Balloon or Foley catheters are a popular method of induction of labour in Australia. They can be used, by applying some pressure on the cervical opening, to ripen and dilate the cervix and stimulate the release of prostaglandins. The catheter is placed through the cervix, toward the bottom of the uterus, and gets inflated with a saline solution.
Although it is quite a simple procedure that can be performed by a doctor or a midwife, it can get tricky to insert and require several attempts, especially if the woman’s cervix is not “ripe” or “favourable” (meaning, the cervix is closed, or very slightly open, and still firm). The balloon catheter may help the ripening of the cervix, making it more likely to go into labour and or respond better to other interventions such as Syntocinon or artificial rupture of membranes.
Research shows that the risk of uterine hyperstimulation and tachysystole (excessively frequent uterine contractions) is reduced with mechanical methods of induction such as the balloon catheter, as opposed to inductions using pharmacological agents (e.g. locally applied prostaglandins such as Misoprostol) (Vaknin et al., 2010).
Foley catheter is considered to be a safe and effective procedure, without major side effects beyond some manageable pain, cramping and irregular contractions. A common concern about the insertion of a balloon catheter is the potential risk for infections, although a 2015 systematic review and meta-analysis including 5,563 participants over 26 randomised trials did not find an association between Foley catheter insertion and increased risk of infection/chorioamnionitis- which is an infection of the placenta and the amniotic fluid (McMaster et al., 2015). In Gu and colleagues' study, a large, randomised control trial conducted in 2015 , the overall chorioamnionitis rate after using a balloon for induction of labour was 3.8%, and the overall c-section rate was 17.8% (Gu et al., 2015). To compare, in 2015 in Australia, the rate of c-sections for first-time mothers with spontaneous labour was 16% (Australian Institute of Health and Welfare 2018).
The insertion of a balloon catheter is usually performed after the woman has emptied her bladder. The bulb is inserted either digitally or visually with the aid of a speculum and/or ring forceps. Then, the balloon is filled with 30 mL or 80 mL water (the use of a 80 mL balloon does not present an advantage over the 30 mL balloon, regarding the of birth, duration of labour or complications for mums and babies). Then, the catheter is taped to the woman’s thigh to exert some tension.
The catheter is removed by deflating the balloon and applying some light traction, either 12 or 24 hours after insertion. Although some researchers suggested that a maximum time limit of 12 hours for the ripening of the cervix might increase the likelihood to give birth vaginally within 24 hours compared to a 24-hour time limit, there is not enough evidence to back up this claim. The balloon can also be removed if the waters spontaneously break, the labour starts, or (rarely) in case of hyperstimulation or foetal distress. The balloon can also fall out by itself once the cervix is dilated, and the caregiver will normally break the waters to further induce labour.
References:
Australian Institute of Health and Welfare 2018. Australia’s health 2018. Australia’s health series no. 16. AUS 221. Canberra: AIHW. Available at: https://www.aihw.gov.au/getmedia/f434bda2-19f9-4a6f-ba8b-71d3008d17a4/aihw-aus-221-chapter-7-15.pdf.aspx
Greenberg, V., & Khalifeh, A. (2015, October). Intracervical Foley balloon catheter for cervical ripening and labor induction: A review. In Seminars in perinatology (Vol. 39, No. 6, pp. 441-443). WB Saunders. Available at: https://www-clinicalkey-com-au.elibrary.jcu.edu.au/#!/content/playContent/1-s2.0-S0146000515000774?returnurl=null&referrer=null
Gu, N., Ru, T., Wang, Z., Dai, Y., Zheng, M., Xu, B., & Hu, Y. (2015). Foley catheter for induction of labor at term: an open-label, randomized controlled trial. PloS one, 10(8), e0136856. Available at : https://go-gale-com.elibrary.jcu.edu.au/ps/i.do?p=AONE&u=james_cook&id=GALE%7CA427517476&v=2.1&it=r
Kruit, H., Heikinheimo, O., Ulander, V. M., Aitokallio-Tallberg, A., Nupponen, I., Paavonen, J., & Rahkonen, L. (2016). Foley catheter induction of labor as an outpatient procedure. Journal of Perinatology, 36(8), 618-622.Available at : https://go-gale-com.elibrary.jcu.edu.au/ps/i.do?p=AONE&u=james_cook&id=GALE|A459985544&v=2.1&it=r
McMaster, K., Sanchez-Ramos, L., & Kaunitz, A. M. (2015). Evaluation of a transcervical Foley catheter as a source of infection: a systematic review and meta-analysis. Obstetrics & Gynecology, 126(3), 539-551. Available at: https://oce-ovid-com.elibrary.jcu.edu.au/article/00006250-201509000-00014/HTML
Price, C. A., & Robinson, S. (2010). Birth: Conceiving, nurturing and giving birth to your baby. Macmillan Publishers Aus.
Safer Care Victoria (2023), Induction of labour. Available at: https://www.safercare.vic.gov.au/clinical-guidance/maternity/induction-of-labour
Vaknin, Z., Kurzweil, Y., & Sherman, D. (2010). Foley catheter balloon vs locally applied prostaglandins for cervical ripening and labor induction: a systematic review and metaanalysis. American journal of obstetrics and gynecology, 203(5), 418-429. Available at: https://www-sciencedirect-com.elibrary.jcu.edu.au/science/article/pii/S0002937810004928?via%3Dihub