Table 3 Characteristics of included studies reporting on multiple clinics
Study details | Characteristics of women cared for in the clinic and spontaneous preterm birth rate | Eligibility criteria for referral to the clinic | Investigations and interventions offered | Timing and frequency of review |
|---|---|---|---|---|
1. Kindinger 2016 Retrospective observational study. January 2004 to January 2014. Queen Charlotte’s Hospital, St Mary’s Hospital and Chelsea and Westminster Hospital; London, UK. | 725 women; Caucasian 66%, Black 18%, Asian 16%. Risk factors for spontaneous preterm birth: previous excisional cervical treatment to a depth of ≥12 mm 100% (women with other risk factors specifically excluded from this study). Spontaneous preterm birth rate < 37 weeks 9%, < 34 weeks 2%. | Previous preterm birth < 37 weeks. Previous mid-trimester miscarriage > 13 weeks. Uterine anomaly. Previous excisional cervical treatment to a depth of ≥12 mm (cone biopsy, LLETZ or LEEP). | Investigations: - Transvaginal cervical length ultrasound scans. Interventions: - Cervical cerclage. | The first visit is planned for 13–16 weeks. Frequency of planned review not reported. Women are discharged at 20–23 weeks. |
2. Watson 2017 Prospective cohort study. April 2012 – November 2016. Guys and St Thomas’ Hospital and University College London Hospital; London, UK. | 66 women; White 61%, Black 32%, Asian/Middle-Eastern 8%. Risk factors for spontaneous preterm birth: previous spontaneous preterm birth or late miscarriage 100%. Spontaneous preterm birth rate < 37 weeks 35%. | Previous spontaneous preterm birth < 37 weeks. Previous spontaneous late miscarriage between 14 and 24 weeks. | Investigations: - Transvaginal cervical length ultrasound scans. Interventions: - Cervical cerclage if cervix < 25 mm. - Vaginal progesterone. - Arabin pessary. | Not reported. |
3. Cohen 2014 Retrospective audit (conference abstract only). January 2013 – May 2014. St Mary’s Hospital and Queen Charlotte’s Hospital; London, UK. | 509 women; Caucasian 59%, Afro-carribean 15%. Risk factors for spontaneous preterm birth: previous preterm labour < 34 weeks 26%, previous mid-trimester miscarriage 17%, previous excisional cervical treatment 50%, uterine anomalies 2%, multiple pregnancy 3%. Spontaneous preterm birth rate < 37 weeks 11%, < 34 weeks 4%. | Previous preterm labour < 34 weeks. Previous mid-trimester miscarriage. Previous excisional cervical treatment. Uterine anomalies. Multiple pregnancy. | Investigations: - Transvaginal cervical length ultrasound scans. Interventions: - Cervical cerclage. - Vaginal progesterone. | Not reported. |
4. Kuhrt 2016 Prospective observational study. October 2010 – July 2014. St Thomas’ Hospital, Queen Charlotte’s Hospital, University College London Hospital, West Middlesex University Hospital; London, UK; Manchester St Mary’s Hospital; Manchester, UK. | 1249 women. Ethnicity: White 56%, Black 29%, Asian 8%, other 9%. Risk factors for spontaneous preterm birth: previous spontaneous preterm birth 38%, previous PPROM 19%, previous late miscarriage 22%, previous cervical surgery 44%, short cervix < 25 mm 15%. Spontaneous preterm birth rate < 37 weeks 15%, < 34 weeks 8%. | Previous spontaneous preterm birth < 37 weeks. Previous PPROM < 37 weeks. Previous late miscarriage 16–24 weeks. Previous cervical surgery. Cervical length < 25 mm in the current pregnancy. | Investigations: - Transvaginal cervical length ultrasound scans. - Quantitative fFN. Interventions: - Cervical cerclage: history-indicated if ≥3 late miscarriages or previous spontaneous preterm births < 34 weeks; ultrasound-indicated if cervix < 25 mm. - Vaginal progesterone. | Gestation of planned first visit not reported. Women seen every 2–4 weeks. Women are discharged at 30 weeks. |
