Identification of biochemical biomarkers associated with premature cervical shortening in high-risk, asymptomatic pregnant women: a retrospective data analysis

Reliably predicting spontaneous preterm birth remains challenging, therefore it persists as a major contributor to perinatal morbidity and mortality. The use of biomarkers to predict premature cervical shortening, a recognised risk factor for spontaneous preterm birth, is yet to be fully explored in current literature. This study evaluates seven cervicovaginal biochemical biomarkers as possible predictors of premature cervical shortening. Asymptomatic, high-risk women (n = 131) presenting to a specialised preterm birth prevention clinic were analysed through a retrospective data analysis. Cervicovaginal biochemical biomarker concentrations were obtained, and the shortest cervical length measurement, up to 28 weeks' gestation, was recorded. Associations between biomarker concentration and cervical length were then analysed. Of the seven biochemical biomarkers, Interleukin-1 Receptor Antagonist and Extracellular Matrix Protein-1 had statistically significant relationships with cervical shortening below 25 mm. Further investigation is required to validate these findings and any downstream clinical utility, with intentions to improve perinatal outcomes.IMPACT STATEMENTWhat is already known on this subject? Preterm birth is a major cause of perinatal morbidity and mortality. A woman's risk of delivering preterm is currently stratified using historical risk factors, mid-gestation cervical length, and biochemical biomarkers such as foetal fibronectin.What do the results of this study add? In a cohort of high-risk, asymptomatic pregnant women, two cervicovaginal biochemical biomarkers, Interleukin-1 Receptor Antagonist and Extracellular Matrix Protein-1, displayed associations with premature cervical shortening.What are the implications of these findings for clinical practice and/or further research? Further investigation into the possible clinical utility of these biochemical biomarkers is warranted, with a view to improving preterm birth prediction and antenatal resource utilisation, thereby reducing the burden of preterm birth and its sequelae in a cost-effective manner.

Psychological well-being of women at high risk of spontaneous preterm birth cared for in a specialised preterm birth clinic: a prospective longitudinal cohort study

OBJECTIVES

To assess the psychological well-being of pregnant women at increased risk of spontaneous preterm birth, and the impact of care from a preterm birth clinic.

DESIGN

Single-centre longitudinal cohort study over 1 year, 2018-2019.

SETTING

Tertiary maternity hospital in Auckland, New Zealand.

PARTICIPANTS

Pregnant women at increased risk of spontaneous preterm birth receiving care in a preterm birth clinic.

INTERVENTION

Participants completed three sets of questionnaires (State-Trait Anxiety Inventory, Edinburgh Postnatal Depression Scale, and 36-Item Short Form Survey)-prior to their first, after their second, and after their last clinic appointments. Study-specific questionnaires explored pregnancy-related anxiety and perceptions of care.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the mean State-Anxiety score. Secondary outcomes included depression and quality of life measures.

RESULTS

73/97 (75.3%) eligible women participated; 41.1% had a previous preterm birth, 31.5% a second trimester loss and 28.8% cervical surgery; 20.6% had a prior mental health condition. 63/73 (86.3%) women completed all questionnaires. The adjusted mean state-anxiety score was 39.0 at baseline, which decreased to 36.5 after the second visit (difference -2.5, 95% CI -5.5 to 0.5, p=0.1) and to 32.6 after the last visit (difference -3.9 from second visit, 95% CI -6.4 to -1.5, p=0.002). Rates of anxiety (state-anxiety score >40) and depression (Edinburgh Postnatal Depression Scale score >12) were 38.4%, 34.8%, 19.0% and 13.7%, 8.7%, 9.5% respectively, at the same time periods. Perceptions of care were favourable; 88.9% stated the preterm birth clinic made them significantly or somewhat less anxious and 87.3% wanted to be seen again in a future pregnancy.

CONCLUSIONS

Women at increased risk of spontaneous preterm birth have high levels of anxiety. Psychological well-being improved during the second trimester; women perceived that preterm birth clinic care reduced pregnancy-related anxiety. These findings support the ongoing use and development of preterm birth clinics.

Impact of past obstetric history and cervical excision on preterm birth rate

INTRODUCTION

To determine the impact on preterm birth (PTB) of a history of large loop excision of the transformation zone (LLETZ)-alone compared with a history of previous preterm birth-alone (PPTB) or a history of both (LLETZ+PPTB). Secondary analyses were performed to evaluate the impact of antenatal interventions, depth of cervical excision, and patient risk factors on PTB rate in each cohort.

MATERIAL AND METHODS

A retrospective observational cohort study of women referred to a tertiary Antenatal Prematurity Prevention Clinic with a history of LLETZ, PPTB, or LLETZ+PPTB. Information was collated from routinely collected clinical data on patient demographics, previous obstetric history, LLETZ dimensions, antenatal investigations/interventions, and gestation at delivery.

