Preterm birth is a leading cause of neonatal mortality and morbidity worldwide, having immense clinical, personal and economic impacts. Effective identification and management of women who will deliver preterm is therefore of high importance. Whilst this has been the focus of a wealth of research, the underlying pathophysiology of preterm birth is largely unknown, and the growing evidence base is often conflicting. This new Virtual Issue from UOG presents a series of papers reporting on predictive tests and interventions for preterm birth, as well as on how best to integrate them into clinical practice. These papers are FREE to read for a limited period.

Please see below a summary of the content in the May Virtual Issue of the Journal. The articles in this Virtual Issue are free to access for 2 months. To view all UOG content, become an ISUOG member today or login and upgrade.

Prediction of preterm birth

Cervical length measurement
Cervical length (CL) measured on second-trimester ultrasound has been shown to be one of the best predictors for PTB in singleton pregnancy. An Editorial by Hughes et al. provides an overview of literature on CL measurement and its reported associations with spontaneous PTB in different populations, advising that, whilst CL surveillance remains an important aspect of assessment in high‐risk women, it is not adequate as a stand‐alone predictor of spontaneous PTB.

Biomarker analysis
Other screening methods for PTB include biomarker analysis. An Original Article by van Baaren et al. evaluated the cost-effectiveness of a screening method combining CL measurement and fetal fibronectin (fFN) testing for symptomatic women, finding it to be a viable method which could lead to considerable short-term cost savings without compromising neonatal health outcome.

Prevention of preterm birth

Cervical pessary
Articles in this Virtual Issue demonstrate the often conflicting evidence surrounding cervical pessary placement for treating cervical insufficiency and preventing PTB. A Randomized Controlled Trial by Berghella et al. found that treatment with cervical pessary was not associated with the prevention of PTB in women with a twin gestation and short mid-trimester CL. There was likewise no association found in a Randomized Controlled Trial by Dugoff et al. which evaluated pessary placement in singleton pregnancy with short CL.

Cervical cerclage
A common prophylactic procedure for PTB is cervical cerclage. An Original Article by Houlihan et al. investigated its effect on spontaneous PTB in twin pregnancy with short cervix, finding that it significantly reduces its incidence. A Systematic Review by Berghella et al., however, found that cerclage is not effective in singleton pregnancy with short CL, although it may be effective in those with CL< 10 mm or undergoing additional therapy with tocolytics or antibiotics.  

Vaginal progesterone
Vaginal progesterone treatment has also been shown to be effective for preventing PTB in women with short CL. This was demonstrated for singleton pregnancy with prior spontaneous PTB in a Systematic Review by Saccone et al. which compared progesterone with 17α‐hydroxyprogesterone caproate, finding the former to be a reasonable, if not better, alternative therapy. A Systematic Review by Romero et al. found vaginal progesterone to also be effective for reducing PTB in women with twin pregnancy and short CL. An Original Article by Vedel et al. investigated whether there was any long-term neurophysiological effect of prenatal progesterone exposure on children, finding second- and third-trimester exposure not to have long-term harmful effects during childhood.

Guiding management

As CL has been shown to be an effective predictor of PTB, it can be used to guide management of patients. A Systematic Review by Berghella et al. evaluated the effect of knowledge of CL on prevention of PTB in singleton pregnancy presenting with threatened preterm labor. It was found to be associated with significantly lower incidence of PTB in these women, suggesting that CL can be used to effectively guide management of these women. Whilst other articles in this issue do not support any benefit of cervical pessary, a secondary analysis by Tajik et al. of the ProTWIN trial identified a model incorporating baseline characteristics that could predict benefit of pessary placement in multiple pregnancy, finding the model to improve upon CL measurement alone.

A treat-all policy for women with threatened PTB, as recommended by the UK National Institute for Health and Care Excellence, may lead to overtreatment of these women. In an Original Article by Watson et al., the QUiPP app was developed with the aim of overcoming this by triaging women according to history of spontaneous PTB, gestational age and quantitative fFN measurement. The app was found to accurately guide management of at-risk women, reducing unnecessary treatment.

Supplement your reading for this virtual issue with specially chosen lectures and CME activities.