Do intrauterine pressure catheters make VBAC safer?

A mom planning a VBA1C (vaginal birth after one cesarean) at a Southern California Kaiser recently emailed me. She discovered while interviewing her care provider and asking how they treat VBAC labors differently than non-VBAC labors (an excellent question), that they require intrauterine pressure catheters (IUPC) in all VBAC labors. She wanted to know what I thought of their policy.

As I read more and more about IUPCs, I was increasingly curious why they would be required.  The evidence for their ability to predict uterine rupture is lacking and as a result major OB/GYN associations do not endorse their use in VBAC labors.  Below you will find the recommendations of the American College of Obstetricians and Gynecologists (ACOG), the Royal College of Obstetricians and Gynaecologists (RCOG aka Canada’s ACOG), abstracts of the studies they reference, as well as questions to ask your care provider if they require IUPCs.  As I find more info, I’ll update this page.

What is an IUPC?

WebMD describes it as “a small catheter that is placed along side the baby [that] measures the strength and duration of contractions.”

In order for the IUPC to be inserted next to the baby in the uterus, the fetal membranes must be ruptured and the cervix dilated to at least 1-2cm (UptoDate, 2011).  I suspect that this greatly, if not entirely, limits mom’s ability to move during labor depending on the policies of the hospital and care provider. This also increases the risk of infection and puts mom on the clock in terms of how long her care provider/hospital permits her to labor once her water has been broken.

Do professional obstetrical associations recommend IUPCs in VBACs?

While trying to find if IUPCs were helpful in labor, particularly in diagnosing uterine ruptures, the National Guideline Clearinghouse (2011) gave me a good starting point:

With regard to intrauterine pressure catheters, RCOG notes that their routine use in the early detection of uterine scar rupture is not recommended. ACOG similarly states that no data suggest that intrauterine pressure catheters are superior to external forms of monitoring, and there is evidence that their use does not assist in the diagnosis of uterine rupture.

What does ACOG say about IUPCs?

As I was interested in the exact language used in ACOG’s (2010) VBAC guidelines, I looked it up and found this:

No data suggest that intrauterine pressure catheters or fetal scalp electrodes are superior to external forms of monitoring, and there is evidence that the use of intrauterine pressure catheters does not assist in the diagnosis of uterine rupture.

What IUPC VBAC studies does ACOG reference?

ACOG cites only two studies in that paragraph. The first was published 18 years before ACOG’s recommendations where released and the second, 21 years before. If these are the best studies ACOG can find, then I’m left thinking that there are not many high quality studies on IUPC through 2010.

The first study cited was Devoe (1992) which concluded (emphasis mine),

Though intrauterine monitoring was brief, this model allows a unique view of ‘controlled’ uterine rupture. Spontaneous uterine rupture may evolve more gradually; however, neither catheter type [fluid-filled or solid] would be likely to aid its early recognition.

The second study was Rodriguez (1989) which found (emphasis mine):

The usefulness of the intrauterine pressure catheter in the diagnosis of uterine rupture was assessed by review of 76 cases of uterine rupture, 39 of which were monitored with an intrauterine pressure catheter. The classic description of a loss of intrauterine pressure or cessation of labor was not observed in any of the patients. However, an increase in baseline intrauterine pressure was observed in four patients with an intrauterine pressure catheter. The increase in pressure was associated with severe variable decelerations such that by itself the intrauterine pressure catheter added little to the diagnosis of uterine rupture.

What does RCOG say about IUPCs?

Then I looked up RCOG’s (2007) VBAC guidelines and it stated (emphasis mine):

The routine use of intrauterine pressure catheters in the early detection of uterine scar rupture is not recommended. Observational studies, with varying methodology and case mix, have shown that intrauterine pressure catheters may not always be reliable and are unlikely to add significant additional ability to predict uterine rupture over clinical and CTG surveillance. Intrauterine catheter insertion may also be associated with risk. Some clinicians may prefer to use intrauterine pressure catheters in special circumstances (such as in women who are obese, to limit the risk of uterine hyperstimulation); this should be a consultant-led decision.

What IUPC VBAC studies does RCOG reference?

RCOG cites four studies in that paragraph. Again, it’s surprising that these studies were published 15 – 25 years before the 2007 RCOG guidelines.

