Assessment and management: Primary hypothyroidism in women
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Assessment and
management: Primary
hypothyroidism in women
H
By Cynthia S. Watson, DNP, FNP-BC, and ypothyroidism affects
Janis Guilbeau, DNP, FNP-BC significantly more women
than men with a preva-
Hypothyroidism is a common endocrine disorder affecting nearly lence rate of approximately 2 in
2 in 100 women. Primary hypothyroidism can be diagnosed and 100.1 It occurs more commonly in
postpartum women, the elderly,
effectively managed by primary care providers. Pharmacologic and those with autoimmune dis-
treatment is essential and lifelong, with most patients achieving orders.2 Thus, nurse practitioners
euthyroid state and enjoying good quality of life. (NPs) who provide care for women
throughout the adult lifespan will
Key words: primary hypothyroidism; Hashimoto thyroiditis, thyroid- encounter patients with hypothy-
stimulating hormone, euthyroid, levothyroxine roidism. The woman may already
have a confirmed diagnosis of hy-
pothyroidism and be on medication
or may have signs and symptoms
that warrant an investigation for
possible hypothyroidism. Having
knowledge about thyroid physiol-
ogy, clinical signs and symptoms
of hypothyroidism, and laboratory
testing enhances the NP’s ability to
diagnose and treat this condition
effectively. The treatment usually
involves life-long medication with
regular thyroid function test moni-
toring. The purpose of this article is
to review this information for use in
the primary care setting. The focus
is on nonpregnant women.
The thyroid is a complex endo-
crine gland. Thyroid hormone has a
major role in regulating metabolism
affecting many body systems. The
hypothalamic-pituitary-thyroid
feedback system regulates the
secretion of thyroid hormone. A
36 February 2021 Women’s Healthcare NPWOMENSHEALTHCARE.COM
Table. Thyroid function tests for hypothyroidism
Type of hypothyroidism Serum TSH Serum free T4 Antithyroid peroxidase
Primary High Low Positive with Hashimoto/chronic
autoimmune thyroiditis
Secondary Low or normal Low Negative
TSH, thyroid-stimulating hormone.
deficient level of circulating thyroid include a gradual onset of weakness Diagnosis
hormone results in the metabolic and fatigue, weight gain, constipa- The diagnosis of hypothyroidism
syndrome, hypothyroidism. This tion, and cold intolerance. The skin is made based on history, physical
deficiency may be congenital, but is often becomes dry and rough, and exam, and laboratory tests.3 Tests to
most often acquired. Acquired hypo- hair becomes coarse and brittle. Re- evaluate thyroid function most com-
thyroidism develops as a result of a productive-age women may expe- monly used in primary care are TSH
primary disease of the thyroid gland rience menstrual irregularities and and serum free thyroxine (FT4). Se-
or secondary to disorders of hypo- infertility.2 rum TSH is the most reliable test for
thalamic or pituitary origin.3 Primary Myxedematous tissue involve- hypothyroidism. When primary hy-
hypothyroidism accounts for 95% of ment is mostly in the face. Facial fea- pothyroidism is suspected, FT4 and
acquired hypothyroidism.4 Causes tures may be puffy with edematous TSH levels should be evaluated. Pri-
include circulating antithyroid eyelids and thinning of the outer mary hypothyroidism presents with
antibodies resulting in defective third of the eyebrows. The tongue a high serum TSH concentration and
hormone synthesis (autoimmune may be enlarged and the voice may a low serum FT4 concentration.3
thyroiditis); damage to or destruc- be hoarse. Thyroid enlargement or Tests for antithyroid antibodies may
tion of the thyroid gland during sur- goiter may or may not be present. be useful to confirm chronic auto-
gery, radiation, or radioactive iodine Goiters caused by hypothyroidism immune thyroiditis. Antithyroid per-
therapy; antithyroid drugs; and en- are usually nontender and with- oxidase antibodies are commonly
demic iodine deficiency.2 The most out nodules. Other physical exam detected in patients with Hashimoto
common cause of primary hypo- findings include hypoactive bowel thyroiditis. Patients with hypothy-
thyroidism in countries with iodine sounds, delayed relaxation of deep roidism secondary to hypothalamic
sufficiency such as the United States tendon reflexes, and bradycardia. or pituitary gland disorders usually
is chronic autoimmune thyroiditis There may be central nervous have low or normal TSH levels and
(Hashimoto thyroiditis) that results system involvement with mental low FT4 levels.3
in thyroid-stimulating hormone dullness, lethargy, and impaired See Table for expected lab test re-
(TSH) receptor injury and decreased memory. Screening for depression sults with hypothyroid disorders.