RESULTS

A total of 1231 women with singleton pregnancies were included, 543 with history of LLETZ-alone, 607 with a history of PPTB-alone and 81 with a history of LLETZ+PPTB. PTB rates were 8.8% in the LLETZ-alone group, which mirrored the PTB rate in the local background obstetric population (8.9%) compared with 28.7% in the PPTB-alone and 37.0% in the LLETZ+PPTB cohorts. PTB rates were higher in LLETZ cohorts treated with antenatal intervention (cervical cerclage or progesterone pessary) and there was no evidence of an effect of intervention on risk of PTB in post-excision patients with identified shortened mid-trimester cervical length. Logistic regression modeling identified PPTB as a strong predictor of recurrent PTB. Excision depth was correlated with gestation at delivery in the LLETZ-alone group (r = -0.183, p < 0.01) although this only reached statistical significance at depths of 20 mm or more (odds ratio [OR] 3.40, 95% CI 1.04-1.11, p = 0.04). Depth of excision was not correlated with delivery gestation in the LLETZ+PPTB group (r = -0.031, p = 0.82).

CONCLUSIONS

PPTB has a greater impact on subsequent PTB risk compared with depth of cervical excisional treatment. The value and nature of antenatal interventions should be investigated in the post-excision population.

The experience and outcomes of a specialised preterm birth clinic in New Zealand

BACKGROUND

A greater understanding of the risk factors for spontaneous preterm birth and the importance of risk stratification to guide interventions has led to the introduction of preterm birth prevention clinics.

AIM

To evaluate the experience and outcomes of the first specialised preterm birth clinic in New Zealand.

MATERIALS AND METHODS

This observational study reviewed pregnancies cared for in a preterm birth clinic from 2013 to 2018. Cases were identified and data collected from a maternity database and electronic medical records. Analysis was by referral type.

RESULTS

A total of 423 cases were included; 309 elective and 22 acute referrals in pregnancy, and 92 consultations outside pregnancy. For those referred electively in pregnancy, 138/309 (44.7%) fulfilled multiple referral criteria, and 57/309 (18.4%) had ≥2 previous spontaneous preterm births or second trimester losses. Excluding five pregnancies with first trimester miscarriage, 77/304 (25.3%) were managed with a history-indicated cerclage (11 placed pre-conception) and 217/304 (71.4%) had cervical surveillance as primary management, of which 133 (61.3%) did not require treatment. The remaining had treatment for a short cervix; 37 (17.0%) received an ultrasound-indicated cerclage only, 21 (9.7%) vaginal progesterone only and 26 (12.0%) both. Five women (1.6%) had a second trimester loss at 13⁺⁰ -19⁺⁶ and 58/297 (19.5%) had a spontaneous preterm birth at 20⁺⁰ -36⁺⁶  weeks. The 'take home baby' rate was 95.4%.

CONCLUSIONS

Pregnancy outcomes were similar to those reported by other preterm birth prevention clinics. The majority of women who received cervical surveillance as primary management were able to avoid additional treatment.

The use of specialised preterm birth clinics for women at high risk of spontaneous preterm birth: a systematic review

Background

Specialised preterm birth clinics care for women at high risk of spontaneous preterm birth. This systematic review assesses current practice within preterm birth clinics globally.

Methods

A comprehensive search strategy was used to identify all studies on preterm birth clinics on the MEDLINE, Embase, PsycINFO, CENTRAL and CINAHL databases. There were no restrictions to study design. Studies were limited to the English language and publications from 1998 onwards. Two reviewers assessed studies for inclusion, performed data extraction and reviewed methodological quality. Primary outcomes were referral criteria, investigations and interventions offered in preterm birth clinics. Secondary outcomes were the timing of planned first and last appointments and frequency of review.

Results

Thirty-two records fulfilled eligibility criteria and 20 studies were included in the main analysis following grouping of records describing the same study or clinic. Studies were of mixed study design and methodological quality. A total of 39 clinics were described; outcome data was not available for all clinics. Referral criteria included previous spontaneous preterm birth (38/38, 100%), previous mid-trimester loss (34/38, 89%) and previous cervical surgery (33/38, 87%). All clinics offered transvaginal cervical length scans. Additional investigations varied, including urogenital swabs (16/28, 57%) and fetal fibronectin (8/28, 29%). The primary treatment of choice for a sonographic short cervix was cervical cerclage in 10/33 (30%) clinics and vaginal progesterone in 6/33 (18%), with 10/33 (30%) using multiple first-line options and 6/33 (18%) using a combination of treatments. The majority of clinics planned timing of first review for 12–16 weeks (30/35, 86%) and the frequency of review was usually determined by clinical findings (18/24, 75%). There was a wide variation in gestational age at clinic discharge between 24 and 37 weeks.

Conclusions

There is variation in the referral criteria, investigations and interventions offered in preterm birth clinics and in the timing and frequency of review. Consistency in practice may improve with the introduction of consensus guidelines and national preterm birth prevention programmes.

Trial registration

Systematic review registration number: CRD42019131470.