Anovulation explained: Why am I not ovulating but having periods?

What is anovulation?

Anovulation, or an anovulatory cycle, is when the ovaries do not release a mature egg cell during a menstrual cycle [1]. Estrogen and follicle stimulating hormone (FSH) work together to develop an egg follicle so it can be released during ovulation [2]. When an egg is not released, the cycle is referred to as anovulatory. 

Anovulation can happen sporadically, which means irregularly or every once in a while, or it can occur chronically, which doctors define as happening during the majority of cycles over the previous 6 months [1]. Researchers investigating sporadic anovulation have found that it doesn’t directly impact your ability to become pregnant for those couples who are having regular sex during the fertile window [3]. Natural Cycles can also help you find fertile days, so you can time sex in the fertile window to increase your chances of conception. Using Natural Cycles doesn’t replace a conversation with your healthcare provider but it can be a useful tool to use alongside. A doctor can diagnose chronic anovulation, a common cause of infertility, and also make treatment recommendations based on individual underlying causes [1].

Is anovulation common?

Having an anovulatory cycle (a menstrual cycle when your ovaries don’t release an egg) is fairly common. While estimates vary, research suggests that between 1 and 15% of cycles can be anovulatory in women with otherwise regular menstrual cycles [3]. Unless you are tracking ovulation, you might be completely unaware that you experienced an anovulatory cycle. Chronic anovulation, on the other hand, is one of the most common forms of female infertility. Researchers estimate that around a quarter of reported infertility is due to chronic anovulation [4]. 

In both cases, the most common observable symptom of anovulation is having an irregular period. Occasional or chronic irregular periods don’t always mean that you aren’t ovulating, either. Research at Natural Cycles has revealed that only an estimated 13% of cycles are 28-days long and that normal cycles can vary in length between 21 and 35 days [5]. However, if you are experiencing cycles that are consistently different lengths month-to-month, have infrequent period bleeding, or irregular, excessive bleeding, it might mean that you aren’t ovulating [1].

What causes anovulation?

Ovulation requires coordination between your brain and your ovaries [6]. The hypothalamus is the region of the brain that produces hormones that the body uses to maintain homeostasis, or internal stability, like body temperature, hunger and thirst, sleep, and stress [7]. The hypothalamus sits right above and is connected to the pituitary gland, which releases two important reproductive hormones: FSH and luteinizing hormone (LH) [8]. Finally, the ovaries house all your egg follicles and produce important hormones like estrogen, testosterone, and progesterone [9]. There are a number of causes of anovulation relating to the brain and the ovaries, so let’s go over some of the more common ones:

• Polyendocrine metabolic ovarian syndrome (PMOS), previously referred to as polycystic ovary syndrome (PCOS), is one of the most common underlying conditions associated with anovulation. PMOS is a hormonal condition that affects your reproductive, metabolic, and psychological health. It is estimated that around 1 in 8 women have PMOS, and the condition accounts for around 70% of cases of chronic anovulation [4,10]. Those with PMOS most often cannot mature and/or release egg follicles, meaning that ovulation does not take place [6].
• Primary ovarian insufficiency, or POI, is when there is a decline or dysfunction in the egg follicles in the ovaries of women under the age of 40. It’s most commonly caused by an underlying chromosomal abnormality or as a side effect from having chemotherapy and/or radiation therapy [11].
• Clinical eating disorders like anorexia and bulimia disrupt the production of important hormones in the brain that affect ovulation and menstruation [12]
• Obesity (having a body mass index or BMI over 30) is linked to a number of health-related issues, including anovulatory-related infertility. While researchers are still trying to figure out exactly why, women living with obesity exhibit higher rates of irregular menstruation and lack of menstruation than those with BMI ranges that are considered medically normal. Researchers suspect that body weight has a direct impact on the body’s hormone-producing and regulating functions, which in turn affects ovulation. [13]
• Some medications have been found to affect ovulation by increasing levels of the hormone prolactin. These include some antidepressants like selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), as well as acid reflux / anti-nausea medications like metoclopramide and cimetidine, and the high blood pressure medication verapamil [14].
• Stress can affect the cycle and is one of the broadest hypothalamic causes of anovulation [15]. Physical, emotional, and nutritional changes can all affect the body’s ability to keep its internal conditions steady and stable. Depending on the severity and duration, stress can lead to both sporadic and chronic anovulation.
• Hypothyroidism, sometimes referred to as an underactive thyroid, happens when the thyroid gland does not make enough thyroid hormone to support the body. In women, hypothyroidism can affect fertility by disrupting the development of egg cells in the ovaries [16]
• Perimenopause is your body’s natural transition to menopause, which is when ovulation and menstruation permanently stop. During this transition, it’s common to experience changes to your periods as well as longer or shorter cycles [17, 23]. Research at Natural Cycles has confirmed while anovulatory cycles are possible, ovulation does continue during perimenopause. 

