From the Guidelines
Clomiphene (Clomid) is the preferred treatment for anovulation in Polycystic Ovary Syndrome (PCOS).
Rationale
- The evidence suggests that Clomiphene citrate is an acceptable alternative to low-dose gonadotrophins for low multiple birth rates and lower costs, although at a lower live birth rate 1.
- Letrozole has been compared to Clomiphene citrate, and the Cochrane systematic review concluded that there is no benefit in using Letrozole compared to Clomiphene citrate (pregnancy rate per couple: OR = 1.2, 95% CI: 0.64–2.1) based upon moderate quality evidence 1.
- Key points to consider when choosing a treatment include:
- Live birth rate: Gonadotrophins have a higher live birth rate compared to Clomiphene citrate, but Clomiphene citrate has a lower multiple pregnancy rate.
- Cost: Clomiphene citrate is a more cost-effective option compared to gonadotrophins.
- Multiple pregnancy rate: Clomiphene citrate has a lower multiple pregnancy rate compared to gonadotrophins, especially when used at a dose of 100 mg per day for 5 days.
- In terms of specific treatment regimens, Clomiphene citrate at a dose of 100 mg per day for 5 days is a commonly used and effective treatment for anovulation in PCOS.
- It is essential to individualize treatment and monitor patients closely to minimize the risk of multiple pregnancies and ovarian hyperstimulation syndrome (OHSS).
From the Research
Comparison of Letrozole and Clomiphene Citrate for Anovulation in PCOS
- The studies 2, 3, 4, 5, 6 compared the efficacy of letrozole and clomiphene citrate for ovulation induction in women with polycystic ovary syndrome (PCOS).
- The results showed that letrozole was associated with a higher ovulation rate compared to clomiphene citrate 3, 4, 5, 6.
- Letrozole was also found to have a higher pregnancy rate compared to clomiphene citrate 4, 6.
- Additionally, letrozole was associated with a higher endometrial thickness compared to clomiphene citrate 4, 5, 6.
- The studies also found that letrozole had a higher monofollicular development rate compared to clomiphene citrate 4, 6.
- However, one study found that there were no significant differences in pregnancy rate, abortion rate, and multiple pregnancy rate between the two groups 2.
Efficacy of Letrozole and Clomiphene Citrate
- The efficacy of letrozole and clomiphene citrate was compared in several studies 2, 3, 4, 5, 6.
- The results showed that letrozole had a significantly better efficacy compared to clomiphene citrate in terms of ovulation induction 3, 4, 5, 6.
- Letrozole was also found to have a higher cumulative ovulation rate compared to clomiphene citrate 6.
- However, one study found that the evidence from ovulation rates was not enough to support either letrozole or clomiphene citrate as the preferred treatment 2.
Safety and Side Effects
- The safety and side effects of letrozole and clomiphene citrate were not extensively discussed in the provided studies.
- However, one study mentioned that the use of letrozole as an ovulation induction agent is not FDA or EMA approved, and its use is "off-label" 3.
- Another study mentioned that the main concern with respect to letrozole regards its potential teratogenic effect on the fetus 3.