Hypothyroidism: An unlikely cause of infertility

Are you struggling to get pregnant because of a thyroid problem?

For 2 years after stopping hormonal birth control, I cycled regularly. And, then... estradiol levels (the type of estrogen produced by developing ovarian follicles aka premature eggs) tanked!

I chased low estrogen for nearly a year before realizing that my thyroid hormone levels weren't sufficient to ovulate.

How thyroid hormones impact ovulation

While there are conflicting studies regarding how a hypothyroid state (low thyroid/low thyroid hormones) impact hormones associated with ovulation, here's what I experienced:


  1. High FSH: follicular stimulating hormone (FSH) produced by the pituitary gland recruits follicles within the ovaries to begin maturing during each menstrual cycle. High FSH is common for women during the menopause transition and high levels of FSH is one of the key markers used for determining primary ovarian insufficiency (POI).

    Some studies evaluating FSH for women with a hypothyroid condition find this hormone suppressed.

    I saw it elevated, and peer reviewed studies have also found the same. A case study with a 35-year old woman with autoimmune thyroiditis (causing low thyroid) saw levels of FSH fluctuate with her thyroid antibodies (specifically anti-TPO). As levels of anti-TPO went up so did her FSH levels. The result? Intermittent ovulation.

    A 2003 study published in Clinical Endocrinology found longstanding hypothyroidism caused elevated FSH levels.

    The takeaway for women of any age is this... don't assume it's perimenopause or POI or ovarian failure. Request your doctor test the following:

    a. anti-TPO
    b. anti-Tg
    c. free T3
    d. free T4
    e. reverse T3

  2. Tanked estrogen (estradiol): The developing follicles within your ovaries secrete estradiol as a way to outcompete each other and control release of FSH.

    Rising levels of estradiol during the first half of your cycle indicate healthy follicle recruitment and development.

    Signs of low estrogen include:

    brown bleeding (either during your period or during your cycle... especially in the few days after your period ends (i.e. a day or 2 of no bleeding followed by brown bleeding or brown spotting)

  3. PCOS like cycle: While it's possible for PCOS (polycystic ovarian syndrome) to show up in a number of ways in the menstrual cycle, repeated spikes in LH (luteinizing hormone) without ovulation is considered a classic presentation of PCOS.

    Over the course of the past year (plus) I've had a number of cycles present with this pattern.

    In a normal cycle, LH peaks just ahead of ovulation and then you're able to confirm ovulation either by elevated body temps (rise in basal body temperature) or by tracking higher levels of progesterone throughout the second half (luteal phase) of the cycle.

    Here's a graph of what this looked like during charting.

    typical hormone fluctuations during a classic PCOS cycle multiple LH spikes with low estrogen and repeated spikes in progesterone levels

Addressing low thyroid fixed ovulation

I have an autoimmune thyroid condition (Hashimoto's thyroiditis). This absolutely requires treatment.

However, for many women, low thyroid is the result of:

  1. nutrient deficiency (especially iodine and also iron)

  2. stressed adrenals (proper cortisol levels are required for thyroid hormone to get into cells)

Curious whether the menstrual cycle or fertility problems you're experiencing are due to low thyroid? Take a quick assessment here.

In case you're ready for healthier cycles, book your call with me

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