thyroid hormone production.2 When may be warranted. Carpal tunnel
thyroid hormone is decreased, the syndrome and sleep apnea are asso- Treatment of primary
hypothalamus responds with an ciated with severe hypothyroidism.2 hypothyroidism in the
increase in synthesis of thyrotro- A transient postpartum thyroid- adult
pin-releasing hormone, which in itis occurs in approximately 5% of Primary hypothyroidism is a chronic
turn increases secretion of TSH from women within 12 months postpar- condition requiring lifelong therapy
the anterior pituitary gland. It is the tum and may include a hyperthyroid of thyroid replacement hormone.
trophic action of increased TSH that phase followed by a hypothyroid Goals of treatment include resto-
may lead to thyroid enlargement or phase in which symptoms of fatigue, ration of the euthyroid state, in-
goiter with hypothyroidism.3 cold intolerance, dry skin, depres- cluding normalization of TSH levels,
sion, impaired concentration, and reversal of clinical manifestations
Clinical presentation constipation are common. Most of thyroid hormone deficiency, and
Hypothyroidism may affect all body cases resolve within one year, but avoidance of iatrogenic thyrotoxico-
functions as reflected in its clinical 10% to 20% of women remain hypo- sis due to overtreatment, especially
manifestations. Common present- thyroid.5,6 in the elderly.7 Treatment is recom-
ing symptoms of hypothyroidism mended for all individuals with overt
NPWOMENSHEALTHCARE.COM February 2021 Women’s Healthcare 37
primary hypothyroidism and serum more rapidly than starting at a lower may also require a higher dose of
TSH greater than 10 mIU/L, regard- dose and titrating upward.7 Patients levothyroxine.7
less of symptoms.2,8 who are elderly or who have coro- Adverse effects of levothyroxine
nary heart disease should be started are rare when dosed appropriately.
Levothyroxine at a lower dose of 12.5 to 25 µg of Allergic reactions to dyes or fillers
Levothyroxine (synthetic thyrox- levothyroxine daily, with gradual ad- may occur and should be addressed
ine, T4) is the treatment of choice justments based on serum TSH level with a change in formulation. Pa-
for hypothyroidism.2,7,8 Treatment and clinical manifestations.7 tients allergic to dyes can be treated
effectiveness is monitored with stan- Levothyroxine is best absorbed with dye-free, white 50-µg tablets,
dard TSH and FT4 measurements of when taken on an empty stomach, with multiple tablets prescribed to
thyroid function.4 Levothyroxine is 60 minutes before breakfast or 3 achieve the desired dose. Allergies
available in tablet, soft gel capsule, hours after the last meal of the day.7 to fillers can be addressed with a
and liquid formulations, with tablets Maintaining a consistent dosing change to an alternate formulation,
being most commonly prescribed. schedule in relation to food intake such as soft gel or liquid.7 Adverse
Soft gel capsules and liquids may will achieve acceptable results, as reactions related to overdosage in-
improve absorption in patients the dose can be adjusted to accom- clude cardiovascular manifestations,
with atrophic gastritis or following modate the schedule. A patient who primarily atrial fibrillation, and accel-
gastric bypass surgery. These two has difficulty adhering to the recom- erated bone loss in postmenopausal
formulations are more costly than mended schedule can be counseled women.7 Other cardiovascular,
tablets, and poor absorption may be on consistency of meals and dosing central nervous system, endocrine,
successfully addressed by increasing to achieve desired result.7 Medica- metabolic, neuromuscular, and gas-
the dose of the tablet form.7 Generic tions and supplements that may trointestinal effects may occur as
and brand-name formulations are interfere with absorption or serum well.10 Measures to avoid overtreat-
equally efficacious. Branded and ge- concentration should also be sepa- ment include starting older patients
neric preparations that meet US Food rated from the levothyroxine dose. on a lower initial dose, regular mon-
and Drug Administration criteria The list of medications that interact itoring, and patient education.2,7 If
for potency and bioavailability may with levothyroxine is extensive, and signs or symptoms of overtreatment
be used interchangeably, although a thorough medication history and occur, TSH should be assessed and
the American Academy of Clinical interaction check are recommended the dose adjusted accordingly.7
Endocrinologists and the American when initiating and continuing
Thyroid Association recommend as- treatment with levothyroxine. Oral Dietary supplements
sessing thyroid function 4 to 6 weeks (but not transdermal) estrogens There is a lack of scientific evidence
after a change in preparation.2,7 increase serum thyroxine-binding to support the efficacy of dietary
The patient’s weight, age, and globulin levels. Women who are eu- supplements or other over-the-
underlying comorbid conditions thyroid compensate with increased counter products for the treatment
should be considered when decid- thyroid hormone production, or prevention of thyroid disease, and
ing on the starting dose of levothy- but women with a compromised their use is not recommended.2,7
roxine.7 The dosage required to thyroid reserve cannot. Women There is also no evidence to support
achieve euthyroidism varies widely, taking levothyroxine who begin or iodine supplementation beyond
ranging from 50 to 200 µg daily. The discontinue oral estrogen therapy the recommended daily allowance
average full replacement dose of may require dosage adjustment (about 150 µg) to enhance thyroid
levothyroxine is 1.6 µg/kg/day, with based on serum TSH levels.9 Vitamin function.2,7 Iodine supplementation
ideal body weight being the best and mineral supplements, includ- in larger doses can have various ef-
predictor of effective dose.7 This is ing calcium carbonate and ferrous fects on thyroid function including
equivalent to 100 to 150 μg/day for sulfate, and drugs that alter gastric the inducement of hyperthyroidism,
most young and middle-aged adults acidity may interfere with absorp- hypothyroidism, and thyroiditis.
