Previous studies of aromatase inhibitors on male infertility have focused on men with low testosterone-oestradiol ratio of less than 10. Can aromatase inhibitors improve spermatogenesis in men with idiopathic male infertility with normal testosterone-oestradiol ratio?
Prospective study of men with idiopathic severe oligozoospermia (sperm concentration <5 million/ml) carried out between February 2015 and March 2017. The objective was to assess if semen-analysis parameters improved after treatment with letrozole. Secondary objectives were to monitor the safety of letrozole in men, and to measure the alterations in serum FSH, LH, oestradiol and testosterone levels.
Fifteen men with normal testosterone-oestradiol ratio (>10) were treated with letrozole 2.5 mg daily for 4 months. This produced a 5.5-fold increase in sperm concentration (P = 0.0068). All men had increased total serum testosterone and suppressed oestradiol levels after treatment, thus raising the overall testosterone-oestradiol ratio (P < 0.0001). Adverse effects from letrozole were relatively minor and included loss of libido (54%), headaches (25%), fatigue (21%), weakness (13%), loss of hair (8%) and dry mouth (8%).
Letrozole improves sperm concentration and increases testosterone-oestradiol ratio for men with oligozoospermia who have normal testosterone-oestradiol ratio; its role in the treatment of male infertility may be extended to this group of patients. In addition, it is a relatively well-tolerated drug with no serious adverse effects.
Reproductive biomedicine online. 2018 Oct 30 [Epub ahead of print]
Liu Shuling, Matthew Lau Sie Kuei, Seyed Ehsan Saffari, Zheng Jiayun, Tan Tse Yeun, Jessie Phoon Wai Leng, Veronique Viardot-Foucault, Sadhana Nadarajah, Jerry Kok Yen Chan, Tan Heng Hao
Department of Reproductive Medicine, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore 229899, Singapore; OBGYN Academic Clinical Program, KK Women's and Children's Hospital, 100 Bukit Timah Road 229899, Singapore. Electronic address: ., Department of Reproductive Medicine, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore 229899, Singapore; Knox Private Hospital, 262 Mountain Highway, Wantirna Victoria 3152, Australia., Centre for Quantitative Medicine, Office of Clinical Sciences, Duke-NUS Medical School, Academia, 20 College Road, Level 6 169856, Singapore., OBGYN Academic Clinical Program, KK Women's and Children's Hospital, 100 Bukit Timah Road 229899, Singapore., Department of Reproductive Medicine, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore 229899, Singapore., Department of Reproductive Medicine, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore 229899, Singapore; Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road 169857, Singapore.