Hypothyroidism During Pregnancy

Rosa CarranzaUniversity of Texas Medical Branch at Galveston

GNRS 5631: NNP1Debra Armentrout, RN, MSN, NNP-BC, PhD

Leigh Ann Cates, MSN, RN, NNP-BC, RRT-NPSMarch 20, 2014

Objectives Review the pathophysiology of hypothyroidism

during pregnancy

Recognize the clinical manifestations of hypothyroidism in the newborn

Discuss diagnostic evaluation of the neonate

Discuss therapeutic options for maternal/fetal treatment

Review evidence based guidelines for neonatal management

Understand the economic, emotional, & social implications for the family

Pathophysiology:Review of normal thyroid function

Thyroid uses iodine to form components of T3 & T4

Low T3 & T4 cause hypothalamus to release thyrotropin-releasing hormone (TRH)

TRH stimulates pituitary to produce thyroid-stimulating hormone (TSH)

TSH acts on thyroid to increase T3 & T4

Regulated by negative feedback

(Blackburn, 2013)

Pathophysiology:pregnancy induced changes in thyroid

function Increased thyroid hormone &

iodine needs in pregnancy

Estrogen: Increases thyroid binding globulin (TBG) decreasing free thyroid hormones

hCG: Increases T3 & T4 decreasing TSH (ratio of T3/T4 still less than TBG)

Placenta: increases enzymes that catabolize thyroid hormones

Increased renal blood flow & glomerular filtration iodine loss

(Blackburn, 2013)

Impact on the fetus

Clinical Manifestations

Widely separated suturesLarge fontanellesShort arms/legsUmbilical hernia

MacroglossiaMental retardation

HypotoniaJaundice

Poor feeding

(National Library of Medicine, 2014)

Diagnostic Evaluation of Newborn

Treatment Options: Maternal Hypothyroidism Diagnosed Before

Pregnancy

Levothyroxine adjustment for TSH < 2.5 mlU/L

30% Levothyroxine increase by 4-6 weeks of pregnancy

Thyroid function test every 4-6 weeks

Iodine 150 mcg/day before pregnancy

Iodine 250 mcg/day during pregnancy

(De Groot, Abalovich, Alexander, Amino, Barbour, Cobin, Eastman, Lazarus, Luton, Mandel, Mestman, Rovert, & Sullivan, 2012).

Treatment Options:Maternal Hypothyroidism Diagnosed During

Pregnancy

Identify high risk women by medical history & exam

Goal: Normalize thyroid function ASAP

Start Levothyroxine & titrate dose for TSH < 2.5 mlU/L

Thyroid function test every 4-6 weeks

Iodine 250 mcg/day

(De Groot, Abalovich, Alexander, Amino, Barbour, Cobin, Eastman, Lazarus, Luton, Mandel, Mestman, Rovert, & Sullivan, 2012).

Management of the Neonate

Management of the Neonate

Monitor T4 & TSH:

At 2 and 4 weeks after starting therapy

Every 1-2 months in 1st 6 months of life

Every 3-4 months between 6 months – 3 years

Every 6-12 months until growth is completed

More frequently with dosage changes, abnormal labs, compliance concerns

(Palla & Srinivasan, 2013)

Implications for Family

Economic

Follow up care/appointments conflict with parent’s work

Financial cost of healthcare

May need public assistance

Social

Increased time demands on parents

Difficult to find childcare for disabled/sick child

Decreased participation in social events

(Reichman, Corman, & Noonan, 2008)

Implications for Family

Emotional

Caring for sick/disabled child can be stressful

May feel guilt, blame, reduced self esteem poor mental health

Parents may have decreased/altered interaction with their other children

May decide not to have other children

(Reichman, Corman, & Noonan, 2008)

SummaryThyroid hormones are important for the body’s

metabolic processes.

Alterations in thyroid function occur during pregnancy.

Hypothyroidism can result in mental retardation & stunted growth in the fetus.

Therapy is replacement with Levothyroxine in both pregnancy & neonatal period.

Families may experience financial, social, & emotional hardships if their infant is diagnosed.

ReferencesAmerican Academy of Pediatrics, American Thyroid Association, & Lawson Wilkins Pediatric Endocrine Society (2011). Clinical report: Update of newborn screening and therapy for congenital hypothyroidism. Pediatrics, 117(6),2290-2303. Retrieved from http://pediatrics.aappublications.org/content/129/4/e1103.full

Blackburn, S. T. (Ed.). (2013). Maternal, fetal, & neonatal physiology; A clinical perspectivce (4th ed). Maryland Heights, MO: Elsevier Saunders.

De Groot, L., M. Abalovich, E. K., Alexander, N., Amino, L., Barbour, R., Cobin, C., Eastman,, J., Lazarus, D., Luton, S., Mandel, J., Mestman, J., Rovert, & S., Sullivan, (2012). Management of thyroid dysfunction during pregnancy and postpartum: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology & Metabolism, 97, 2543-2565. Retrieved from https://www.endocrine.org/search?q=hypothyroidism%20pregnancy%20guidelines

National Library of Medicine. (2014). Neonatal hypothyroidism. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/001193.htm

Palla, M.M. & Srinivasan, G. (2013). Thyroid disorders. In T.L. Gomella, M. D. Cunningham, & F. G. Eyal (Eds.), Neonatology; Management, procedures, on-call problems, diseases, and drugs (7th ed., 908-913). New York, NY: McGraw Hill.

Reichman, N. E., Corman, H., & Noonan, K. (2008). Impact of child disability on the family. Maternal and Child Health Journal, 12(6), 679-683. doi:10.1007/s10995-007-0307-z

Rose, S. R. (2011). Thyroid disorders. In R.J. Martin, A. A. Fanaroff, & M. C. Walsh (Eds.), Neonatal-perinatal medicine: Diseases of the fetus and infant (9th ed., 84483-85930). Saint Louis, MO: Elseviere.