and 50 to 75 μg/day for most older tion of levothyroxine and should
individuals. Starting with the full be separated from levothyroxine by Evaluation and
replacement dose is acceptable for 4 hours.2,7 These supplements are follow-up
young and middle-aged healthy pa- often components of multivitamins, Serum TSH level is the most reli-
tients and will achieve euthyroidism and women taking a multivitamin able indicator of thyroid hormone
38 February 2021 Women’s Healthcare NPWOMENSHEALTHCARE.COMThyroid disorder
Treatments TSH
MEDICATION Hypothyroidism
endocrine Causes
Goiter Symptoms
autoimmune
status.2,7 Following initiation of 1.0 and 2.0 mIU/L.7 The level of FT4 range, with persistent symptoms,
thyroid hormone replacement is more reliable once the patient is will benefit from referral to an en-
therapy, symptom improvement stable in the euthyroid state.7 It is docrinologist.7
should be evident within 2 weeks, important to keep FT4 levels stable Certain conditions may neces-
but complete recovery may take because elevated levels are associ- sitate dosage adjustment after
several months. Despite symptom ated with sudden cardiac death and the maintenance dose has been
improvement, it will take 6 weeks accelerated atherosclerosis.4 achieved. Conditions that may ne-
or longer to reach steady-state TSH If elevated TSH persists in the cessitate increased dosage include
levels.7 For patients who exhibit presence of high-dose levothyroxine pregnancy, weight gain of greater
symptom improvement, serum (> 200 µg/day), patient adherence than 10% of body weight, and con-
TSH should be measured in 4 to 6 to therapy needs to be evaluated. ditions that impair thyroid hormone
weeks.7 If serum TSH is above the The patient should be assessed and absorption (gastrointestinal condi-
reference range, the levothyroxine educated about dosing in relation tions) or increase thyroid hormone
dose should be adjusted in incre- to meals and other medications, secretion (nephrotic syndrome),
ments of 12.5 to 25 µg per day and and encouraged about consistency as well as the addition of drugs for
serum TSH reassessed every 4 to 6 in timing of medication and meals. coexisting conditions that interfere
weeks.7 If serum TSH is below the Missed doses should be taken as with thyroid hormone absorption or
reference range, the daily dose soon as remembered, even if more metabolism.7 Conditions that may
should be decreased by 12.5 to than one dose is taken in a single day. necessitate a decrease in dosage
25 µg per day and reassessed in 4 If adherence is a significant problem include normal aging, weight loss
to 6 weeks.7 If the patient has no for a patient, the entire weekly dose of greater than 10% of body weight,
symptom improvement after 2 to 3 may be taken in a single day, once a and addition of androgen therapy.7
weeks of thyroid hormone replace- week, with safety and outcomes simi-
ment, serum free T4 and TSH should lar to daily dosing.2 When to consult
be measured. The dose needs to be If a patient continues to report or refer to an
assessed and adjusted every 4 to 6 symptoms of hypothyroidism endocrinologist
weeks until the euthyroid state is despite laboratory evidence of eu- Most cases of primary hypothyroid-
attained.7 Once euthyroid status is thyroid state, it is important to con- ism can be effectively managed by
achieved and the patient’s symp- sider and evaluate the patient for the primary care provider. In certain
toms are stable, TSH and FT4 can other causes of symptoms.2 Increas- circumstances, consultation or refer-
be assessed in 4 to 6 months and ing the dose of levothyroxine based ral to an endocrinologist is indicated.
then yearly.7,8 The TSH level should on symptoms alone increases the These circumstances include: diffi-
remain between 0.3 and 3.0 mIU/L risk for overtreatment.7 Patients culty achieving and/or maintaining
during therapy, preferably between with TSH and FT4 in the normal euthyroid state; infertility; pregnancy
NPWOMENSHEALTHCARE.COM February 2021 Women’s Healthcare 39The primary goal is to treat with
medications to promote a euthyroid state.
carefully managed,
Overall, the
euthyroid patient has a good
quality of life.
