Phosphorylated isoforms of insulin-like growth factor binding protein-1 in the cervix as a predictor of cervical ripeness.
OBJECTIVE
To study the isoforms of insulin-like growth factor binding protein-1 (IGFBP-1) in cervical secretion and to evaluate whether their assessment could serve in prediction of cervical ripeness at term.


METHODS
We measured the concentrations of IGFBP-1 in cervical swab samples of 64 women scheduled for labor induction by amniotomy or cervical ripening with prostaglandin E2 gel. Two immunoenzymometric assays were used: a previously described assay 1, which detects the nonphosphorylated and lesser phosphorylated isoforms, and a novel assay 2, which detects the lesser and highly phosphorylated isoforms of IGFBP-1. A set of 39 amniotic fluid (AF) samples also was analyzed to compare the phosphorylation status of IGFBP-1 in cervical secretion with that in AF.


RESULTS
In all cervical samples, IGFBP-1 concentration was higher by assay 2 than by assay 1, whereas in all AF samples, the results were the opposite. Initially, the median IGFBP-1 concentration in the ripe cervices (Bishop scores 6 or greater; n = 29) was approximately four times as high as that in the unripe cervices (Bishop scores 5 or less; n = 35). The cervical IGFBP-1 concentrations increased eight-fold in 6 hours after the first application of PGE2.


CONCLUSIONS
Phosphorylated isoforms of IGFBP-1, different from those in AF, are present in the cervical secretion of women with intact fetal membranes and reflect cervical ripeness. A bedside test for those IGFBP-1 isoforms might help in predicting amenability for labor induction.
Nuutila
M
M
Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Finland. mika.nuutila@huch.fi
Hiilesmaa
V
V
Kärkkäinen
T
T
Ylikorkala
O
O
Rutanen
E M
EM
D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry; D020070:Cervical Ripening / Q000187:drug effects / Q000378:metabolism*; D015232:Dinoprostone / Q000494:pharmacology; D005260:Female; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000032:analysis* / Q000378:metabolism; D007751:Labor, Induced; D010120:Oxytocics / Q000494:pharmacology; D010766:Phosphorylation; D011247:Pregnancy; D020033:Protein Isoforms / Q000032:analysis / Q000378:metabolism
D018970:Insulin-Like Growth Factor Binding Protein 1; D010120:Oxytocics; D020033:Protein Isoforms; D015232:Dinoprostone