The term decreased ovulation refers to situations where a woman does not release an egg (oocyte) each month resulting in the most common symptom of irregular menstrual cycles.
Ovulation and Decreased Ovulation
Yet regular menstrual cycles do not guarantee ovulation; the more regular the cycle the more likely ovulation occurs in most cycles. In comparison the more irregular the cycle the less likely ovulation occurs in many cycles.
At Southern Ontario Fertility Technologies (S.O.F.T.) we use the term decreased ovulation rather than anovulation. It is true that there are some women who hardly ever ovulate, but it is usually not an all or nothing phenomenon. Usually the more irregular your cycles are the less common ovulation occurs. The woman least likely to ovulate at all is the woman with no menstrual cycles. However, even in this situation a rare ovulation can occur and a spontaneous pregnancy may result.
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Are You at Risk of Decreased Ovulation?
There are many ways of determining if ovulation occurs but none with the exception of a pregnancy is foolproof.
One of the most common ways of determining ovulation is luteal phase progesterone. In general the more regular the cycles are the more likely it is that ovulation will occur in any given cycle. It also demonstrates that even with extremely regular cycles ovulation is not guaranteed in every cycle. Women with very irregular cycles probably do ovulate occasionally.
The shortcoming of using a luteal phase progesterone test to determine if ovulation occurred is that it is determined at Day 21 of your cycle and therefore detects only ovulations that occur at the usual time of the cycle. From monitoring so many cycles at S.O.F.T. we know that late ovulations can occur and can result in a pregnancy.
|
Cycle Length Variability (Days) |
Percent Ovulating |
|
0 -1 |
85% |
|
2 -4 |
60% |
|
5 – 10 |
40% |
|
10 – 20 |
25% |
|
> 20 |
<10% |
Chance of ovulating with different Cycle Patterns. Based on 1132 cycles analysed at S.O.F.T. from 2000 to 2002.
Determining if Ovulation Occurs
There are a number of ways of determining if ovulation occurs but none of them are 100% accurate except when we know a pregnancy occurred. A regular cycle of about 28 to 30 days predicts that ovulation has occurred 85% of the time as demonstrated in the table.
You can also detect ovulation by watching for changes in your cervical mucous, the fluid normally released from your vagina. At the start of the menstrual cycle, this mucus is sparse, tacky, and dense, but around the time of ovulation it becomes increasingly plentiful and slippery, with qualities very similar to the white of a raw egg.
Basal body temperature charts can perhaps indicate ovulation but are time consuming and subjective; meaning how you interpret them leads to different outcomes. If it is done we would recommend that the testing is done one or twice at the most.
The LH surge can be detected by urine tests or newer saliva tests. Trying to choose amongst the dozen or so ovulation prediction kits now available at the drugstore can be difficult. These kits detect a surge in luteinizing hormone, which signals ovulation will occur in the next 24 to 36 hours from the start of the surge.
Luteal phase progesterone (P4) is a blood test done for progesterone in the last half of the cycle. It is a fairly accurate way of determining if ovulation occurred in that particular cycle. It is done 6 days before the next period is expected to occur. For example if the cycle is expected to be 28 days the progesterone would be done on day 22 and if the cycle was expected to be 32 days it would be done on day 26. It is probably only important to know the progesterone level in usual cycle lengths as they are probably ovulatory. If the cycle lengths are extremely variable, ovulation is unlikely to occur in most of them and some treatment is indicated. Progesterone level of 16 or greater indicates ovulation. A progesterone level of less than 16 indicates that ovulation did not occur or did not occur at the usual time.
Ovulation is detected and timed at S.O.F.T. using a combination of blood tests (estradiol and LH) and vaginal ultrasounds. This is the backbone of our intrauterine insemination (IUI) program for which the exact prediction of when ovulation will occur can be critical. We don’t believe that such precise monitoring of the cycle is necessary however, occasionally, when the cycle is confusing we will do a monitored cycle. This is where we monitor like an IUI cycle in order to time intercourse for the couple. The format of a monitored cycle is presented below.
A monitored cycle is done to clarify the timing of ovulation or release of the egg from the ovary or if there is something unusual about the cycle. Usually blood tests are performed daily starting from day 10 or 11 until an LH surge is detected. The LH surge refers to a rapid release of luteinizing hormone from the pituitary gland before ovulation occurs. Patients also have vaginal ultrasounds to follow the development of a follicle every few days.
In a spontaneous cycle (no medications) usually one follicle develops. It starts small and precipitates ovulation, usually when its diameter becomes greater than 20 mm. Intercourse should occur the day after the surge. The results of the blood test required for this monitoring have to be available the same day. This usually requires them to be done here at our clinic in London as very few labs have the capability to perform the tests and send results in the same time period. Unfortunately if blood tests are done outside of our clinic we are not able to take responsibility for those results, but we can provide a short list (depending on your location) of labs we feel try their best to provide us with same day results.
Blood testing, ultrasounds and inseminations may need to be performed 7 days a week. For this purpose S.O.F.T. is open for monitoring from 7:00am to 11:30am weekdays and 8:00am to 10:30am on weekends. On weekends and holidays only the back door will be open.
A LH surge does not always occur in cycles being monitored. This can happen even if there is normal egg development. If an LH surge does not occur we can help you ovulate by giving you an injection of HCG or Ovidrel® which will cause you to ovulate in 36 hours. Usually if you are monitored for a spontaneous cycle and no LH surge occurs some form of ovulation induction will be recommended in the next cycle. This is usually done with clomiphene citrate or letrozole.
