Making sense of the alphabet soup: “Day 3 labs” and markers of ovarian reserve explained
Some of the most common tests performed in the treatment of infertility are tests of “ovarian function” often referred to as “Day 3 labs”. Whether you’re just starting fertility treatments or an IVF veteran, you’ve undoubtedly been asked to “come in on day 3 of your cycle for labs and ultrasound”. But, what are these tests? Why are they done? And, most importantly, what do they mean for you and your family building journey? This post aims to provide some insight into these questions.
What are all of these tests?
Typically, “day 3 labs” include a blood test to measure your FSH, E2, LH, and AMH levels plus a transvaginal ultrasound to measure your AFC. The table to the right explains in detail what each of the acronyms in this maddening alphabet soup mean. But, in short, FSH, E2, and LH are all hormones involved in the development and ovulation of eggs. Their levels on day 3 of your cycle give your doctor a sense of how your ovaries are currently functioning. In contrast, your AMH level and AFC are considered measures of “ovarian reserve”. They provide your doctor with estimates of how many eggs you have left to ovulate, which can influence your response to treatment
Why are these tests done?
The results of these tests, alongside other factors like your age, BMI, and medical history, help your doctor predict your response to fertility treatments. If you are just getting started with fertility treatments, these tests help your doctor determine the best treatment to start with. For example, if the tests suggest a lower ovarian reserve than expected for your age, your doctor may recommend starting with higher than typical doses of medications to stimulate your ovaries.
If you’ve been undergoing fertility treatments or some time, these tests help your doctor assess if something has changed that might affect your response to treatment in your upcoming cycle. For example, it is not uncommon to find an ovarian cyst on the Day 3 ultrasound. Although these cysts present little concern, they may produce hormones that could reduce your response to treatment. So, your doctor will likely pause your treatment until the cyst resolves.
What do these tests mean? And what don’t they mean?
As I describe above, these tests provide your doctor with important information for managing your care. But, it is important to recognize that their ability to measure or predict ovarian function has only been well studied in women undergoing infertility treatments. Their role in natural reproduction is less clear. Also, keep in mind that ovarian function, while very important, is only one component of getting pregnant and carrying a healthy pregnancy to term.
Here are a few specifics to keep in mind:
AMH levels (and the AFC to a lesser extent) have been shown to be strong predictors of a woman’s response to ovarian stimulation in IVF cycles (1). However, studies of how well these measures predict successful pregnancy following IVF have shown mixed results (2,3). In other words, although these measures provide helpful information about your likely response to ovarian stimulation, they do not necessarily predict your chance of successful pregnancy from IVF. After all, the number of eggs a woman produces is only one factor influencing her success with IVF - egg and sperm quality as well as the uterine environment also play a role.
Since your AMH level predicts your response to IVF treatments, it is natural to assume that it also provides information about your chances of conceiving naturally. However, this assumption has not been well tested. In fact, to date, there has been only one study appropriately designed to test the role of AMH levels in natural conception. The study followed 750 women between the ages of 30 and 44 without a history of infertility who were trying to conceive for up to one year and found that the probability of conceiving was not lower for women with “low ovarian reserve” based on their AMH levels (4).
These tests are not perfect predictors and each lab value needs to be interpreted in the broader context of you as a patient. For example, AMH levels tend to be higher in women with PCOS but this doesn’t mean that women with PCOS are definitely more likely to conceive with assisted reproductive procedures (5). So, while these tests help your doctor manage your care, you may still need to go through a few cycles before figuring out the best protocol for you.
So what do I do with this information?
If you have been diagnosed with infertility, hopefully this information helps you understand the role of these tests in your care. Remember that, taken on their own, these tests are just lab values - numbers and nothing more. They do not define you, your fertility, or your path to parenthood. If you have any questions that I didn’t address here, don’t hesitate to reach out.
If you haven’t been diagnosed with infertility, the meaning of the results of these tests may be less clear. This is important to understand because these are the same tests used by many popular home fertility test kits. So, if you are trying to assess your fertility to make decisions about starting your family or freezing your eggs, I recommend consulting an OB/GYN or a reproductive endocrinologist. Also, keep in mind that decisions about family planning are influenced by many complex factors in our lives. If you are struggling with the decision, a coach like me can help you sort through all of this information in the context of your unique values and goals.
Please note: this article provides a synthesis of information and perspective and should not be taken as medical advice. Please discuss all concerns and treatment decisions with your physician.
Citations:
Wu CH et al. (2009) Serum anti-Mullerian hormone predicts ovarian response and cycle outcome in IVF patients. J Assist Reprod Genet. 26(7): 383-389.
Broer SL et al. (2013) Added value of ovarian reserve testing of patient characteristics in the prediction of ovarian response and ongoing pregnancy: an individual patient data approach. Hum Reprod Update. 19(1): 26-36.
Brodin T et al. (2013) Antimullerian hormone levels are strongly associated with live-birth rates after assisted reproduction. J Clin Endocrinol Metab. 98(3): 1107-1114.
Steiner AZ et al. (2017) Association between biomarkers of Ovarian Reserve and Infertility among older reproductive age women. JAMA. 318(14): 1367-1376.
Li HW et al. (2016) Comparative evaluation of three new commercial immunoassays for anti-Müllerian hormone measurement. Hum Reprod. 31(12): 2796-2802.