Factors contributing to preterm birth in patients presenting at tertiary care hospitals in Punjab.

Objective: To determine the various causes and factors leading to preterm birth in women presenting at tertiary care hospitals. METHODS: The cross-sectional, prospective study was conducted from June 19, 2021, to January 19, 2022, at the Central Park Teaching Hospital, Lahore, Pakistan, in collaboration with other tertiary care teaching hospitals in Lahore, and comprised pregnant women aged 15-45 years with preterm birth. Demographic and obstetric data was collected. Depending on the factors contributing to preterm birth, the subjects were categorised as spontaneous labour group A, preterm prelabour rupture of membrane group B, and iatrogenic preterm birth group C. Data was analysed using SPSS 25. RESULTS: Of the 1,300 recorded births, 200(15.38%) were preterm. Group A had 86(43%) women with mean age 28.55±4.68 years, group B had 43(21,5%) women with mean age 27.14±3.25 years, and group C had 71(35.5%) women with mean age 28.28±3.74 years (p>0.05). There was significant difference among the groups with respect to body mass index (p=0.001) and parity (p=0.021). Vaginal and urinary tract infections were significantly higher in group A compared to the other groups (p<0.05). In group C, pre-eclampsia was the main reason for preterm birth 45(63.38%). Conclusion: Medically indicated preterm birth rate was found to be high, and pre-eclampsia was noted as the main cause in iatrogenic preterm birth.

Novel identification and modulation of the mechanosensitive Piezo1 channel in human myometrium.

Approximately 10% of US births deliver preterm before 37 weeks of completed gestation. Premature infants are at risk for life-long debilitating morbidities and death, and spontaneous preterm labour explains 50% of preterm births. In all cases existing treatments are ineffective, and none are FDA approved. The mechanisms that initiate preterm labour are not well understood but may result from dysfunctional regulation of quiescence mechanisms. Human pregnancy is accompanied by large increases in blood flow, and the uterus must enlarge by orders of magnitude to accommodate the growing fetus. This mechanical strain suggests that stretch-activated channels may constitute a mechanism to explain gestational quiescence. Here we identify for the first time that Piezo1, a mechanosensitive cation channel, is present in the uterine smooth muscle and microvascular endothelium of pregnant myometrium. Piezo is downregulated during preterm labour, and stimulation of myometrial Piezo1 in an organ bath with the agonist Yoda1 relaxes the tissue in a dose-dependent fashion. Further, stimulation of Piezo1 while inhibiting protein kinase A, AKT, or endothelial nitric oxide synthase mutes the negative inotropic effects of Piezo1 activation, intimating that actions on the myocyte and endothelial nitric oxide signalling contribute to Piezo1-mediated contractile dynamics. Taken together, these data highlight the importance of stretch-activated channels in pregnancy maintenance and parturition, and identify Piezo1 as a tocolytic target of interest. KEY POINTS: Spontaneous preterm labour is a serious obstetric dilemma without a known cause or effective treatments. Piezo1 is a stretch-activated channel important to muscle contractile dynamics. Piezo1 is present in the myometrium and is dysregulated in women who experience preterm labour. Activation of Piezo1 by the agonist Yoda1 relaxes the myometrium in a dose-dependent fashion, indicating that Piezo1 modulation may have therapeutic benefits to treat preterm labour.

Validation of parental recall questionnaire to classify preterm delivery subtypes: Spontaneous preterm labour, preterm premature rupture of membranes and clinician-initiated preterm delivery.

BACKGROUND: Preterm delivery (PTD) includes three main presenting subtypes: spontaneous preterm labour (sPTL), preterm premature rupture of membranes (pPROM) and clinician-initiated preterm delivery (ciPTD). PTD subtype data are rarely available from birth registries and are onerous to derive from medical records. OBJECTIVES: To develop and test the validity of a questionnaire to classify PTD subtype based on birthing parent recall of labour and delivery events. METHODS: The questionnaire was sent in 2022 to 581 patients with PTD history documented in the LIFECODES study, a hospital-based birth cohort in Boston, Massachusetts. Eighty-two respondents reported 94 PTDs that could be linked to medical records. Data on PTD subtype were extracted from medical records as the reference standard. RESULTS: Medical records indicated 47 spontaneous (24 sPTL, 23 pPROM) and 47 ciPTD deliveries occurring a median eight years earlier. The sensitivity and specificity of the recall questionnaire were 88% (95% confidence interval: 68, 97%) and 89% (79, 95%) for sPTL; 96% (78, 100%) and 94% (86, 98%) for pPROM; and 83% (69, 92%) and 100% (92, 100%) for ciPTD, respectively. Greater time since pregnancy did not degrade the sensitivity or specificity of the parental recall questionnaire. CONCLUSIONS: Although derived from a modest sample, the moderate-to-high sensitivity and specificity of the parental recall questionnaire to classify sPTL, pPROM and ciPTD demonstrates its potential for large studies of PTD and for correction of misclassification bias. Future studies are required to test the questionnaire in a variety of populations.

