< Back to the Blog

What Is Ovarian Stimulation?

Clara Siegmund
Clara Siegmund

Ovarian stimulation is a crucial first step in many fertility treatments, including IVF and IUI. Read on to learn what ovarian stimulation is, and what to expect when you undergo treatment.

No items found.
Modified On:
Published:
May 26, 2025
Est. Read Time:
0
Published:
May 26, 2025
Est. Read Time:
0

Ovarian stimulation is a crucial first step in many fertility treatments, including IVF and IUI. Read on to learn what ovarian stimulation is, and what to expect when you undergo treatment.

Fertility
Share to:

Ovarian stimulation is a crucial first step in many fertility treatments, including IVF and IUI. Read on to learn what ovarian stimulation is, and what to expect when you undergo treatment.

Dealing with fertility issues when trying for a baby can feel frustrating, scary, upsetting—you name it. 

Luckily, fertility treatment can help you achieve pregnancy, and as methods become more advanced, pregnancy success rates continue to rise. 

Ovarian stimulation is a crucial part of many types of fertility treatment. Read on to find out what ovarian stimulation is, how this treatment works, which assisted reproductive technology (ART) procedures use ovarian stimulation, and more.

What is ovarian stimulation?

Ovarian stimulation, sometimes called controlled ovarian stimulation (COS), is a fertility treatment. 

Ovarian stimulation addresses fertility issues using hormone-based medications to help your body make more eggs. Once those eggs are mature, your doctor extracts them from your ovaries or induces ovulation.

Ovarian stimulation may be a treatment option for you if:

  • You don’t ovulate regularly and need a little boost
  • You have a reproductive health condition that impacts fertility, like PCOS
  • You’re dealing with other sources of infertility

Ovarian stimulation on its own doesn’t make you conceive. Instead, it’s a crucial step in a larger process, including in multiple assisted reproductive technology (ART) procedures. 

To potentially achieve pregnancy, you’ll need to combine ovarian stimulation with another fertility treatment or fertility-boosting strategy.

How does ovarian stimulation work?

To understand ovarian stimulation, let’s look at ovulation and how the body produces eggs.

In a typical menstrual cycle, your body develops an egg over the first half of your cycle, then releases it from your ovaries when you ovulate. If fertilized, the egg may implant in the uterus and you may become pregnant.

All this happens in response to hormonal activity. Follicle-stimulating hormone (FSH) triggers your ovaries to start making follicles, which is where the egg will grow. Later, when an egg is mature and ready to go, a surge in luteinizing hormone (LH) triggers your ovaries to release the egg.

Ovarian stimulation uses medication to induce these hormone-driven processes, stimulating and supporting egg production in your ovaries. Here’s how.

>>MORE: What Is Fertility Preservation?  

Step one: Growing the eggs

To undergo ovarian stimulation, you’ll take a few different hormone-based medications as pills, shots, or both, starting around the beginning of your cycle:

  • Medication that mimics FSH to help your body develop multiple follicles and grow eggs
  • Medication that suppresses LH to stop your ovaries from releasing the eggs too early
  • Medication that mimics the LH surge to bring the eggs to full maturity (taken right before egg retrieval or induced ovulation)

Ideally, your body will develop two dominant follicles, giving you two mature eggs. (When ovulation occurs naturally, there’s typically only one dominant follicle and one mature egg—except in cases of hyperovulation.)

Throughout this phase of ovarian stimulation, you’ll have regular ovarian ultrasounds to check follicular development and make sure you’re safe and responding well to treatment. Your doctor will measure factors like follicle size and number to determine when the eggs have developed to maturity.

Step two: Using the eggs

Once the follicles have reached the right size and the eggs are mature, you move on to the next step. 

Depending on what your fertility treatment plan is, your doctor will either:

  • Retrieve your eggs: like for IVF or egg freezing
  • Induce ovulation: like for IUI or timed intercourse

Fertility treatments with ovarian stimulation 

Ovarian stimulation is frequently part of assisted reproductive technology (ART) procedures, helping your body prepare for the next steps in your treatment. 

These are some of the fertility procedures that can include ovarian stimulation.

