Cervical pessary versus vaginal progesterone in women with a singleton pregnancy, a short cervix, and no history of spontaneous preterm birth at less than 34 weeks' gestation: open label, multicentre, randomised, controlled trial.

OBJECTIVE: To compare the effectiveness of cervical pessary and vaginal progesterone in the prevention of adverse perinatal outcomes and preterm birth in pregnant women of singletons with no prior spontaneous preterm birth at less than 34 weeks' gestation and who have a short cervix of 35 mm or less. DESIGN: Open label, multicentre, randomised, controlled trial. SETTING: 20 hospitals and five obstetric ultrasound practices in the Netherlands. PARTICIPANTS: Women with a healthy singleton pregnancy and an asymptomatic short cervix of 35 mm or less between 18 and 22 weeks' gestation were eligible. Exclusion criteria were prior spontaneous preterm birth at less than 34 weeks, a cerclage in situ, maternal age of younger than 18 years, major congenital abnormalities, prior participation in this trial, vaginal blood loss, contractions, cervical length of less than 2 mm or cervical dilatation of 3 cm or more. Sample size was set at 628 participants. INTERVENTIONS: 1:1 randomisation to an Arabin cervical pessary or vaginal progesterone 200 mg daily up to 36 weeks' of gestation or earlier in case of ruptured membranes, signs of infection, or preterm labour besides routine obstetric care. MAIN OUTCOME MEASURES: Primary outcome was a composite adverse perinatal outcome. Secondary outcomes were rates of (spontaneous) preterm birth at less than 28, 32, 34, and 37 weeks. A predefined subgroup analysis was planned for cervical length of 25 mm or less. RESULTS: From 1 July 2014 to 31 March 2022, 635 participants were randomly assigned to pessary (n=315) or to progesterone (n=320). 612 were included in the intention to treat analysis. The composite adverse perinatal outcome occurred in 19 (6%) of 303 participants with a pessary versus 17 (6%) of 309 in the progesterone group (crude relative risk 1.1 (95% confidence interval (CI) 0.60 to 2.2)). The rates of spontaneous preterm birth were not significantly different between groups. In the subgroup of cervical length of 25 mm or less, spontaneous preterm birth at less than 28 weeks occurred more often after pessary than after progesterone (10/62 (16%) v 3/69 (4%), relative risk 3.7 (95% CI 1.1 to 12.9)) and adverse perinatal outcomes seemed more frequent in the pessary group (15/62 (24%) v 8/69 (12%), relative risk 2.1 (0.95 to 4.6)). CONCLUSIONS: In women with a singleton pregnancy with no prior spontaneous preterm birth at less than 34 weeks' gestation and with a midtrimester short cervix of 35 mm or less, pessary is not better than vaginal progesterone. In the subgroup of a cervical length of 25 mm or less, a pessary seemed less effective in preventing adverse outcomes. Overall, for women with single baby pregnancies, a short cervix, and no prior spontaneous preterm birth less than 34 weeks' gestation, superiority of a cervical pessary compared with vaginal progesterone to prevent preterm birth and consecutive adverse outcomes could not be proven. TRIAL REGISTRATION: International Clinical Trial Registry Platform (ICTRP, EUCTR2013-002884-24-NL).

Uniform International Method to Measure Cervical Length: Are We There Yet?

