Tuesday October 20 2009
Women who have trouble conceiving can see their GP and may be invited for fertility tests
Newspapers have reported that women should not rely on high street fertility tests to find out how many childbearing years they have left.
Health experts have warned that home-test kits for checking the biological clock “could give women false hope”, with the Daily Mail saying that even though the tests show how many eggs a woman has left, they do not reveal anything about their quality.
Reports also say that the tests do not take into account factors that can lead to infertility, such as blocked fallopian tubes.
What are high street fertility tests?
Follicle stimulating hormone (FSH) triggers the development of immature eggs in the ovaries and levels of the hormone fluctuate during a normal menstrual cycle. Levels also rise during the menopause, when the body tries to stimulate the ovaries into producing more oestrogen to compensate for a natural fall in levels of the hormone.
Unexpectedly high or low levels of FSH in women of a fertile age may indicate fertility or hormonal problems.
Many high street fertility tests are based on measuring FSH levels in urine at a certain point in the menstrual cycle (usually the third day). This is believed to give an indication of how fertile a woman is.
The FSH level is used as a proxy measure of what is called ovarian reserve, which is how many eggs a woman has left. The news reports warn that the high street tests may give women false hope and should not be relied on as an accurate measure of fertility.
Another measure of ovarian reserve is performed using ultrasound to count the number of small undeveloped eggs (antral follicles). A count of the antral follicles is often used to get an idea of how many eggs will be retrieved during ovarian stimulation in IVF. This ultrasound test may be used when infertility is being investigated by a doctor.
What is the basis for these current reports?
The news reports are based on a presentation made this week at the conference of the American Society for Reproductive Medicine. The presentation, in Atlanta, Georgia, was by Drs Deutch and Sherbahn from the Advanced Fertility Center of Chicago, and was based on a retrospective study they carried out in women undergoing IVF, and who therefore had been identified as having fertility problems.
The researchers reviewed records from their IVF database on women aged 35 and under who were undergoing infertility treatment, to determine if they had abnormal levels of particular fertility markers.
The researchers were particularly interested in whether levels of follicle stimulating hormone (FSH) and the numbers of eggs at a certain stage of development (antral follicles) fluctuated in this group and whether abnormal results on one or both of these tests was linked to poor outcomes of IVF: lower pregnancy/live birth rates or high miscarriage rates.
Of the 1,380 women who had IVF, there were poorer outcomes (reduced pregnancy rates) for those with either abnormal FSH levels or number of antral follicles than women with normal results for both tests. Only 2.5% of the women in the sample had both abnormal antral follicle count and FSH levels, and for these women the outcomes of IVF were poor, with the lowest pregnancy rate and the highest rate of miscarriage.
The researchers concluded that tests for ovarian reserve using FSH and counts of antral follicles are “appropriate in women under 35 seeking infertility treatment”.
Have the newspapers interpreted this study correctly?
Some of the headlines may imply that this study has tested the accuracy of high street fertility tests for all women trying to conceive: this is not the case, as this study was only of young women (35 and under) undergoing IVF, who by definition already have diagnosed fertility problems.
The study found that of these women, those with normal FSH and antral follicle counts were more likely to have better outcomes from IVF, while those with one abnormal test result had poorer outcomes.
The worst outcomes (low rate of pregnancy and high miscarriage rates) were in women who had both abnormal FSH levels and low antral follicle counts. These findings are not unexpected given that FSH and the number of follicles are indicators of fertility.
The lead researcher is quoted by the Daily Mail as saying, “Even if both tests are normal, the live birth rate is 50 to 60% – it’s not 100% in this group of IVF-treated women. Both tests being normal by no means guarantees that a woman won’t have any problems conceiving.”
This is the statement that the newspapers appear to have extrapolated and applied to all women buying high street fertility tests, rather than just those with known fertility problems.
What does this study actually mean for women without diagnosed fertility problems who are trying to conceive?
It is true that, in this study, even if both tests are normal, fertility may not be optimal (in the study the live birth rate was under 100%), but this was in women with acknowledged fertility problems who were receiving IVF treatment. It is impossible to apply these findings to women who may have normal fertility and use the tests to monitor their fertility.
There are many causes of infertility. It is not surprising then that in this study, some of the women having IVF (who had therefore previously experienced fertility problems) had normal FSH levels and normal antral follicle counts but still did not have 100% successful IVF. Their fertility problems may be due to other reasons undetected by either test.
Overall, the number of women with low levels of both FSH and antral follicles who are helped by buying the high street test is likely to be low. The number whose tests indicate a need for further investigation will be less than two to three women in every hundred, based on the number of women with fertility problems in this study that had abnormal levels of both FSH and antral follicles.
It is unknown how many women using the home test without the ultrasound examination will be falsely reassured.
How can my doctor test my fertility?
Women under 35 who have had trouble conceiving for a year or more can see their GP and may be invited for further fertility tests. For women over 35, the time threshold is lowered to six months. These tests include a range of investigations to look at all the causes of infertility, including:
- hormone tests,
- semen analysis,
- ultrasound to assess the health of the ovaries, and possibly,
- investigations into the state of the fallopian tubes and the uterus.