[Is universal screening for cervical length among singleton pregnancies with no history of preterm birth justified?].

The ultrasonographic measurement of cervical length with a cutoff of 15mm is currently the best method to identify a group of asymptomatic women in the general population at risk of spontaneous preterm birth, especially among asymptomatic patients with a singleton pregnancy with no history of preterm birth. Cerclage and 17 alpha-hydroxyprogesterone caproate (17OHP-C) are ineffective to reduce the risk of preterm birth among asymptomatic patients with a short cervix in midtrimester. However, vaginal progesterone (200-mg capsules of micronized progesterone or gel containing 90mg progesterone) has been demonstrated effective in 2 large randomized trials to reduce the risk of preterm birth and possibly the composite morbidity and perinatal mortality associated among asymptomatic women with a short cervix in the general population screened by ultrasound of the cervix in midtrimester. Three cost-effectiveness analyses are converging to show that universal screening for cervical length with vaginal progesterone treatment seems to be cost-effective compared with no screening. However, it is too early to definitively conclude that universal screening is justified for several reasons: many women must be screened to prevent a relatively small number of preterm births. Moreover, the epidemiology of preterm delivery is such that the use of progesterone in asymptomatic women with a short cervix screened by ultrasound in midtrimester in the general population will not significantly reduce the prevalence of preterm births; there are no data comparing the effectiveness of universal ultrasound screening followed by vaginal progesterone treatment in case of short cervix versus no universal screening associated to a progesterone treatment in case of incidentally observed short cervix; the universal ultrasound screening may not produce the same results in practice than those observed in published randomized trials, due to population differences, "indication creep", or "stretching of the cutoff" defining the short cervix. Moreover, the implementation of unevaluated or not recommended treatments, such as bed rest, tocolytics, 17OHP-C or cerclage, can potentially cause unintended deleterious consequences and reduce the cost-effectiveness; the cost-effectiveness analyses evaluating universal screening for cervical length present uncertainties on critical variables, notably the short cervix prevalence and the progesterone efficacy. In conclusion, although the implementation of such a screening strategy can be considered by individual practitioners, this screening cannot be universally mandated.

Rozenberg P 《-》

[Prevention of spontaneous preterm birth (excluding preterm premature rupture of membranes): Guidelines for clinical practice - Text of the Guidelines (short text)].

To determine the measures to prevent spontaneous preterm birth (excluding preterm premature rupture of membranes)and its consequences. The PubMed database, the Cochrane Library and the recommendations from the French and foreign obstetrical societies or colleges have been consulted. In France, premature birth concerns 60,000 neonates every year (7.4 %), half of them are delivered after spontaneous onset of labor. Among preventable risk factors of spontaneous prematurity, only cessation of smoking is associated to a decrease of prematurity (level of evidence [LE] 1). This is therefore recommended (grade A). Routine screening and treatment of vaginal bacteriosis in general population is not recommended (grade A). Asymptomatic women with single pregnancy without history of preterm delivery and a short cervix between 16 and 24 weeks is the only population in which vaginal progesterone is recommended (grade B). A history-indicated cerclage is not recommended in case of only past history of conisation (grade C), uterine malformation (Professional consensus), isolated history of pretem delivery (grade B) or twin pregnancies in primary (grade B) or secondary (grade C) prevention of preterm birth. A history-indicated cerclage is recommended for single pregnancy with a history of at least 3 late miscarriages or preterm deliveries (grade A).). In case of past history of a single pregnancy delivery before 34 weeks gestation (WG), ultrasound cervical length screening is recommended between 16 and 22 WG in order to propose a cerclage in case of length<25mm before 24 WG (grade C). Cervical pessary is not recommended for the prevention of preterm birth in a general population of asymptomatic women with a twin pregnancy (grade A) and in populations of asymptomatic women with a short cervix (Professional consensus). Although the implementation of a universal transvaginal cervical length screening at 18-24 weeks of gestation in women with a singleton gestation and no history of preterm birth can be considered by individual practitioners, this screening cannot be universally recommended. In case of preterm labor, (i) it is not possible to recommend one of the methods over another (ultrasound of the cervical length, vaginal examination, fetal fibronectin) to predict preterm birth (grade B); (ii) routine antibiotic therapy is not recommended (grade A); (iii) prolonged hospitalization (grade B) and bed rest (grade C) is not recommended. Compared with placebo, tocolytics are not associated with a reduction in neonatal mortality or morbidity (LE2) and maternal severe adverse effects may occur with all tocolytics (LE4). Atosiban and nifedipine (grade B), contrary to betamimetics (grade C), can be used for tocolysis in spontaneous preterm labour without preterm premature rupture of membranes. Maintenance tocolysis is not recomended (grade B). Antenatal corticosteroid administration is recommended to every woman at risk of preterm delivery before 34 weeks of gestation (grade A). After 34 weeks, evidences are not consistent enough to recommend systematic antenatal corticosteroid treatment (grade B), however, a course might be indicated in the clinical situations associated with the higher risk of severe respiratory distress syndrome, mainly in case of planned cesarean delivery (grade C). Repeated courses of antenatal corticosteroids are not recommended (grade A). Rescue courses are not recommended (Professional consensus). Magnesium sulfate administration is recommended to women at high risk of imminent preterm birth before 32WG (grade A). Cesarean is not recommended in case of vertex presentation (Professional consensus). Both planned vaginal or elective cesarean delivery is possible in case of breech presentation (Professional consensus). A delayed cord clamping may be considered if the neonatal or maternal state so permits (Professional consensus). Except for antenatal corticosteroid and magnesium sulfate administration, diagnostic tools or prenatal pharmacological treatments implemented since 30 years to prevent preterm birth and its consequences have not matched expectations of caregivers and families.

