A comparison of dosages of norethisterone for synchronization of cycles in a fixed regimen of follicular augmentation and in vitro fertilization.
Twenty-four patients undergoing elective laparoscopic sterilization were randomized in a fixed schedule of follicular augmentation, oocyte recovery, and in vitro fertilization (IVF) using either 2.5 or 10 mg of norethisterone (NE) in the luteal phase of the previous cycle. The objectives of the study were to determine the effect of a synthetic progestin, given for 5 to 14 days beginning on day 21 of the cycle before the IVF cycle, on folliculogenesis, estrogen secretion, the luteinizing hormone (LH) surge, luteal function, and IVF success. It was found that this treatment was easy to administer and well tolerated by patients. At the 10-mg dose, patients uniformly had vaginal bleeding 2 to 4 days after NE, whereas 40% of patients using the 2.5-mg dose bled before NE was discontinued. Significantly lower estrone glucuronide excretion in the early follicular phase and lower luteal phase pregnanediol excretion in patients receiving 10 mg NE suggested a delay or reduction of developing follicles after luteal phase suppression. No spontaneous LH surges were found in the 10-mg group, compared with surges in 5 of the 13 cycles of the 2.5-mg group. There were no differences between regimens in cycle or luteal phase length. It is postulated that NE, by suppressing folliculogenesis in the luteal phase, may provide for a smaller, but more homogenous cohort of follicles available for exogenous stimulation and recovery.
Thatcher
S S
SS
Department of Obstetrics and Gynaecology, University of Edinburgh, Scotland.
Boyle
H P
HP
Glasier
A F
AF
Hillier
S G
SG
Baird
D T
DT
D003404:Creatinine / Q000097:blood; D004970:Estrone / Q000031:analogs & derivatives / Q000097:blood; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D005498:Follicular Phase; D006801:Humans; D008183:Luteal Phase; D009640:Norethindrone / Q000008:administration & dosage* / Q000627:therapeutic use; D006080:Ovarian Follicle / Q000187:drug effects*; D011247:Pregnancy
C015856:estrone-3-glucuronide; D004970:Estrone; D003404:Creatinine; D009640:Norethindrone