5. Vousden 2015 Prospective observational study. November 2010 – July 2014. Fifteen hospitals across the UK, nine of which have preterm birth clinics – St Thomas’ Hospital, Queen Charlotte’s Hospital, University College London Hospital, West Middlesex University Hospital; London; Royal Infirmary of Edinburgh, Edinburgh; Sunderland Royal Hospital; Sunderland; Manchester St Mary’s Hospital; Manchester; University Hospital; Coventry; Royal Victoria Infirmary; Newcastle. | 54 women; Black 46%, White 35%, other 19%. Risk factors for spontaneous preterm birth: previous preterm birth 44%, previous second trimester miscarriage 72%, previous cervical surgery 7%. Spontaneous preterm birth rate < 34 weeks 11%. | Previous preterm birth. Previous second trimester miscarriage. Previous cervical surgery. | Investigations: - Transvaginal cervical length ultrasound scans. Interventions: - Cervical cerclage. - Vaginal progesterone. | Not reported. |
6. Care 2019 Cross-sectional study (survey). March 2017 – July 2017. Thirty-three unnamed clinics across the UK (list obtained from authors but not included here). Primary and secondary outcome data also obtained from Sharp 2014, which was the original study updated by Care 2019. | This study reports on the typical practice of preterm birth clinics, not on individual women cared for in them. | Percentage of clinics with each referral criteria (n = 32 clinics): Previous preterm birth, 100%, at gestations of: < 37 weeks 13%. < 35 weeks 3%. < 34 weeks 65%. < 32 weeks 13%. < 28 weeks 3%. Other 3%. Previous PPROM, 91%, at gestations of: < 37 weeks 16%. < 34 weeks 55%. < 32 weeks 13%. < 28 weeks 6%. Other 10%. Recurrent second trimester loss 91%. Previous cervical surgery: ≥1 LLETZ 47%. ≥2 LLETZ 100%. Cone biopsy 100%. Uterine anomalies 75%. Recurrent first trimester loss 16%. Threatened preterm labour 13%. Incidental finding of a short cervix 88%. | Investigations (n = 32 clinics): - Transvaginal cervical length ultrasound scans 100%. Additional Investigations (n = 22 clinics from Sharp 2014, not reported in Care 2019): - Vaginal flora swabs 59%. - Vaginal acidity 0%. - Cervical stress test 14%. - fFN 32%. Interventions (n = 32 clinics): Primary treatment choice for asymptomatic women with a short cervix on ultrasound: - Cervical cerclage 30%. - Vaginal progesterone 18%. - IM progesterone 0%. - Arabin cervical pessary 3%. - Combination treatment (most commonly cervical cerclage and vaginal progesterone) 18%. - Multiple first line treatment options 30%. Treatment threshold: - < 25 mm 55%. - < 15 mm 3%. - Centile charts 15%. - Centile chart and/or < 25 mm 12%. - Other cervical length cutoff 3%. QUIPP App 12%. Additional advice (n = 22 clinics from Sharp 2014, not reported in Care 2019): - Restricting physical activity 45%. - Sick leave 27%. - Refraining from sexual intercourse 41%. - Nutrition 27%. - Bed rest 0%. - No further advice 36%. | Gestation of planned first visit (n = 32 clinics): - < 12 weeks 9%. - 12–14 weeks 38%. - 15–16 weeks 50%. - > 16 weeks 3%. - As soon as referred 0%. Frequency of planned review (n = 22 clinics from Sharp 2014, not reported in Care 2019): - Every 2 weeks 18%. - Every 4 weeks 5%. - Based on clinical findings 77%. Gestation of planned last visit after a diagnosis of short cervix (n = 22 clinics from Sharp 2014, not reported in Care 2019): - 24 weeks 5%. - 28 weeks 41%. - 30 weeks 5%. - 34 weeks 36% - 37 weeks or delivery 14%. |