INTRODUCTION: Cervical length is an important predictor of spontaneous preterm birth. So far, the best way to measure cervical length has not been established. We aimed to compare the incidence of short cervical length between three methods of cervical length measurement with and without the inclusion of cervico-isthmic complex (CIC) (six methods in total) and to determine the positive predictive value for spontaneous preterm birth. MATERIAL AND METHODS: We performed a prospective single-center cohort study in women with a singleton pregnancy between August 2014 and December 2018. During the routine fetal anomaly scan (18-22 weeks), women were offered transvaginal ultrasound for cervical length measurement to screen for the risk of spontaneous preterm birth. Each cervix was measured in six different ways: single-line, two-line, and tracing method between the internal and external os of the cervix with and without CIC. We evaluated the predictive value of the different measurements for spontaneous delivery before 37 weeks using positive predictive values. RESULTS: Our final study population comprised 1,691 women. The overall rate of preterm birth <37 weeks was 8.0% (4.6% spontaneous, 3.4% iatrogenic preterm birth). The mean gestational age at cervical length measurement was 19+6 weeks. The different measuring techniques resulted in significant different cervical lengths, showing a maximum difference of >8 mm between the techniques (41.04 mm [SD 7.1] with one-line without CIC and 49.18 [SD 9.05] mm with trace with CIC) with an incidence of short cervical length below <25 mm ranging from 0.4% to 1.1% (p = 0.18). The positive predictive values for spontaneous preterm birth <37 weeks ranged from 42.9% to 20.0%. CONCLUSION: Different measurement methods for cervical length resulted in statistically significant differences in measured cervical length. Depending on the chosen cut-off this translates to different incidences of short cervical length and influences the number of women designated as high risk for preterm birth and receiving treatment. For interpretation and comparability between (inter-) national studies, it is important to adequately report on the employed technique. Future research should focus on determining the optimal measuring technique and a universal method of measurement.

The association between parity and spontaneous preterm birth: a population based study.

BACKGROUND: Preterm birth is the leading cause of perinatal mortality and neonatal morbidity worldwide. Many factors have been associated with preterm birth, including parity. The aim of the present study was to investigate associations between parity and risk of spontaneous preterm birth. METHODS: We conducted a retrospective study including live singleton births (≥22 weeks) of women with a first, second, third, fourth or fifth pregnancy in The Netherlands from 2010 through 2014. Our primary outcome was risk of spontaneous preterm birth < 37 weeks. Secondary outcomes were spontaneous preterm birth < 32 and < 28 weeks. RESULTS: We studied 802,119 pregnancies, including 30,237 pregnancies that ended spontaneously < 37 weeks. We identified an increased risk for spontaneous preterm birth < 37 weeks in nulliparous women (OR 1.95, 95% CI 1.89-2.00) and women in their fifth pregnancy (OR 1.26, 95% CI 1.13-1.41) compared to women in their second pregnancy. Similar results were seen for spontaneous preterm birth < 32 and < 28 weeks. CONCLUSION: Our data show an independent association between nulliparity and spontaneous preterm birth < 37, < 32 and < 28 weeks. Furthermore, we observed an increased risk for spontaneous preterm birth in women in their fifth pregnancy, with highest risk for preterm birth at early gestational age.

Trends in preterm birth in singleton and multiple gestations in the Netherlands 2008-2015: A population-based study.

OBJECTIVE: Preterm birth is the most important cause of perinatal morbidity and mortality. Over the past years several preventive measures have been studied and implemented. Preterm birth percentage in 2015 in the Netherlands was 6.9 %, according to data from the European Peristat project, reporting on perinatal health in Europe. Various preventive measures might have influenced the incidence and outcome of preterm birth. Our aim was to give an overview of the trends in preterm births for both singleton and multiple gestations in the Netherlands in order to guide future research. STUDY DESIGN: We studied a nationwide cohort including both singleton and multiple gestations without congenital anomalies between 2008 and 2015. Outcomes were total preterm birth (defined as birth before 37 weeks of gestation), spontaneous and iatrogenic preterm birth < 37 weeks, spontaneous and iatrogenic preterm birth percentages between 34-36 weeks, 32-34 weeks, 28-31 weeks and ≤ 27 weeks using a moving average technique. Trend analysis was performed using the Cochran Armitage test. Singleton and multiple gestations were analyzed separately. RESULTS: Our final study population comprised 1,303.786 women with a singleton and 44,951 women with a multiple pregnancy. Preterm birth < 37 weeks in singletons decreased from 5.6 % in 2008 to 5.3 % in 2015 (P < 0.0001), in both spontaneous and iatrogenic preterm birth. Preterm birth ≤ 27 weeks increased from 0.40 % to 0.45 % (P for trend <0.0001). The number of multiple gestations decreased over the years, as well as the percentage of multiples conceived through IVF/ICSI. There was an increase in total and iatrogenic preterm birth < 37 weeks from 36.7-38.2% (P < 0.0001) in multiples. The number of multiples <32 decreased, in both the spontaneous and iatrogenic group. CONCLUSION: In the Netherlands preterm birth risk in singletons decreased between 2008 and 2015 but an increase was noted in preterm birth ≤ 27 weeks. In multiples the total preterm birth risk increased, due to an increase in indicated preterm birth.