Progestogen maintenance therapy for prolongation of pregnancy after an episode of preterm labour: A systematic review and meta-analysis.

BACKGROUND: Evidence for progestogen maintenance therapy after an episode of preterm labour (PTL) is contradictory. OBJECTIVES: To assess effectiveness of progestogen maintenance therapy after an episode of PTL. SEARCH STRATEGY: An electronic search in Central Cochrane, Ovid Embase, Ovid Medline and clinical trial databases was performed. SELECTION CRITERIA: Randomised controlled trials (RCT) investigating women between 16+0 and 37+0 weeks of gestation with an episode of PTL who were treated with progestogen maintenance therapy compared with a control group. DATA COLLECTION AND ANALYSIS: Systematic review and meta-analysis were conducted. The primary outcome was latency time in days. Secondary neonatal and maternal outcomes are consistent with the core outcome set for preterm birth studies. Studies were extensively assessed for data trustworthiness (integrity) and risk of bias. MAIN RESULTS: Thirteen RCT (1722 women) were included. Progestogen maintenance therapy demonstrated a longer latency time of 4.32 days compared with controls (mean difference [MD] 4.32, 95% CI 0.40-8.24) and neonates were born with a higher birthweight (MD 124.25 g, 95% CI 8.99-239.51). No differences were found for other perinatal outcomes. However, when analysing studies with low risk of bias only (five RCT, 591 women), a significantly longer latency time could not be shown (MD 2.44 days; 95% CI -4.55 to 9.42). CONCLUSIONS: Progestogen maintenance therapy after PTL might have a modest effect on prolongation of latency time. When analysing low risk of bias studies only, this effect was not demonstrated. Validation through further research, preferably by an individual patient data meta-analysis is highly recommended.

A prospective, double-blinded cohort study using quantitative fetal fibronectin testing in symptomatic women for the prediction of spontaneous preterm delivery.

BACKGROUND: Spontaneous preterm birth (PTB) affects 6.5% of deliveries in Hong Kong. Quantitative fetal fibronectin (fFN) is under-utilised as a test for PTB prediction in Hong Kong. Our objective was to evaluate the effectiveness of quantitative fFN in predicting spontaneous PTB in women with symptoms of threatened preterm labour (TPTL) in our population. METHODS: A prospective, double-blinded cohort study of women with a singleton gestation and TPTL symptoms presenting to a tertiary hospital in Hong Kong between 24 + 0 to 33 + 6 weeks was performed from 1st October 2020 and 31st October 2021. Women with vaginal bleeding, ruptured membranes, and cervical dilation > 3 cm were excluded. The primary outcome was to test the characteristics of quantitative fFN in predicting spontaneous PTB < 37 weeks. Secondary outcome was to investigate the relationship between fFN value and time to PTB. Test characteristics of quantitative fFN at different thresholds were evaluated. RESULTS: 48 women with TPTL were recruited. All had fFN testing at admission with the results being concealed from the obstetrician managing the patient. 10 mothers had PTB (< 37 weeks' gestation). 7/48 (15%) had a subsequent PTB within 14 days from testing and 5 (10%) delivered within 48 h. The negative predictive value (NPV) of predicting delivery within 14 days was 97.3% and 100% when using a cut-off of < 50ng/ml and < 10ng/ml respectively. Using > 200 ng/ml as cut-off can also reliably predict delivery within 48 h - 7 days with positive predictive value PPV of 100%; as well as PTB before 37 weeks. CONCLUSIONS: Quantitative fFN has predictive value for spontaneous PTB prediction in symptomatic women in a Hong Kong population. fFN concentration could help clinicians rule out PTB and avoid unnecessary interventions and hospitalisation.

New medicines for spontaneous preterm birth prevention and preterm labour management: landscape analysis of the medicine development pipeline.

