The aim of the study was to evaluate the ovulation stimulatory effect of a combination
of clomiphene citrate (CC) and tamoxifen (T) or letrozole (L) in CC-resistant polycystic
ovary syndrome women.
Patients and methods
The study included 120 polycystic ovary syndrome women who were randomly allocated
into three equal groups. All enrolled patients received CC (100mg/day) as a fixed
therapy in addition to either tamoxifen citrate at 20mg twice daily (group T) or letrozole at
5 or 7.5mg once daily (groups L5 and L7.5, respectively) for 5 days. Vaginal ultrasound
was performed on day 11 of the cycle to evaluate the growth of follicles, and Gonal-f was
given to complete the follicle growth. Ovulation was monitored by measuring serum
progesterone concentration on day 21 of the menstrual cycle. Serum progesterone levels
of at least 25 nmol/l were used to indicate ovulation, which was confirmed using
transvaginal ultrasonography for evident ovulation with a dominant follicle size greater
than 18mm. The appearance of these follicles was considered as successful ovulation. AQ5
Timed intercourse was assigned and pregnancy was diagnosed chemically and
confirmed bytransvaginal ultrasonography, and the pregnancy rate was calculated.
Results
Both tamoxifen and letrozole successfully induced ovulation. Throughout the 3-month
study period, the proportion of trials/patients that achieved ovulation was significantly AQ6
higher in group L5 compared with groups T and L7.5, with significantly higher
frequency in group T compared with group L7.5. Ovulation was achieved in 88, 83, and
85 trials in groups T, L5, and L7.5, respectively, with an ovulatory success rate of 83.8,
74.8 and 86.7%, respectively. The frequency of successful ovulatory trials in group L5
was significantly lower than that in groups T and L7.5, which showed nonsignificant
difference. From the total ovulatory cycles, 50 women became pregnant, resulting in a
total pregnancy rate of 19.5% cycles and 41.7% patients. The frequency of pregnancy
as outcome/patient was significantly lower in group L5 compared with groups T and
L7.5, with nonsignificantly lower pregnancy rate in group T compared with group L7.5.
Conclusion
Letrozole successfully induced dose-dependent ovulation and pregnancy rate per
cycle and per patient. Tamoxifen also successfully induced ovulation and pregnancy
rates with a frequency significantly higher than that of letrozole at 5 mg/day and
nonsignificantly lower than that of letrozole at 7.5 mg/day. Combination of CC with
either tamoxifen or letrozole at a dose of 7.5 mg/day is equally effective and could be
prescribed according to the patient’s condition and physician’s preference.
Keywords:
clomiphene resistance, induction of ovulation, letrozole, pregnancy rate, tamoxifen |