In vitro fertilization (IVF)

For IVF, eggs are retrieved from the ovaries then fertilized with sperm in a lab. From there, an embryo is transferred to the uterus.

Before the eggs can be retrieved, though, your body has to grow them—that’s where ovarian stimulation comes in. Typically, you can expect to start your IVF cycle with ovarian stimulation. While it is possible to skip this step, IVF without ovarian stimulation has a lower pregnancy rate.

Once it’s time for egg retrieval (also called egg harvesting), your doctor will guide a thin needle through the vagina, insert it into the ovaries, and extract the mature eggs from the follicles. You’ll be under anesthesia (general, local, or somewhere in between) for the duration of the short procedure.

Intrauterine insemination (IUI)

With IUI, sperm are injected directly into the uterus around the time of ovulation. 

Ovarian stimulation is frequently used before insemination. This phase ensures your body produces an egg, controls ovulation timing, and aligns the timing of the IUI procedure with ovulation.

There’s no need to extract the mature eggs from your body for IUI. Instead, your doctor medically induces ovulation, then sperm are injected into your uterus around 24 to 48 hours later.

Egg freezing

Egg freezing, another type of ART, enables you to preserve your fertility for a potential later pregnancy instead of having a baby in the immediate future.

When you decide to freeze your eggs, you’ll likely start with ovarian stimulation in order to develop as many eggs for cryopreservation (freezing) as possible. The mature eggs will then be extracted from your ovaries through the egg retrieval procedure, and frozen for later use.

Timed intercourse

Ovarian stimulation medications can sometimes be used without a follow-up ART procedure, to regulate ovulation. 

In this case, you’ll take ovulation-boosting medication to grow eggs and trigger ovulation at a specific moment. Then, you’ll time sex to ovulation.

Incorporating at-home tools throughout this process may help you improve your chances of pregnancy. At-home ovulation trackers are one useful option for measuring and monitoring your hormone levels and tracking ovulation, alongside your doctor.

Is ovarian stimulation safe?

Ovarian stimulation is standard treatment for managing fertility issues. It’s safe for both the person undergoing treatment and for any children born from the treatment.

You may experience certain side effects from the medications you take for ovarian stimulation, including:

  • Hot flashes
  • Abdominal discomfort
  • Light spotting
  • Emotional changes or mood swings
  • Injection site irritation (if you’re using shots)

Like any medical treatment, ovarian stimulation also comes with some risks, though they’re relatively low. The main risks associated with ovarian stimulation are:

  • Ovarian hyperstimulation syndrome (OHSS): a condition in which the ovaries become enlarged, requiring treatment. 
  • Multiple pregnancies: pregnancies with more than one baby (twins, triplets, or more), which call for special monitoring and care .

Your doctor will discuss any risks and side effects with you as you determine the right fertility treatment for you on your path to parenthood.

What is ovarian stimulation: the bottom line

Ovarian stimulation treats fertility issues using hormone-based medication to stimulate egg production. Depending on the rest of your fertility treatment plan, the next step will either be to retrieve the mature eggs or induce ovulation. 

Ovarian stimulation is a key part of ART procedures like IVF, IUI, and egg freezing. Certain ovulation-regulating medications may also help you conceive without additional ARTs, depending on your health needs. 

With ovarian stimulation alongside accompanying ART procedures and fertility strategies, you just may overcome fertility issues and achieve pregnancy.

About the author

Clara Siegmund
Clara Siegmund is a writer, editor, and translator (French to English) from Brooklyn, New York. She has a BA in English and French Studies from Wesleyan University and an MA in Translation from the Sorbonne. She is passionate about literature, reproductive justice, and using language to make information accessible.‍

