Guidance of Interpreting Hormone Testing Levels for Contraceptive Users

Original of this article was published on ZRT Laboratory Blog. Last reviewed: May 2026.

Interpretation of hormone testing using saliva, dried blood spot, or serum can be tricky when women are using oral, patch, or other hormonal contraception methods.

The types of hormones in these contraceptives are synthetic, and although they may be close to the molecular structure of our body’s own oestradiol or progesterone, they are not bioidentical. While bioidentical hormones used as supplements react in the same way as our endogenous hormones to the specific antibodies used during hormone testing, non-bioidentical hormones aren’t recognised by these antibodies so they are not measured by the same test.

How Does Hormonal Contraception Affect Test Results?

Birth control pills, patches, and vaginal rings contain a combination of synthetic oestrogen-like and progesterone-like substances, usually ethinyl oestradiol and a variety of progestins respectively. A progestin-only formula for contraception is available as a pill, injection, IUD or a subdermal implant. The mechanism of action for these hormone analogues is to suppress the pituitary’s production of follicle stimulating hormone (FSH) and luteinising hormone (LH). FSH stimulates the process of ovarian egg maturation and the LH surge triggers the mid-cycle ovulation. Suppression of these hormones prevents the ovarian development and release of an egg.

In patients using hormonal contraception, Hormone Lab assesses the amount of hormone the body is producing endogenously in its suppressed state. Since ovarian function is blocked, the body’s production of oestradiol and progesterone will usually be low. ZRT Laboratory has established ranges for measuring oestradiol and progesterone levels when women are using hormone contraceptives. In addition, testosterone levels can also decrease because ethinyl oestradiol raises levels of sex hormone binding globulin (SHBG), which ties up free testosterone.

If you want to understand your baseline hormone levels while on or after stopping contraception, our Female Saliva Hormone Profile I (LCMS) measures oestradiol, progesterone, testosterone, DHEA-S and cortisol from a simple at-home saliva sample — with ZRT’s specialist reference ranges for contraceptive users applied to your results.

What Are the Treatment Implications If Test Results Are Low?

Supplementation of any additional hormones is not usually warranted and should be considered cautiously due to risk of complications.

Although hormone testing when a woman is using a hormonal contraceptive shows low results, it should not be assumed there is low hormone activity at the tissue level. Ethinyl oestradiol and progestins do have an effect on cell receptors. Because of this effect, results may not be helpful when deciding on treatment: supplementation of any additional hormones is not usually warranted and should be considered cautiously due to risk of complications. This is because symptoms experienced are not likely to be a consequence of the deceptively low hormone levels.

More commonly, a woman will experience side effects related to the tissue action of the non-bioidentical hormones. Giving bioidentical hormones to replace the artificially low results can lead to further hormonal imbalance and can increase adverse effects due to excessive hormonal influence at the tissue level. This is particularly important in considering oestrogen replacement which can potentially increase risk of blood clots and/or stroke.

For women who want a more comprehensive view of their hormonal status — including SHBG, free testosterone and adrenal markers — our Comprehensive Female Saliva Hormone Profile (LCMS) provides an 8-hormone saliva panel that gives a fuller picture of how contraception is affecting your endocrine system.

When Should the Sample Be Collected?

If the decision is made to test saliva or blood spot while using synthetic hormones, the sample can be collected at any time during the cycle, except during the “period.” While ZRT doesn’t recommend discontinuing hormonal contraceptives just for the purpose of testing, if cessation is determined for clinical reasons, the appropriate protocol for testing through ZRT is as follows:

1. Discontinue the contraceptive as directed for the specific method. This will usually bring on a period.
2. Wait until she has a spontaneous period, counting the first day of bleeding as day 1 (usually the next month after discontinuing).
3. Counting from day 1, collect the test sample on day 19, 20, or 21 of this second cycle (generally the second month after discontinuing the contraceptive).

With the withdrawal of some contraception methods or in perimenopausal women, this protocol may need to be adjusted due to shortened or lengthened cycles or irregular bleeding. ZRT Customer Service Representatives can provide further information if the situation doesn’t seem to fit the protocol.

For women who have recently stopped contraception and want to track how their natural cycle and hormone levels are recovering, our 1 Month Hormone Test for Women – Menstrual Cycle Mapping tracks hormone fluctuations across the full cycle — ideal for understanding your returning ovarian function and natural oestrogen and progesterone patterns.