study of obstetric intervention patterns with an eye towards improved contemporary obstetric process management.

References

Laughon, S.K., Branch, D.W., Beaver, J., Zhang, J., Changes in labor patterns over 50 years,American Journal of Obstetrics and Gynecology (2012), doi: 10.1016/j.ajog.2012.03.003.

Many thanks to Robin Elise Weiss, LCCE, who graciously helped out with her reporting expertise on this post!

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