Sources

perimenopause-periods
Should I still see my gynecologist if my periods are just "weird" but not painful?
Yes. Annual visits remain important during perimenopause. Your provider can help determine if your "weird" periods are typical perimenopause changes or something requiring attention. They can also discuss management options to improve your quality of life.
perimenopause-periods
How long do irregular periods last before menopause?
Irregular perimenopause periods typically last 4 to 8 years before your final period, though this varies greatly. Some women experience irregularity for just a few months, while others have irregular periods for over a decade before reaching menopause.
perimenopause-periods
Is it normal to have two periods in one month during perimenopause?
Yes, this can happen, especially in early perimenopause when cycles shorten. You might have a 21 day cycle, meaning you could have a period at the beginning and end of the same calendar month. Track these patterns to distinguish between short cycles and abnormal bleeding.
perimenopause-periods
Why are my periods suddenly so heavy in my 40s?
Heavy perimenopause periods often result from estrogen dominance. When progesterone drops but estrogen remains high, your uterine lining builds up more than usual, causing heavier bleeding when it sheds. This is common in perimenopause but should be evaluated if it affects your daily life.
perimenopause-periods
Can I still get pregnant if my periods are irregular during perimenopause?
Yes. As long as you're having periods, even irregular ones, you may still be ovulating. Pregnancy is possible until you've gone 12 full months without any period. If you don't want to become pregnant, continue using contraception throughout perimenopause.
perimenopause-and-weight-gain
Can you prevent perimenopause weight gain completely?
While you may not prevent all weight changes during perimenopause, you can minimize gain through proactive strategies. Starting strength training before perimenopause, maintaining consistent sleep habits, and managing stress can help your body adapt to hormonal changes more smoothly. Remember, some body changes during this transition are normal and healthy.
perimenopause-and-weight-gain
At what age does perimenopause weight gain typically start?
Perimenopause weight gain can begin in your late 30s or early 40s, often coinciding with the first hormonal changes. Many women notice gradual changes starting 5 to 10 years before their final period. The timing varies greatly based on genetics, lifestyle, and overall health.
perimenopause-and-weight-gain
Does everyone gain the same amount during perimenopause?
No. Perimenopause weight gain varies significantly. Some women gain 5 pounds, others 20 or more, and some maintain their weight. Factors include genetics, starting weight, activity level, stress, sleep quality, and how dramatically hormones fluctuate. Your experience is unique to your body.
Is perimenopause weight gain different from regular aging weight gain?
Yes. While metabolism naturally slows with age, perimenopause weight gain has distinct characteristics. The hormonal shifts cause fat redistribution to the midsection, even if overall weight doesn't change dramatically. This abdominal weight gain pattern is specifically linked to declining estrogen and progesterone, not just aging.
perimenopause-and-weight-gain
Will the weight come off after menopause?
Perimenopause weight gain often stabilizes after menopause when hormones level out, but the weight doesn't automatically disappear. The metabolic and body composition changes that occur during perimenopause tend to persist. However, with consistent healthy habits, weight management becomes more predictable post menopause than during the fluctuating perimenopause years.
https://www.oova.life/blog/progesterone-supplementation-guide
Can I take progesterone if I'm breastfeeding?
Yes, progesterone is generally safe while breastfeeding and doesn't significantly affect milk supply. However, always discuss with your healthcare provider before starting any hormone supplementation while nursing.
https://www.oova.life/blog/progesterone-supplementation-guide
Is it safe to take progesterone throughout pregnancy?
Yes, when prescribed by your healthcare provider. Progesterone supplementation in early pregnancy is safe and can reduce miscarriage risk in women with low progesterone or a history of pregnancy loss. Most providers continue supplementation through the first trimester (weeks 10-12) when the placenta takes over.
https://www.oova.life/blog/progesterone-supplementation-guide
Can progesterone supplementation cause weight gain?
