What are the side effects of ovulation induction?

We know that the combination of sperm and egg is the first step to successful conception. If a woman does not ovulate, there will be no sperm and egg combination, and pregnancy will naturally become a fantasy. Therefore, women with ovulation disorders must actively receive treatment so that pregnancy is possible. Some women may need ovulation induction treatment to increase the chance of conception. Letrozole is one of the commonly used ovulation induction drugs. So, what are the side effects of Letrozole inducing ovulation?

1. What is Letrozole

Letrozole (LE) is a third-generation aromatase inhibitor with high specificity.

LE is rapidly and widely distributed in peripheral tissues, and can reversibly inhibit the activity of aromatase, preventing the synthesis of estrogen in the peripheral blood, causing a low estrogen state in the blood circulation, and feedback-induced the pituitary gland to secrete gonadotropin, thereby promoting the growth and development of follicles.

Letrozole has been widely used in the treatment of estrogen-dependent tumors. However, with the increase in research on LE in clinical ovulation induction treatment for assisted reproduction, its ovulation-inducing effect has become increasingly prominent.

Second, the advantages of letrozole

Letrozole can prevent the conversion of androgens into estrogens, which can significantly reduce the body's estrogen levels, thereby relieving the negative feedback inhibitory effect of estrogen on the hypothalamus and pituitary gland, stimulating the pituitary follicle-stimulating hormone

(FSH)

Increased secretion promotes the development of follicles and ovulation.

At the same time, letrozole helps androgens accumulate in the ovarian follicles, increasing the follicles'

FSH

Sensitivity, promote ovulation.

3. Precautions for Letrozole

1. Letrozole has a short half-life.

Letrozole exerts its ovulation-promoting effect both peripherally and centrally, which is similar to the anti-estrogen effect of clomiphene. Relatively speaking, letrozole has a good ovulation-inducing effect and has little effect on cervical mucus, endometrium and sex hormone levels.

2. Letrozole, a new generation of ovulation-stimulating drugs

Letrozole can be used for ovulation induction in patients with clomiphene resistance and polycystic ovary syndrome. Now, letrozole is increasingly likely to become the main drug for in vitro fertilization ovulation induction.

It can improve the assisted pregnancy outcomes of patients with poor ovarian response, reduce the dosage of gonadotropin, lower the cost of treatment, and can also be used to promote ovulation in patients with malignant tumors.

4. Precautions for Letrozole

1. Since letrozole has only been used as an ovulation-stimulating drug by assisted reproductive doctors in recent years, it is best for women to use letrozole, a drug originally used to treat estrogen-dependent malignant tumors such as breast cancer, under the guidance of a doctor.

2. In most cases, letrozole only induces the development of a single follicle. This method has advantages and disadvantages. For example, this method of ovulation induction can effectively prevent the occurrence of OHSS and multiple pregnancies. However, it may also reduce the success rate of IVF.

However, according to statistics, the ovulation rate of letrozole is 54.6% and the clinical pregnancy rate is 25%.

3. Letrozole and clomiphene

Clomiphene is the main ovulation-inducing drug currently used.

Letrozole and clomiphene have similar therapeutic effects in the treatment of female infertility caused by PCOS.

However, compared with clomiphene, letrozole can increase women's ovulation rate and has fewer complications, especially in ovulation induction programs for patients with breast diseases.

5. Side effects of letrozole

Since letrozole has been used for in vitro fertilization ovulation induction for a short period of time, the safety of letrozole for ovulation induction still needs long-term follow-up studies.

For drugs whose clinical research is limited to those with known pharmacological effects, researchers may choose to use animal studies to determine whether the drug is safe for human use.

Oral administration of letrozole may slightly increase the incidence of teratogenesis in pregnant rats.

However, it is difficult to determine whether this is an indirect result of the pharmacological properties (inhibition of estrogen biosynthesis) or a direct effect of letrozole itself.

Therefore, relevant experts recommend that letrozole be prohibited during pregnancy and lactation.