Kinetics and secretion of placental growth hormone around parturition.
OBJECTIVE
During pregnancy, placental growth hormone (PGH) is secreted into the maternal circulation, replacing pituitary GH. It is controversial whether PGH levels decline during vaginal birth. After placental expulsion, PGH is eliminated from the maternal blood. GH binding protein (GHBP) and body mass index (BMI) influence GH kinetics, but their impact on PGH kinetics is unknown. The present study was undertaken to define the kinetics of PGH during vaginal delivery and Caesarian section and to relate these kinetics to GHBP and BMI.


METHODS
A short term, prospective cohort study.


METHODS
Twelve women had repeated blood samples drawn during vaginal delivery. From 26 women undergoing planned Caesarian delivery (CS) repeated blood samples were withdrawn before, during and after the CS, allowing PGH half-life determination.


RESULTS
During vaginal delivery, median PGH values did not change before expulsion of the placenta, although individual fluctuations were seen. Clearance of PGH from the maternal circulation was best described by a two-compartment model. The initial half-life of serum PGH was (mean +/- s.d.) 5.8 +/- 2.4 min, and the late half-life was (median) 87.0 min (range: 25.1-679.6 min). The late half-life was correlated to the pre-gestational BMI (r = 0.39, P = 0.047), but not to the serum GHBP concentration.


CONCLUSIONS
Serum PGH did not decrease significantly during vaginal delivery. Elimination of PGH fitted a two-compartment model, with an estimated initial half-life of 5.8 min. The late phase serum half-life of PGH was related to BMI, suggesting a role for maternal fat mass in PGH metabolism.
Fuglsang
Jens
J
Gynecological/Obstetrical Research laboratory Y, Aarhus University Hospital, Skejby Sygehus, Denmark. Fuglsang@ki.au.dk
Sandager
Puk
P
Møller
Niels
N
Fisker
Sanne
S
Orskov
Hans
H
Ovesen
Per
P
D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D001623:Betamethasone / Q000627:therapeutic use; D002352:Carrier Proteins / Q000378:metabolism; D002585:Cesarean Section; D015331:Cohort Studies; D005260:Female; D006207:Half-Life; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D007213:Indomethacin / Q000627:therapeutic use; D007700:Kinetics; D007752:Obstetric Labor, Premature / Q000517:prevention & control; D036801:Parturition / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy
D000894:Anti-Inflammatory Agents, Non-Steroidal; D002352:Carrier Proteins; D019382:Human Growth Hormone; D001623:Betamethasone; C051815:somatotropin-binding protein; D007213:Indomethacin