To evaluate the efficacy of co-administration of low-dose aspirin (LDA) and tamoxifen on ovulation rates, endometrial thickness and clinical pregnancy rates in anovulatory PCOS women.

A randomized clinical trial was conducted among 188 anovulatory PCOS women at Suez Canal University Hospitals, Ismailia – Egypt. Patients were divided into 2 groups. The study group received a daily oral dose of 81 mg of LDA, while the control group received placebo (oral vitamin B12 tablets). Both groups started tamoxifen 10 mg twice daily from 3rd day to 7th day of the cycle. Folliculometry was performed by transvaginal sonography every other day starting from the 9th day of the cycle. Human Chorionic Gonadotrophin 5000 I.U. was given I.M. when at least one dominant follicle was present. The outcome measures included the number of mature follicles (≥18 mm in diameter), endometrial thickness and appearance in addition to the clinical pregnancy rates.

The mean number of follicles per patient was significantly more in the study group (1.4 ± 0.8 vs. 1.1 ± 0.4; p value=<0.05). In addition, the endometrium was significantly thicker on study group (9.6 ± 1.4 mm vs. 7.8 ± 1.2 mm; p value=<0.01). Significantly, the pregnancy rate was more in the study compared to the control group (37.2% vs. 22.3% respectively; p value=<0.03).

Co-administration of LDA with tamoxifen significantly improves ovarian response to stimulation, endometrial thickness and pregnancy rates in anovulatory PCOS patients. This combination is an effective, cheap and safe protocol for infertile PCOS women undergoing ovulation induction.