Evidence-Based Management of the Second Stage of Labor (Guerrero 4/1/2020)

Muchas Gracias to Dr. Kiana Guerrero, who delivered our second shelter-in-place zoom Grand Rounds at SSRRH. She did so with great grace and great thought-- as she does most things. The topic was Evidence-Based Management of the Second Stage of Labor.

Some definitions:

• Second stage of labor: full cervical dilation (10cm) to delivery
• Spontaneous vaginal delivery: delivery that occurs without the use of forceps, vacuum, or cesarean delivery
• Delayed pushing: delay after full cervical dilation to allow for spontaneous decent. Patient starts pushing on average 60 mins – 180 mins after complete dilation
• Immediate pushing: patient would start pushing on average 15 mins after complete dilation
• Spontaneous pushing/physiological pushing: pushing after full dilation without instructions; may push with an open glottis and vocalization or use an intermittent
• Directed pushing/Valsalva pushing: pushing after full dilation against a closed glottis

Question 1: Should we encourage patients with an epidural to "labor down"?
Answer: Probably not.

In a 2018 Randomized Control Trial of  2414 nulliparous women, >37 weeks, all with an epidural, randomized to immediate pushing vs. delayed pushing

• There was NO difference in normal spontaneous spontaneous delivery and NO difference in rates of c-section in the two groups
• However, there were differences in postpartum hemorrhage (PPH), chorio, newborn outcomes, and other potentially important secondary outcomes
• The immediate pushing group  had shorter total duration of second stage, lower risk of  PPH and lower risk of chorioamnionitis, as well as  a lower likelihood of neonatal acidemia and suspected neonatal sepsis
• The delayed pushing group had shorter mean duration of active pushing (by about 9 minutes) and a lower likelihood of third degree laceration

(Reference: Cahill, Alison G., et al. Effect of Immediate vs Delayed Pushing on Rates of Spontaneous Vaginal Delivery Among Nulliparous Women Receiving Neuraxial Analgesia.)

After reviewing this study, Dr. Guerrero was left with more questions: 

• Would even more time for laboring down (i.e. >60 minutes) be better?
• Would the outcomes be different for multiparous women?

Dr. Guerrero used a 2012 Systematic Review  Tuuli, et al, to answer these questions. This review featured 12 RCTs (~1500 patients in each group: immediate vs. delayed), with primary outcome spontaneous vaginal delivery. There was variable quality and mixed results, but here are Dr. Guerrero's take home points:

Answer 1a: Longer isn't better. Largest study showed that maternal fever was nearly two-fold higher among women who delayed pushing. Risk of maternal fever increased in a dose–response fashion

• RR 1.14, 95% CI 0.54–2.38 for delayed less than 1 hour
• RR 1.73, 95% CI 1.10 –2.72, for delay of 1–2 hours
• RR 2.33, 95% CI 1.54 –3.51 for delay greater than 2 hours

Answer 1b: There isn't enough data specifically for multiparous women; the studies that have been done with multips are of poor quality.

(Reference: Tuuli, et al, Immediate Compared with Delayed Pushing in the Second Stage of Labor: A Systematic Review and Meta-Analysis, Obstetrics and Gynecology, September 2012, Voume 120, Issue 3, 660-668)

Question 2: Should we control how a woman pushes during the second stage?
Answer: Probably not.

Dr. Guerrero cited a Cochrane Review (see reference) of 8 trials, including 884 women. The largest study in the meta-analysis found the following:

• NO clear difference in spontaneous vaginal delivery comparing spontaneous pushing and directed pushing groups
• Spontaneous pushing may decrease the duration of pushing by about 10 minutes
• No difference in rates of perineal tears (3rd and 4th degree), risk of episiotomy, admission to NICU or 5 minute APGAR <7

(Reference: Lemos, Andrea, et al. Pushing/Bearing down Methods for the Second Stage of Labour. Cochrane Database of Systematic Reviews, 2017)

Question 3: Is there a "best" position for women to be in during second stage?
Answer: We don't know.

Dr. Guerrero gave us a quick peek at two recent studies asking whether a woman's position affects the birth outcomes: a 2017 Cochrane meta-analysis and a 2017 BUMPES RCT (comparing upright vs lying down)

• A 2017 Cochrane Review found that for nulliparous women without an epidural, the upright position showed a reduction in rates of episiotomy, assisted vaginal delivery and a very small reduction of duration of second stage 
• BUT upright position was associated with an increase risk of 2nd degree tears and blood loss >500mL
• The 2017 BUMPES RCT concluded that for nulliparous women with low-does epidural, the lying down position results in more spontaneous vaginal delivery
• Hmmm. . . .

(References:  Gupta et al, Position in the second Stage of Labor for Women without Epidural Anesthesia, Cochrane Systematic Review, 25 May 2017 and  

Brocklehurst et al, Upright versus lying down position in second stage of labour in nulliparous women with low dose epidural: BUMPES randomized controlled trial, BMJ 2017). 

Grand Rounds often one leaves with more questions than answers. See you next time!