The Length of Third Stage of Labor and Risk of Postpartum Hemorrhage

Abstract & Commentary

John C. Hobbins, MD, Professor and Chief of Obstetrics, University of Colorado Health Sciences Center, Denver, is Associate Editor for OB/Gyn Clinical Alert

Synopsis: A third stage of labor longer than 18 minutes is associated with a significant risk of postpartum hemorrhage. After 30 minutes the odds of having postpartum hemorrhage are 6 times higher than before 30 minutes.

Source: Magann EF, et al. Obstet Gynecol. 2005;105:290-293.

How long does one wait for a placenta to deliver without help? A paper recently surfaced to answer that question. Magann and colleagues reviewed 2 hours worth of data from one hospital involving 6588 vaginal deliveries. These deliveries were attended by nurse midwives under guidelines that included watchful waiting during the third stage of labor until 30 minutes, after which an attempt was made to remove the placenta through manual extraction. The appealing feature of the study was that postpartum blood loss was compulsively assessed by use of collection devices and the weighing of linens. Magann et al defined postpartum hemorrhage (PPH) as a total maternal blood loss of > 1000 cc. Hemodynamic stability or drop in hematocrit were not used as dependent variables. The results were interesting in that the median third-stage times were only 2 minutes different between those experiencing PPH and those not having this complication (9 minutes vs 7 minutes). However, the results indicated that the longer the placenta stayed in, the greater the chance of PPH. The risk was significant at 10 minutes (OR, 2.1; 95% CI, 1.6-2.6). At 20 minutes the OR was 4.3 (95% CI, 3.3-5.5) and after 30 minutes, the OR was 6.2 (95% CI, 4.6-8.2).

Comment by John C. Hobbins, MD

Others have reported that:

  1. Significant PPH occurs in 4% of deliveries;1
  2. Third stage length of more than 30 minutes has been associated with a significant increase in PPH;2
  3. Although controversial, some have indicated that active management of the third stage (with ecbolics such as methergine or oxytocin, etc) results in shorter third stages and less blood loss compared with the passive approach.3,4

There were a few interesting wrinkles in the above study that might possibly affect its interpretation. For example, despite the usual hands-off approach by nurse midwives, oxytocin was given with the anterior shoulder (our practice is to routinely use a pitocin drip only after delivery of the placenta). Also, Magann et al state that the vast majority of deliveries were accomplished under epidural anesthesia and one wonders whether these results would apply to those not having epidurals.

The most puzzling part of the study has to do with an apparent discrepancy between the study protocol and the results. Supposedly placentas were all manually removed after thirty minutes following delivery of the neonate. However, the results showed a 6-times greater risk of PPH after 30 minutes and their 90th percentile started at 1 hour and 48 minutes. Since the median difference between groups was only 2 minutes, a few "maverick" values could be skewing the results.

It is clear from this study and others that the longer the placenta stays in the greater the chance of PPH. However, is it the presence of the unextracted placenta or the reason the placenta is retained that is responsible for the hemorrhage? Also, how large a role does our answer to retained placenta (manual extraction and D & C) play in the ultimate total blood loss? Is the solution actually the cause?

Retained placentas come in 3 varieties—those that are separated and are in the lower uterine segment or vagina; those that are separated but still in the uterus; and those that have not yet separated. Wherever they are, if they are separated, a gentle pull on the cord should suffice to deliver the placenta. If not, how long should we wait for the rare adherent one to separate? This dilemma lends itself to further investigation through simple ultrasound evaluation—something that is underway at our institution.

I have a feeling that the above study, with all its limitations, will start a dictum that at 18 minutes 30 seconds all placentas should be manually extracted. Worse yet, since after 10 minutes of third-stage labor the study showed a doubling of risk, even earlier aggressive interventions would now be entertained. This could then prompt the logical sequel on inverted uteri and PPH.

References

  1. Combs CA, Laros RK. Obstet Gynecol. 1991;77:863-867.
  2. Prendiville WJ, et al. (Cochrane Review). In: The Cochrane Library, Issue 3, 2000. Oxford: Update Software.
  3. Rogers J, et al. Lancet. 1998;351:693-699.
  4. Combs CA, et al. Obstet Gynecol. 1991;77:69-76.