Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Randomized Controlled Trial
. 2023 Mar 22;20(1):47.
doi: 10.1186/s12978-022-01557-w.

Association between cervical length and gestational age at birth in singleton pregnancies: a multicentric prospective cohort study in the Brazilian population

Thais Valéria Silva  1   2 , Anderson Borovac-Pinheiro  1 , José Guilherme Cecatti  1 , Ben Willem Mol  3   4 , Fabricio Silva Costa  5 , Marcelo Santucci França  6 , Renato Teixeira Souza  1 , Roland Devlieger  7 , Renato Passini Jr  1 , Rodolfo Carvalho Pacagnella  8 ; P5 working group
Collaborators, Affiliations
Randomized Controlled Trial

Association between cervical length and gestational age at birth in singleton pregnancies: a multicentric prospective cohort study in the Brazilian population

Thais Valéria Silva et al. Reprod Health. .

Abstract

Background: Short cervical length measured during the second trimester of pregnancy is an important risk factor for spontaneous preterm birth (sPTB). The aim of this study is to identify the association between mid-pregnancy cervical length (CL) and gestational age at birth in asymptomatic singleton pregnant women.

Methods: This is a prospective cohort study involving singleton pregnant women who participated in the screening phase of a Brazilian multicenter randomized controlled trial (P5 trial) between July 2015 and March 2019. Transvaginal ultrasound 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. For this analysis we considered all women with CL ≤ 30 mm receiving progesterone and a random selection of women with CL > 30 mm, keeping the populational distribution of CL. We obtained prognostic effectiveness data (area under receive operating characteristic curve (AUC), sensitivity and specificity and estimated Kaplan-Meier curves for preterm birth using different CL cutoff points.

Results: We report on 3139 women and identified a negative association between cervical length and sPTB. CL ≤ 25 mm was associated with sPTB < 28, sPTB < 34 and sPTB < 37 weeks, whereas a CL 25-30 mm was directly associated with late sPTB. CL by transvaginal ultrasound presented an AUC of 0.82 to predict sPTB < 28 weeks and 0.67 for sPTB < 34 weeks. Almost half of the sPTB occurred in nulliparous women and CL ≤ 30 mm was associated with sPTB at < 37 weeks (OR = 7.84; 95%CI = 5.5-11.1). The number needed to screen to detect one sPTB < 34 weeks in women with CL ≤ 25 mm is 121 and we estimated that 248 screening tests are necessary to prevent one sPTB < 34 weeks using progesterone prophylaxis.

Conclusions: CL measured by transvaginal ultrasound should be used to predict sPTB < 34 weeks. Women with CL ≤ 30 mm are at increased risk for late sPTB.

Keywords: Cervical length; Number needed to screen; Pregnancy; Preterm birth; Short cervix.

PubMed Disclaimer

Conflict of interest statement

BWM is supported by a NHMRC Investigator Grant (GNT1176437). BWM reports consultancy for ObsEva and Merck and travel support from Merck.

Figures

Fig. 1
Fig. 1
ROC curve analysis of PTB and sPTB at different gestational ages
Fig. 2
Fig. 2
Kaplan-Meyer survival analysis for PTB considering different ranges of CL
See this image and copyright information in PMC

References

    1. Saigal S, Doyle LW. An overview of mortality and sequelae of preterm birth from infancy to adulthood. Lancet (London, England) 2008;371(9608):261–269. doi: 10.1016/S0140-6736(08)60136-1. - DOI - PubMed
    1. Chawanpaiboon S, Vogel JP, Moller A-B, et al. Global, regional, and national estimates of levels of preterm birth in 2014: a systematic review and modelling analysis. Lancet Glob Heal. 2019;7(1):e37–e46. doi: 10.1016/S2214-109X(18)30451-0. - DOI - PMC - PubMed
    1. March of Dimes, PMNCH, Save the Children, WHO. Born Too Soon: The Global Action Report on Preterm Birth.; 2012.
    1. Larma JD, Iams JD. Is sonographic assessment of the cervix necessary and helpful? Clin Obstet Gynecol. 2012;55(1):324–335. doi: 10.1097/GRF.0b013e3182487e96. - DOI - PMC - PubMed
    1. Liu CZ, Ho N, Nguyen AD, Lehner C, Sekar R, Amoako AA. The risk of preterm delivery and pregnancy outcomes in women with asymptomatic short cervix: a retrospective cohort study. J Matern Neonatal Med. 2019;1–7. 10.1080/14767058.2019.1647163. - PubMed

Publication types

LinkOut - more resources