BACKGROUND: There are few medicines in clinical use for managing preterm labor or preventing spontaneous preterm birth from occurring. We previously developed two target product profiles (TPPs) for medicines to prevent spontaneous preterm birth and manage preterm labor. The objectives of this study were to 1) analyse the research and development pipeline of medicines for preterm birth and 2) compare these medicines to target product profiles for spontaneous preterm birth to identify the most promising candidates. METHODS: Adis Insight, Pharmaprojects, WHO international clinical trials registry platform (ICTRP), PubMed and grant databases were searched to identify candidate medicines (including drugs, dietary supplements and biologics) and populate the Accelerating Innovations for Mothers (AIM) database. This database was screened for all candidates that have been investigated for preterm birth. Candidates in clinical development were ranked against criteria from TPPs, and classified as high, medium or low potential. Preclinical candidates were categorised by product type, archetype and medicine subclass. RESULTS: The AIM database identified 178 candidates. Of the 71 candidates in clinical development, ten were deemed high potential (Prevention: Omega-3 fatty acid, aspirin, vaginal progesterone, oral progesterone, L-arginine, and selenium; Treatment: nicorandil, isosorbide dinitrate, nicardipine and celecoxib) and seven were medium potential (Prevention: pravastatin and lactoferrin; Treatment: glyceryl trinitrate, retosiban, relcovaptan, human chorionic gonadotropin and Bryophyllum pinnatum extract). 107 candidates were in preclinical development. CONCLUSIONS: This analysis provides a drug-agnostic approach to assessing the potential of candidate medicines for spontaneous preterm birth. Research should be prioritised for high-potential candidates that are most likely to meet the real world needs of women, babies, and health care professionals.

Association between lower uterine wall thickness measured at 18-22 weeks of gestation and risk of Preterm Birth: a prospective cohort study.

BACKGROUND: Preterm labour prediction has been relied on history of previous preterm birth and cervical length of current pregnancy. However, universal cervical length measurement has some limitation. We aim to find a surrogate marker of cervical length to close the gap in preterm prevention program and lower uterine wall thickness seems promising. We generate the nomogram of lower uterine wall thickness during 18-22 weeks of gestation and evaluate the accuracy of LUW thickness as a predictor of preterm delivery before 37 weeks. METHODS: This prospective cohort study included 524 Thai singleton pregnant women at 18-22 weeks of gestation between November 2016 and October 2017. After signing informed consent, transabdominal ultrasonography was performed to examine fetal anatomical structures and to measure LUW thickness. The results were blinded to the caregivers. The outcomes of all pregnancies were followed. The LUW thickness at 10th percentiles was established and was correlated with the outcomes of pregnancy. The performance of LUW thickness at 10th percentile as a predictor of preterm delivery was calculated. The intra-observer and inter-observer reliability of measurement were assessed by intraclass correlation coefficient and Bland-Altman plot. RESULTS: Of the 524 pregnant women, 64 (12.2%) delivered before 37 weeks of gestation. The reference value of lower uterine wall thickness at 18-22 weeks was established. Mean and 10th percentile of LUW thickness were 6.2 and 4.5 mm respectively. The inter-observer and intra-observer variation of measurement were small (intraclass correlation coefficient = 0.926 and 0.989 respectively). Using LUW thickness at less than 4.5 mm as a predictor of preterm delivery, we found a 2.37 folds increased risk of preterm delivery after adjustment of other factors (p = 0.037). Sensitivity, specificity, positive predictive value and negative predictive value were 14% (95% CI: 6.64-25.02), 92.8% (95% CI: 90.06-95.12), 22.5% (95% CI: 12.66-36.76) and 88% (95% CI: 86.92-89.08) respectively. CONCLUSIONS: The measurement of LUW thickness by transabdominal ultrasonography is feasible and reproducible. The risk of delivery before 37 weeks of gestation is increased significantly if the LUW thickness at 18-22 weeks is less than 4.5 mm. TRIAL REGISTRATION: The study protocol was approved by institutional ethical committee (COA No. Si 657/2016).

The acceptability of cervical electrical impedance spectroscopy within a multi-modal preterm birth screening package: a mixed methods study.

BACKGROUND: Reducing the rate of preterm birth is a cornerstone of global efforts to address child mortality, however existing screening tests offer imperfect prediction. Cervical electrical impedance spectroscopy (EIS) is a novel technique to quantify the ripening changes which precede labour. Mid-trimester EIS measurements have been shown to accurately predict preterm birth in asymptomatic women. This study aimed to comprehensively evaluate the acceptability of cervical EIS to low and high-risk women as part of a package of screening tests performed during a larger prospective trial. METHODS: In this parallel convergent mixed methods study, 40 women completed questionnaires before and after screening tests (EIS, cervical length measurement and fetal fibronectin quantification). Quantitative outcomes were anxiety levels before and after screening (Spielberger State Trait Anxiety Inventory, STAI-6), pain (Short Form McGill Pain Questionnaire) and ratings of EIS device appearance and test acceptability (visual analogue scales). Twenty-one women (11 high-risk, 10 low-risk) also attended a semi-structured qualitative interview. Interviews were recorded and transcribed, then thematic analysis was performed. A convergence coding matrix was constructed to enable triangulation of quantitative and qualitative results. RESULTS: High risk women demonstrated a significant reduction in anxiety following screening (mean STAI-6 score 34.5 vs. 29.0, p = 0.002). A similar trend was observed among low-risk participants. Ratings of pain, EIS device appearance and procedural acceptability did not differ between groups. Mean pain ratings were low (visual analogue scale 0.97 and 1.01), comparing favourably to published evaluations of conventional screening tests. Qualitative analysis provided insight into both the physical consequences and emotional experiences of screening. Additional determinants of the screening experience included device design, pre-existing perspectives on intimate examination, attitudes to knowledge in pregnancy and interaction with clinical staff. Finally, a range of practical considerations regarding wider use of EIS were identified, with valuable complementary detail regarding acceptability for use in antenatal care. CONCLUSIONS: Cervical EIS is well tolerated and acceptable to both low and high-risk women when performed as part of a multi-modal screening package. These results provide useful insights to inform the design of future study and screening protocols.