Progesterone can cause temporary water retention and bloating, which may show up as a few pounds on the scale, but it doesn't cause true fat weight gain. Most women don't experience significant weight changes from progesterone supplementation.
https://www.oova.life/blog/progesterone-supplementation-guide
Can I switch from pills to suppositories or vice versa?
Yes, but only under your doctor's guidance. The dosing and timing may need adjustment when switching between forms since they're absorbed differently. Never switch on your own, especially if you're pregnant or undergoing fertility treatment.
https://www.oova.life/blog/progesterone-supplementation-guide
Will progesterone supplementation delay my period?
Yes, progesterone keeps the uterine lining intact, so if you're not pregnant and continue taking progesterone, your period will be delayed. Once you stop taking it, your period should start within 2-10 days. If you are pregnant, progesterone helps maintain the pregnancy and you won't get a period.
https://www.oova.life/blog/progesterone-supplementation-guide
Should I take progesterone pills orally or vaginally?
For fertility and pregnancy support, vaginal progesterone is usually preferred because it delivers higher concentrations directly to the uterus. For perimenopause or general hormone balance, oral progesterone often works well and is more convenient. Your doctor will recommend the best route based on your specific needs.
https://www.oova.life/blog/progesterone-supplementation-guide
When should I start taking progesterone after ovulation?
Typically, progesterone supplementation for luteal phase support starts 2-3 days after ovulation (confirmed by LH surge or temperature rise). Your doctor will give you specific timing based on your protocol. Some women start immediately after a positive ovulation test.
https://www.oova.life/blog/progesterone-supplementation-guide
What's better: progesterone cream or pills?
Pills (oral micronized progesterone) are generally more effective and reliable than creams because absorption from creams is inconsistent. For medical conditions like fertility issues, low progesterone, or HRT, prescription pills or suppositories are strongly recommended over over-the-counter creams.
https://www.oova.life/blog/low-vs-high-progesterone-symptoms
How can I tell if I have low or high progesterone?
The only definitive way to know is through hormone testing via blood tests or at-home urine tests that measure progesterone metabolites. However, symptom patterns can provide clues: anxiety and irregular periods suggest low progesterone, while bloating and extreme fatigue suggest high progesterone.
https://www.oova.life/blog/low-vs-high-progesterone-symptoms
When during my cycle should I test progesterone levels?
Test progesterone levels during the luteal phase, typically 7 days after ovulation or around day 21 of a 28-day cycle. This is when progesterone should be at its peak, making it easier to identify if levels are too low or too high.
https://www.oova.life/blog/low-vs-high-progesterone-symptoms
What are the main differences between low and high progesterone symptoms?
Low progesterone typically causes irregular or heavy periods, anxiety, hot flashes, and sleep issues. High progesterone causes bloating, fatigue, intense breast tenderness, and depression-like mood changes. Low progesterone symptoms persist throughout your cycle, while high progesterone symptoms are most intense during the luteal phase.
https://www.oova.life/blog/low-vs-high-progesterone-symptoms
Can you have symptoms of both low and high progesterone?
Some symptoms like breast tenderness and mood changes can occur with both low and high progesterone, making it confusing. However, the timing, intensity, and accompanying symptoms differ. Hormone testing is the best way to determine which imbalance you're experiencing.
https://www.oova.life/blog/10-dpo
Can stress affect 10 DPO symptoms?
Yes, stress can worsen or mimic 10 DPO symptoms. Stress increases cortisol, which can cause cramping, fatigue, and mood changes similar to both PMS and early pregnancy. During the two-week wait, try stress-reduction techniques like gentle exercise, meditation, or spending time with loved ones.
https://www.oova.life/blog/10-dpo
Is it better to test at 10 DPO or wait?
It's better to wait until 12–14 DPO for more accurate results. Testing at 10 DPO often leads to false negatives because hCG levels may still be too low. If you absolutely can't wait, use a sensitive early detection test with first morning urine, and be prepared to retest in 2–3 days if negative.
https://www.oova.life/blog/10-dpo
What does implantation bleeding look like at 10 DPO?
Implantation bleeding at 10 DPO is typically light pink or brown, much lighter than a period, and lasts 1–2 days. It's often just spotting when you wipe or a few drops on a panty liner. However, only 15–20% of pregnant women experience implantation bleeding—most don't have any bleeding at all.