Symptoms of anovulation

The main symptom of anovulation is irregular periods, which means cycles that vary in length, in duration of period bleeding, and in the amount of bleeding you experience. If these changes are mild, if you aren’t tracking ovulation using Natural Cycles or a method such as ovulation strips, it can be difficult to assess on your own if and when a cycle is anovulatory. Many of us may only discover we are experiencing anovulatory cycles when it comes to trying to conceive.

The thing that makes spotting anovulatory cycles tricky is even if you did not ovulate, you can still get your period. Medically, doctors refer to this kind of bleeding as abnormal uterine bleeding, or AUB. Not ovulating can cause periods lighter, irregular, or heavier, especially if you have not ovulated for several menstrual cycles. [18, 23]

Anovulation can be sporadic and only last for a cycle or two, or it can be chronic, where cycles may continue to be irregular for a long time. If you notice any changes to your period, it's recommended to take note of when bleeding occurs and the amount of bleeding you experience. It’s also helpful to remember that some women can experience early pregnancy bleeding or light spotting during ovulation. Irregular periods are also a common symptom of perimenopause, the natural phase of life that leads up to menopause [17]. If you are experiencing irregular periods and/or suspect that you aren’t ovulating regularly, it’s important to consult a doctor to help determine the underlying cause.

Treatment options for anovulation

Anovulation can be treated in different ways depending on the underlying cause. Treatments can include both medical and lifestyle interventions. Treatments can also vary depending on whether you are looking to regulate your menstrual cycle or if you are trying to conceive. If you are experiencing chronic irregular periods, have any concerns about your overall reproductive health, or are having difficulty conceiving, it’s important to consult a medical professional. Alongside a physical examination, medical history, and lab tests (like bloodwork and ultrasounds), your medical care team can help assess any underlying issues and make recommendations for treatment. [6]

Sometimes medications that stimulate certain hormones (like clomiphene citrate), or contain hormones themselves, can help encourage the egg cells in the ovaries to mature and release during ovulation [4]. If you are not trying to become pregnant, hormonal birth control might be recommended [4]. Hormonal birth control can also be used to manage the symptoms of certain cycle conditions, such as PMOS or endometriosis [10,19]. 

In cases when anovulation is linked to a high BMI or obesity, lifestyle modifications and weight loss may also be recommended. If you are suffering from an eating disorder, specialist care, professional therapy, and lifestyle interventions can also help to restore regular ovulation. Finally, trying to manage overall stress is widely recommended both for your overall health, but also to encourage regular menstrual cycles. [12,13,15]

When to see your doctor

If you are having irregular periods, including periods that are especially painful, long, or any bleeding that is unusual for you, it’s important to see a doctor. Similarly, if you experience pain during sex, bleeding between periods, or have other symptoms like weight gain or fatigue, speak with a healthcare professional. [20]

If you are having difficulty conceiving, the general recommendation is to see a doctor after 1 year of having regular sex without any form of birth control (6 months if you’re older than 35, or right away if you’re over 40). However, if you know you have a condition that might affect your fertility, consulting with a medical professional when you first start trying to conceive is recommended. [21]

Understanding your body better with Natural Cycles

As the first FDA-cleared birth control app, our mission at Natural Cycles is to empower every woman with the knowledge she needs to take charge of her health. Whether you’re trying to better understand your own menstrual cycle, track your fertile window, plan a pregnancy, or begin your journey through perimenopause, the Natural Cycles app gives you the tools to better understand what is going on in your body. The app’s shareable Cycle Report can help you speak to your doctor about your menstrual cycle, ovulation, or fertility. Why not see if Natural Cycles is right for you today?