The quality of intrapartum cardiotocography in preterm labour.

OBJECTIVES: The aim of this study is to determine the quality of the foetal heart rate (FHR) recording, defined as signal loss, during preterm labour below 28 weeks gestational age (GA) and contribute to the discussion if cardiotocography (CTG) is of value for the extreme preterm foetus. METHODS: From January 2010 to December 2019 a retrospective study was conducted with data of 95 FHR recordings of singletons born between 24 and 28 weeks GA at the Amsterdam University Medical Centre, location VUmc. FHR tracings had a duration of at least 30 min and were obtained via external ultrasound mode. Data of all recordings were divided in two groups according to gestation (24-26 weeks and 26-28 weeks). Signal loss was analysed. Statistical significance was calculated by non-parametric tests and chi-square tests. The median signal loss and the proportion of cases exceeding the International Federation of Gynaecology and Obstetrics Guidelines (FIGO) threshold of 20% signal loss were calculated. RESULTS: One-third of the recordings exceeded the 20% FIGO-criterion for adequate signal quality during the first stage of labour. In the second stage, this was nearly 75%. Similarly, the median signal loss was 13% during the first and 30% during the second stage of labour (p<0.01). CONCLUSIONS: The quality of FHR monitoring in the extreme preterm foetus is inadequate in a large proportion of the foetuses, especially during the second stage. FHR monitoring is therefore controversial and should be used with caution.

Management of an incompetent mid-second (mid-2nd) trimester absent ecto-cervix: a case series. Cervical amplification pre-cerclage insertion.

BACKGROUND: Cervical cerclage is a treatment for an incompetent cervix, the latter being a contributor to spontaneous preterm birth. There is significant difficulty with a transvaginal cerclage insertion for the absent vaginal or ecto-cervix in the mid-2nd trimester period resulting in a higher risk of late miscarriages, extremely preterm labour with increased neonatal morbidity and mortality. METHODS: A retrospective review of 5 consecutive cases managed by a surgical technique-modified high vaginal cerclage insertion at 18-20 weeks-and adjunct protocols which included vaginal progesterone use, serial infection screening and lifestyle advice, over a 12-month period ending in August 2021, is presented. Inclusion criteria included minimal or absent ecto-cervix, singleton pregnancies with an incompetent cervix attending for a vaginal cerclage whilst exclusion criteria were the usual contraindications to a cerclage insertion. Primary outcome was delivery after 34 weeks whilst seconday outcomes included maternal hemorrhage, bowel/bladder injury, chorioamnionitis and neonatal admission. RESULTS: A increased gestational latency of 13 gestational weeks (range 12-18). Mean gestational age at delivery was 36 weeks +1 (253 days) with a range of 241-264 days. Delivery after 34 weeks gestational age was 100% with no maternal surgical complications and corresponding neonatal outcomes. CONCLUSION: There is a potential therapeutic benefit of this technique and adjunct management, in managing an incompetent mid-2nd trimester absent ecto-cervix.

Prediction of preterm delivery in threatened preterm labour with short cervical length.

