Authors
Jennifer Kask MD CCFP FCFP (biography, no disclosures) and Kirsten Duckitt MA MB BChir FRCOG FRCS (C) (biography and disclosures)
Dr. Duckitt disclosures: Received honoraria from Bayer and Merck pharmaceutical companies to provide educational talks and training in long-term reversible contraception. Mitigating potential bias: Treatments and recommendations in this article are unrelated to products/treatments involved in disclosure statements. Recommendations are consistent with published guidelines (SOGC Guideline 398: 2020).
What I did before
Preterm birth is the leading cause of perinatal morbidity and mortality in British Columbia and worldwide, accounting for up to 70% of perinatal deaths. The rate of preterm birth in BC has been about 7.4%,1 but in some communities is 2–3 times higher.2,3 Preterm birth is costly to families affected and also costly to the health system. Families from rural and remote communities often have to travel very long distances from home, their supports, and other children, to be at the bedside of their infant in a NICU in a tertiary care centre.
When we elicited a history of preterm birth, we would offer vaginal progesterone therapy for the prevention of preterm birth, as per The Society of Obstetricians and Gynaecologists of Canada (SOGC) Technical Update No. 202: The Use of Progesterone for Prevention of Preterm Birth,4 but the uptake was variable and some pregnant individuals were reluctant to take it, due to cost or concern about harm to their growing baby.
We continued to see pregnant individuals in our practice presenting in preterm labour who had a history of 1, 2, or 3 previous preterm births. Most had not been offered any interventions to reduce their risk of recurrence.
What changed my practice
In the spring of 2018, we took on a small quality improvement project to look at the prevention of preterm birth. We focused on the identification of individuals at risk of preterm birth, and interventions to offer them. Barriers to use of vaginal progesterone were identified — the cost specifically. We worked with staff at BC Pharmacare to develop a pre-printed Special Authority form to request vaginal progesterone therapy for prevention of preterm birth to be covered under exceptional circumstances.5
We discovered that although pregnant individuals now had the cost of their progesterone therapy covered, they continued to be reluctant to take it. We worked with the communications department at First Nations Health Authority (FNHA) to develop a patient-focused handout about vaginal progesterone therapy and a poster to inform women about preterm birth.6,7
In May 20208 the SOGC revised their 2008 guideline and recommended starting daily vaginal micronized progesterone at 16 to 24 weeks of gestational age (GA) in women with previous spontaneous preterm birth or with short cervical length (at a dose of 200mg for singleton pregnancies and 400mg for multiple pregnancies), continuing up to 34 to 36 weeks GA (strong recommendation, moderate-quality evidence). The authors define short cervical length as 25 mm or less at 16 to 24 weeks GA. For women with prior preterm birth or short cervical length, vaginal progesterone reduces the risks of preterm birth (< 37 weeks GA; odds ratio = 0.51, NNT = 7) and neonatal death (odds ratio = 0.41, NNT = 30). Other meta-analyses also recommend progesterone therapy as an effective intervention to prevent preterm birth and its subsequent morbidity and mortality.9,10
What I do now
We now carefully elicit any history of previous preterm birth and offer vaginal progesterone therapy for ANY history of spontaneous preterm birth. We fill in the Special Authority Request and give out the patient handout even before the patient goes to the pharmacy. We also encourage women to continue the medications until 37 weeks GA, since in our rural context birth before 37 weeks will still require a transfer to a Higher Level of Care (HLOC).
References and resources
- Statistics Canada. Preterm live births in Canada, 2000-2013. Catalogue no. 82-625-X. ISSN 1920-9118. Oct 26, 2016. Accessed January 24, 2023. https://www150.statcan.gc.ca/n1/pub/82-625-x/2016001/article/14675-eng.htm
- Island Health. Vancouver Island North – 434. Local Health Area Profile. Accessed January 24, 2023. https://www.islandhealth.ca/sites/default/files/vancouver-island-north-local-health-area-profile.pdf
- Island Health. Vancouver Island West – 433. Local Health Area Profile. Accessed January 24, 2023. https://www.islandhealth.ca/sites/default/files/vancouver-island-west-local-health-area-profile.pdf
- Farine D, MD, Mundle WR, MD, Dodd J, MD, et al. RETIRED: The Use of Progesterone for Prevention of Preterm Birth. J Obstet Gynaecol Can. 2008;30:67-71. doi:10.1016/S1701-2163(16)32716-5 (View with CPSBC or UBC)
- Ministry of Health. Special Authority Request. PharmaCare Form. HLTH 5328. Revised September 30, 2019. Accessed January 24, 2023. (Download PDF)
- First Nations Health Authority. Preventing Preterm Birth. Vaginal progesterone therapy. Accessed January 24, 2023. https://www.fnha.ca/Documents/FNHA-Preventing-Preterm-Birth.pdf
- First Nations Health Authority. Tips on Preventing a Birth Before 37 Weeks of Pregnancy. Created in partnership with Campbell River and District Division of Family Practice. Accessed January 24, 2023. https://www.fnha.ca/Documents/FNHA-preventing-preterm-birth-8.5×11.pdf
- Jain V, McDonald SD, Mundle WR, Farine D. Guideline No. 398: Progesterone for Prevention of Spontaneous Preterm Birth. J Obstet Gynaecol Can. 2020;42(6):806-812. doi:10.1016/j.jogc.2019.04.012. (View with CPSBC or UBC)
- Dodd JM, Jones L, Flenady V, Cincotta R, Crowther CA. Prenatal administration of progesterone for preventing preterm birth in women considered to be at risk of preterm birth. Cochrane Database Syst Rev. 2013;(7):CD004947. doi: 10.1002/14651858.CD004947.pub3. (View with CPSBC or UBC)
- Care A, Nevitt SJ, Medley N, et al. Interventions to prevent spontaneous preterm birth in women with singleton pregnancy who are at high risk: systematic review and network meta-analysis. BMJ. 2022;376:e064547. doi:10.1136/bmj-2021-064547 (View)
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In the absence of a short cervix, the evidence for vaginal progesterone in preterm birth prevention is actually very weak…though it is benign.
See below and the associated meta analysis. Romero might be the world’s expert on preterm birth.
https://today.wayne.edu/medicine/news/2022/06/07/progress-toward-personalized-prevention-of-preterm-birth-when-progesterone-works-and-when-it-does-not-48407
Good review!
Very interesting article. Though I now would have my patients cared for by maternity clinics/obstetricians by 12 weeks gestation, there are the odd patients who might not be seen by them by 14 weeks. I would definitely make sure that they have the Rx for vaginal micronized progesterone if that is the case if they fit the criteria. On reading the SOGC guideline on this topic, I am glad to learn that this treatment is now preferred over cervical cerclage for this indication except for rescue cerclage for an examination-based diagnosis (i.e., an effaced or dilated cervix). Thank you.