Sentilhes L ，Sénat MV ，Ancel PY ，Azria E ，Benoist G ，Blanc J ，Brabant G ，Bretelle F ，Brun S ，Doret M ，Ducroux-Schouwey C ，Evrard A ，Kayem G ，Maisonneuve E ，Marcellin L ，Marret S ，Mottet N ，Paysant S ，Riethmuller D ，Rozenberg P ，Schmitz T ，Torchin H ，Langer B ... -  《-》

Utility of follow-up cervical length screening in low-risk women with a cervical length of 26 to 29 mm.

In women with a previous preterm birth, a protocol for serial cervical length screening has been studied and recommended for the identification and treatment of a short cervix. Cervical length screening along with vaginal progesterone has been suggested for low-risk women with singleton pregnancies to treat a short cervix and reduce preterm birth. However, specific protocols for single vs serial ultrasound measuring cervical length in this population are not established. Cost-effectiveness of universal cervical length screening depends on the cost of screening; follow-up of borderline measurements can contribute to increased costs with uncertain benefit. This study aimed to determine the utility of follow-up cervical length screening in otherwise low-risk women with singleton pregnancies with a midtrimester cervical length measurement of 26 to 29 mm through the assessment of the rate of short cervix (≤25 mm) on follow-up ultrasound and subsequent delivery outcomes. This was a 2-year retrospective cohort study at a single urban institution of women with singleton pregnancies with no previous spontaneous preterm birth and an initial transvaginal ultrasound cervical length measurement of 26 to 29 mm identified during universal cervical length screening at time of anatomy ultrasound (18 0/7 to 22 6/7 weeks' gestation). The primary outcome was the rate of short cervix (defined as ≤25 mm on transvaginal ultrasound) on follow-up ultrasound at <24 weeks' gestation. Secondary outcomes included the rate of spontaneous preterm birth (<37 and <34 weeks' gestation). During the study period, there were 2801 women with singleton pregnancies at 18 0/7 to 22 6/7 weeks' gestation with transvaginal ultrasound cervical length screening at time of anatomy scan. Among those women, 201 had a cervical length of 26 of 29 mm, and 184 (7%) had no previous spontaneous preterm birth and were included in the study. Furthermore, 144 women (78%) had a follow-up cervical length completed before 24 weeks' gestation. The mean follow-up interval was 1.5±0.6 weeks. Overall, the percentage of short cervix (≤25 mm) on follow-up was 15% (n=21). Baseline characteristics were similar, but the initial cervical length measurement was shorter in women who subsequently developed a short cervix (26.7±0.8 vs 27.8±1.0; P<.01). Delivery outcomes were available for 126 patients. The rate of spontaneous preterm birth at <37 weeks' gestation in women with an initial cervical length 26 to 29 mm and subsequent short cervix was significantly higher than the rate of spontaneous preterm birth in a historical cohort of low risk women with an initial cervical length >25 mm (16% vs 3%; P=.03). The rate of spontaneous preterm birth at <34 weeks' gestation in women with a subsequent short cervix was 11% (2 of 19). Here, approximately 15% of low-risk women with singleton pregnancies with a midtrimester cervical length measurement of 26 to 29 mm will experience cervical shortening of ≤25 mm before 24 weeks' gestation. Compared to women with singleton pregnancies without a history of preterm birth, the rate of spontaneous preterm birth (16%) in women with an initial cervical length of 26 to 29 mm and a subsequent cervical shortening of ≤25 mm is significantly higher. A total of 111 follow-up ultrasounds measuring cervical length would be required to prevent 1 early preterm birth at <34 weeks' gestation.

Boelig RC ，Kripalu V ，Chen SL ，Cruz Y ，Roman A ，Berghella V ... -  《-》

17-alpha-hydroxyprogesterone caproate versus vaginal progesterone suppository for the prevention of preterm birth in women with a sonographically short cervix: A randomized controlled trial.

