July 2015

Apart from being healthy, what might help you get pregnant? Knowing the right time to have intercourse.

The fertile window
The fertile window is the days in a woman’s menstrual cycle where pregnancy is possible. Technically, pregnancy is only possible during the five days before the woman ovulates to the day of ovulation itself. This is because the lifespan of sperm is only five days maximum, while the lifespan of the ovum is 24 hours.

The best chance of conceiving is from having intercourse in the two to three days preceding ovulation and including the day of ovulation. Once ovulation has occurred the probability of pregnancy declines rapidly, and within 12 to 24 hours the woman will no longer be able to get pregnant during that cycle

If a woman has sex on any of these three days, she has a 15-25% chance of becoming pregnant.

What is ovulation?
Ovulation is when a mature egg is released from the ovary, moves down the fallopian tube, and is available in the fallopian tube to be fertilised.

Tracking your ovulation

  • Work out the length of your average menstrual cycle. Day one is the first day of the menstrual period and the last day is the day before the next period begins.
  • Ovulation happens about two weeks before the next expected period. So if your average menstrual cycle is 28 days, you should ovulate around day 14.

Remember the ‘fertile window’ is the six days leading up to and including ovulation. The three days leading up to and including ovulation are the most fertile. Depending on your cycle length the most fertile days in the cycle varies:

  • If you have 28 days between periods ovulation typically happens on day 14, and the most fertile days are days 12, 13, and 14.
  • If you have longer cycles, say 35 days between periods, ovulation happens on day 21 and the most fertile days are days 19, 20, and 21.
  • If you have shorter cycles, say 21 days between periods, ovulation happens on day 7 and the most fertile days are days 5, 6, and 7.

How do you know you’re ovulating?
Women’s cycles can vary, so to know that you are ovulating and on which day of your cycle you are ovulating, observe your fertility signs throughout your cycle and record them on a chart.
The most accurate methods of working out when ovulation is about to occur are:

  • Keep an eye out for changes in your mucus. Around the time of ovulation, you may notice your vagina’s mucus is clear, slick and slippery, the consistency of egg white. This is the best sign of when ovulation is actually happening.
  • Use an ovulation predictor kit. You can start testing with your ovulation predictor kit a few days before your estimated day of ovulation. Subtract 17 days from your average cycle length and start testing from this day of your cycle, e.g. if you have a 28 day cycle, you would start testing from day 11. A positive result means you are going to ovulate within the next 24 to 36 hours.
  • Record your basal body temperature (BBT) each day before getting out of bed. A special basal body temperature thermometer will ensure accurate measurement. Your BBT rises about half a degree Celsius after ovulation has occurred. By charting your temperature, it’s easy to see when the rise in temperature and ovulation happens. This can help you work out your own pattern of ovulation. However, because at that stage ovulation has already passed, it does not help you pinpoint the fertile window but may guide you for next month.

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:

  • Obesity
  • Too low body weight
  • Extreme exercise
  • Hyperprolactinemia
  • Premature ovarian failure
  • Perimenopause, or low ovarian reserves
  • Thyroid dysfunction (either hyperthyroidism or hypothyroidism)
  • Extremely high levels of stress

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. The most common treatment for anovulation are 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. 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 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.

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.

Important Facts

  • 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.
  • 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.



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