In this study, we evaluated the value of the uterocervical angle (UCA), myometrial thickness (MT), sICAM-1, sVCAM-1, soluble E-selectin (sE-selectin) and pentraxin 3 (PTX3) levels in women with threatened preterm labour (TPL) in predicting spontaneous preterm birth (sPTB) within 14 days in symptomatic women with cervical length (CL) measurements between 10 and 25 mm. Forty-six patients diagnosed with TPL, 47 healthy pregnant women were evaluated in a case-control study. sE-selectin (AUC = 0.744, p = .007) and PTX3 (AUC = 0.711, p = .019) were found to be effective in predicting preterm delivery within 14 days. In conclusion, maternal sE-selectin and PTX3 levels may be helpful in identifying pregnancies that will deliver within 14 days in symptomatic women with CL measurements between 10 and 25 mm. However, maternal sICAM-1 and sVCAM-1 levels, MT and UCA are not effective in the prediction of sPTB in TPL pregnancies. Impact StatementWhat is already known on this subject? Aetiology of spontaneous preterm birth (sPTB) is unclear and believed to be multifactorial, infection, inflammation, vascular endothelial dysfunction and uteroplacental ischaemia are all considered to be related to preterm delivery syndrome. Transvaginal cervical length (CL) measurement is a good indicator of increased risk of sPTB. Inflammation is accepted to have a central role in the process of labour.What do the results of this study add? soluble E-selectin (sE-selectin) and pentraxin 3 (PTX3) levels may be helpful in identifying pregnancies that will deliver within 14 days in symptomatic women with CL measurements between 10 and 25 mm.What are the implications of these findings for clinical practice and/or further research? This study will help understand the important role of the inflammatory process in predicting spontaneous preterm birth.

Prediction of preterm birth using artificial intelligence: a systematic review.

Preterm birth is the leading cause of neonatal death. It is challenging to predict preterm birth. We elucidated the state of artificial intelligence research on the prediction of preterm birth, clarifying the predictive values and accuracy. We performed a systematic review using three databases (PubMed, Web of Science, and Scopus) in August 2020, with keywords as 'artificial intelligence,' 'deep learning,' 'machine learning,' and 'neural network' combined with 'preterm birth'. We included 22 publications between 2010 and 2020. Regarding the predictive values, electrohysterogram images were mostly used, followed by the biological profiles, the metabolic panel in amniotic fluid or maternal blood, and the cervical images on the ultrasound examination. The size of dataset in most studies was hundred cases and too small for learning, although only three studies used the medical database over a hundred thousand cases. The accuracy was better in the studies using the metabolic panel and electrohysterogram images. Impact statementWhat is already known on this subject? Preterm birth is the leading cause of newborn morbidity and mortality. Presently, the prediction of preterm birth in individual cases is still challenging.What the results of this study add? Using artificial intelligence such as deep learning and machine learning models, clinical data could lead to accurate prediction of preterm birth.What the implications are of these findings for clinical practice and/or further research? The size of the datasets was too small for the models using artificial intelligence in the previous studies. Big data should be prepared for the future studies.

The evaluation of maternal systemic thiol/disulphide homeostasis for the short-term prediction of preterm birth in women with threatened preterm labour: a pilot study.

The aim of this study was to investigate maternal systemic thiol/disulphide homeostasis (TDH) for the short-term prediction of preterm birth in women with threatened preterm labour (TPL). This prospective study included 75 pregnant women whose pregnancies were complicated by TPL. Thirty-seven of them delivered within 7 days and 38 of them delivered beyond 7 days. Maternal serum samples were collected at the day of diagnosis and the TDH was measured. The maternal disulphide level was significantly higher in pregnant women who delivered within 7 days (25.0 ± 9.8 µmol/L vs 19.4 ± 9.8 µmol/L, p: .015). The threshold value of 22.1 µmol/L for maternal disulphide level predicted delivery within 7 days with 62.2% sensitivity and 60.5% specificity (area under curve 0.651, confidence interval 0.53-0.78). The likelihood ratios for short cervix (≤25 mm) and maternal disulphide level (≥22 µmol/L) to predict delivery within 7 days was found to be 8.7 and 7.3, respectively. The likelihood ratio of combining two tests to predict delivery within 7 days was found to be 11.4. The maternal TDH, which is an indicator of oxidative stress status in maternal compartment, is disturbed in TPL cases who delivered within 7 days. Elevated maternal disulphide level along with cervical length screening predicts a short latency period in pregnancies with TPL. IMPACT STATEMENTWhat is already known on this subject? Spontaneous preterm delivery is one of the major complication of pregnancy and the common cause of neonatal morbidity and mortality. Threatened preterm labour (TPL) is also a frequent complaint in obstetric emergency care units in all around the world. Triaging women with TPL is mandatory for planning further management therapies, since the most of them will eventually deliver at term. Only the measurement of cervical length in symptomatic women has moderate accuracy in predicting preterm delivery. Short cervix is described as an independent predictor of preterm delivery in women with TPL, its predictive accuracy as a single measurement is relatively limited. On this account, several potential markers like foetal fibronectin in the cervicovaginal fluid, salivary oestriol, prolactin in vaginal discharge, maternal serum calponin and interleukin-6 in the amniotic fluid were examined to predict preterm delivery in previous studies. However, none of them represented an excessive predictive accuracy like high sensitivity, PPV or NPV.What do the results of this study add? We report a method which has higher diagnostic and predictive performance to identifying TPL women with high risk of preterm delivery. According to the current literature, there are accumulated data about the correlation between oxidative stress (OS) and preterm delivery regardless of the amniotic membrane status. However, it is still debated whether OS is a trigger or a consequence of preterm delivery. Our study provides evidence for the first time that maternal serum thiol/disulphide homeostasis, which is an indicator of OS in maternal compartment, is disturbed in TPL cases who delivered within 7 days. The high disulphide level in maternal serum, along with cervical length measurement (short cervix) accurately predicts a short latency period in TPL cases.What are the implications of these findings for clinical practice and/or further research? This novel test combination (maternal serum disulphide level and cervical length measurement) could be used clinically to triage pregnant women presenting with TPL, avoiding overtreatment, unnecessary hospitalisations and increased medical costs. The future research would be addressed on reducing maternal OS by using new antioxidant treatment strategies to improve perinatal and long-term childhood outcomes.