The aim of this study was to compare 17-alpha-hydroxyprogesterone caproate (17OHP-C) with vaginal progesterone suppository for the prevention of preterm birth in women with a sonographically short cervix and to evaluate the changes of the cervical length (CL) over time. In this prospective randomized controlled trial, eligible patients were asymptomatic pregnant women with a sonographically short cervix. The participants in group 1 (n = 147) received vaginal progesterone suppositories at a dose of 400 mg daily and the women in group 2 (n = 150) received an i.m. dose of 250 mg 17OHP-C once a week. Transvaginal sonography was repeated every 3 weeks until 36 gestational weeks or the occurrence of preterm labor. A total of 304 singleton pregnant women between 16 and 24 gestational weeks with CL < 25 mm were enrolled in our study. The rates of preterm birth were 10.4% in the progesterone group and 14% in the 17OHP-C group: a difference that was not statistically significant (P = 0.416). Moreover, 264 participants underwent ultrasound examination five times and CL changes were studied for 15 weeks. The results showed that the CL changes over 15 weeks were statistically significant (P < 0.001), but the method of intervention (progesterone/17OHP-C) had no significant effect on CL change (P = 0.64). Our findings showed that vaginal progesterone and 17OHP-C had the same effect on the risk of preterm labor in asymptomatic women with a sonographically short cervix. We detected no significant difference between the effect of 17OHP-C and vaginal progesterone on CL changes over time.

Pirjani R ，Heidari R ，Rahimi-Foroushani A ，Bayesh S ，Esmailzadeh A ... -  《-》

Prevention of spontaneous preterm birth: Guidelines for clinical practice from the French College of Gynaecologists and Obstetricians (CNGOF).

In France, 60,000 neonates are born preterm every year (7.4%), half of them after the spontaneous onset of labor. Among preventable risk factors of spontaneous prematurity, only cessation of smoking is associated with decreased prematurity (level of evidence [LE]1). It is therefore recommended (Grade A). Routine screening and treatment of vaginal bacteriosis is not recommended in the general population (Grade A). The only population for which vaginal progesterone is recommended is that comprising asymptomatic women with singleton pregnancies, no history of preterm delivery, and a short cervix at 16-24 weeks of gestation (Grade B). A history-indicated cerclage is not recommended for women with only a history of conization (Grade C), uterine malformation (professional consensus), isolated history of preterm delivery (Grade B), or twin pregnancies for primary (Grade B) or secondary (Grade C) prevention of preterm birth. A history-indicated cerclage is recommended for a singleton pregnancy with a history of at least 3 late miscarriages or preterm deliveries (Grade A). Ultrasound cervical length screening is recommended between 16 and 22 weeks for women with a singleton previously delivered before 34 weeks gestation, so that cerclage can be offered if cervical length <25mm before 24 weeks (Grade C). A cervical pessary is not recommended for the prevention of preterm birth in a general population of asymptomatic women with twin pregnancies (Grade A) or in populations of asymptomatic women with a short cervix (professional consensus). Although the implementation of universal screening by transvaginal ultrasound for cervical length at 18-24 weeks of gestation in women with a singleton gestation and no history of preterm birth can be considered by individual practitioners, this screening cannot be universally recommended. In cases of preterm labor, (i) it is not possible to recommend any one of the several methods (ultrasound of the cervical length, vaginal examination, or fetal fibronectin assay) over any other to predict preterm birth (Grade B); (ii) routine antibiotic therapy is not recommended (Grade A); (iii) prolonged hospitalization (Grade B) and bed rest (Grade C) are not recommended. Compared with placebo, tocolytics are not associated with a reduction in neonatal mortality or morbidity (LE2) and maternal severe adverse effects may occur with all tocolytics (LE4). Atosiban and nifedipine (Grade B), unlike beta-agonists (Grade C), can be used for tocolysis in spontaneous preterm labor without preterm premature rupture of membranes. Maintenance tocolysis is not recommended (Grade B). Antenatal corticosteroid administration is recommended for all women at risk of preterm delivery before 34 weeks of gestation (Grade A). After 34 weeks, the evidence is insufficiently consistent to justify recommending systematic antenatal corticosteroid treatment (Grade B), but a course of this treatment might be indicated in clinical situations associated with high risk of severe respiratory distress syndrome, mainly in case of planned cesarean delivery (Grade C). Repeated courses of antenatal corticosteroids are not recommended (Grade A). Rescue courses are not recommended (Professional consensus). Magnesium sulfate administration is recommended for women at high risk of imminent preterm birth before 32 weeks (Grade A). Cesareans are not recommended for fetuses in vertex presentation (professional consensus). Both planned vaginal and elective cesarean delivery are possible for breech presentations (professional consensus). Delayed cord clamping may be considered if the neonatal or maternal state allows (professional consensus).

Sentilhes L ，Sénat MV ，Ancel PY ，Azria E ，Benoist G ，Blanc J ，Brabant G ，Bretelle F ，Brun S ，Doret M ，Ducroux-Schouwey C ，Evrard A ，Kayem G ，Maisonneuve E ，Marcellin L ，Marret S ，Mottet N ，Paysant S ，Riethmuller D ，Rozenberg P ，Schmitz T ，Torchin H ，Langer B ... -  《-》