There is a lot to know about getting pregnant with Clomid or Letrozole. It is estimated that 10% of women in the United States face infertility and have trouble getting pregnant. This condition can pose many challenges and doesn’t always have a clear cause. But it’s important to understand there are possible solutions. Let’s discuss two types of medications that are commonly used to treat infertility by acting on your body’s ability to ovulate (release an egg): Clomid and Femara.
Typically, women produce and release one egg each month, but some women do not ovulate regularly. For women who do ovulate each month, these medications are used to increase the follicles produced each month, which is called controlled ovarian hyperstimulation. For women who don’t ovulate regularly, these medications are used to induce ovulation.
Learning more about your options may help you and your OBGYN create a path forward as you navigate the complexities of your condition before you visit a fertility clinic.
What is Clomid (aka clomiphene citrate)?
Clomid, also known generically as clomiphene citrate, is an oral medication used to treat infertility in women. It is often a 50-milligram pill taken on days 3-7 or 5-9 of your menstrual cycle. Your OBGYN will typically start you on a low dose, and then increase it incrementally each month until it is clear you are ovulating.
How does Clomid work?
Clomid tricks the body into thinking that your estrogen levels are lower, which makes the pituitary gland increase follicle-stimulating hormones (FSH). Ultimately, this helps stimulate the ovary to produce eggs that can be released during ovulation. It essentially stimulates the ovarian follicles (tiny fluid sacs in the ovaries), which hold an immature egg. Encouraging this growth can help those immature eggs turn into mature eggs, be released, and meet with sperm in hopes of becoming fertilized.
Clomid can be taken as part of fertility treatment before intrauterine insemination (IUI), or in combination with IUI.
Is Clomid right for you?
Clomid is typically best for those who have been unable to get pregnant for about a year, or who have unexplained infertility. If you have irregular periods, talk to your doctor right away. They may suggest Clomid sooner (don’t wait a year). If you have polycystic ovarian syndrome (PCOS), a different medication called Femara (Letrozole) may work better for you than Clomid (more on that later).
If you have been diagnosed with hypothalamic amenorrhea, premature ovarian insufficiency or breast cancer, Clomid may not be a good fit for you.
Clomid side effects
Clomid’s side effects include hot flashes, mood swings, and pelvic pain. Other potential side effects include nausea, breast discomfort, blurred vision, headaches, and spotting. If you experience vision changes while taking Clomid, contact your OBGYN immediately.
In our experience at Madison Women’s Health, most women don’t complain of many side effects from this medication as they are only taking it for five days each cycle.
It’s worth noting that those who take Clomid have an increased risk of carrying multiple babies, like twins or more.
What is Femara (aka letrozole)?
Femara, also known generically as letrozole, is an oral medication commonly used for estrogen-sensitive breast cancer in postmenopausal women. In 2004, it became an off-label treatment for fertility, as it can help trigger ovulation in some women, especially women with PCOS. While it is not yet FDA-approved for fertility treatment, it is considered by many physicians to be a better choice than Clomid for anovulatory women.
To induce ovulation, letrozole is typically taken once a day for five days, beginning on days 3-7 or 5-9 of your menstrual cycle.
How does letrozole work?
Letrozole blocks a protein called aromatase, which helps make estrogen. Letrozole decreases the amount of estrogen in the body. Regarding fertility, lowering estrogen levels can help the body release other hormones and chemicals that can help immature eggs (known as follicles) grow and mature, increasing the likelihood of pregnancy.
Is letrozole right for you?
When deciding whether to prescribe Clomid or letrozole, your OBGYN will take into consideration why your ovaries may not be releasing eggs. If the cause is PCOS, then your OBGYN will likely recommend you take letrozole instead of Clomid.
If a different issue is affecting ovulation, such as hypothalamic amenorrhea or premature ovarian insufficiency, letrozole may not be beneficial. Ovarian insufficiency can occur when the ovaries are not functioning normally and don’t produce the typical amount of estrogen or don’t release eggs regularly. It can be confused with premature menopause.
