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. 2019 Sep 25;9(9):CD007235.
doi: 10.1002/14651858.CD007235.pub4.

Cervical assessment by ultrasound for preventing preterm delivery

Vincenzo Berghella  1 , Gabriele Saccone
Affiliations

Cervical assessment by ultrasound for preventing preterm delivery

Vincenzo Berghella et al. Cochrane Database Syst Rev. .

Abstract

Background: Measurement of cervical length by ultrasound is predictive of preterm birth (PTB). There are three methods of ultrasound cervical assessment: transvaginal (TVU), transabdominal (TAU), and transperineal (TPU, also called translabial). Cervical length measured by TVU is a relatively new screening test, and has been associated with better prediction of PTB than previously available tests. It is unclear if cervical length measured by ultrasound is effective for preventing PTB. This is an update of a review last published in 2013.

Objectives: To assess the effectiveness of antenatal management based on transvaginal, transabdominal, and transperineal (also called translabial) ultrasound screening of cervical length for preventing preterm birth.

Search methods: For this update, we searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP) to 30 August 2018; reviewed the reference lists of all articles, and contacted experts in the field for additional and ongoing trials.

Selection criteria: We included published and unpublished randomised controlled trials (RCT) including pregnant women between the gestational ages of 14 to 32 weeks, for whom the cervical length was screened for risk of PTB with TVU, TAU, or TPU. This review focused on studies based on knowledge versus no knowledge of cervical length results, or ultrasound versus no ultrasound for cervical length. We excluded studies based on interventions (e.g. progesterone, cerclage) for short cervical length.

Data collection and analysis: We followed standard Cochrane methods.

Main results: We included seven RCTs (N = 923): one examined asymptomatic women with twin pregnancies; four included women with singleton pregnancies and symptoms of preterm labour (PTL); one included women with singleton pregnancies and symptoms of preterm premature rupture of membranes (PPROM); and one included asymptomatic singletons. All trials used TVU for screening.We assessed the risk of bias of the included studies as mixed, and the quality of the evidence for primary outcomes as very low for all populations.For asymptomatic women with twin pregnancies, it is uncertain whether knowledge of TVU-measured cervical length compared to no knowledge reduces PTB at less than 34 weeks (risk ratio (RR) 0.62, 95% confidence intervals (CI) 0.30 to 1.25; 1 study, 125 participants) because the quality of the evidence is very low. The results were also inconclusive for preterm birth at 36, 32, or 30 weeks; gestational age at birth, and other maternal and perinatal outcomes.Four trials examined knowledge of TVU-measured cervical length of singletons with symptoms of PTL versus no knowledge. We are uncertain of the effects because of inconclusive results and very low-quality evidence for: preterm births at less than 37 weeks (average RR 0.59, 95% CI 0.26 to 1.32; 2 studies, 242 participants; I² = 66%; Tau² = 0.23). Birth occurred about four days later in the knowledge groups (mean difference (MD) 0.64 weeks, 95% CI 0.03 to 1.25; 3 trials, 290 women). The results were inconclusive for the other outcomes for which there were available data: PTB at less than 34 or 28 weeks; birthweight less than 2500 g; perinatal death; maternal hospitalisation; tocolysis; and steroids for fetal lung maturity.The trial of singletons with PPROM (N = 92) evaluated safety of using TVU to measure cervical length in this population as its primary outcome, not its effect on management. The results were inconclusive for incidence of maternal and neonatal infections between the TVU and no ultrasound groups.In the trial of asymptomatic singletons (N = 296), in which women either received TVU or not, the results were inconclusive for preterm birth at less than 37 weeks (RR 1.27, 95% CI 0.61 to 2.61; I² = 0%), gestational age at birth, and other perinatal and maternal outcomes.We downgraded evidence for limitations in study design, inconsistency between the trials, and imprecision, due to small sample size and wide confidence intervals crossing the line of no effect.No trial compared the effect of knowledge of the CL with no knowledge of CL in other populations, such as asymptomatic women with singleton pregnancies, or symptomatic women with twin pregnancies.

