Transvaginal sonographic evaluation of cervical length in the second trimester of asymptomatic singleton pregnancies, and the risk of preterm delivery.
OBJECTIVE
To evaluate cervical length in asymptomatic women with singleton pregnancies in the second trimester by means of transvaginal ultrasonography, and to examine the relation between cervical length and spontaneous preterm delivery.


METHODS
Observational, prospective study.


METHODS
A university hospital and a county hospital in Western Sweden.


METHODS
A total of 2122 asymptomatic women with live singleton pregnancies without fetal anomalies.


METHODS
Cervical length was measured at between 16 and 23 weeks of gestation by means of transvaginal ultrasonography. Data were analysed using logistic regression analysis.


METHODS
Cervical length in relation to spontaneous preterm delivery <34 weeks (primary outcome) and <37 weeks of gestation (secondary outcome).


RESULTS
Eleven women had a cervical length of ≤25 mm (0.5%) and 73 women had a cervical length of ≤30 mm (3.4%). Spontaneous preterm delivery at <34 weeks occurred in 22/2061 women (1.1%) and at <37 weeks in 87/2061 women (4.2%). There was a significant association between cervical length and spontaneous preterm delivery at <34 weeks (odds ratio 1.78; 95% confidence interval 1.19-2.65 for a decrease of cervical length by 5 mm) but no significant association at <37 weeks.


CONCLUSIONS
The rate of short cervical length of ≤25 mm was lower than expected. The study confirmed the increased risk of spontaneous preterm delivery in women with a short cervix, although the analysis was based on only a few cases. In Sweden, a larger study is needed to evaluate the prevalence of short cervical length and the possible association with preterm delivery before universal screening can be recommended.
Institute for Clinical Sciences, Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Pihla
P
Kuusela
Institute for Clinical Sciences, Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Division of Epidemiology, Department of Genes and Environment, Norwegian Institute of Public Health, Oslo, Norway.
Bo
B
Jacobsson
Institute for Clinical Sciences, Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Mona
M
Söderlund
Norra Älvsborg County Hospital, Trollhättan, Sweden.
Carina
C
Bejlum
Norra Älvsborg County Hospital, Trollhättan, Sweden.
Elisabeth
E
Almström
Institute for Clinical Sciences, Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Lars
L
Ladfors
Institute for Clinical Sciences, Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Centre for the Developing Brain, Department of Perinatal Imaging and Health, King's College London, St Thomas' Hospital, London, UK.
Henrik
H
Hagberg
Institute for Clinical Sciences, Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Ulla-Britt
UB
Wennerholm
D000328:Adult; D002584:Cervix Uteri / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D047928:Premature Birth / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D012306:Risk; D013548:Sweden; D016216:Ultrasonography, Prenatal; D014621:Vagina
Transvaginal ultrasonography; cervical length; preterm delivery; screening