Objective: To identify the association between cervical length (CL) and gestational age at birth. Design: Prospective cohort study. Setting: Seventeen Brazilian reference hospitals. Population: A cohort of 3139 asymptomatic singleton pregnant women who participated in the screening phase of a Brazilian multicenter randomized controlled trial (P5 trial). Methods: Transvaginal ultrasound (TVU) to measure CL was performed from 18 to 22+6 weeks. Women with CL ≤ 30 mm received vaginal progesterone (200 mg/day) until 36 weeks’ gestation. Main Outcome Measures: Area under receive operating characteristic curve (AUC), sensitivity, specificity, Kaplan-Meier curves for preterm birth (PTB), number needed to screen (NNS). Results: CL ≤25mm was associated with extremely severe, severe, moderate and late PTB, whereas a CL 25–30mm was directly associated with late sPTB. The AUC to predict sPTB<28 weeks was 0.82 and for sPTB<34 weeks was 0.67. Almost half of the sPTB occurred in nulliparous women and CL ≤30mm was associated with sPTB <37 weeks (OR = 7.84; 95%CI = 5.5–11.1). The NNS to detect one sPTB <34 weeks in women with CL ≤25mm is 121 and 248 screening tests are necessary to prevent one sPTB <34 weeks using vaginal progesterone prophylaxis. Conclusions: CL measured by TVU is associated with sPTB <34 weeks. Women with CL ≤30mm are at increased risk for late sPTB. Funding: Bill & Melinda Gates Foundation [OPP1107597], the Brazilian Ministry of Health, and the Brazilian National Council for Scientific and Technological Development (CNPq) [401615/20138]. Keywords: cervical length; number needed to screen; preterm birth; short cervix.

Objective: We developed a research usefulness tool collating published criteria and examined if randomised controlled trials (RCTs) addressing preterm birth were useful. Search Strategy: Cochrane library. Selection Criteria: Published RCTs within 56 preterm birth Cochrane reviews. Data Collection and Analysis: A usefulness tool was developed with eight criteria combining 13 items identified through literature searches and consensus. RCTs were evaluated for compliance with each item by multiple assessors (reviewer agreement 95-98%). Proportions with 95% confidence interval (CI) were calculated and compared for change over time using ≧ 2010 as a cut-off, with relative risks (RR). Main Results: Among 350 selected RCTs, only 38 (11%, 95% CI 8-15%) met half of the usefulness criteria. Compared to trials before 2010, recent trials used composite or surrogate (less informative) outcomes more often (13% vs 25%, RR 1.87, 95% CI 1.19-2.93). Only 17 trials reflected real life (pragmatism) in design (5%, 95% CI 3-8%), with no improvements over time. No trials reported involvement of mothers to reflect patients’ top priorities in question definition or outcomes selection. Recent trials were more transparent with prospective registration (0.5% vs 28%, RR 58, 95% CI 8-420%), availability of protocol (0.5% vs 15%, RR 32, 95% CI 4-237%) and data sharing statements (2% vs 8%, RR 3, 95% CI 1-10%). Conclusion: Clinical trials in preterm birth lacked many usefulness features, with one tenth of trials meeting half of the items evaluated. Use of informative outcomes, patient centeredness, pragmatism and transparency should be key targets for future research planning.

Background: Postpartum Haemorrhage (PPH) remains a leading cause of maternal mortality and morbidity worldwide, and the rate is increasing. Using a reliable predictive model could identify those at risk, support management and treatment, and improve maternal outcomes. Objectives: To systematically identify and appraise existing prognostic models for PPH and ascertain suitability for clinical use. Search strategy: MEDLINE, CINAHL, Embase, and the Cochrane Library were searched using combinations of terms and synonyms including ‘postpartum haemorrhage’, ‘prognostic model’, and ‘risk factors’ that were developed from a scoping review. Selection Criteria: Observational or experimental studies describing a prognostic model for risk of PPH, published in English. Data Collection and Analysis: The Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist informed data extraction and Prediction Model Risk of Bias Assessment Tool guided analysis. Main Results: 16 studies met the inclusion criteria after screening 1612 records. All studies were hospital settings from 8 different countries. Models were developed for women who experienced vaginal birth (n=7), caesarean birth(n=2), any type of birth(n=2), hypertensive disorders(n=1) and those with placental abnormalities(n=4). All studies were at high risk of bias due to use of inappropriate analysis methods or omission of important statistical considerations or suboptimal validation. Conclusions: No existing prognostic models for PPH are ready for clinical application. Future research is needed to externally validate existing models and potentially develop a new model that is reliable and applicable to clinical practice. Funding: This study received no funding. Keywords: Postpartum haemorrhage, prognostic model, prediction tool.