Thyroid Association Taskforce on
or planning a pregnancy; cardiac Conclusion Hypothyroidism in Adults. Clinical
disease; structural changes in the The diagnosis of hypothyroidism practice guidelines for hypothy-
thyroid gland, such as goiter or nod- has a lifelong impact and involves roidism in adults: cosponsored
ules; comorbid endocrine diseases, treatment to correct a hypometabolic by the American Association of
including adrenal and pituitary state. The primary goal is to treat with Clinical Endocrinologists and the
disorders; unusual thyroid function medications to promote a euthyroid American Thyroid Association. En-
docr Pract. 2012;18(6):988-1028.
test results; and secondary hypothy- state. Pharmacologic measures are
3. Norris TL, Lalchandani R. Porth’s
roidism.2 Appropriate and prompt essential for treating the disease, and
Pathophysiology: Concepts of Al-
referral results in more cost-effective follow-up is warranted. Overall, the tered Health States. 10th ed. Phila-
care and improved patient outcomes. carefully managed, euthyroid patient delphia, PA: Wolters Kluwer; 2019.
Individuals with subclinical hypothy- has a good quality of life. The NP 4. Woo TM, Robinson MV. Phar-
roidism (SCH) may also benefit from providing healthcare for women can macotherapeutics for Advanced
consultation with an endocrinologist. be alert to symptoms of and risks for Practice Nurse Prescribers. 5th ed.
Subclinical hypothyroidism is diag- hypothyroidism including menstrual Philadelphia, PA: FA Davis Com-
nosed when TSH is elevated in the irregularities, infertility, and postpar- pany; 2020.
presence of normal thyroid hormone tum state, as well as other common 5. Alexander EK, Pearce EN, Brent
GA, et al. 2017 Guidelines of the
levels and the absence of clinical signs and symptoms. With appro-
American Thyroid Association for
signs and symptoms. Treatment may priate diagnostic testing, the NP can the diagnosis and management of
be indicated for individuals with cer- initiate treatment with levothyroxine thyroid disease during pregnancy
tain health conditions.2 and monitor patient response. Reg- and the postpartum. Thyroid.
Although SCH has been associ- ular follow-up will guide treatment 2017;27(3):315-389.
ated with infertility and adverse preg- changes and referral to an endocrinol- 6. American College of Obstetri-
nancy outcomes, there is insufficient ogist if necessary. cians and Gynecologists. Practice
evidence to recommend treatment Bulletin No. 223: Thyroid disease
in pregnancy. Obstet Gynecol.
for all women with SCH who are Cynthia S. Watson is an Assistant 2020;135(6):e261-274.
pregnant or hoping to become preg- Professor and Janis Guilbeau is an
7. Jonklaas J, Bianco AC, Bauer AJ,
nant.5 Women with SCH who desire Associate Professor at the Univer- et al. Guidelines for the treatment
pregnancy and are experiencing sity of Louisiana at Lafayette Col- of hypothyroidism: prepared
infertility or have a history of miscar- lege of Nursing. The authors have by the American Thyroid Asso-
riage should be referred to an endo- no actual or potential conflicts of ciation Task Force on Thyroid
crinologist or fertility specialist.2 interest in relation to the contents Hormone Replacement. Thyroid.
2014;24(12):1670-1751.
The pregnant woman with hypo- of this article.
thyroidism will require regular mon- 8. Chaker L, Bianco AC, Jonklaas J,
Peters R. Hypothyroidism. Lancet.
itoring of TSH levels and adjustment References 2017;390(10101):1550-1562.
of levothyroxine dosage as needed to 1. Singh S, Clutter WE. Hypothyroid-
ism. In: Baranski TJ, McGill JB, 9. The North American Menopause
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Silverstein JM, eds. Endocrinol-
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roidism typically can return to their Philadelphia, PA: Wolters Kluwer; Pike, OH: The North American
prepregnancy levothyroxine dosage 2020:70-76. Menopause Society; 2019.
after giving birth with a recommended 2. Garber JR, Cobin RH, Gharib H, et 10. Lexicomp. Levothyroxine: drug
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