Prolonged third stage of labor linked to increased postpartum hemorrhage risk

Prolonged third stage of labor linked to increased postpartum hemorrhage risk | Image Credit: © Gorodenkoff - © Gorodenkoff - stock.adobe.com.

The risk of adverse maternal outcomes is increased by third stage of labor (TSL) longer than 15 minutes in vaginal birth, but data does not indicate manual labor of the placenta may reduce these risks, according to a recent study published in the American Journal of Obstetrics & Gynecology.¹

Mild and severe postpartum hemorrhage (PPH) rates have recently increased, highlighting a need to establish better recommendations for PPH prevention. The timing of manual removal of retained placenta (MROP) following vaginal birth with a prolonged TLS has been considered a potential risk factor of PPH.²

TLS is defined as the time from birth until expulsion of the placenta and membranes.¹ Currently, data about the best duration of TLS is lacking, leading to discrepancies in guidelines about the timing of MROP. It is also unclear whether MROP would improve overall maternal outcomes.

Investigators conducted a review to evaluate the link between TLS and adverse maternal outcomes after vaginal birth. The PubMed, MEDLINE, Embase, Cochrane Library, and additional databases were searched for articles published from January 1, 2000, to June 13, 2023.

The risk of adverse maternal outcome based on TSL length was reported as the primary outcome of the analysis. Adverse maternal outcomes were complications occurring during birth or after delivery, such as PPH, intensive care unit admission, blood transfusion, and peripartum hysterectomy.

Blood loss and declining hemoglobin level were also reported when available. Adverse outcomes were reported based on the timing of MROP as a secondary outcome.

Two authors performed title, abstract, and full-text screening. The 2 authors also performed data extraction. Categories of articles included those evaluating the link between TSL length and adverse maternal outcome and those evaluating the timing of MROP and maternal outcome.

There were 18 articles included in the final analysis, 16 of which focused on TSL length and maternal outcome while 3 evaluated MROP’s impact on maternal outcome when bleeding was not present. Sixteen studies occurred in high-income countries, 13 were single-center studies, and 5 were multicenter studies. The overall risk of bias was low.

Variations in the definition of adverse maternal outcome were reported between studies. An odds ratio (OR) for PPH was reported in 9 studies. Three evaluating red blood cell transfusion risk were included.

The risk of PPH was increased 5-fold by a TSL of at least 15 minutes, with an OR of 5.55. In comparison, the OR was 2.20 among women with a low risk profile. The highest pooled OR of 4.50 was reported among women with blood loss of at least 1000 mL.

A 3-fold increased risk of PPH was reported for a TSL over 30 minutes in women with a mixed risk profile for PPH. For those with a low risk profile, the OR was 3.28. When the TSL was over 60 minutes, the risk of PPH increased nearly 4-fold.

One study reported a correlation between blood loss quantity and TSL length, but a critical TSL length was not identified. In another study, an OR of 3.23 was reported for blood transfusion when the TSL length was over 30 minutes.

The risk of adverse maternal outcome based on MROP timing was only intended for assessment in 1 study. This analysis found a 19.2% increased incidence of hemodynamic compromise among women with placental removal after 15 minutes, vs a 6.4% increase when removal occurred after 10 minutes. In another study, an OR of 9.5 was reported for PPH when women underwent MROP vs those without spontaneous placenta expulsion.

These results indicated increased PPH risk in women with a TSL over 15 minutes, but no data supporting earlier MROP to reduce TSL. Investigators recommended randomized controlled trials be conducted to evaluate this issue further.

References

1. De Vries P, Veenstra E, Baud D, Legardeur H, Kallianidis AF, Van den Akker T. Time to redefine prolonged third stage of labor? A systematic review and meta-analysis of the length of the third stage of labor and adverse maternal outcome after vaginal birth. American Journal of Obstetrics & Gynecology. 2024;232(1):26-41. doi:10.1016/j.ajog.2024.07.019
2. Cheung WM, Hawkes A, Ibish S, Weeks AD. The retained placenta: historical and geographical rate variations. J Obstet Gynaecol. 2011;31(1):37-42. doi:10.3109/01443615.2010.531301