The effect of gestational age and cervical length measurements in the prediction of spontaneous preterm birth in twin pregnancies: an individual patient level meta-analysis.
OBJECTIVE
To assess the effect of gestational age (GA) and cervical length (CL) measurements at transvaginal ultrasound (TVUS) in the prediction of preterm birth in twin pregnancy.


METHODS
Individual patient data (IPD) meta-analysis.


METHODS
International multicentre study.


METHODS
Asymptomatic twin pregnancy.


METHODS
MEDLINE and EMBASE searches were performed and IPD obtained from authors of relevant studies. Multinomial logistic regression analysis determined probabilities for birth at ≤28(+0) , 28(+1) to 32(+0) , 32(+1) to 36(+0) , and ≥36(+1) weeks as a function of GA at screening and CL measurements.


METHODS
Predicted probabilities for preterm birth at ≤28(+0) , 28(+1) to 32(+0) , and 32(+1) to 36(+0) .


RESULTS
A total of 6188 CL measurements were performed on 4409 twin pregnancies in 12 studies. Both GA at screening and CL had a significant and non-linear effect on GA at birth. The best prediction of birth at ≤28(+0) weeks was provided by screening at ≤18(+0) weeks (P < 0.001), whereas the best prediction of birth between 28(+1) and 36(+0) weeks was provided by screening at ≥24(+0) weeks (P < 0.001). Negative prediction value of 100% for birth at ≤28(+0) weeks is achieved at CL 65 mm and 43 mm at ultrasound GA at ≤18(+0) weeks and at 22(+1) to 24(+0) weeks, respectively.


CONCLUSIONS
In twin pregnancies, prediction of preterm birth depends on both CL and the GA at screening. When CL is <30 mm, screening at ≤18(+0) weeks is most predictive for birth at ≤28(+0) weeks. Later screening at >22(+0) weeks is most predictive of delivery at 28(+1) to 36(+0) weeks. In twins, we recommend CL screening in twins to commence from ≤18(+0) weeks.


CONCLUSIONS
An individual patient meta-analysis assessing gestation and CL in the prediction of preterm birth in twins.
Institute of Reproductive and Developmental Biology, Imperial College London, London, UK.|Fetal Medicine Unit, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK.
L M
LM
Kindinger
Fetal Medicine Unit, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK.|Harris Birthright Research Centre for Fetal Medicine, Kings College Hospital, London, UK.
L C
LC
Poon
Institute of Reproductive and Developmental Biology, Imperial College London, London, UK.
S
S
Cacciatore
Institute of Reproductive and Developmental Biology, Imperial College London, London, UK.
D A
DA
MacIntyre
Maternal Fetal Medicine Associates, PLLC, New York, NY, USA.
N S
NS
Fox
Stanford Prevention Research Center, Stanford University, Stanford, CA, USA.
E
E
Schuit
The Robinson Research Institute, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, SA, Australia.
B W
BW
Mol
Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
S
S
Liem
Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
A C
AC
Lim
Maternal-Fetal Medicine Unit, Instituto Valenciano de Infertilidad, University of Valencia, Valencia, Spain.
V
V
Serra
Department of Paediatrics, Obstetrics and Gynaecology, La FE, University and Polytechnic Hospital, University of Valencia, Valencia, Spain.
A
A
Perales
Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
F
F
Hermans
Department of Academic Surgery, St Marys Hospital, Imperial College Healthcare NHS Trust, London, UK.
A
A
Darzi
Institute of Reproductive and Developmental Biology, Imperial College London, London, UK.
P
P
Bennett
Harris Birthright Research Centre for Fetal Medicine, Kings College Hospital, London, UK.
K H
KH
Nicolaides
Fetal Medicine Unit, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK.
T G
TG
Teoh
D054791:Cervical Length Measurement; D002584:Cervix Uteri / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D005260:Female; D005865:Gestational Age; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D059285:Pregnancy, Twin; D047928:Premature Birth / Q000000981:diagnostic imaging*
Cervical length; individual patient meta-analysis; prematurity; preterm birth; twin pregnancy