Breast milk expression as a challenge for mothers of premature infants.

The aim of this study was to examine the psychometric properties of the 11-item Breast Milk Expression Experience Scale and determine the level of breast milk expression experience of mothers after preterm delivery in Turkey. 165 mothers who agreed to participate between February 2019 and March 2020 used the Breast Milk Expression Experience Scale (BMEE-S). The general Cronbach alpha coefficient was 0.82 for the BMEE-S. The fit indices calculated by confirmatory factor analysis were χ2 (41) = 87.95, p = .00003, χ2/sd = 2.15, GFI = 0.91, NNFI = 0.93, CFI = 0.95, RMSEA = 0.08 and SRMR = 0.078. The BMEE-S three-factor structure was verified by the confirmatory factor analysis. The BMEE-S was a valid and reliable instrument for mothers of preterm infants. Multiparity and high-risk pregnancy history negatively affected the milk expression experience, whereas spousal support positively affected it.Impact statementWhat is already known on this subject? The risk of infectious diseases, obesity, diabetes, and impaired intellectual development increases in children who do not breast milk (Verduci et al. 2014). International breastfeeding guidelines recommend supporting all mothers to start breastfeeding within one hour of birth, and counselling mothers who are separated from their babies about expressing milk.What the results of this study add? The breast milk expression experience scale is a valid and reliable tool for women who give preterm birth and express milk. The experience of expressing breast milk can affect the amount of milk that passes from mother to baby. Multiparity and high risk pregnancy history of mothers negatively affects the milk expression experience while husband support positively affects the milk expression experience.What the implications are of these findings for clinical practice and/or further research? Our study provides a quantitative examination of the experiences of mothers who are separated from their babies. The BMEE-S should be adapted to different cultures and the experiences of mothers in this process should be determined.

The association between threatened preterm labour and perinatal outcomes at term: a population-based cohort study.

OBJECTIVE: To estimate the association between threatened preterm labour (TPTL) and perinatal outcomes of infants born at term. DESIGN: A population-based cohort study of perinatal outcomes following TPTL <37 weeks of gestation with delivery at term. SETTING: Nova Scotia, Canada. POPULATION: All non-anomalous, singleton pregnancies ≥37 weeks of gestation without antepartum haemorrhage from 1988 to 2019. METHODS: Using data from the Nova Scotia Atlee Perinatal Database, TPTL was defined as pregnancies with a hospital admission between 20 and 37 weeks of gestation, with a diagnosis code denoting TPTL with administration of antenatal corticosteroids, or with administration of any tocolysis. Poisson regression models were used to estimate the risk ratios (RR) with 95% CI of maternal and perinatal outcomes in women who had an episode of TPTL relative to those who did not. MAIN OUTCOME MEASURES: Birthweight for gestational age below the tenth centile and a composite of perinatal mortality or severe perinatal morbidity. RESULTS: Of 256 599 term deliveries meeting the inclusion criteria, 2278 (0.9%) involved TPTL. The risks of the primary outcomes were higher among those with TPTL relative to those without: birthweight for gestational age below the tenth centile (RR 1.24, 95% CI 1.11-1.39) and the composite of perinatal mortality/severe perinatal morbidity (RR 1.33, 95% CI 1.15-1.54). CONCLUSIONS: Although the prevalence of TPTL in term deliveries is low, affected pregnancies are at increased risk for adverse perinatal outcomes. Increased fetal surveillance should be considered in the management of pregnancies affected by TPTL.

Caesarean birth and risk of subsequent preterm birth: a retrospective cohort study.

