Why am I not ovulating but having periods

Having a regular menstrual bleed but not ovulating can feel confusing and concerning, especially when you are trying to conceive or simply wish to understand your body’s rhythms. Ovulation is the release of an egg from the ovary, and without it the menstrual cycle relies on a different hormonal process to shed the uterine lining. This type of bleeding—often called anovulatory bleeding—can occur for a variety of reasons, from lifestyle factors to underlying health conditions. Understanding why you may be menstruating without ovulation empowers you to make informed choices about your health and, if needed, seek appropriate medical support.

The difference between ovulatory and anovulatory cycles
In a typical ovulatory cycle, rising levels of follicle‑stimulating hormone cause ovarian follicles to develop, one of which matures and releases an egg under the surge of luteinising hormone. After ovulation the corpus luteum produces progesterone, stabilising the uterine lining until, if fertilisation does not occur, progesterone falls and the lining sheds as a period. In anovulatory cycles no egg is released, progesterone production is minimal, and unopposed oestrogen stimulation causes the lining to grow irregularly. The eventual drop in oestrogen triggers bleeding, but this bleed may be heavier, more irregular or longer than a true menstrual period.

Hormonal imbalances and polycystic ovary syndrome
One of the most common causes of anovulation despite regular bleeding is polycystic ovary syndrome. In PCOS hormonal signals are disrupted, with elevated androgens inhibiting follicle maturation and ovulation. Insulin resistance, often associated with PCOS, further aggravates hormone imbalance by encouraging excess androgen production in the ovaries. Women with PCOS may notice irregular cycle lengths, heavier or lighter bleeding, acne or unwanted hair growth. Blood tests measuring luteinising hormone, follicle‑stimulating hormone, testosterone and insulin, along with ultrasound imaging of the ovaries, help confirm the diagnosis.

Thyroid disorders
The thyroid gland regulates metabolism but also influences reproductive hormones. Both underactive and overactive thyroid conditions can disrupt the delicate balance of oestrogen, progesterone and gonadotropin‑releasing hormone. In hypothyroidism oestrogen clearance slows and prolactin levels may rise, preventing normal ovulation. In hyperthyroidism cortisol levels shift and can disturb the menstrual cycle. Even if you bleed monthly, your cycle may not include an ovulatory phase. A simple blood test measuring thyroid‑stimulating hormone and free thyroid hormones determines whether your thyroid is contributing to anovulation.

Excessive exercise and low body weight
When you engage in high‑intensity training or maintain very low body fat, your body may interpret conditions as stressful or unfavourable for pregnancy. Energy availability drops below what is needed for basic functions, prompting the brain to conserve resources by suppressing reproductive hormone production. This effect, seen in athletes and those with eating disorders, leads to irregular bleeding or spotting despite absent ovulation. Restoring a healthier balance of nutrition and moderating exercise intensity often allows ovulation to resume.

Stress and the hypothalamic‑pituitary‑ovarian axis
Chronic stress elevates cortisol, the body’s stress hormone, which can interfere with signals from the hypothalamus that initiate the menstrual cycle. When gonadotropin‑releasing hormone pulses become erratic, downstream signals to the pituitary and ovaries falter, preventing reliable follicle development and ovulation. You may still experience bleed‑like episodes when oestrogen levels fluctuate, but without the predictable ovulatory midcycle peak. Incorporating stress‑reduction techniques such as mindfulness, therapy or gentle exercise helps restore hormonal harmony.

Perimenopause and age‑related changes
As you approach menopause, ovarian reserve declines and cycles often become anovulatory before full cessation of periods. You may notice variations in flow, cycle length and ovulation symptoms such as midcycle cramping. These anovulatory cycles are a normal part of the transition, reflecting diminishing egg supply and changing hormone patterns. Tracking your cycle and discussing any concerns with your GP can help you monitor perimenopausal changes and manage symptoms effectively.

Medications and contraceptives
Certain medications, including antidepressants, antipsychotics and chemotherapy agents, can interfere with ovulation by affecting hormone levels or ovarian function. Hormonal contraceptives such as the pill, patch or coil deliberately prevent ovulation; breakthrough bleeding during use is not true menstruation but a withdrawal bleed. If you stop hormonal contraception and experience regular bleeds without ovulation symptoms within a few cycles, further evaluation may be needed to ensure your reproductive axis resets properly.

Hyperprolactinaemia and pituitary disorders
Elevated prolactin, the hormone that stimulates breast milk production, suppresses gonadotropin‑releasing hormone and can block ovulation. Prolactin levels rise with stress, certain medications and pituitary adenomas. Women with hyperprolactinaemia may have irregular cycle lengths, galactorrhoea or headaches. A blood test for prolactin and imaging of the pituitary gland help identify the cause. Treatment with dopamine agonists usually restores normal prolactin levels and ovulation.

Uterine and structural factors
Rarely, structural issues such as uterine fibroids or endometrial polyps can cause abnormal bleeding that mimics a period without ovulation. These growths may bleed unpredictably and lead to heavy, prolonged periods. Transvaginal ultrasound or hysteroscopy helps visualise and treat structural abnormalities, ensuring you receive appropriate care for bleeding that is not linked to your cycle’s ovulatory phase.

When to seek medical evaluation
If you experience bleeding but have no signs of ovulation—no midcycle breast tenderness, cervical mucus changes or ovulation test positives—for three consecutive cycles or longer, consult your GP or a reproductive specialist. A comprehensive evaluation includes hormone blood tests such as FSH, LH, oestrogen, progesterone and thyroid hormones, along with pelvic ultrasound. Early diagnosis of conditions like PCOS, thyroid dysfunction or prolactin disorders allows timely treatment and preserves fertility options.

Self‑care and lifestyle adjustments
Supporting your body’s natural cycle involves maintaining a balanced diet rich in whole foods, regular moderate exercise, good sleep hygiene and stress management. Tracking your cycle with an app or diary helps you identify patterns and ovulation signs. Ensuring a healthy weight and addressing any nutritional deficiencies supports hormone production and ovulation. When recommended, supplements such as inositol or vitamin D under professional guidance may also aid in restoring ovulation.

Summary
Bleeding without ovulation can arise from hormonal imbalances in PCOS, thyroid disorders, stress, excessive exercise, perimenopause, medications, elevated prolactin or structural uterine issues. While occasional anovulatory cycles may be normal, persistent monthly bleeds without ovulation signs warrant evaluation. By tracking your cycle, optimising lifestyle factors and seeking timely medical advice, you can identify the underlying cause, restore regular ovulatory cycles and safeguard your reproductive health.