The effect of multifetal pregnancy reduction on serum relaxin.
OBJECTIVE
To determine the effect of multifetal pregnancy reduction on circulating relaxin levels.


METHODS
Patients with multifetal pregnancies had relaxin levels determined on the day of multifetal pregnancy reduction, after the procedure, and late in pregnancy.


RESULTS
Forty-eight women (26 presenting with three fetuses and 22 with four or more) were studied. All pregnancies followed some form of ovulation induction. All pregnancies (except for one, which was reduced to a singleton) were reduced to twins. Pre-procedure, post-procedure and late-pregnancy relaxin levels were significantly higher in the in vitro fertilization (IVF)-gamete intrafallopian transfer (GIFT) group compared with the human menopausal gonadotropin (hMG)-alone group (P < .05). The initial number of fetuses had no significant effect on relaxin levels. Although post-procedure relaxin levels were significantly lower than pre-procedure levels (P = .002), relaxin levels continued to decrease throughout pregnancy, as evidenced by even lower levels later on (P = .0001).


CONCLUSIONS
Serum relaxin levels were significantly higher in the IVF-GIFT group than in the hMG-alone group, which probably reflects more aggressive ovulation induction in the former. Because relaxin levels continued to decrease throughout pregnancy, the difference observed between pre- and post-procedure levels are not considered to be due to the procedure itself.
Lynch
L
L
Department of Obstetrics, Gynecology and Reproductive Science, Mount Sinai Medical Center, New York, New York, USA.
Berkowitz
R L
RL
Weiss
G
G
Goldsmith
L T
LT
Lapinski
R
R
Wein
R
R
D005260:Female; D005307:Fertilization in Vitro; D015181:Gamete Intrafallopian Transfer; D006801:Humans; D008596:Menotropins; D010062:Ovulation Induction; D011247:Pregnancy; D018607:Pregnancy Reduction, Multifetal; D011261:Pregnancy Trimester, First / Q000097:blood; D012065:Relaxin / Q000097:blood*
D008596:Menotropins; D012065:Relaxin