Cord blood thyroid-stimulating hormone level and risk of acidosis at birth.
OBJECTIVE
Cord blood thyroid-stimulating hormone level is elevated in neonates who had undergone more perinatal stresses. The present study aimed to evaluate the cord blood acid-base status in neonates with elevated thyroid-stimulating hormone level.


METHODS
The study population consisted of 2366 singleton, term pregnancies. Subjects were categorized by their cord blood thyroid-stimulating hormone level into four quartiles, and cord blood acid-base parameters were compared among the four groups. The correlations between cord acid-base parameters and thyroid-stimulating hormone level were also studied.


RESULTS
Cord blood pH was significantly lower in the highest (arterial, 7.27+/-0.08; venous, 7.32+/-0.07) and second highest thyroid-stimulating hormone quartile groups (arterial, 7.29+/-0.07; venous, 7.34+/-0.06) compared to the lowest quartile group (arterial, 7.30+/-0.06; venous, 7.35+/-0.05). Incidences of cord arterial pH < or =7.20 were 4.7%, 6.8%, 10.9%, and 17.3% in lowest to the highest thyroid-stimulating hormone quartile groups, respectively. There was a significant negative correlation between cord blood thyroid-stimulating hormone level and cord arterial and venous pH (r=-0.26, P<0.001). When stratified according to the mode of delivery, the negative correlations remained significant in neonates delivered vaginally and by intrapartum emergency cesarean section but not in neonates delivered by elective cesarean section.


CONCLUSIONS
Incidence of cord blood acidosis is significantly higher in neonates with elevated thyroid-stimulating hormone level. This findings support the postulation that stress-induced elevation of cord blood thyroid-stimulating hormone level may be mediated through intrapartum fetal hypoxia.
Chan
Louis Yik-Si
LY
Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Room 520N, HAHO Building, 147B Argyle Street, Kowloon, Hong Kong. chanysl@ha.org.hk
Fok
Wing Yee
WY
Sahota
Daljit
D
Lau
Tze Kin
TK
D000136:Acid-Base Equilibrium / Q000502:physiology*; D000138:Acidosis / Q000503:physiopathology*; D000704:Analysis of Variance; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D008297:Male; D010100:Oxygen / Q000097:blood; D011247:Pregnancy; D012189:Retrospective Studies; D013972:Thyrotropin / Q000097:blood*
D002245:Carbon Dioxide; D013972:Thyrotropin; D010100:Oxygen