https://www.oova.life/blog/10-dpo
Why am I cramping at 10 DPO?
Cramping at 10 DPO can be caused by elevated progesterone (whether you're pregnant or not), implantation (if you're pregnant), or premenstrual cramping. Unfortunately, cramping alone can't tell you if you're pregnant since progesterone causes similar symptoms in both scenarios.
https://www.oova.life/blog/10-dpo
What are the chances of a BFP at 10 DPO?
If you're pregnant, you have about a 50–60% chance of getting a positive test at 10 DPO. This means there's a 40–50% chance of a false negative even if you conceived. Chances improve significantly by 12–14 DPO.
https://www.oova.life/blog/10-dpo
What DPO is most accurate for pregnancy testing?
14 DPO (the day of your missed period) is the most accurate time to test, with 99% accuracy. 12 DPO offers 80–90% accuracy. 10 DPO has only 50–60% accuracy. For best results, wait as long as you can—ideally until 12–14 DPO.
https://www.oova.life/blog/10-dpo
Is 10 DPO too early to test?
10 DPO is considered early for pregnancy testing. While some women get positives at 10 DPO, accuracy is only 50–60% if you're pregnant. For best results, wait until 12 DPO (80–90% accuracy) or 14 DPO/missed period (99% accuracy).
https://www.oova.life/blog/10-dpo
Can you have implantation at 10 DPO?
Yes, implantation can still occur at 10 DPO, though 84% of women have already implanted by this point. Late implantation at 10–12 DPO is normal. If implantation happens at 10 DPO, you won't get a positive pregnancy test for another 2–3 days.
https://www.oova.life/blog/10-dpo
What does a negative test at 10 DPO mean?
A negative test at 10 DPO does not mean you're not pregnant. It's very common to get negatives at 10 DPO even if you conceived. Your hCG levels may still be too low, or implantation may have occurred later. Wait until 12–14 DPO to retest for more accurate results.
https://www.oova.life/blog/10-dpo
Can you get a positive pregnancy test at 10 DPO?
Yes, but only about 50–60% of pregnant women will get a positive at 10 DPO. The other 40–50% have hCG levels that are still too low to detect. If you test negative at 10 DPO, wait 2–3 days and test again.
https://www.oova.life/blog/high-progesterone-symptoms
Can high progesterone cause weight gain?
Yes, elevated progesterone can cause temporary weight gain through water retention and bloating. This is a normal part of the luteal phase and early pregnancy.
https://www.oova.life/blog/how-to-increase-estrogen
Does stress affect estrogen levels?
Yes, chronic stress elevates cortisol, which can suppress estrogen production and disrupt hormonal balance. Stress reduction through meditation, yoga, adequate sleep, and self-care practices helps maintain optimal estrogen levels.
https://www.oova.life/blog/how-to-increase-estrogen
When should I consider medical treatment for low estrogen?
Consider medical intervention if natural methods don't improve symptoms after 3 months, if symptoms severely impact quality of life, if you're experiencing early menopause (before 40), or if you have fertility concerns. Hormone replacement therapy may be appropriate in these cases.
https://www.oova.life/blog/how-to-increase-estrogen
What are the signs that my estrogen is increasing?
Signs of rising estrogen include more regular menstrual cycles, reduced hot flashes, improved vaginal lubrication, better mood stability, increased energy, and improved skin elasticity. You may also notice reduced symptoms that originally indicated low estrogen.
https://www.oova.life/blog/how-to-increase-estrogen
Can exercise increase estrogen levels?
Yes, moderate exercise stimulates estrogen release and helps maintain hormonal balance. Aim for 150 minutes of moderate cardio weekly plus strength training twice per week. However, excessive exercise can actually lower estrogen, so balance is key.
https://www.oova.life/blog/how-to-increase-estrogen
How long does it take to increase estrogen naturally?
With consistent dietary and lifestyle changes, you may notice improvements in symptoms within 4-8 weeks. However, significant hormonal changes typically take 2-3 months. Tracking your cycle and symptoms can help you monitor progress.
https://www.oova.life/blog/how-to-increase-estrogen
What foods increase estrogen levels naturally?
Foods high in phytoestrogens can help increase estrogen naturally. The best options include flax seeds (high in lignans), soy products (tofu, tempeh, edamame), lentils, chickpeas, whole grains (oats, quinoa, brown rice), and garlic. These plant compounds mimic estrogen's effects in the body.
https://www.oova.life/blog/perimenopause
What helps relieve hot flashes quickly?
