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Anovulatory Cycle

What Is It, Causes, Treatment, and More

Author: Ashley Mauldin, MSN, APRN, FNP-BC

Editors: Alyssa Haag, Kelsey LaFayette, BAN, RN 

Illustrator: Abbey Richard

Copyeditor: Joy Mapes

What is an anovulatory cycle?

An anovulatory cycle, also referred to as anovulation, refers to a menstrual cycle in which the release of an egg from the ovaries does not occur.  Chronic anovulation, or anovulation that persists for a year or longer, can be a common cause of infertility. 

In general, the menstrual cycle is a hormonal process to prepare the body for a potential pregnancy. The menstrual cycle is marked by monthly bleeding, commonly referred to as one’s “period,” and also typically involves ovulation, or the release of an ovum (i.e., egg), midway through each cycle. Although individuals with an anovulatory cycle do not experience ovulation, they may still experience bleeding due to changes in hormone levels. This bleeding is usually referred to as withdrawal bleeding. 

What causes an anovulatory cycle?

Many different factors can lead to an anovulatory cycle; however, anovulation is most commonly related to hormone imbalances. Ovulation, or the release of an egg, is a complex process that involves many different hormones, including progesterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH). To trigger ovulation, hormone levels must reach a certain threshold for the release of an egg to occur. Any disruptions in this process can lead to anovulatory cycles. 

Disruption of ovulation hormones can occur when using certain hormonal birth control, like the pill, patch, injection, ring, or some intrauterine devices (IUD), as these birth control methods are designed to prevent ovulation. Being underweight or overweight, exercising excessively, or not consuming enough calories can also induce hormone imbalances that may cause an individual to experience anovulatory cycles. In addition, significant stress can affect hormone levels in the body and subsequently disrupt ovulation. Finally, polycystic ovary syndrome, or PCOS, is a common condition that causes anovulation by triggering the body to overproduce hormones, like testosterone and LH. The high levels of these hormones may result in anovulation. 

How common is an anovulatory cycle?

Intermittent and chronic anovulation are common in the reproductive years, which is usually between the ages of 12 and 51. However, it most frequently occurs during the time around the first menstrual cycle (i.e., menarche) and around the time of one’s last menstruation (i.e, menopause). 

What are the signs of an anovulatory cycle?

Irregular periods or lack of a period can be signs of anovulation. Menstrual bleeding that is lighter or heavier than usual may also suggest an anovulatory cycle. For those trying to conceive, infertility, or the inability to get pregnant, can also be a sign of an anovulatory cycle. Regardless, some anovulatory cycles occur without any noticeable signs. 

How long does an anovulatory cycle last?

The length an anovulatory cycle lasts varies for each individual, largely depending on the cause of anovulation. Anovulatory cycles can last the same length as regular cycles -- generally between 28 and  36 days -- or they can be shorter or longer in duration. 

When is ovulation expected after an anovulatory cycle?

After an anovulatory cycle, the return of ovulation varies for each individual. Some individuals ovulate during the next menstrual cycle, while others may not ovulate for months to years.  

How is an anovulatory cycle diagnosed?

The first step in diagnosing anovulation is to determine if ovulation is occuring. This can be accomplished through a medical history, physical exam, and review of the individual’s menstrual schedule. Reviewing accompanying symptoms, such as breast tenderness, cervical mucus discharge, and body temperature while resting, can also be helpful in diagnosing an anovulatory cycle. 

Blood tests may also be conducted based on the medical advice of the healthcare provider. Blood tests can measure levels of progesterone, prolactin, thyroid hormone, testosterone, and other hormones. Sometimes, ultrasound imaging may be recommended. Ultrasounds can be medically reviewed to look for any concerns in the pelvic organs or lining of the uterus. A referral to a gynecologist may also be recommended. 

How is an anovulatory cycle treated?

The treatment for an anovulatory cycle is largely dependent on the cause, but it often begins with lifestyle changes. If the cause of anovulation is due to the individual’s weight, then returning to and maintaining a healthy body weight can help trigger ovulation. In addition, stress management, good nutrition, and moderate physical activity may encourage the body to correct hormone imbalances. 

Medications that increase hormone levels, like clomiphene citrate (i.e., Clomid), may be prescribed to help trigger the release of an egg. 

For those who are experiencing infertility related to anovulation, in vitro fertilization (IVF) may be an alternative path to pregnancy. IVF is a procedure in which eggs are manually extracted from the ovaries, fertilized with sperm, and implanted in the uterus. IVF is reserved for those who have been experiencing anovulation for over a year. 

What are the most important facts to know about an anovulatory cycle?

An anovulatory cycle is a menstrual cycle in which ovulation, or the release of an egg from the ovaries, does not occur. Anovulation is often due to hormonal imbalances that can be the result of using hormonal birth control, being underweight or overweight, exercising excessively, or experiencing significant stress. PCOS is another common cause of anovulation. Anovulation commonly occurs during an individual’s reproductive years. Signs of an anovulatory cycle vary for each individual and can include irregular periods, lack of a period, unusually heavy or light menstrual bleeding, infertility, or no noticeable signs. The length of an anovulatory cycle and the time it takes for ovulation to return is different for each individual and largely depends on the cause. Diagnosis is made through a review of health history, physical examination, and, at times, blood tests. An ultrasound of the pelvic organs and uterine lining may also be administered to look for any other concerns. Treatment of anovulation depends on the underlying cause, but it frequently features lifestyle changes and medications that induce ovulation. 

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