Hj. Ingerslev et al., A randomized study comparing IVF in the unstimulated cycle with IVF following clomiphene citrate, HUM REPR, 16(4), 2001, pp. 696-702
The efficiency of IVF in unstimulated cycles was compared with that followi
ng ovarian stimulation with clomiphene citrate in a simple protocol with ul
trasound monitoring only. A total of 132 couples with no previous IVF attem
pts, selected by female age <35 years, indication for intracytoplasmic sper
m injection or infertility caused by tubal factor or unexplained infertilit
y were randomized to the two protocols. Randomization yielded two comparabl
e groups. The clomiphene group (68 couples) performed significantly better
than the unstimulated group (64 couples) in terms of number of cycles with
oocyte harvest (90/111 or 81% versus 65/114 or 57%; <chi>(2) = 9.21, P < 0.
002), embryo transfers per started cycle (59/111 or 53% versus 29/114 or 25
%; <chi>(2) = 18.14, P < 0.0001), live intrauterine pregnancy rate per star
ted cycle (20/111 or 18% versus 4/114 or 4%; <chi>(2) = 12.42, P < 0.0001),
live intrauterine pregnancy rate per embryo transfer (20/59 or 34% versus
4/29 or 14%; <chi>(2) = 3.96, P = 0.047), but not in terms of implantation
rate (22/85 or 26% versus 4/29 or 14%; chi (2) = 1.65). Only two twin pregn
ancies occurred. Modest side-effects were recorded following clomiphene, Ac
cordingly, a simple clomiphene citrate protocol, but not IVF in unstimulate
d cycles, seems compatible with the concept of 'friendly IVF', yielding a f
air pregnancy rate both per cycle started and per embryo transfer in select
ed patients. The results do not substantiate any important negative anti-oe
strogenic effects of clomiphene.