Anovulation is the failure of the ovary to release an egg (oocyte) over a period of time generally exceeding 3 months. Normal ovulation occurs monthly from alternating ovaries. The normal functioning ovary releases one ovum every 25–28 days. The oocyte develops in a small fluid collection in the ovary called a “follicle” and ovulation occurs when this follicle ruptures. Usually one oocyte is released every month. A small gland in the base of the brain called the “pituitary gland” regulates ovulation. This average time between ovulation events is variable, especially during puberty and the peri-menopause period. For non-pregnant women aged 16–40 anovulation is considered abnormal and a cause of infertility in approximately 30% of fertility patients.
Usually, women with anovulation will have irregular periods. Or, in the worst case, they may not get their cycles at all. If your cycles are shorter than 21 days, or longer than 36 days, you may have ovulatory dysfunction. Also, if your cycles fall within the normal range of 21 to 36 days, but the length of your cycles varies widely from month to month, that may also be a sign of ovulatory dysfunction. (For example, one month your period is 22 days, the next it’s 35). It is possible to get your cycles on an almost normal schedule and not ovulate, though this isn’t common.
How Does Anovulation and Ovulatory Dysfunction Cause Infertility?
For a couple without infertility, the chances of conception are about 25% each month in women under 35 years of age. So even when ovulation happens, conception is not guaranteed.
When a woman is anovulatory, she can’t get pregnant because there is no egg to be fertilised. If a woman has irregular ovulation, she has fewer chances to conceive, since she ovulates less frequently. Plus, it seems that late ovulation doesn’t produce the best quality eggs, which may also make fertilisation less likely.
It’s also important to remember that irregular ovulation means the hormones in the woman’s body aren’t quite right. These hormonal irregularities can sometimes lead to other issues, like lack of fertile cervical mucus, thinner or over thickening of the endometrium (where the fertilised egg needs to implant), abnormally low levels of progesterone, and a shorter luteal phase.
What Causes Anovulation?
Anovulation and ovulatory dysfunction can be caused by a number of factors. The most common cause of ovulatory dysfunction is polycystic ovarian syndrome, PCOS. Other potential causes of irregular or absent ovulation include:
- Too low body weight
- Extreme exercise
- Premature ovarian failure
- Perimenopause, or low ovarian reserves
- Thyroid dysfunction (either hyperthyroidism or hypothyroidism)
- Extremely high levels of stress
How is Anovulation Diagnosed?
You may be slightly confused by the outcome of your self-assessment of ovulation. Do not despair even your doctor may be uncertain when you present the results of especially the basal body temperature chart. Special investigations will shed more light in doubtful cases.
- Serum progesterone assessment: The pathologist takes blood on request from your doctor approximately 7 days after ovulation for progesterone assessment. There are different views on what the minimum normal ovulatory levels are. Usually a level of more than 30 nmol/l is regarded as an optimal result.
- Ultrasound evaluation: Examination of your ovaries before and after ovulation to detect the presence of a follicle and its subsequent disappearance is the best way of assessing ovulation since ovulation day can be accurately predicted once the size of the follicle is known. However, you will only find adequate ultrasound equipment for this purpose at Infertility Clinics and some Gynaecologists’ consulting rooms.
- Endometrial biopsy : This relatively painful procedure is only rarely performed by your doctor to identify subtle hormonal disorders associated with ovulation abnormalities. A small sample of the uterine lining is obtained by means of a thin plastic needle and is assessed by a Pathologist.
What are the Potential Treatments for Anovulation?
Treatment will depend on the cause of the anovulation. Some cases of anovulation can be treated by lifestyle change or diet. If low body weight or extreme exercise is the cause of anovulation, gaining weight or lessening your exercise routine may be enough to restart ovulation. The same goes for obesity. If you are overweight, losing even 10% of your current weight may be enough to restart ovulation.
The most common treatment for anovulation is fertility drugs. Usually, Clomid (clomiphene citrate) is the first fertility drug tried. Clomid can trigger ovulation in 80% of anovulatory women, and help about 45% get pregnant within six months of treatment. If Clomid doesn’t work, there are other drugs that may be used such as Femara (Letrazole).
For women with PCOS, insulin sensitising drugs such as Glucophage (metformin) that may help a woman start ovulating again. Usually, six months of treatment is required before you’ll know if the particular drug you have been prescribed will work. If this alone doesn’t help, using fertility drugs in combination has been shown to increase the chance of success in women who didn’t ovulate on fertility drugs alone.
If the cause of anovulation is premature ovarian failure, or low ovarian reserves, then fertility drugs are less likely to work. In that case, your doctor may suggest using an egg donor, or an alternative family building option like adoption.
- Ovulation does not equal pregnancy. If everything is normal and you have intercourse at exactly the right time the chance of pregnancy is roughly 25%!!!
- The best way for you to determine the optimal time for conception is by evaluating your cervical mucus by means of the Billings method. Your finger is placed through the vagina until the cervix is touched (feels like the tip of your nose). The mucus is then examined by rolling your forefinger and thumb together and stretching the mucus as far as possible. When the mucus is clear, stretchable and slippery ovulation is close.
- Sperm will survive for approximately 12 hours and the oocyte 48 hours. It is therefore advisable to have intercourse every 2nd day during the fertile period.
- Do not think that by abstaining in order to “get the sperm build up” will improve your chances. Indeed, abstinence for more than 2 – 3 days may be disastrous for sperm quality in certain circumstances.