Authors' conclusions: There are limited data on the effects of knowing the cervical length, measured by ultrasound, for preventing preterm births, which preclude us from drawing any conclusions for women with asymptomatic twin or singleton pregnancies, singleton pregnancies with PPROM, or other populations and clinical scenarios.Limited evidence suggests that knowledge of transvaginal ultrasound-measured cervical length, used to inform the management of women with singleton pregnancies and symptoms of preterm labour, appears to prolong pregnancy by about four days over women in the no knowledge groups.Future studies could look at specific populations separately (e.g. singleton versus twins; symptoms versus no symptoms of PTL), report on all pertinent maternal and perinatal outcomes, and include cost-effectiveness analyses. Most importantly, future studies should include a clear protocol for management of women based on TVU-measured cervical length.

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Conflict of interest statement

Vincenzo Berghella: is a co‐author on one of the included trials (Ness 2007). VB was not involved in the assessment of eligibility or risk of bias for this trial; it was assessed by Gabriele Saccone.

Gabriele Saccone: is lead author on two ongoing trials (NCT02923973; NCT02928302). GS was not involved in the assessment of eligibility for these trials; they were assessed by the Cochrane Pregancy and Childbirth Group editorial staff.

Figures

1
1
Study flow diagram
2
2
'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies
3
3
'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study
1.1
1.1. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 1 Preterm birth < 36 weeks.
1.2
1.2. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 2 Preterm birth < 34 weeks.
1.3
1.3. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 3 Preterm birth < 32 weeks.
1.4
1.4. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 4 Preterm birth < 30 weeks.
1.5
1.5. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 5 Gestational age at delivery.
1.6
1.6. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 6 Maternal hospitalisation for PTL.
1.7
1.7. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 7 Tocolysis.
1.8
1.8. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 8 Steroids for fetal lung maturity.
1.9
1.9. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 9 Cervical cerclage.
1.10
1.10. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 10 Birthweight (g).
1.11
1.11. Analysis
Comparison 1 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic women with twins, Outcome 11 NICU admission.
2.1
2.1. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 1 Preterm birth < 37 weeks.
2.2
2.2. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 2 Preterm birth < 34 weeks.
2.3
2.3. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 3 Preterm birth < 28 weeks.
2.4
2.4. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 4 Gestational age at delivery (weeks).
2.5
2.5. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 5 Birthweight < 2500 g.
2.6
2.6. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 6 Perinatal death.
2.7
2.7. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 7 Maternal hospitalisation.
2.8
2.8. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 8 Tocolysis.
2.9
2.9. Analysis
Comparison 2 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with symptoms of PTL, Outcome 9 Steroids for fetal lung maturity.
3.1
3.1. Analysis
Comparison 3 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with PPROM, Outcome 1 Birthweight (g).
3.2
3.2. Analysis
Comparison 3 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with PPROM, Outcome 2 Chorioamnionitis.
3.3
3.3. Analysis
Comparison 3 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with PPROM, Outcome 3 Endometritis.
3.4
3.4. Analysis
Comparison 3 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ singletons with PPROM, Outcome 4 Neonatal infection.
4.1
4.1. Analysis
Comparison 4 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic singletons, Outcome 1 Preterm birth < 37 weeks.
4.2
4.2. Analysis
Comparison 4 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic singletons, Outcome 2 Birthweight (g).
4.3
4.3. Analysis
Comparison 4 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic singletons, Outcome 3 Respiratory distress syndrome (RDS).
4.4
4.4. Analysis
Comparison 4 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic singletons, Outcome 4 NICU admission.
4.5
4.5. Analysis
Comparison 4 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic singletons, Outcome 5 Intraventricular haemorrhage (IVH).
4.6
4.6. Analysis
Comparison 4 Knowledge versus no knowledge of transvaginal ultrasound (TVU)‐measured cervical length (CL) ‐ asymptomatic singletons, Outcome 6 Neonatal death.
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References

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References to other published versions of this review

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