Vaginal ultrasound monitoring of cycles is extremely important. It is sometimes employed in spontaneous cycles but is more commonly used in cycles using some form of medication. In spontaneous cycles an ultrasound is done on day 11 to see determine the endometrial thickness and to make sure the body has recruited as follicle for ovulation. The endometrium should be at least 6mm in diameter and a recruited follicle should be at least 11 mm in diameter. It is important in cycles where a spontaneous LH surge does not occur and helps to determine when HCG should be given. In spontaneous cycles were a LH surge does not occur by day 14, a vaginal ultrasound can be performed on day 15 to determine if an appropriate sized follicle is present. If it is, HCG or Ovidrel® can be given to create an artificial LH surge.
|
Cycle Day |
Estradiol E2 |
LH |
Follicle Size (mm) |
|
Day 1 |
50 |
4 |
2 |
|
Day 3 |
100 |
3 |
5 |
|
Day 6 |
200 |
4 |
8 |
|
Day 8 |
250 |
3 |
11 |
|
Day 10 |
320 |
4 |
14 |
|
Day 11 |
400 |
3 |
15 |
|
Day 12 |
550 |
6 |
17 |
|
Day 13 |
600 |
42 |
19 |
|
Day 14 |
300 |
25 |
21 |
Timing Ovulation to Promote Pregnancy
The timing ovulation in order to know when to have intercourse or perform an insemination is controversial. There are many articles written and many proponents of this. However, our philosophy at S.O.F.T. is that it is better to have frequent intercourse over the time of potential ovulation than to try and time it. This philosophy only changes to timing ovulation when we advance to intrauterine insemination.
The reasons for frequent intercourse rather than timing intercourse and ovulation are the following:
1. Timing ovulation can be stressful
2. Intercourse on demand when ovulation is occurring is usually not fun!
3. Several studies have indicated that couples who have intercourse more often, no matter when in their cycle, get pregnant faster. In fact, the Environmental Health Sciences study found that the more sex you have, the greater your chances of getting pregnant.
4. Intercourse should be relationship building
5. Newer studies indicate intercourse is good for general health in both men and women
6. Frequent intercourse (or ejaculation) probably promotes improved sperm production
7. According to a groundbreaking 1995 study by the National Institute of Environmental Health Sciences a woman’s fertile period lasts six days: the five days leading up to and the day of ovulation. Therefore, if a couple waits until the LH surge, they could have lost 4 of the 6 days!
8. What’s more, the same study showed that the likelihood of pregnancy decreased from about 36% (if intercourse occurred two days before and/or on the day of ovulation) to 10% (if it occurred four to six days before). Since sperm may live up to five days, even older sperm can fertilize an egg; although not as likely.
Our recommendation at S.O.F.T. is not to try timing intercourse. This is reserved for when you get to the level of intrauterine insemination. Our recommendation is to have intercourse as often as possible over an 8 day period which shifts slightly depending on the length of the cycles.
For example, if the cycle is 28 days long usually, we recommend intercourse as frequently as possible from day 10 to 18. If the cycles are usually only 24 days long, intercourse should be between day 6 and 14 and if 32 days long, between day 14 to 22.
The next question of course is how often during this period of time. It’s long been thought that a man should abstain from sex for several days prior to his wife’s fertile time in order to build up his sperm count. Part of this presumption is true in that studies have shown that the more frequently a man ejaculates over a period of several days, the lower his sperm count. But, although the husband’s sperm count may get lower the more often he has intercourse it’s still plenty high enough for achieving pregnancy. It has been found that couples who had intercourse every other day during their fertile days still had a 22% chance of conceiving per cycle, compared to 25 percent for those who had sex every day. However, couples who made love weekly reduced their chances of conception to 10% per cycle, since they were more likely to miss the key baby-making window of opportunity.
Therefore, because we believe sperm survive in the female genital tract about 48 hours and because the pregnancy rate is not much different between every day and every other day, we recommend intercourse at least every other day over the fertile period of time. This at least takes a little of the pressure of but allows some spontaneity if there is a holiday away in the fertile period.
Causes of Decreased Ovulation
Irregular cycles and decreased ovulation have three general causes. The ovaries may not work, the pituitary isn’t working or the pituitary and ovaries are not talking to each other.
If the ovaries do not work it is referred to as ovarian failure (or in younger women as premature ovarian failure).
If the pituitary (or hypothalamus: the hypothalamus is the part of the brain that directs the pituitary) is not working it is referred to as hypothalamic amenorrhea.
If the ovary and pituitary are not talking to each other it is referred to as polycystic ovary syndrome or PCOS.
Polycystic ovary syndrome (PCOS) makes up 90% of patients. PCOS is not a disease but a diagnostic category meaning the women who have it may not be similar at all. Premature ovarian failure and ovarian failure make up 9%. Hypothalamic amenorrhea makes up only 1%.
The body mass index (BMI) is a common medical way to express body composition and can impact ovulation. The BMI is the weight in kilograms squared over the height in centimeters. Menstrual cycles may become irregular at a BMI of 15 (underweight) and stop at 14 or 13 but they will not become regular again until a BMI of 17 to 19
Treatment of Decreased Ovulation
Ovulation Induction
James Martin MD ©
