UOG Journal Club: July 2016

1. UOG Journal Club: July 2016 Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study J Min, HA Watson, NL Hezelgrave, PT Seed and AH Shennan Volume 48, Issue 1, Date: July, pages 38–42 Journal Club slides prepared by Dr Joel Naftalin (UOG Editor for Trainees)

2. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Background • Preterm birth and its consequences are the biggest cause of neonatal morbidity and mortality • Preterm delivery is difficult to predict in asymptomatic women, even if they are high risk • Clinical history, measurement of cervical length and fetal fibronectin have all been used to try and accurately predict preterm labor • More accurate prediction of preterm labor could lead to the more efficient use of prophylactic interventions and treatments

3. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Objective To identify whether a preterm surveillance clinic (PSC) risk-stratifies asymptomatic high-risk women accurately

4. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Patients and Methods • This was subanalysis of a large observational study (Evaluation of Quantitative Instrument in the Prediction of Preterm birth) • Women with a singleton pregnancy who were asymptomatic but high risk for preterm delivery were seen between 23+0 and 28+0 weeks’ gestation • Fetal fibronectin and cervical length measurement were used in conjunction with clinical history to assess risk • Following the assessment, women deemed high risk were admitted to hospital and managed according to local protocols

5. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Patients and Methods • Inclusion criteria were: • previous late miscarriage (16 to 23+6 weeks) • previous preterm birth (<37 weeks) • previous preterm prelabor rupture of membranes (<37 weeks) • previous cervical surgery (e.g. LLETZ, cone biopsy) • uterine abnormality • cervical length <25mm on transvaginal ultrasound • Exclusion criteria were: • vaginal bleeding • preterm prelabor rupture of membranes in index pregnancy • multiple pregnancy • cervical dilation ≥ 3cm

6. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Patients and Methods • A comparison was made between women who were managed as outpatients and those who were admitted after assessment • Outcomes compared were: • gestational age at delivery • stillbirth/neonatal death • admission to NICU • birth weight • respiratory distress syndrome • intraventricular hemorrhage • 5-min Apgar score <7

7. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Statistics and analysis • The primary outcomes were mean gestational age at delivery and delivery <30 weeks • Secondary outcomes were mean birth weight and delivery <34 and <37 weeks • All categorical variables were compared using the chi-square test with statistical significance set at P <0.001 (multiple hypothesis testing) • Student’s t-test was used to compare the average maternal age, average gestational age at delivery and average birth weight

8. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 There were statistically significant differences between the two groups whereby the rate of cervical surgery was higher in the outpatient group and the rate of second-trimester miscarriage was higher in the inpatient group Results

9. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Table showing outcomes in 1130 asymptomatic pregnant women at high risk of preterm birth and either admitted to hospital (inpatient) or managed as an outpatient Results

10. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Results • Women admitted following assessment at the PSC were significantly more likely to deliver before 30 weeks (relative risk, 27.6 (95% CI, 15.0–50.1)) than were women who were not admitted • Despite their risk factors, women who were not admitted had a low rate of preterm delivery before 30 weeks (1.32%), comparable to the background rate in England and Wales (1.2% deliver < 31 weeks) • The mean gestational age at delivery in those managed as outpatients was significantly higher than in those admitted (38.4±2.5 vs 31.2 ±5.6 weeks; P<0.0001) • All secondary outcomes were consistent, with worse clinical outcomes in the group of women managed as inpatients

11. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Conclusion • PSCs measuring cervical length and quantitative fetal fibronectin accurately triage asymptomatic high-risk pregnant women, enabling those at highest risk of adverse outcome to be identified for elective admission to hospital and appropriate management

12. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Strengths • The study used prospectively collected data • The study contained a large group of asymptomatic women who were at high risk for preterm birth • The study used an already established treatment protocol

13. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Limitations • The two groups underwent substantially different management which may have impacted the measured outcomes • The authors imply that discretion was occasionally used when deciding whether or not to admit women from the clinic • The study did not evaluate medium- and long-term neonatal outcomes

14. Ability of a preterm surveillance clinic to triage risk of preterm birth: a prospective cohort study Min et al., UOG 2016 Discussion points • Can this data be extrapolated to asymptomatic high-risk women attending general antenatal clinics rather than specialist preterm birth clinics? • Given the significant differences between the two groups with regards to history of second-trimester miscarriage and cervical surgery, might the clinic protocol be adapted to give different weightings to these factors? • Does our increasing reliance on objective tests (e.g. fetal fibronectin and cervical length) blunt our clinical judgment? • How can we reduce the social and emotional burden on women being admitted to hospital from as early as 23 weeks?