Why am I not ovulating but having periods? Understanding anovulatory cycles

You’re bleeding every month, so that must mean you’re ovulating, right? Not necessarily. 

While it’s true that you can’t have a true period (menstruation) without ovulating first, it’s still possible to experience vaginal bleeding without ovulation. This bleeding can look and feel just like a regular period, but biologically, it’s not the same. Instead, it’s often referred to as anovulatory bleeding or a withdrawal bleed, and it happens for different reasons than a typical menstrual period.

In this article, we’ll explain what ovulation is, how to recognize when it’s missing, what causes anovulatory cycles, and what that can mean for your health. Whether you’re trying to conceive or want to understand your cycle better, it’s important to know the difference between a period and bleeding without ovulation.

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What is ovulation

Ovulation is the process where one of your ovaries releases an egg. This usually occurs once a month, around the middle of your cycle (roughly day 14 for a regular 28 day cycle). 

The egg travels down your fallopian tube and can survive for around 24 hours, if it’s not fertilized by a sperm cell during this time, hormone levels shift, and your body sheds the uterine lining, resulting in what we call menstruation, or a true period.

Why does ovulation matter?

Ovulation is at the heart of a healthy menstrual cycle, and it’s essential for pregnancy. If you’re not ovulating, conception isn’t possible. 

But ovulation isn’t just about fertility; it’s also a key part of hormonal balance. In fact, the relationship goes both ways: hormone imbalances can disrupt ovulation, and missing ovulation can throw off your hormone levels further. Reproductive hormones like estrogen and progesterone influence everything from mood and energy to sleep, bone health, and even weight regulation. That’s why the effects of a hormone imbalance can go far beyond your menstrual cycle.

What is anovulation?

‍Anovulation is when you have a menstrual cycle without ovulating, meaning no egg is released from the ovaries during that cycle. If your body doesn’t ovulate during a cycle, then you cannot get pregnant; however, you may still have a bleed that resembles a period. 

Can you have a period without ovulating?

Technically, no - you can’t have a true menstrual period without ovulating first. A true period happens when your body releases an egg, the egg isn’t fertilized, and hormone levels drop, causing the uterine lining to shed. 

However, you can have vaginal bleeding without ovulating. This is known as anovulatory bleeding, and it can easily be mistaken for a normal period, especially if it happens around the time you’re expecting a period. Anovulation usually happens because of an imbalance of one or more hormones. Anovulatory bleeding is commonly caused when too much estrogen is produced, causing the uterine lining to thicken, and then drops off without the help of progesterone.  This sudden hormonal shift can trigger bleeding, even though ovulation never occurred. However, an imbalance of other hormones like prolactin and androgens can also cause anovulatory bleeding.

Signs of anovulatory bleeding

It can be difficult to spot the difference between a period and anovulatory bleeding, but often there are subtle differences between the two. Here’s how to tell them apart:

1. Cycle Regularity

• Anovulatory bleeding tends to occur unpredictably. Bleeding may happen more or less often than once a month, and cycles may be irregular in length.
• True periods usually follow a regular monthly rhythm, typically every 21–35 days.

2. Flow and Duration

• Anovulatory bleeding is often heavier than your usual period and may last longer than expected.
• True periods tend to have a consistent flow and duration that aligns with your normal pattern—usually lasting the same number of days each month.

3. Associated Symptoms

• Anovulatory bleeding often lacks typical premenstrual symptoms. You might not experience sore breasts, mood swings, fatigue, or bloating.
• True periods are usually preceded by recognizable PMS symptoms and other menstrual signs your body is familiar with.

4. Signs of Ovulation

• In anovulatory cycles, there are usually no signs of ovulation—no LH surge, no shift in basal body temperature, and no noticeable changes in cervical mucus.
• In ovulatory cycles, you may observe signs like an LH surge, increased cervical mucus, or a temperature rise if you're tracking.

5. Hormonal Patterns

• An LH surge typically occurs 24–36 hours before the egg is released during ovulation. This can be detected using ovulation tests.
• However, a positive LH surge doesn’t always mean ovulation occurs. In conditions like PCOS, it’s possible to experience an LH surge without actually releasing an egg.

6. Fertility Implications

• Anovulatory cycles do not result in the release of an egg, so conception cannot occur during these cycles.
• Ovulatory cycles are fertile. In fact, around 80% of women under 35 conceive within six months of trying if they’re ovulating regularly.

