#breech
Day 2
Day 2
Dr. Sophie Alexander:
The PREMODA study
Dr. Sophie Alexander participated in the Belgian arm of the PREMODA study, which is often referred to as the "antidote to the Term Breech Trial." In France and Belgium, there’s always been a strong tradition of vaginal breech birth (VBB) and a strong belief in the value of vaginal birth. Thus VBB is still formally taught in residency programs.
After the TBT and other studies came out, PREMODA (an observational prospective study) was designed. They used the same criteria and outcome measures as the TBT, except the decision for a cesarean section (CS) or VBB was the woman’s, not randomized. It was a huge study with over 8,000 women registered. If a hospital participated, then all term breech presentations in the entire hospital were included in the study. Thus there were no recruitment issues as with the TBT.
The PREMODA study investigated 3 groups: planned CS, planned VBB, and unplanned CS during a planned VBB. Data collection took place over 1 year from June 1 2001- May 31 2002. In total there were 8,105 women in the study. 28% of planned VBB ended in a cesarean during labor. They had much less crossover in the planned CS arm (< 1%) than in the TBT (10%).
Their results were significantly different from the TBT's results. In the PREMODA study, none of the antepartum deaths were related to choosing a vaginal breech birth. Almost all neonatal deaths were due to lethal conditions or severe congenital malformations. There were two deaths associated with unbooked (unplanned) home births, one of which was a concealed pregnancy.
The PREMODA study found somewhat higher levels of immediate morbidity (low Apgars, need for ventilation) after a VBB compared to a planned CS, which is not surprising. The differences were small and transient. Vaginally born breech babies had somewhat more birth trauma, but levels were not very significant.
Overall, if you compare the TBT with the PREMODA study, rates of death or serious neonatal morbidity were much lower in the PREMODA study. Remember that the criteria and outcome measures were identical in both studies, making it easy to draw comparisons between the two.
Since the original PREMODA study, they’ve written up two more articles based on the data they collected:
- Azria E et al. Factors associated with adverse perinatal outcomes for term breech fetuses with planned vaginal delivery. Am J Obstet Gynecol. 207.4 (Oct 2012):285.
- Carayol M et al. Non-clinical determinants of planned cesarean delivery in cases of term breech presentation in France. Acta Obstet Gynecol Scand. 86.9 (2007):1071-8.
Based on this study, the RCOG came up with new breech guidelines in 2009. Dr. Alexander commented, "We think the antidote is working."
After Dr. Alexander's presentation, there was an interesting discussion:
Q: How many deliveries constitutes an experienced attendant?
A: At her hospital, they require at least 5 year’s residency to be considered experienced in breech. They have 5-6 breeches/month, and residents work 1 day in 4. So on average, a resident could see up to 75-90 planned VBBs over a 5-year period. They allow for the individual's feeling of confidence and interest in doing VBB.
Anke Reitter: In Frankfurt, they train as many people as they can, but then they leave and go onto other units and stop doing VBBs. It’s really just her and Frank Louwen doing all the vaginal breech births.
Sophie Alexander: Her unit has at least 7 people who are comfortable with VBB.
Betty-Anne Daviss: The Canadian guidelines are now turning to require a certain amount of VBBs on hands and knees, since that’s what women are asking for. Some of the older OBs who have done lots of breech births aren’t skilled enough in this new technique.
Marek Glezerman: How do we define who is skilled in VBB? The TBT study defined it as “someone who considered themselves skilled and was approved by the department chair.” He finds this very problematic. He strongly believes that we need standardization in breech skills. We need a model that’s the same everywhere--we can do this via simulation training. Residents should undergo a structured theoretical and practical training program with drills.
He was a pilot years ago, and he learned again and again how to do emergency landings. Even today, whenever he is on an airplane he instinctively searches out good locations for an emergency landing. The same goes for OBs. All OBs should have thorough breech training on a model so they have the skills if needed (even if they don’t choose to attend planned VBB).
Don’t forget the importance of peer pressure among OBs—if you can get some obstetricians who are confident in VBB, it might pressure the others into obtaining those skills so they don’t look bad in front of their peers.
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Hmmm, you say that PREMODA used the same criteria as the TBT, but in my understanding that wasn't correct. The original PREMODA study notes, "comparison of PREMODA and the Term Breech Trial shows that
ReplyDeletephysicians in the former used pelvimetry in the planned vaginal delivery group much more often (82.4% vs
9.8%).
Management of labor also differed between these studies. Fetal surveillance of all PREMODA cases, but only 33.4% of those in the Term Breech Trial, used continuous FHR. The percentage of women with an active phase of the second stage of labor longer than 60 minutes was only 0.2% versus 5.0% in the Term Breech
Trial.
A secondary analysis of the latter reported that an adverse perinatal outcome was associated with an
active phase of the second stage 60 minutes or more.Active pushing began after the presenting part reached the high pelvic straits in only 3.6% of cases (information not reported in the Term Breech Trial). French guidelines recommend waiting to initiate active pushing in breech presentation until the presenting part reaches the outlet. This practice often leads to a long passive phase of the second stage of labor: 60 minutes or more in 18.1% in the PREMODA study versus 3.1% in the Term Breech Trial.
Finally, only 3.8% of cases in our vaginal delivery group involved labor that failed to progress for more than 2 hours."
They also note, "The low risk in the planned vaginal delivery group may be associated with more prudent obstetric practices since the publication of the Term Breech Trial. According, the rate of cesarean delivery before labor for singleton term breech infants in France has increased from 49.0% in 1998 to 75.0% in 2003 (Enquête National Périnatale 2003, unpublished data), a rise also seen in the Netherlands, Australia, and New Zealand.
Although we do not have historic data for neonatal outcome in France, it is possible that the situation is similar to that observed in the Netherlands, where perinatal mortality decreased from 0.35% to 0.18% between 1998 and
2002."
Not only are there in fact some significant differences in management between TBT and PREMODA, but some of PREMODA's caution may be directly in response to the TBT findings.
Yes Becky, good points. I think I should have used the phrase "outcome criteria" or "outcome measures" to be more specific. Basically, they designed the study to be able to compare as many outcomes side-by-side as possible. But it's true that labor management criteria were different.
DeleteI would like to know what is the criteria or guidelines for pushing with vaginal breech. What are the doctors using to determine how long second stage is? If there is progress? If there is no progress after one hour of pushing?
ReplyDeleteI have seen a 1 hour limit be used. After one hour of pushing if it's determined there has been no further progress in that hour, then it goes to a Cesarean. I am looking for the research regarding this.
Thanks very much. Debra Woods, birth doula
Debra,
DeletePushing guidelines vary by country. In the Frankfurt clinic, they have a 4-hour time limit from full dilation (not necessarily pushing) to birth. In Canada they allow 90 minutes passive 2nd stage plus 60 minutes active 2nd stage. Off the top of my head I couldn't cite the research for making those guidelines, but I'm sure it exists. I know many of the Canadian guidelines were formed by looking at breech studies and trying to see where the bad outcomes happened, then making guidelines to exclude those labor/pushing patterns. I'd read the SOGC breech guidelines for more information and for further references.