OBJECTIVE: To determine the risk of spontaneous and medically indicated preterm birth associated with mode of birth in previous term-born pregnancy. DESIGN: Retrospective cohort study. SETTING: Two UK maternity units. POPULATION OR SAMPLE: A total of 16 340 women with first two consecutive singleton births and the first birth at term. METHODS: Retrospective cohort study using routinely collected clinical data. MAIN OUTCOME MEASURES: Incidence of spontaneous preterm birth and medically indicated preterm birth at less than 37 weeks of gestation after term birth, in relation to mode of birth in first pregnancy. Subgroup analysis on cervical dilatation at the time of first caesarean birth. RESULTS: Compared with vaginal birth, emergency caesarean birth at full dilatation was associated with an increase in spontaneous preterm birth (2.3% vaginal birth versus 4.5% full dilatation caesarean; adjusted odds ratio [aOR] 3.29, 95% CI 2.02-5.13, P < 0.001). Elective caesarean, emergency caesarean at <4 cm dilatation, and emergency caesarean at 4-9 cm dilatation were associated with increased medically indicated preterm birth (0.8% vaginal births versus 1.9% elective caesarean, 3.3% <4 cm caesarean, 1.3% 4-9 cm caesarean; aOR 2.30, 95% CI 1.19-4.15, P = 0.009; aOR 4.68, 95% CI 2.98-7.24, P < 0.001; and aOR 2.43, 95% CI 1.43-4.00, P = 0.001, respectively). CONCLUSIONS: Term caesarean in the first stage of labour or performed prelabour is associated with medically indicated preterm birth. Term caesarean in the second stage of labour is associated with spontaneous preterm birth. TWEETABLE ABSTRACT: Caesarean in the second stage of labour is associated with spontaneous preterm birth.

Association between chorionicity and preterm birth in twin pregnancies: a systematic review involving 29 864 twin pregnancies.

BACKGROUND: The perinatal mortality and morbidity among twins vary by chorionicity. Although it is considered that monochorionicity is associated with an increased risk of preterm birth in twin pregnancies, no systematic review exists evaluating this association. OBJECTIVES: This systematic review was undertaken to assess the association between preterm birth and chorionicity in twin pregnancies. SEARCH STRATEGY: We searched the electronic databases from January 1990 to July 2019 without language restrictions. SELECTION CRITERIA: All studies on twin pregnancies where chorionicity and preterm birth were evaluated were included. DATA COLLECTION AND ANALYSIS: Findings are reported as odds ratios with 95% confidence intervals. The estimates are pooled using random-effects meta-analysis. MAIN RESULTS: From 13 156 citations, we included 39 studies (29 864 pregnancies). Monochorionicity was significantly associated with increased risk of preterm birth at ≤28, ≤32, ≤34 and <37 weeks in women asymptomatic and symptomatic for preterm labour (odds ratio [OR] 2.14, 95% CI 1.52-3.02, I2  = 46%, OR 1.55, 95% CI 1.27-1.89 I2  = 68%, OR 1.47, 95% CI 1.27-1.69, I2  = 60%, OR 1.66, 95% CI 1.43-1.93, I2  = 65%, respectively). Among those asymptomatic for preterm labour, significantly increased odds of preterm birth were seen for monochorionicity at gestations ≤34 weeks (OR 1.85, 95% CI 1.42-2.40, I2  = 25%) and <37 weeks (OR 1.75, 95% CI 1.22-2.53, I2  = 61%). Sensitivity analysis showed significantly increased odds of spontaneous preterm birth at ≤34 and <37 weeks for monochorionicity (OR 1.25, 95% CI 1.01-1.55, I2  = 0% and OR 1.41, 95% CI 1.13-1.78, I2  = 0%). CONCLUSIONS: Monochorionicity is significantly associated with preterm birth at all gestations. TWEETABLE ABSTRACT: In twin pregnancies, monochorionicity is associated with an increased risk of preterm birth at all gestations.

The effect of mode of delivery and duration of labour on subsequent pregnancy outcomes: a retrospective cohort study.