Objective: To compare the effect of a hysteroscopic niche resection with a Levenorgestrel-releasing intrauterine device (LNG-IUD) on postmenstrual spotting in women with a symptomatic niche in the uterine cesarean scar. Design: Single center, prospective cohort study. Setting: A hospital affiliated to a medical college in China. Population: Women diagnosed with a niche by MRI scan and postmenstrual spotting of at least two days. Method: Women were allocated to two groups based on the shared medical decision-making approach, and were followed up for 1 year after treatment. Main outcome measures: The primary outcome was effectiveness in reducing postmenstrual spotting. Secondary outcomes were menstrual characteristics, direct medical costs, complications and side effects. Results: Effectiveness of LNG-IUD was significantly higher than a hysteroscopic niche resection during the first year, based on linear mixed models (P=0.009), and the effectiveness increased overtime within 1 year. Postmenstrual spotting reduced statistically in both groups. More slight side effects, although not statistically significant, were reported in LNG-LUD group at obviously lower direct medical costs. Conclusion：LNG-IUD is more effective in the treatment of postmenstrual spotting from the 6th month onwards than a hysteroscopic niche resection in women with a symptomatic niche at lower direct costs. Key Words：Niche, uterine cesarean scar, hysteroscopy niche resection, LNG-IUD, postmenstrual spotting, amenorrhea Tweetable abstract: LNG-IUD is more effective in the treatment of postmenstrual spotting related to a niche than hysteroscopic niche resection.

Background: The optimal duration of magnesium administration postpartum for prevention of eclampsia has not yet been established. Objective: To investigate the effect of early discontinuation of postpartum magnesium on the rates of postpartum eclampsia when compared to continuation for 24-hour postpartum. Search Strategy: Searches were performed using keywords related to “preeclampsia” and “magnesium sulfate” from inception of database until March 2019. Selection Criteria: Randomized controlled trials of women with preeclampsia receiving magnesium prior to delivery randomized to early discontinuation of magnesium postpartum. The control group was 24-hours of magnesium postpartum. Data Collection and Analysis: The primary outcome was the rate of postpartum eclampsia. Main Results: Eight RCTs with 2,183 women were included with five different magnesium administration time-frames. Eclampsia rates were not different between the two groups (5/1,088 (0.5%) after early discontinuation, versus 2/1,095 (0.2%) in the 24-hour group; RR 2.25, 95% CI 0.5-9.9, I2=0%, 8 studies, 2,183 participants). A number needed to treat was calculated; 370 women would need to receive 24-hours of magnesium postpartum to prevent one episode of postpartum eclampsia. The early discontinuation group had a significant decrease in time to ambulation and breastfeeding. Conclusions: Compared to continuation of magnesium for 24 hours postpartum, early magnesium discontinuation postpartum does not significantly increase the rate of postpartum eclampsia. The largest proportion of women did not receive magnesium postpartum after receiving at least 8 grams intrapartum, thus it is reasonable to consider discontinuation of magnesium postpartum if a woman has received similar adequate dose prior to delivery.

Dear Editor,We would like to comment on the systematic review by Li et al.(1)The use of steroid hormones in the first trimester is a serious issue as organogenesis takes place at this time and therefore there is the possibility of harm from not only congenital anomalies, but also long-term, and even inter-generational effects. Anyone investigating the use of steroid hormones in the first trimester should remember the diethylstilbestrol legacy of devastating harm. Oestrogen (C18H24O2) and diethylstilbestrol (C18H20O2) have similar molecular composition, but their effects are poles apart. In this review, the authors have combined progesterone with progestogens; however they are not the same, in the same way that oestrogen and diethylstilbestrol are not the same. Vaginal micronized progesterone, which we used in our large and high-quality trials (the PROMISE (2) and PRISM (3) trials), has identical molecular structure to natural progesterone, but the other drugs included in this review do not (Table 1). We chose to study vaginal micronized progesterone, as it is identical in structure to natural progesterone, and the available evidence and expert opinion suggested that this is least likely to cause harm. It is important to note that there is evidence of potential harm from dydrogesterone, particularly congenital heart disease.(4)The authors make a bold statement in the abstract about the effects of dydrogesterone on live birth rate. However, they don’t fully address the weaknesses in the evidence. Therefore, we wish to highlight the significant deficiencies in the two trials that contributed live birth data that led to the assertion of beneficial effects from dydrogesterone. Both studies were single centre, open-label studies without placebo control. El-Zibdeh et al did not randomise participants, but instead allocated patients to dydrogesterone on Saturdays, Mondays and Wednesdays, and to no treatment on Sundays, Tuesdays and Thursdays. The trial by Pandian RU was not just a single-centre, but also a single-author study, with insufficient details of the methods to assess its quality. Thus, the effectiveness evidence from these trials cannot be considered reliable.Approximately 80% (4038 of 5056) of the data used in this systematic review come from our PRISM trial.(3) The PRISM trial is a prospectively-registered, randomised, placebo-controlled, multi-centre trial conducted to the highest standards in the UK. The trial found a 3% increase in live birth rate, but with borderline statistical significance (RR, 1.03; 95% CI, 1.00 to 1.07; P=0.08). A pre-specified subgroup analysis in women with the dual risk factors of current pregnancy bleeding and one or more previous miscarriages found a 5% increase in live birth rate (RR, 1.09; 95% CI, 1.03-1.15; P=0.003). In those with three or more previous miscarriages, a 15% increase in live birth rate was observed (RR, 1.28; 95% CI, 1.08 to 1.51; P=0.004).(3, 5) No short-term safety concerns were identified. Based on these data, our recommendation is to consider vaginal micronized progesterone for women with early pregnancy bleeding and one or more previous miscarriages. As for the role of dydrogesterone, we need not only high-quality, randomised trial evidence of its effects but also credible evidence of its safety. As dydrogesterone is a synthetic progesterone-like drug, i.e. a progestogen but not progesterone, the burden of proof to demonstrate short- and long-term safety rests on those promoting this drug.