The predictive capacity of uterine artery Doppler for preterm birth-A cohort study.

INTRODUCTION: Mid-trimester uterine artery resistance measured with Doppler sonography is predictive for iatrogenic preterm birth. In view of the emerging association between hypertensive disease in pregnancy and spontaneous preterm birth, we hypothesized that uterine artery resistance could also predict spontaneous preterm birth. MATERIAL AND METHODS: We performed a cohort study of women with singleton pregnancies. Uterine artery resistance was routinely measured at the 18-22 weeks anomaly scan. Pregnancies complicated by congenital anomalies or intrauterine fetal death were excluded. We analyzed if the waveform of the uterine artery (no notch, unilateral notch or bilateral notch) was predictive for spontaneous and iatrogenic preterm birth, defined as delivery before 37 weeks of gestation. Furthermore, we assessed whether the uterine artery pulsatility index was associated with the risk of preterm birth. RESULTS: Between January 2009 and December 2016 we collected uterine Doppler indices and relevant outcome data in 4521 women. Mean gestational age at measurement was 19+6  weeks. There were 137 (3.0%) women with a bilateral and 213 (4.7%) with a unilateral notch. Mean gestational age at birth was 38+6  weeks. Spontaneous and iatrogenic preterm birth rates were 5.7% and 4.9%, respectively. Mean uterine artery resistance was 1.12 in the spontaneous preterm birth group compared with 1.04 in the term group (P = 0.004) The risk of preterm birth was increased with high uterine artery resistance (OR 2.9 per unit; 95% CI 2.4-3.9). Prevalence of spontaneous preterm birth increased from 5.5% in women without a notch in the uterine arteries to 8.0% in women with a unilateral notch and 8.0% in women with a bilateral notch. For iatrogenic preterm birth, these rates were 3.9%, 13.6% and 23.4%, respectively. Likelihood ratios for the prediction of spontaneous preterm birth were 1.6 (95% CI 1.0-2.6) and 1.9 (95% CI 1.0-3.5) for unilateral and bilateral notches, respectively, and for iatrogenic preterm birth they were 3.6 (95% CI 2.5-5.2) and 6.8 (95% CI 4.7-9.9) for unilateral and bilateral notches, respectively. Of all women with bilateral notching, 31.4% delivered preterm. CONCLUSIONS: Mid-trimester uterine artery resistance measured at 18-22 weeks of gestation is a weak predictor of spontaneous preterm birth.

Large-for-gestational-age fetuses have an increased risk for spontaneous preterm birth.

OBJECTIVE: Our aim was to investigate the association between large-for-gestational-age and the risk of spontaneous preterm birth. STUDY DESIGN: We studied nulliparous women with a singleton gestation using data from the Dutch perinatal registry from 1999 to 2010. Neonates were categorized according to the Hadlock fetal weight standard, into 10th to 90th percentile, 90th to 97th percentile, or above 97th percentile. Outcomes were preterm birth <37+0 weeks and preterm birth between 25+0-27+6 weeks, 28+0-30+6 weeks, 31+0-33+6 weeks, and 34+0-36+6 weeks. RESULTS: We included 547,418 women. The number of spontaneous preterm births <37 weeks was significantly increased in the large-for-gestational-age group ( > p97) compared with fetuses with a normal growth (p10-p90) (11.3% vs. 7.3%, odds ratio (OR) 1.8; 95% CI 1.7-1.9). The same results were found when limiting analyses to women with certain pregnancy duration (after in vitro fertilization). CONCLUSION: Large-for-gestational-age increases the risk of spontaneous preterm delivery from 25 weeks of gestation onwards.

