Open AccessInfluences of perinatal factors on cord blood thyroid‐stimulating hormone level
Author(s) -
Chan Louis YikSi,
Leung Tse Ngong,
Lau Tze Kin
Publication year - 2001
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.1034/j.1600-0412.2001.801108.x
Subject(s) - medicine , cord blood , thyroid stimulating hormone , thyroid , fetal distress , incidence (geometry) , hormone , obstetrics , birth weight , gestation , fetus , pregnancy , physics , biology , optics , genetics
Background. Cord blood thyroid‐stimulating hormone level is affected by various perinatal factors. The aim of this study is to investigate the relative impact of these factors on the cord blood thyroid‐stimulating hormone results in singleton pregnancies. Methods. The study group consisted of 20,086 consecutive singleton deliveries over a 3 year period. The effect of mode of delivery, infant sex, gestation at birth, birth weight, and duration of labor on the incidence of false elevation of cord blood thyroid‐stimulating hormone was assessed by univariate analysis and logistic regression. Results. There was an independent positive association between false elevation of cord blood thyroid‐stimulating hormone (≥15.0 mIU/L) and birth weight ( p =0.005), male infant sex ( p <0.001), and instrumental delivery ( p <0.001). Both elective and emergency cesarean section were negatively associated with elevated cord thyroid‐stimulating hormone level ( p <0.001). When the cutoff level was raised to 40.0 mIU/L, none of the variables examined were significant. The incidence of false positive tests (≥15.0 mIU/L) was higher in neonates born by cesarean section for failed instrumental delivery and fetal distress than for failure to progress of labor (34.7% vs 4.5% vs 1.3% respectively, p <0.001). Conclusions. While the incidence of false positive screening was significantly affected by various perinatal factors when the thyroid‐stimulating hormone cutoff level is low, it was unaffected at a high cutoff level. The present study also provides further evidence that cord blood thyroid‐stimulating hormone level reflects fetal response to perinatal stress events.