Predicting preterm delivery in asymptomatic patients with prior preterm delivery by measurement of cervical length and phosphorylated insulin-like growth factor-binding protein-1.
OBJECTIVE
To evaluate the efficacy of cervical length measurement in combination with a bedside assessment of phosphorylated insulin-like growth factor-binding protein-1 (phIGFBP-1) as a predictor of preterm delivery in asymptomatic pregnant women with a history of preterm birth.


METHODS
Cervical length was measured using transvaginal sonography at 22-24 weeks of gestation in 105 singleton pregnancies and a rapid strip test was performed to detect phIGFBP-1 in cervical secretions from 24 to 34 weeks. Receiver-operating characteristics (ROC) curves were constructed to compare the performance of phIGFBP-1 at different gestational ages, and cervical length at 22-24 weeks, in predicting preterm delivery.


RESULTS
The rate of spontaneous delivery before 37 and 34 weeks was 23.8% and 11.4%, respectively. Women with cervical lengths less than 20 mm had a risk of spontaneous preterm delivery before 34 and 37 weeks of 43.5% and 69.6%, respectively. The performance of phIGFBP-1 levels as a predictor of preterm delivery was significantly higher when the test was carried out at 30 weeks' gestation. Cervical assessment in combination with phIGFBP-1 at 30 weeks had the steepest ROC curve (area under the curve=0.93; 95% CI, 0.88-0.98, P<0.001).


CONCLUSIONS
Both cervical length and phIGFBP-1 measurement are useful in the prediction of preterm delivery in patients with a history of preterm birth and the combined method of measuring cervical length at 22-24 weeks and phIGFBP-1 at 30 weeks improves upon either method used alone.
Bittar
R E
RE
Obstetric Clinic, University of São Paulo Medical School, São Paulo, Brazil. rebittar@usp.br
da Fonseca
E B
EB
de Carvalho
M H B
MH
Martinelli
S
S
Zugaib
M
M
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D001724:Birth Weight; D002584:Cervix Uteri / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D005865:Gestational Age; D020073:Gravidity; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000032:analysis*; D010766:Phosphorylation; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D047928:Premature Birth / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism; D012372:ROC Curve; D018570:Risk Assessment / Q000379:methods; D014463:Ultrasonography
D015415:Biomarkers; C032231:IGFBP1 protein, human; D018970:Insulin-Like Growth Factor Binding Protein 1