16th January 2013 | by Dr. William Buckett
I am a 34 year old woman and wondering about the easiest and best way to test my fertility. Would the fact that I’m currently using birth control (depo provera injections every 3 months) interfere with fertility testing or affect the accuracy of the results?
Written by our medical expert, Dr. William Buckett.
Unfortunately, there is no reliable way to test anyone’s fertility except by trying to conceive. This is because there are multiple reasons why a particular couple may have difficulties in achieving a pregnancy. When couples do not conceive, it is normal to investigate all aspects of fertility and most clinics would check sperm function, ovarian function including ovulation, tubal patency (no blockages), and any problems with the uterus prior to determining any treatment.
However, as women age, fertility declines, particularly after the age of 35 (See Figure 1) (1). This age-related decline has been noted for centuries, but more recently decisions to delay childbearing until late 30s and early 40s have led to an increase in infertility. Although the rates of infertility for women aged 15-24 are about 6%, this figure jumps to 30% in women aged 35-44 (2).
Figure 1
This age-related decline in fertility is due mainly to reproductive or ovarian aging – where the pool and quality of available oocytes (eggs) diminishes. Ovarian aging begins well before women show any pre-menopausal symptoms. There is also a huge variability in the rate of ovarian aging.
Ovarian reserve testing has been developed as a possible means to determine female fertility potential (3). The most frequently used tests are blood tests – primarily cycle day 3 or basal serum FSH and serum AMH. As well, a transvaginal ultrasound might be recommended to measure ovarian volume and antral follicle count (4). Serum FSH rises as fertility falls and serum AMH, ovarian volume, and ovarian antral follicle counts fall as fertility falls. Less common tests include serum estradiol, serum inhibin B, and the clomiphene citrate challenge test.
When considering fertility testing, it is important to know that these tests have been mainly performed in women with infertility, and often in those about to undergo IVF or other fertility treatments. Although ovarian reserve testing in women with infertility can predict the probability of pregnancy with treatment (5), it cannot be used to reliably predict infertility or time to infertility in a general population (4, 5). So far, however, only one published study has shown an effect of ovarian reserve testing in the general population. In this study 100 women (who were aged 30-42 years and were trying to conceive) underwent various ovarian reserve tests. The only difference the study showed was a lower spontaneous (non-treatment) pregnancy rate in the 18 women who had a low AMH test result (6). The absolute effect of this and any relation to age are not clear.
Another problem with ovarian reserve testing in the general population is that a ‘normal’ result does not mean that you will be able to conceive normally and an ‘abnormal’ result does not mean that you will have infertility or not be able to conceive normally. Therefore, before any firm conclusions can be drawn regarding ovarian reserve testing in the general population of presumed fertile women, further studies are still needed.
This situation is even more complicated when a woman is on Depo-provera (DMPA – Medroxyprogesterone acetate. Depo-provera is an effective contraceptive. Its main mechanism of action is inhibiting normal ovarian function and therefore ovulation, as well as having some effects on cervical mucus and endometrial structure. It is known that DMPA decreases serum estradiol levels and also has an effect on serum FSH levels (7). Therefore tests to measure serum FSH levels as a predictor of ovarian reserve would not be accurate.
In theory, DMPA would also affect ovarian antral follicle count as ovarian function is disrupted, but serum AMH should be unaffected. This suggests that it may be possible to test for serum AMH while on DMPA. However no studies have looked at either serum FSH or serum AMH testing specifically in women taking DMPA. So it is not possible to ascertain the reliability of these tests results for women on Depo-provera.
The only really good test of current fertility would be to try and get pregnant! However, if you did want to pursue ovarian reserve testing, being on Depo-provera would affect some of the test results. Therefore it would be better to stop taking DMPA at least 4 months before any fertility testing and after you have a return to normal menstruation.
References
1. Menken J, Trussell J, Larsen U. Age and infertility. Science 1986; 233: 1389-1394.
2. Abma JC, Chandra A, Mosher WD, et al. Fertility, family planning, and women’s health: new data from the 1995 National Survey of Family Growth. Vital Health Stat 1997; 23: 1-114.
3. Broekmans FJ, Kwee J, Hendriks DJ, et al. A systematic review of tests predicting ovarian reserve and IVF outcome. Hum Reprod Update 2006; 12: 685-718.
4. SOGC Clinical Practice Guideline No.269, November 2011. Advanced reproductive age and fertility. J Obstet Gynaecol Can 2011; 33: 1165-1175.
5. Steiner AZ. Clinical implications of ovarian reserve testing. Obstet Gynecol Surv 2009; 64: 120-128.
6. Steiner AZ, Herring AH, Kesner JS, et al. Antimullerian hormone as a predictor of natural fecundability in women aged 30-42 years. Obstet Gynecol 2011; 117: 798-804.
7. Mishell DR. Pharmacokinetics of depot medroxyprogesterone acetate contraception. J Reprod Med 1996; 41: 381-390.
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