How Epidurals Affect Labor

A recent study done from the University of California San Francisco (UCSF) shed some interesting light on how epidurals may impact the amount of time you’ll spend pushing your baby out. Even though we already knew that epidurals do prolong the pushing part of labor (known as the second stage), this study shows it may be longer than we previously thought. The study also showed that women without epidurals also take longer to push than what was previously considered normal.

The large study looked at approximately 42,000 women who delivered at UCSF between 1976 and 2008. About half of the women had epidurals. What they found was striking: for women who had epidurals and were having their first baby, their second stage could last as long as 5.6 hours versus first-time moms without epidurals, who pushed an average of 3.3 hours. Women who already had given birth and were pushing with an epidural could take as long as 4.25 hours versus 1.35 hours without.

You might wonder why these average times matter. One of the main reasons women undergo their first Cesarean section in the United States is for prolongation or arrest of the second stage (meaning mom was pushing but the baby could not deliver, or she was not progressing fast enough). In fact, this accounts for 10-25 percent of all C-sections in the US.

Current guidelines from the American Congress of Obstetricians and Gynecologists (ACOG) state that first-time moms should deliver within 2 or 3 hours of pushing (with or without an epidural) and moms who’ve had babies before should take 1 or 2 hours (with or without an epidural). Based on this newest study, these timeframes are much shorter than they should be, leading to a possible overutilization of C-sections.

Although ACOG is still maintaining these guidelines, there has been some movement toward allowing longer stage two labor. In 2012, an ACOG working group suggested giving more time in the second stage of labor before recommending a C-section. The group recommended adding an additional hour to each category. Some practitioners have already put this into practice.

Lastly, it is important to note that longer time spent in labor is not risk-free. Moms are at higher risk for postpartum hemorrhage, need for forceps/vacuum delivery, worse vaginal lacerations with subsequent issues of urinary and fecal incontinence, and infection. Babies are also at higher risk for minor birth trauma.

So what does this all mean? Overall, the old labor curves we’ve been using to monitor labor progress are outdated and likely not applicable to our current obstetric population in the US. While epidurals do increase the length of time needed to push, many moms and babies will do well even with the longer times, and we can probably decrease our C-section rate without too many additional complications. However, it is important to always take into account the whole clinical picture, and be sure to make an informed decision with your midwife or doctor.

Reviewed by Dr. Jen Lincoln, November 2018

Sources:

• Cheng, Y et al
• Second Stage of Labor and Epidural Use: A Larger Effect Than Previously Suggested
• Obstet Gynecol
• 4 Feb 2014.
  American Congress of Obstetrics and Gynecology
• Practice Bulletin #49: Dystocia and Augmentation of Labor.
  Spong CY et al
• Preventing the First Cesarean Delivery
• Obstet Gynecol
• 2012.

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