M. Fukuda et al., CONTRALATERAL OVULATION SHORTENS FOLLICULAR PHASE LENGTH AND FAVORS PREEMBRYO DEVELOPMENT DURING OVARIAN STIMULATION WITH CLOMIPHENE CITRATE, Human reproduction (Oxford. Print), 13(6), 1998, pp. 1590-1594
The present study was undertaken to evaluate whether the site of ovula
tion affects the following follicular phase length and pre-embryo deve
lopment during infertility treatment with ovarian stimulation using cl
omiphene citrate. a total of 363 cycles in 97 patients undergoing infe
rtility treatment (182 intrauterine insemination (IUI) cycles in 60 pa
tients and 181 in-vitro fertilization (IVF) cycles in 52 patients) wer
e studied, The cycles mere divided into two main groups: preceding uni
lateral ovulation (PUO) and preceding bilateral ovulation (PBO), In th
e PUO group, the cycles were subdivided into contralateral ovulation,
bilateral ovulation and ipsilateral ovulation, In IVF cycles alone, bi
lateral ovulations mere further divided into bilateral ovulation-contr
alateral side and bilateral ovulation, ipsilateral side, Contralateral
ovulations were seen in 134 of 240 cycles (56%), excluding bilateral
ovulation and PBO, The follicular phase length in contralateral ovulat
ion (16.2 +/- 2.6 days, mean +/- SD) was significantly (P < 0.05) shor
ter than that of ipsilateral ovulation (16.9 +/- 2.8). There were no s
ignificant differences of follicular phase length among contralateral
ovulation, bilateral ovulation and PBO, Of IVF cycles including contra
lateral ovulation-ipsilateral ovulation and bilateral ovulation a tota
l of 107 preovulatory follicles was assessed in the contralateral side
(contralateral ovulation + bilateral ovulation-contralateral side) an
d 97 in the ipsilateral side (ipsilateral ovulation + bilateral ovulat
ion, ipsilateral side). The oocyte retrieval rate (88%), fertilization
rate (84%), cleavage rate (95%), embryo transfer rate (70%) of contra
lateral follicles were higher than those of ipsilateral follicles (71,
62, 86, 38% respectively) and those of PBO (76, 62, 87, 41% respectiv
ely). The total pregnancy rate of both IUI and IVF did not differ amon
g contralateral ovulation (15%), ipsilateral ovulation (8%), bilateral
ovulation (11%) and PBO (10%). The results confirm and extend our pre
vious findings in natural cycles, suggesting that local ovarian factor
s, e.g. from corpus luteum, affect the health of preovulatory follicle
and the enclosed oocyte in the same ovary (ipsilateral) negatively, C
ontralateral selection of preovulatory follicles in the succeeding cyc
le shortens the follicular phase length and favours pre-embryo develop
ment, The chance of conceiving during ovarian stimulation with clomiph
ene citrate may thus be affected by the site of ovulation in the previ
ous cycle.