If you’re on birth control and considering taking a fertility test, you might wonder whether the contraceptives will affect the accuracy of the results. The short answer is yes, they often will, but that doesn’t mean you have to stop using birth control before taking a diagnostic test. 

However, the results might be influenced by the contraceptive, so it’s important to know how and why before you can determine your true fertility levels. It’s also vital that you consult with an expert before and after taking the test. Let's dive deeper into how different types of fertility tests are impacted by birth control.

Here is a quick guide to the contraceptives and abbreviations we will refer to in this blog:

• IUD: intrauterine device

• POP: progestogen-only pill

• COCP: combined oral contraceptive pill

1. AMH (Anti-Müllerian Hormone) test

What it measures: The AMH test measures the levels of anti-Müllerian hormone, which is an indicator of ovarian reserve. This test provides an indication of the number of viable eggs remaining and can be a useful measure of fertility even while on birth control.

Impact of birth control: This study gives a detailed run down of the effects of various types of contraceptives on AMH levels based on data from 27,125 participants.

AMH levels were 7% lower in women on hormonal IUD 15% lower in those on POP, 22% lower in vaginal ring users, 23% lower in those on implant and 24% lower in those on the COC. The AMH in women using a copper intrauterine device did not differ significantly from AMH in women who were not on contraceptives 

2. Ovulation tests

What they measure: Ovulation tests detect the surge in luteinizing hormone (LH) that precedes ovulation.

Impact of birth control: Birth control such as COCP and depot contraception, and some POPs work by switching off ovulation, so there won’t be an LH surge, and also FSH and LH levels are very low.  As a result, you might not experience the LH surge that these tests are designed to detect. Therefore, taking an ovulation test while on these particular birth controls is unlikely to provide useful information about your ovulatory status. However other methods such as Mirena coil don’t work by switching off these hormones.

3. Hormone level tests

What they measure: Blood tests for hormones such as follicle-stimulating hormone (FSH), LH, estradiol, and progesterone.

Impact of birth control: Hormonal contraceptives can alter the natural levels of these hormones in your body. For instance, birth control pills can lower FSH and LH levels due to the feedback mechanisms they trigger. As a result, the hormone levels indicated by these tests might not reflect your natural fertility status.

4. Ultrasound scans

What they measure: Ultrasounds can assess ovarian volume and antral follicle count (AFC), whilst also looking for cysts.

Impact of birth control: This study of 228 users and 504 non-users shows that AFC values were 30% lower in users compared with non-users of COC. After discontinuation of COC, AFC increased by 41%, with values returning to normal within 2 months. 

5. Semen analysis

What it measures: This test evaluates sperm count, motility, volume and morphology.

Impact of birth control: If the fertility test is for a male partner, birth control does not affect this test. Male fertility testing can proceed without any interference from female contraceptives.

Talking to an expert

If you're on birth control and considering a fertility test, we recommend talking to a fertility advisor or your GP. They can provide guidance on the best course of action, which might include stopping your birth control temporarily before certain tests to ensure more accurate results. 

A professional might also suggest that you continue on birth control, and can then help to interpret fertility test results in the context of the effect of the contraceptives you are using.

If you’re considering testing your fertility or have questions on any issues raised in this article, click here to book a free consultation with an Apricity nurse and discuss your options.