Cervical length measurement and cervical phosphorylated insulin-like growth factor binding protein-1 testing in prediction of preterm birth in patients reporting uterine contractions.
OBJECTIVE
To evaluate the performance of cervical phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1) testing and cervical length measurement separately and in combination with physician's clinical judgment in prediction of preterm birth among patients with self-reported uterine contractions and intact membranes.


METHODS
We enrolled a total of 246 women between 22 and 34 weeks of gestation.


METHODS
The initial evaluation included cervical length measurement using transvaginal ultrasonography. Short cervix was defined as <25 mm. A swab sample was obtained from the cervix for phIGFBP-1. Admission was used as a clinical marker of an increased risk of preterm delivery <or=34 weeks. The diagnostic performances of the tests and clinician's judgment, as well as likelihood ratios (LRs) were calculated.


METHODS
Delivery <or=34 weeks and within 14 days.


RESULTS
The overall rate of spontaneous preterm delivery <or=34 weeks was 4.1% (10/246). Short cervix, positive phIGFBP-1 test, combination of both, and clinician's judgment were all associated with preterm delivery <or=34 weeks or within 14 days (p<0.01). The negative predictive values for delivery <or=34 weeks were 97.4, 97.6, 97.1, and 98.7%, respectively, and within 14 days 98.7, 99.0, 98.3, and 99.6%, respectively. The corresponding positive LRs for delivery <or=34 weeks were 6.8, 3.8, 75.0, 14.9, and within 14 days 9.7, 5.5, 107.3, 17.1. The negative LRs were 0.6, 0.6, 0.7, 0.3 and 0.5, 0.3, 0.6, 0.2.


CONCLUSIONS
The rapid phIGFBP-1-test has a high negative predictive value for preterm delivery, comparable to that of ultrasonographic cervical length measurement.
Rahkonen
Leena
L
Department of Obstetrics and Gynaecology, Helsinki University Central Hospital, Helsinki, Finland. leena.rahkonen@hus.fi
Unkila-Kallio
Leila
L
Nuutila
Mika
M
Sainio
Susanna
S
Saisto
Terhi
T
Rutanen
Eeva-Marja
EM
Paavonen
Jorma
J
D000293:Adolescent; D000328:Adult; D002584:Cervix Uteri / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000378:metabolism*; D009929:Organ Size; D011237:Predictive Value of Tests; D011247:Pregnancy; D047928:Premature Birth / Q000209:etiology / Q000378:metabolism* / Q000473:pathology*; D015203:Reproducibility of Results; D012307:Risk Factors; D016216:Ultrasonography, Prenatal; D014626:Vaginal Smears; D055815:Young Adult
D018970:Insulin-Like Growth Factor Binding Protein 1