Causes of anovulation

There are many reasons why your body might skip ovulation from time to time. Sometimes it’s temporary and nothing to worry about, but in other cases, it can signal an underlying hormonal imbalance or health issue.

Here are some of the most common causes of anovulation:

• Polycystic Ovary Syndrome (PCOS): The leading cause of female infertility around the globe and the most common cause of chronic anovulation. PCOS is a hormonal condition that causes an imbalance in the reproductive hormones, interfering with regular ovulation.
• Thyroid disorders: Both an underactive (hypothyroidism) and an overactive thyroid (hyperthyroidism) can disrupt hormonal balance and prevent ovulation. 
• Body weight: Having a very low BMI, either from excessive exercise or not eating enough, can halt ovulation. Having a very high BMI can also disrupt reproductive hormones and prevent ovulation.
• Primary ovarian insufficiency: Occurs when the ovaries stop releasing eggs regularly before age 40. The ovaries also stop producing the right amount of estrogen. You may have irregular or occasional periods.
• Age: If you’re just starting your periods or approaching menopause, then hormonal disturbance and anovulatory cycles are common at this stage of your reproductive life.
• High prolactin levels (hyperprolactinemia): Raised prolactin levels can impact the hormones needed to trigger ovulation and cause anovulation. Hyperprolactinemia can be natural, for example, during breastfeeding you have raised prolactin levels, or caused by certain medical conditions or medications. 
• Certain medications: Some medications, including hormonal contraceptives, antidepressants, and anti-epileptic drugs can cause anovulation.

When to see a doctor

Occasional anovulatory cycles can happen to anyone and are often nothing to worry about. But, if you consistently notice any of the following signs, it’s a good idea to speak to your healthcare provider:

• Consistently irregular cycles. If your cycles are consistently irregular or you find it difficult to predict when your period will arrive, then this could be a sign of anovulatory cycles.
• No signs of ovulation. If you have no changes to your cervical mucus or basal body temperature over several cycles, it could be a sign that you’re not ovulating.  
• Unable to get pregnant. If you’re under 35 and haven’t conceived after 12 months of regular, unprotected sex - or over 35 and it’s been more than 6 months - it’s time to talk to your healthcare provider.  
• Missing periods altogether. If you’re not pregnant but are missing periods altogether, then you may need further investigation or treatment.
• Unusual bleeding. Unusual vaginal bleeding, like bleeding after sex or between periods, or bleeding that is very heavy, can be a sign of an underlying health issue and needs further investigation.
• Symptoms of a hormonal imbalance. Acne, unwanted hair growth, hair thinning, and weight changes can all be signs of an underlying hormonal imbalance.
• You’re in your 30s or 40s and noticing cycle changes that might be related to perimenopause.

Diagnosing and treating anovulation

If your doctor suspects you’re not ovulating, then they may suggest some of the following investigations to look for a cause:

• Tracking your cycle: Including dates, flow, and any symptoms, as well as ovulation tracking with ovulation predictor kits can help to see if you’re ovulating.
• Blood tests: To check levels of key hormones like FSH, LH, estrogen, progesterone, testosterone, thyroid hormones, and prolactin.
• Ultrasound: To look at your ovaries and uterine lining.

Once the cause is identified, treatment depends on the underlying issue. Common treatment options include:

• Lifestyle changes: Managing stress, adjusting exercise regimes, or reaching a healthy weight.
• Treating underlying conditions: Such as PCOS or thyroid disorders.
• Medications: Ovulation-stimulating drugs for example, clomiphene citrate or HCG injections can help your ovaries to release eggs. Other medications may also need adjusting if they’re affecting ovulation.
• Hormonal support: In some cases, hormonal therapy may help regulate your cycle

The good news? In many cases, ovulation can be restored with the right support, and many women will go on to conceive. 

Key takeaways

• You can’t have a true period without ovulation, but you can have bleeding that looks like one.
• Anovulatory bleeding may be irregular, have an unusual flow, and lack typical PMS symptoms.
• Ovulation is essential for both fertility and overall hormonal health.
• Common causes of anovulation include PCOS, thyroid issues, weight changes, and per menopause.
• If you’re not ovulating regularly or have unusual bleeding, it’s worth speaking to your healthcare provider.

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