If you have a history of breast cancer, letrozole would also be the medication of choice to help induce ovulation. Expect to have close monitoring by your oncologist.
Letrozole side effects
Common side effects of letrozole can include hot flashes, joint pain, exhaustion, headaches, nausea, spotting, cysts, and dizziness. (Women who are taking letrozole for breast cancer will have more side effects because they are taking much higher doses of the medication.)
Before beginning infertility treatments, your OBGYN will want to determine if you’re ovulating regularly. This is important when it comes to conception because it is when the mature egg leaves the ovaries and travels down the fallopian tube, where it can be fertilized. Ovulation occurs approximately two weeks before the start of the next period or menstrual cycle, but this can vary based on your cycle.
If you have a regular menstrual cycle, there’s a good chance that you’re ovulating. However, some women may not experience a normal 28-day cycle or may have a condition that makes cycles less predictable.
Signs that you’re ovulating can include:
- Cervical mucus secretions that are clear, wet, and elastic (like egg whites).
- A positive result using an ovulation predictor kit (OPK). Ovulation predictor kits measure luteinizing hormone (LH) levels in your urine. Your OBGYN provider may recommend you begin measuring your LH levels around cycle day 10. You can purchase an OPK at most retail pharmacies.
Progesterone levels in the second half of our cycle are another way to help your OBGYN determine if you are ovulating. Or, if you are using ovulation predictor kits, your OBGYN provider may recommend you have your progesterone levels checked about seven to eight days after a positive OPK result (or peak LH).
We often recommend our patients use an app that collects all of this data in one place and helps to visualize what is happening. A popular app our patients enjoy using is FLO.
Effectiveness of fertility drugs
The effectiveness of the medications you’re prescribed varies on many things, including any other diagnoses you may have. For instance, if you have PCOS, your physician will likely begin at a lower dose of fertility medication and increase it if results are not seen within about three months. If ovulation is absent, the beginning step would be to address ovulation first. In 2019, the Clomid success rate was 21.4%. Letrozole has a similar success rate but has shown higher success rates with those diagnosed with PCOS.
How long does it take to get pregnant on Clomid or Letrozole?
This is a common question we are asked, but it has a complex answer. If you are ovulating already, these medications can speed up the process to become pregnant. If you’re not ovulating, then you could become pregnant within 6-12 months of taking these medications.
We start our patients on the lowest dose for these medications and typically increase the dose until they ovulate. There is no limit to the number of cycles you can take these medications, but if you have not achieved pregnancy after 9 cycles, you should be evaluated for other possible causes of infertility. Expect some additional bloodwork and an ultrasound to look at your fallopian tubes and uterine anatomy.
You can also read more about common infertility causes and treatments here.
Which fertility drug should you choose?
While these medications act similarly, the first step in any treatment should be to speak with your provider or fertility specialist. They’ll review a detailed history including other results, lab work, or medications you may be taking that can help determine the best choice for your body. It’s important to keep in mind that other diagnoses, like PCOS or potential side effects, can also impact your decision. Determining if you’re ovulating is a good initial step.
Speak with your OBGYN provider to get more information about fertility treatments and what may be the best option for you. We’re dedicated to helping you achieve your health and family goals and will do what we can before referring you to a reproductive specialist or fertility clinic.
Vicki Slager-Neary, OBGYN, WHNP, A.P.N.P, has been serving women in the Madison area as board-certified Women’s Health Nurse Practitioner since 2016. She has provided patient care for over 17 years as a nurse in the Emergency Department, Labor and Delivery, Fertility, and OBGYN. Vicki has extensive experience working in Reproductive Endocrinology and Infertility for the past 10 years. Her areas of special interest include preconception counseling and treatment, contraception, and pregnancy. Vicki has a wide variety of experience managing infertility conditions including PCOS, amenorrhea, recurrent pregnancy loss and unexplained infertility.