Cool environments, layered clothing, herbal teas, and medical treatments like gabapentin or HRT may help—depending on severity. Lifestyle changes like reducing caffeine and alcohol can also provide relief.
https://www.oova.life/blog/perimenopause
Are there tests to confirm perimenopause?
Yes. Tests measuring estradiol, LH, and FSH levels can indicate hormonal shifts—but diagnosis is often symptom-based since hormone levels fluctuate widely during perimenopause.
https://www.oova.life/blog/perimenopause
How do I know it's perimenopause and not something else?
A doctor may recommend hormone testing (like LH, E3G, and PdG) and track symptom timing. Diagnosis is often based on symptoms combined with age and menstrual pattern changes.
https://www.oova.life/blog/perimenopause
What's the earliest age perimenopause can start?
Some women begin experiencing symptoms as early as their mid-30s, though perimenopause typically starts between ages 38-45.
https://www.oova.life/blog/perimenopause
Does perimenopause affect mental clarity?
Yes. Brain fog and difficulty concentrating are common during hormone fluctuations in perimenopause.
https://www.oova.life/blog/TBD-10-symptoms-and-how-to-get-relief
What happens after the last sign of perimenopause?
After your final period, you enter postmenopause. You'll need 12 consecutive months without a period to confirm menopause. Many symptoms gradually improve, though some like vaginal dryness may persist without treatment.
https://www.oova.life/blog/TBD-10-symptoms-and-how-to-get-relief
When do perimenopause symptoms finally stop?
Some symptoms like brain fog improve after menopause, while others like hot flashes may continue for up to 10 years post-menopause. Vaginal symptoms often persist or worsen without treatment. Each person's timeline is different.
https://www.oova.life/blog/high-progesterone-symptoms
Is high progesterone a sign of pregnancy?
Yes, high progesterone is one of the earliest indicators of pregnancy. Progesterone levels rise significantly after conception to support the developing embryo and reach their peak during the third trimester.
https://www.oova.life/blog/TBD-10-symptoms-and-how-to-get-relief
Can you still get pregnant in late perimenopause?
Yes, you can still get pregnant during perimenopause as long as you're having periods, even if they're infrequent. Continue using birth control until you've gone 12 consecutive months without a period and have officially reached menopause.
https://www.oova.life/blog/TBD-10-symptoms-and-how-to-get-relief
Do symptoms get worse before perimenopause ends?
Yes, most perimenopause symptoms intensify in the final 1-2 years before menopause. Hot flashes peak around your final period, vaginal symptoms worsen, and mood changes increase. However, brain fog typically improves in late perimenopause.
https://www.oova.life/blog/TBD-10-symptoms-and-how-to-get-relief
How long does late perimenopause last?
Late perimenopause typically lasts 1-3 years before your final period. However, the exact duration varies significantly from person to person. You've reached menopause after 12 consecutive months without a period.
https://www.oova.life/blog/high-progesterone-symptoms
What are the symptoms of high progesterone?
High progesterone symptoms include fatigue, bloating, breast tenderness, weight gain, anxiety, depression, headaches, and food cravings. During pregnancy, you may also experience increased nipple sensitivity and muscle aches.
https://www.oova.life/blog/TBD-10-symptoms-and-how-to-get-relief
What are the first signs that perimenopause is ending?
The earliest signs include longer gaps between periods (60+ days), intensifying hot flashes that peak around your final period, and worsening vaginal dryness. These symptoms typically increase in late perimenopause before you reach official menopause.
https://www.oova.life/blog/high-progesterone-symptoms
When should I be concerned about high progesterone?
Consult a healthcare provider if you experience high progesterone symptoms outside your luteal phase when not pregnant, or if symptoms include severe pelvic pain, abnormal vaginal bleeding, or rapid weight gain while on hormone therapy.
https://www.oova.life/blog/high-progesterone-symptoms
How do you test progesterone levels?
Progesterone can be measured through blood tests at your doctor's office or at-home urine tests that measure PdG (a progesterone metabolite). Testing is typically done during the luteal phase, about 7 days after ovulation.

About the Oova Blog:
Our content is developed with a commitment to high editorial standards and reliability. We prioritize referencing reputable sources and sharing where our insights come from. The Oova Blog is intended for informational purposes only and is never a substitute for professional medical advice. Always consult a healthcare provider before making any health decisions.