Clomiphene compared with other drugs in terms of ovulation, EMT, pregnancy and live births: systematic review and meta-analysis

Ovulation induction with Clomiphene Citrate (CC) in women with WHO group II ovulatory disorders results in lower endometrial thickness (EMT) as compared to other regimens. The regimen also resulted in lower number of pregnancies and live births reports the results of systematic review and meta-analysis published in Journal Ultrasound in Obstetrics and Gynecology.

WHO group II ovulation disorders are defined as dysfunctions of the hypothalamic-pituitary-ovarian axis. This category includes conditions such as polycystic ovary syndrome (PCOS) and hyperprolactinaemic amenorrhoea. Around 85% of women with ovulation disorders have a group II ovulation disorder.

This systematic review and meta-analysis only focused on randomized control trials(RCTs) and included all those studies comparing CC with any other regimens and looked at EMT and rates of ovulation, pregnancy and live births.

The other regimens included in the study were Letrozole, CC plus metformin, CC plus N-acetyl cysteine (NAC), CC + nitric oxide (NO) donor and Tamoxifen.

The researchers selected 33 RCTs from 1718 articles that fitted the inclusion criteria amounting a total of 4349 women and 7210 ovulation induction cycle.

Maximum number (15) of RCTs compared CC with Letrozole. Overall the mean EMT was 1.39mm lower in CC group as compared to Letrozole. (WMD, −1.39; 95% CI, −2.27 to −0.51; I² = 100%), and women on CC had a 22% lower chance of pregnancy and 30% lower chance of live births. The ovulation rates were comparable between the two groups.

Only 2 RCTS were found comparing CC with CC plus metformin and no significant difference were noted in any of the outcome parameters between the groups.

When comparing CC with CC plus N-acetyl cysteine (NAC) and CC plus nitric oxide (NO) donor, EMT was lower in CC only group, along with ovulation and pregnancy rates.

When the CC regimen was compared with Tamoxifen, lower EMT and comparable ovulation and pregnancy rates were noted.

The authors concluded that in women with WHO group II ovulatory disorders, Letrozole seems to benefit these women more in terms of increased EMT, ovulation, pregnancy rates and live births. 

Whether the increase pregnancy rates and live births rates are due to increase in EMT has not been looked at in this study.

Abstract