Can balloon catheters cause cord prolapse?

medium_12818434054I’m always a bit wary of the shortness of many modern forms of media, and this includes blog and facebook posts, because it’s all too easy to post something which doesn’t say enough about the context of the information presented, or include enough caveats for those who happen upon one offering without being aware that there is a bigger landscape.  So before I start today’s post ‘for real’, I wanted to begin by saying that I am going to write about a research study which raises an issue which is very interesting and potentially worrying, but which (at the time of posting) needs more investigation and needs to be considered within that wider landscape.

One of the things that can occasionally go wrong during birth is known as umbilical cord prolapse, and this term describes a situation where the baby’s cord slips down past her head, which means it can get compressed between her head and her mum’s pelvis, which can cut off the oxygen supply to the baby.  When an umbilical cord prolapses, an emergency caesarean section is almost always recommended.  We already know that just under half of all cases of umbilical cord prolapse are iatrogenic; that is, caused by medical interventions such as artificial rupture of membranes (where a midwife or doctor breaks a woman’s waters), attempted rotation of the baby’s head or the insertion of a device such as an intrauterine pressure catheter, fetal scalp electrode (for monitoring the baby’s heartbeat), cervical ripening balloon catheter (sometimes used for induction of labour) or amnioinfusion (Murphy and MacKenzie 1995, Usta et al 1999, Phelan and Holbrook 2013).

Hasegawa et al (2015), a team of researchers based in Tokyo, were interested in looking for more data which might help “clarify whether the use of balloons for cervical ripening is associated with the occurrence of umbilical cord prolapse.”  To this end, they sent questionnaires to the 2,683 institutions that provide maternity services across Japan, receiving replies from 942.  The analysis of the data confirmed that, “the risk of umbilical cord prolapse was significantly increased during the use of balloons for cervical ripening, especially in cases involving the use of disk-type and ball-type balloons filled with large amounts of water.”

medium_16084605One of the reasons I began this post with the caveat is that, while it is always great to see people looking for further information on topics of concern to women and families, different types of research have different pros and cons which need to be taken into account. In this case, the use of questionnaires is a relatively cheap* way of exploring this question, as it allowed the researchers to ask many, many institutions for data.

*Yes, I know that would have been a lot of stamps / email sending time … but RCTs still cost an awful lot more 😉

The downsides of this kind of retrospective research include that it is only as reliable as the people who filled out the woman’s and baby’s medical records, the people who inputted that data onto the maternity compiuter system and, later, the people who used to computer data to fill out the questionnaires.  This is a significant source of potential bias in the West, and we all know how often professionals are filling out forms when under intense pressure, so it’s probably easy to imagine how mistakes could be made in the first place, and the multiple translations of information from one form to another compounds the situation.  It may be unfair to just assume that the same is true within Japan though. The researchers believe their data quality is good, and their concern was more for the fact that the smaller hospitals did not have computerised records, which meant that the questionnaries could not be filled out from these.

That note of caution aside, the authors state that, “this is the first large population-based investigation to demonstrate the exact prevalence of umbilical cord prolapse in association with the use of balloons for cervical ripening.”  Even if the retrospective use of medical records as data means that this is not the exact prevalence, I certainly think the results should give us pause for thought and prompt us to consider where we go next with this.

One paragraph which I think will be of particular interest to birth professionals is this one:

“According to the answers to questions in which prolapse of the umbilical cord occurring during labor  associated with the use of balloons for cervical ripening, umbilical cord prolapse occurred after a while balloon removal (sic) in more than half of the cases (53%). Even when umbilical cord prolapse did not occur during the use of a balloon or at removal, it may be possible to preserve the elevating fetal presenting part out of the pelvis and induce the wrong rotation of the fetal head, resulting in umbilical cord prolapse. Furthermore, the use of a balloon may involve occult umbilical cord prolapse during the procedure, after which umbilical cord prolapse is detected due to the identification of the descending fetal presenting part or rupture of the  membranes. Unfortunately, only 57% of doctors participated (sic) in the present study answered that umbilical cord presentation was routinely confirmed using ultrasound scans during the use of a balloon for cervical ripening (data are not shown). Thus, the ultrasound confirmations of the umbilical cord presentation to diagnose fore-lying and occult prolapse of the umbilical cord before balloon placement, after and prior to removal might improve perinatal outcomes.”

All interventions carry possible risks, and those possible risks need to be weighed up against the possible benefits of intervention, and in my humble opinion this needs to be done on an individual basis, by and for individual women and babies and families.  Each time a team such as that led by Hasegawa et al (2015) publish a study like this, it gives us another piece of the puzzle.

The Research

Background: To clarify whether the use of balloons for cervical ripening is associated with the incidence of umbilical cord prolapse.

Methods: A postal questionnaire survey was distributed in Japan. Cases of umbilical cord prolapse occurring during labor in association with the use of balloons for cervical ripening between 2007 and 2011 in Japan were analyzed.

Results: Answers from 942 institutions were obtained. The subjects included 369 patients with fore-lying or prolapse of the umbilical cord among a total of 2,037,460 deliveries. Among the singleton vertex cases, fore-lying or prolapse of the umbilical cord during labor were observed in 88 (0.005%) of 1,891,189 deliveries not associated with the use of balloons for cervical ripening and in 93 (0.064%) of 146,271 deliveries associated with the use of balloons for cervical ripening (Odds ratio 13.67, 95% confidence interval 10.21, 18.30). All types of balloons were significantly associated with the occurrence of fore-lying or prolapse of the umbilical cord. A total of 39% of cases of umbilical cord prolapse occurred during manual or spontaneous balloon removal, while 53% of cases occurred after a while not directly associated with balloon removal.

Conclusion: The risk of umbilical cord prolapse was significantly increased during the use of balloons for cervical ripening, especially in cases involving the use of disk-type and ball-type balloons filled with large amounts of water.
References

Hasegawa J (2015).  The use of balloons for uterine cervical ripening is associated with an increased risk of umbilical cord prolapse: population based questionnaire survey in JapanBMC Pregnancy and Childbirth 2015, 15:4  doi:10.1186/s12884-015-0432-4

Murphy DJ, MacKenzie IZ (1995). The mortality and morbidity associated with umbilical cord prolapse. British Journal of Obstetrics and Gynaecology. 1995;102(10):826–30

Phelan ST, Holbrook BD (2013).  Umbilical cord prolapse.  A plan for an OB emergency.  Contemporary OB/GYN

Usta IM, Mercer BM, Sibai BM (1999). Current obstetrical practice and umbilical cord prolapse. American Journal of Perinatology. 16(9): 479–84.

photo credits: acase1968 and itchys via photopin cc and cc

2 comments for “Can balloon catheters cause cord prolapse?

  1. Emmy
    August 6, 2015 at 12:01 am

    This is something that may have happened in the birth of my son 2 months ago. I was almost at 42 weeks so decided to try a Folley Catheter to induce labor. Went into labor the next day, after 4 hours went to the birth center where the fetal heart tones were taken and he was in extreme distress. Ended with an emergency C section that showed his cord was next to his head (occult cord prolapse) it is disturbing to think this could have been caused by the folley catheter. Luckily he was born completely healthy.

  2. Emmy
    August 6, 2015 at 12:47 am

    I should add to my earlier comment that this was my first pregnancy, there were no complications and the baby was in an ideal position.

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