OBJECTIVE: To assess whether delivery mode and duration of labour in a first labour of spontaneous onset is associated with gestational length, delivery mode and neonatal outcome in the subsequent pregnancy. STUDY DESIGN: Retrospective analysis of prospectively collected data. SETTING: 15 Maternity units in North West London (1988-2000). POPULATION: 30 840 women with spontaneous onset of labour in pregnancy 1 and a subsequent birth reported in the same database. METHODS: Assessment of outcomes by mode of delivery in pregnancy 1, restricting the analysis to the difference in the gestational length between pregnancy 1 and 2. MAIN OUTCOME MEASURES: Gestational length, mode of delivery and neonatal unit admission in pregnancy 2. RESULTS: Caesarean section (CS) in the first or second stage of labour in pregnancy 1 was associated with pregnancy 2 being a median of 5 and 8 days shorter and a preterm birth rate of 6.0% and 10.1%, respectively, whereas following a normal or instrumental vaginal birth in pregnancy 1, the median duration was similar, with preterm delivery rates of 4.5% and 3.9%. In all, 56.2% of women with a CS in pregnancy 1 had a repeat CS and 12.5% of their babies were admitted to a neonatal unit, compared with 5.3% of women with vaginal birth. Longer labours were associated with shorter gestations in pregnancy 2. CONCLUSIONS: Compared with vaginal birth, an emergency CS in the first-term pregnancy is associated with a shorter gestational length, increased rate of repeat CS and increased risk of NNU admission in the next pregnancy. TWEETABLE ABSTRACT: An emergency caesarean section in the first-term pregnancy affects the duration and outcome of the next pregnancy.

Prediction of labour onset in women who present with symptoms of preterm labour using cervical length.

BACKGROUND: Diagnosis of preterm labour is difficult because initial symptoms and signs are often mild and may occur in continuing pregnancies. This study aims to investigate the utility of measuring cervical length, using transvaginal ultrasound, in women presenting to the delivery suite with symptoms of preterm labour. METHODS: This was a prospective cohort study performed in KK Women's and Children's Hospital, Singapore from September 2017 to July 2018. Women with singleton pregnancies, presenting with symptoms of contraction pain, between 24+ 0 to 36+ 6 weeks gestation, were included. Transvaginal ultrasound cervical length measurements were done at presentation to the labour ward, after four hours and in the following morning. The primary outcome of the study was delivery within 1 week. All statistical analyses were conducted with Microsoft Excel and Statistical Package for the Social Sciences. RESULTS: A total of 95 subjects were included. A one-millimeter increase in the 1st cervical length increases scan-to-delivery time by 0.802 days (p-value 0.003, CI 0.280-1.323). Receiver Operator Characteristic (ROC) curve analysis for prediction of delivery within 1 week showed an Area Under Curve (AUC) of 0.667, optimal cut-off value of 27.5mm (sensitivity 77.8 %, specificity 61.6 %). A one-millimetre increase in the 3rd cervical length increases scan-to-delivery time by 0.770 days (p-value 0.023, CI 0.108-1.432). ROC curve analysis for prediction of delivery within 1 week showed an AUC of 0.915, optimal cut-off value of 25.5mm (sensitivity 100 %, specificity 73.6 %). However, the change in cervical length over a period of 1 day was not significant in predicting delivery within 1 week. CONCLUSIONS: Our results indicate that by using a cervical length cut off of 27.5mm at presentation, we would have predicted 77.8 % of deliveries within 1 week. If we were to repeat the cervical length scan the next day, with the same cut-off of 27.5mm, we would have predicted 100 % of deliveries within 1 week. In our study, measuring the transvaginal ultrasound cervical length is a reliable diagnostic test for delivery within 1 week. However, the results are limited by the small sample size. Further studies should be conducted with a larger sample size.

Does the length of second stage of labour or second stage caesarean section in nulliparous women increase the risk of preterm birth in subsequent pregnancies?

OBJECTIVES: This study aimed to investigate the role of prolonged second stage of labour and second stage caesarean section on the risk of spontaneous preterm birth (sPTB) in a subsequent pregnancy. METHODS: This was a retrospective cohort study of nulliparous women with two consecutive singleton deliveries between 2014 and 2017 at a tertiary centre. In the vaginal delivery cohort, subsequent pregnancy outcomes for women with a prolonged second stage (>2 h) were compared with those with a normal second stage (≤2 h). In the caesarean delivery cohort, women with a first stage or a second stage were compared with the vaginal delivery cohort. The primary outcome was subsequent sPTB. RESULTS: A total of 821 women met inclusion criteria, of which 74.8% (614/821) delivered vaginally and 25.2% (207/821) delivered by caesarean section. There was no association between a prolonged second stage in the index pregnancy and subsequent sPTB (aOR 0.70, 95% CI 0.13-3.83, p=0.7). The risk of subsequent sPTB was threefold for those with a second stage caesarean section; however this did not reach statistical significance. CONCLUSIONS: A prolonged second stage of labour in the index pregnancy is not associated with an increased risk of subsequent sPTB. A second stage caesarean section in the index pregnancy may be associated with an increased risk of subsequent sPTB, however there was no statistically significant difference. These findings are important for counseling and suggest that the effects of these factors are not clinically significant to justify additional interventions in the subsequent pregnancy.