First, Arulkumaran (1992) which I found so interesting, I included the entire abstract (emphasis mine):

To evaluate the symptoms and signs of scar rupture with special reference to intrauterine pressure measurement a retrospective analysis of labour records of those women who had trial of labour with a previous Caesarean scar in the National University Hospital over a period of 6 years (1985-1990) was carried out. Known symptoms and signs associated with scar rupture, cardiotocographic tracings and fetal and maternal outcome in these patients were studied. Of the 1,018 women with previous Caesarean scar (4.2% of our pregnant population at term) 722 (70.9%) had trial of labour; 70% delivered vaginally. There were 4 (0.55%) incomplete and 5 (0.69%) complete scar ruptures. All 9 women had an oxytocin infusion; 3 were diagnosed postdelivery (all 3 had complete ruptures); 3 of the 6 who had rupture prior to delivery had sudden reduction in uterine activity, 1 had scar pain and prolonged bradycardia and 2 had no symptoms or signs. Continuous cardiotocography with intrauterine pressure measurements may help to identify scar rupture early and may be of value especially in those who have an oxytocin infusion.

Second, Beckley(1991) whose abstract doesn’t give us much information:

A series of 12 trials of scar associated with scar rupture is reviewed. Uterine activity patterns were assessable in 10 of them. Clinical features and characteristics of the intrauterine pressure waveform and uterine activity are discussed in relation to the integrity of the scar.

The third study RCOG cited was Rodriguez (1989) which ACOG also cited and I previously shared.

Fourth, Madanes (1982) whose abstract also is lacking any conclusions or major findings:

A case of uterine perforation by an intrauterine pressure catheter is described. Five similar cases from the literature are reviewed. A revision of the pressure catheter insertion technique is discussed.

Do IUPCs pose any risks to the baby?

I was very disappointed in the overall lack of published research on IUPCs in VBACs. I was further disappointed that there was very little discussion on the specific risks of IUPCs to mom or baby and at what rate these complications occur. I found Wilmink (2008) which discusses the IUPC related complications in two labors resulting in one infant death:

CASES: We describe the placement of an IUPC during induction of labor with oxytocin in two cases, one presenting with a singleton pregnancy and the other a twin pregnancy. After introduction of the IUPC, both cases were complicated by blood loss and signs of fetal distress on cardiotocography. An emergency cesarean section was performed in both cases. In the first case, extramembranous placement of the IUPC was observed, whereas in the second case, the IUPC had lacerated an arteriovenous anastomosis in the membranes, resulting in perinatal [infant] death. CONCLUSION: Placement of an intrauterine pressure catheter instead of external tocodynamometry has a small risk for serious fetal complications.

It would be helpful to have a large scale study on IUPCs conducted so we know how frequently complications like this occur.  It’s very difficult to weigh the pros and cons of IUPCs if we don’t fully understand the risks that they pose.  Is it worth mandating the use of IUPCs in VBAC labors if it means that the misplacement of the IUPC could sever the blood, and thus oxygen, supply to baby?

If your care provider requires IUPCs, what questions should you ask?

I posted on my Facebook page requesting the opinion of various midwives and OB/GYNs I know on the use of IUPCs in VBAC labors. Barbara Herrera provided this excellent list of questions:

  1. How will you know if there is a UR [uterine rupture]? What signs are you looking for?
  2. What is the process you go through to know it is a UR and not the IUPC misplacement or falling out?
  3. Who puts the IUPC in? The RN? Or you (the doc)? Who has more experience putting it in?
  4. How do we assure its proper placement?
  5. Will I be able to move about the bed and beside the bed once the IUPC is placed?
  6. If the IUPC registers something is amiss, as long as the FHR [fetal heart rate] is still okay, can I trust those around me not to freak out until we know if it is dislodged or misplaced? (Most women are much more able to move around with the IUPC than the external monitors.)
  7. Will using the IUPC mean I am going to have pitocin augmentation at some point?

