Each month, the ovaries typically release one mature ovum (egg). However, this process can be interrupted, leading to menstrual bleeding appearing as usual, but without an egg being released from the ovary.
Dr. Nguyen Hoang Tung, a specialist in obstetrics and gynecology at Tam Anh Cau Giay General Clinic, states that numerous factors can lead to an anovulatory cycle. Common causes include hormonal imbalances resulting from abnormal activity of the hypothalamic-pituitary-ovarian axis. Polycystic ovary syndrome, thyroid disorders, premature ovarian failure, medication side effects, prolonged stress, significant weight changes, and excessive exercise are also risk factors.
This condition is quite prevalent but often overlooked due to its subtle symptoms. Many women only discover it when they encounter difficulties becoming pregnant. Dr. Tung highlights several identifying signs below.
Irregular menstrual cycles
A healthy menstrual cycle typically lasts 21-35 days and recurs with relative regularity. After ovulation, the remaining part of the follicle forms the corpus luteum, which secretes progesterone. This hormone helps stabilize and regulate the shedding of the uterine lining.
When ovulation does not occur, the body lacks progesterone, causing the cycle to become erratic. If cycles are consistently shorter than 21 days, longer than 35 days, or even absent (amenorrhea), there is a high risk that the ovaries are not releasing an egg. This indicates an interrupted endocrine axis, preventing follicles from developing or ovulating.
Abnormal menstrual blood flow
Some women experience regular periods but are not actually ovulating. In such cases, the uterine lining, under prolonged influence of estrogen, thickens over time. At a certain threshold, this lining is no longer adequately nourished and sheds, causing bleeding similar to menstruation.
Due to the lack of progesterone to stabilize the uterine lining, the shedding process occurs asynchronously, leading to abnormal blood flow. Some women experience light bleeding for one to two days, while others may have heavy or prolonged bleeding lasting over one week.
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Doctors at the Center for Obstetrics and Gynecology examining a patient. Photo: Tam Anh Ha Noi General Hospital |
Absence of characteristic cervical mucus
In a normal cycle, as ovulation approaches, elevated estrogen levels stimulate the cervix to produce abundant cervical mucus. This discharge is typically clear, stretchy, slippery, and can be pulled into threads like egg white, facilitating sperm movement. Conversely, if the vaginal area is consistently dry or if the mucus is scant, thick, and does not change throughout the cycle, this may indicate that ovulation is not occurring.
No change in body temperature
After ovulation, progesterone causes a slight increase in basal body temperature, typically around 0,3-0,5 degrees Celsius. This change creates two distinct phases on a basal body temperature chart. In an anovulatory cycle, this temperature increase does not occur, resulting in a temperature chart with almost no clear separation between the first and second halves of the cycle.
Absence of premenstrual symptoms
In an ovulatory cycle, many women may experience symptoms such as mild mid-cycle pain, breast tenderness, bloating, back pain, or mood changes before their period. Conversely, in an anovulatory cycle, the body does not undergo significant hormonal fluctuations, so these symptoms are often absent or very subtle.
Endocrine disorders such as acne, excessive hair growth, weight gain, difficulty managing weight, or hair loss can also suggest an anovulatory state.
Over the long term, the most evident sign is difficulty conceiving. Dr. Tung advises that if a couple has regular, unprotected intercourse for 6-12 months without conception, especially when accompanied by menstrual irregularities, the woman should seek gynecological examination to assess ovarian function.
For diagnosis, doctors often combine several methods, including ultrasound to monitor follicular development, hormone tests (follicle-stimulating hormone, luteinizing hormone, progesterone, prolactin), or the use of ovulation predictor kits to detect the luteinizing hormone surge. Early detection helps identify the cause and select appropriate treatment methods.
Trinh Mai