Pessary or Progesterone to Prevent Preterm delivery in women with short cervical length: the Quadruple P randomised controlled trial.

BACKGROUND: Preterm birth is in quantity and in severity the most important topic in obstetric care in the developed world. Progestogens and cervical pessaries have been studied as potential preventive treatments with conflicting results. So far, no study has compared both treatments. METHODS/DESIGN: The Quadruple P study aims to compare the efficacy of vaginal progesterone and cervical pessary in the prevention of adverse perinatal outcome associated with preterm birth in asymptomatic women with a short cervix, in singleton and multiple pregnancies separately. It is a nationwide open-label multicentre randomized clinical trial (RCT) with a superiority design and will be accompanied by an economic analysis. Pregnant women undergoing the routine anomaly scan will be offered cervical length measurement between 18 and 22 weeks in a singleton and at 16-22 weeks in a multiple pregnancy. Women with a short cervix, defined as less than, or equal to 35 mm in a singleton and less than 38 mm in a multiple pregnancy, will be invited to participate in the study. Eligible women will be randomly allocated to receive either progesterone or a cervical pessary. Following randomization, the silicone cervical pessary will be placed during vaginal examination or 200 mg progesterone capsules will be daily self-administered vaginally. Both interventions will be continued until 36 weeks gestation or until delivery, whichever comes first. Primary outcome will be composite adverse perinatal outcome of perinatal mortality and perinatal morbidity including bronchopulmonary dysplasia, intraventricular haemorrhage grade III and IV, periventricular leukomalacia higher than grade I, necrotizing enterocolitis higher than stage I, Retinopathy of prematurity (ROP) or culture proven sepsis. These outcomes will be measured up until 10 weeks after the expected due date. Secondary outcomes will be, among others, time to delivery, preterm birth rate before 28, 32, 34 and 37 weeks, admission to neonatal intensive care unit, maternal morbidity, maternal admission days for threatened preterm labour and costs. DISCUSSION: This trial will provide evidence on whether vaginal progesterone or a cervical pessary is more effective in decreasing adverse perinatal outcome in both singletons and multiples. TRIAL REGISTRATION: Trial registration number: NTR 4414 . Date of registration January 29th 2014.

Prevention of preterm delivery: current challenges and future prospects.

Preterm birth (PTB), defined as delivery at <37 weeks of gestation, is the most important cause of neonatal morbidity and mortality. Therefore, preventing PTB is one of the main goals in obstetric care. In this review, we provide an overview of the current available literature on screening for risk factors for PTB and a summary of preventive strategies in both low-risk and high-risk women with singleton or multiple gestations. Furthermore, current challenges and future prospects on PTB are discussed. For an optimal prevention of PTB, risk stratification should be based on a combination of (maternal) risk factors, obstetric history, and screening tools. Cervical length measurements can help identify women at risk. Thereafter, preventive strategies such as progesterone, pessaries, and cerclage may help prevent PTB. Effective screening and prevention of PTB vary between the different pregnancy populations. In singleton or multiple pregnancies with a short cervix, without previous PTB, a pessary or progesterone might prevent PTB. In women with a (recurrent) PTB in the past, progesterone and a cerclage may prevent recurrence. The effect of a pessary in these high-risk women is currently being studied. A strong collaboration between doctors, patients' organizations, pharmaceutical companies, and (international) governments is needed to reduce the morbidity and mortality as a result of spontaneous PTB.