The take away message

In light of the fact that

  • ACOG and RCOG do not recommend the use of IUPCs in VBACs as
  • IUPCs have not been proven effective in predicting uterine rupture and as
  • IUPCs can pose risks to babies (including blood loss and signs of fetal distress resulting in emergency cesareans and infant death) at a rate that we do not yet know while
  • requiring the (premature) breaking of fetal membranes (“breaking your water”),
  • increasing the risk of infection, and
  • possibly restricting mom to bed for her labor,

I can’t imagine why any hospital or OB would require their use.*

Elizabeth Allemann, MD left this comment on my Facebook page which I think summed up the issue well:

If a woman has decided to labor and birth with a uterine scar, she’s made her decision. If she wants to be successful, she’ll need what every woman needs to give birth: privacy, love, good nutrition, time, patience, touch, and care by a team that trusts her to give birth. And she’ll need that even more because she’s been scarred–in her heart and soul, not just on her uterus. And we need things to come down and out. An IUPC isn’t going to give her any of that. It’s a sad state of affairs when we can’t provide any of that in the hospital (generally) for any women and we end up forcing women to birth at home, just to get a chance to birth at all. Not that there’s anything wrong with home birth, but if a woman wants to give birth in the hospital, we should be able to provide that for her without a Niagara Falls of interventions waiting to pounce on her.

_____________________________________

* I had a conversation with a friend who teaches Bradley childbirth classes recently. She said that OBs/hospitals use IUPCs because then they can show that they “did everything” to protect the mom from uterine rupture and in the event that a UR did occur and they were taken to court, they could bring that information with them. But I responded with the fact that IUPCs have not been proven effective in predicting UR and ACOG/RCOG don’t recommend their use, so I don’t believe that would be a strong enough argument hold up in court.  I’m not an attorney, so I could be completely wrong, but that is what makes sense to my non-legal mind.

_____________________________________

American College of Obstetricians and Gynecologists (ACOG). Vaginal birth after previous cesarean delivery. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2010 Aug. 14 p. (ACOG practice bulletin; no. 115).

Arulkumaran S, Chua S, Ratnam SS. Symptoms and signs with scar rupture: value of uterine activity measurements. Aust N Z J Obstet Gynaecol 1992;32:208–12.

Beckley S, Gee H, Newton JR. Scar rupture in labour after previous lower uterine segment caesarean section: the role of uterine activity measurement. Br J Obstet Gynaecol 1991;98: 265–9.

Devoe LD, Croom CS, Youssef AA, Murray C. The prediction of “controlled” uterine rupture by the use of intrauterine pressure catheters. Obstet Gynecol 1992; 80:626-9. (Level II-2)

Lucidi RS, Chez RA, Creasy RK. The clinical use of intrauterine pressure catheters. J Matern Fetal Med. 2001 Dec;10(6):420-2. Review. PubMed PMID: 11798454.

Madanes AE, David D, Cetrulo C. Major complications associated with intrauterine pressure monitoring. Obstet Gynecol 1982;59: 389–91.

National Guideline Clearinghouse (NGC). Guideline synthesis: Vaginal birth after cesarean (VBAC). In: National Guideline Clearinghouse (NGC) [Web site]. Rockville (MD): 2011 Jan. [cited YYYY Mon DD]. Available: http://www.guideline.gov.

Royal College of Obstetricians and Gynaecologists (RCOG). Birth after previous caesarean birth. London (UK): Royal College of Obstetricians and Gynaecologists (RCOG); 2007 Feb. 17 p. (Green-top guideline; no. 45).

Rodriguez MH, Masaki DI, Phelan JP, Diaz FG. Uterine rupture: are intrauterine pressure catheters useful in the diagnosis? Am J Obstet Gynecol 1989; 161:666-9. (Level III)

Wilmink FA, Wilms FF, Heydanus R, Mol BW, Papatsonis DN. Fetal complications after placement of an intrauterine pressure catheter: a report of two cases and review of the literature. J Matern Fetal Neonatal Med. 2008 Dec;21(12):880-3.

9 thoughts on “Do intrauterine pressure catheters make VBAC safer?

  1. Davie

    Thank you for this article! I did not know anything about this until my doctor mentioned it to me today. I want a VBA2C and here in south Texas have found little support in the medical community. They either won’t touch me or want me hooked up to every monitor possible. I have a very supportive doula and hope to labor at home as long as possible. I will be taking this article to my next appointment and really digging into WHY this is something that must be done.

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *