[Health Column] How Much Does Femara, an Ovulation Inducer, Increase the Success Rate of Natural Pregnancy? Exploring Its Effects and Principles Through Two Research Papers

 

hello, Director Lee Hyo-jin of Lee Hyo-jin Obstetrics and Gynecology Clinic It is. 🩺

 

"Does taking ovulation induction drugs increase the chances of natural pregnancy?", "How much does taking Femara increase the pregnancy success rate?", "Is ovulation induction drug necessary even if my periods are regular?"

This is a question frequently asked in the clinic by those preparing for pregnancy. As the wait for conception lengthens, interest in ovulation-inducing drugs naturally grows. 😊

 

Femara It is a drug containing the active ingredient letrozole, used for the purpose of ovulation induction in women whose ovulation is irregular or does not occur normally. Actual medical studies have also confirmed its effectiveness in increasing ovulation and fertility rates in patients with specific ovulation disorders.

 

but Taking Femara does not increase the chances of pregnancy for all women.

 

Today, based on two major medical papers, I will explain step-by-step the mechanism of action of Femara, actual fertility rates, and the things you need to check before taking it. ✨

 

 

1️⃣ How does the ovulation induction drug Femara work?

It is a drug that temporarily reduces estrogen to increase the secretion of follicle-stimulating hormone (FSH) and helps follicle growth and ovulation.

 

Femara is a drug originally used to treat hormone receptor-positive breast cancer. Aromatase inhibitor It corresponds to and acts to temporarily reduce the production of estrogen in the body.

 

So, how do drugs that reduce estrogen help with ovulation? The principle can be explained in three main steps.

 

🔸 ① Estrogen production temporarily decreases.
Femara reduces estrogen production by inhibiting the aromatase enzyme.

 

🔸 ② Follicle-stimulating hormone (FSH) secretion may increase.
When estrogen decreases, negative feedback acting on the brain and pituitary gland decreases, which can increase FSH secretion.

 

🔸 ③ Promotes follicle growth and ovulation.
FSH is a hormone that helps follicles in the ovaries grow. Therefore, using Femara in women with irregular ovulation can increase the likelihood of follicle growth and ovulation.

 

 

In addition, unlike clomiphene, Femara does not directly block estrogen receptors, so it is characterized by relatively less anti-estrogen activity on the endometrium and cervical mucus. However, this difference does not guarantee a higher pregnancy rate for all women.

 

💡 Expert advice
The key point is that Femara is not a drug that directly induces pregnancy, A drug that increases the chance of ovulation in women with ovulation disorders The point is that. 🩺

 

2️⃣ Femara Natural Pregnancy Success Rate: How Much Higher Is It According to Actual Research Papers?

It was found to have a higher fertility rate than clomiphene in women with polycystic ovary syndrome (PCOS) who have ovulation disorders.

 

To accurately understand the effects of Femara, rather than just the pregnancy rate Which women were studied, and what the actual rate of childbirth was It is important to check.

 

📄 Paper ① 2014 NEJM Study — Cumulative fertility rate 27.5%

international medical journal New England Journal of Medicine (NEJM) A study published in [Journal Name] compared the effects of Femara and Clomiphene on 750 women with ovulation disorders due to polycystic ovary syndrome. Participants attempted to conceive through sexual intercourse while receiving ovulation induction treatment for up to 5 cycles.

 

Evaluation items	Femara	Clomiphen
cumulative fertility rate	27.5%	19.1%
Ovulation rate per treatment cycle	61.7%	48.3%
Twin pregnancy rate	3.4%	7.4%

 

The cumulative fertility rate of women using Femara was 8.4 percentage points higher than that of the clomiphene group, which was approximately 1.44 times higher.

 

 

🔸 A point that must be addressed here
The figure of 27.5% is not the pregnancy success rate when taking Femara for one month. Cumulative rate leading to actual childbirth after up to 5 treatment cycles Also, since the results were compared with clomiphene rather than with women who did not use the drug, the same success rate cannot be applied to all women preparing for pregnancy.

 

📄 Paper ② 2022 Cochrane Study — Comprehensive Analysis of 41 Clinical Trials

A Cochrane systematic review published in 2022 analyzed data from 6,522 women who participated in 41 randomized clinical trials. This study also confirmed evidence that Femara is a useful treatment for women with polycystic ovary syndrome who have ovulation disorders.

 

In an analysis of marital relations treatment after ovulation induction compared with clomiphene, Femara significantly increased the likelihood of childbirth, and the odds ratio (OR) for the fertility rate was 1.72 (95% confidence interval 1.40–2.11) Assuming a fertility rate of 20% with the use of existing medications, the expected fertility rate for the Femara group is approximately 26–35%. This is a statistical estimate and is not a guaranteed success rate for individual patients.

 

💡 Combining the two papers
Femara, in particular Women with polycystic ovary syndrome who have ovulation disorders It can be understood as a treatment that can increase the birth rate more than clomiphene.

 

3️⃣ Would taking Femara be helpful for women with regular periods?

For women who ovulate normally, it is difficult to say that it necessarily increases the success rate of natural pregnancy.

 

The primary target group for which the effectiveness of Femara has been well-established is women with polycystic ovary syndrome who have irregular or absent ovulation. On the other hand, using Femara in women who ovulate normally does not necessarily increase the success rate of natural pregnancy.

 

The American Society for Reproductive Medicine (ASRM) guidelines for unexplained infertility also explain that there is insufficient evidence to suggest that attempting pregnancy through sexual intercourse after taking Femara is more effective than attempting pregnancy without specific treatment.

 

The reason is This is because pregnancy is not determined by ovulation alone. Pregnancy involves various factors, including not only the condition of the egg but also the condition of the sperm, the function of the fallopian tubes, the uterine environment, and the woman's age. If ovulation is already occurring normally, additionally inducing follicular growth may not yield the expected results.

 

🔸 example : Rather than immediately reaching for ovulation-inducing drugs simply because pregnancy is delayed despite a regular cycle, it is more accurate to first check if ovulation is actually occurring and rule out other causes through tests such as fallopian tube and semen analysis. 😌

 

4️⃣ Why are ultrasound examinations important before and after taking Femara?

It helps determine the direction of treatment by checking how the ovaries respond to medication.

 

In Femara treatment, it is important not only to decide whether to take the medication but also to check how the ovaries respond to it. Depending on the patient's condition, gynecological ultrasound examinations may be utilized.

 

🔸 ① Check the condition of the ovaries and follicles
It allows us to examine the morphology of the ovaries, the number of follicles, and their growth status. However, polycystic ovary syndrome cannot be confirmed based on ultrasound findings alone; menstrual patterns and hormonal status must also be evaluated.

 

🔸 ② Check ovarian response to ovulation induction agents
You can check if the follicles are growing properly after taking the medication. If multiple follicles are growing simultaneously, the direction of treatment must be determined by considering the possibility of a multiple pregnancy.

 

🔸 ③ Check the condition of the endometrium
You can examine the thickness and shape of the endometrium. However, the success of a pregnancy cannot be determined solely by endometrial thickness.

 

🔸 ④ Confirm ovulation timing and treatment plan
We can estimate the timing of ovulation based on the follicle growth status and conduct additional evaluations, such as hormone tests, if necessary.

 

 

Not all patients require the same number of ultrasound examinations every time. The important thing is to select the necessary tests based on the patient's ovulation status and ovarian response.

 

⚠️ Precautions when taking Femara
Femara is generally taken for a certain period starting from the beginning of menstruation, but the specific dosage and schedule vary depending on the patient's condition. Side effects such as headache, dizziness, fatigue, and facial flushing may occur during use, and It should not be taken during pregnancy, so it is important to check for the possibility of pregnancy before starting treatment. You must avoid arbitrarily increasing the dosage or taking it according to another person's prescription.

 

 

💬 Frequently Asked Questions (FAQ)

Q1. What is the success rate of natural pregnancy when taking Femara?

A. In a study of women with polycystic ovary syndrome, the cumulative fertility rate after up to 5 cycles of treatment was 27.5%. This does not represent an individual's pregnancy success rate per cycle, and results may vary depending on age and ovulation status.

 

Q2. Which drug is more effective, Femara or Clomiphene?

A. In women with polycystic ovary syndrome experiencing ovulation disorders, Femara demonstrated higher ovulation and fertility rates than clomiphene. However, the appropriate medication may vary depending on the individual's medical history and treatment goals.

 

Q3. Does taking Femara increase the risk of twin pregnancy?

A. If multiple follicles develop, there is a possibility of multiple pregnancy. In a representative PCOS study, the twin pregnancy rate was 3.4% in the Femara group and 7.4% in the Clomifen group, but the difference between the two groups was not statistically significant.

 

Q4. Is it mandatory to have an ultrasound examination after taking Femara?

A. Not all women require the same ultrasound examination schedule. However, medical staff may recommend the examination to check follicular growth, ovarian response, and the risk of multiple pregnancy.

 

Q5. Can I take Femara even if my periods are regular?

A. Regular menstruation suggests a high probability of normal ovulation, but ovulation status can be confirmed if necessary. Since Femara does not necessarily increase the success rate of natural conception in women who ovulate normally, the need for treatment must be assessed first.

 

🎯 Conclusion & Summary

The thing I am most curious about while preparing for pregnancy is ultimately How to increase the chances of pregnancy It is likely. Femara is a treatment that can be helpful for women with ovulation disorders, and actual studies have confirmed its effectiveness in increasing ovulation and fertility rates in patients with polycystic ovary syndrome.

 

However, the same effect cannot be expected for all women. While ovulation induction drugs may be a necessary treatment for some, for others... The process of identifying causes other than ovulation is necessary first. You can do it.

 

The starting point is to examine whether ovulation is occurring normally, how the follicles are developing, and whether there are any additional factors that need to be checked. Treatment for pregnancy does not involve using more medication, It starts with understanding exactly what treatment I need. Please make sure to remember that it works. 🩺

 

 

Lee Hyo-jin OB/GYN

Chief Director Lee Hyo-jin

Graduated from Konkuk University School of Medicine

Fellow and Clinical Professor of Gynecological Oncology, Department of Obstetrics and Gynecology, Hanyang University

 

Former Director of Yunho Hospital

Former Director of Jangse Women's Hospital

Former Director of Dream Obstetrics and Gynecology Clinic

 

Regular member of the Korean Society of Obstetrics and Gynecology

Regular member of the Korean Society of Contraception and Reproductive Health

Regular member of the Korean Menopause Society

Regular member of the Korean Society of Sexual Medicine

Current Chief Director of Lee Hyo-jin Obstetrics and Gynecology Clinic

 

The medical content of this column is based on the following papers and clinical guidelines.
· Legro RS, et al. Letrozole versus Clomiphene for Infertility in the Polycystic Ovary Syndrome. N Engl J Med. 2014;371:119–129. DOI: 10.1056/NEJMoa1313517
· Franik S, et al. Aromatase inhibitors (letrozole) for ovulation induction in infertile women with polycystic ovary syndrome. Cochrane Database Syst Rev. 2022. DOI: 10.1002/14651858.CD010287.pub4
· American Society for Reproductive Medicine (ASRM). Evidence-based treatments for couples with unexplained infertility: a guideline. 2020.
※ This column provides general health information and does not guarantee the diagnosis or treatment outcomes of individual patients. Approval guidelines for the use of Femara for ovulation induction may vary by country, and the decision regarding drug use and dosage should be made in consultation with a healthcare professional.

 

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