Racial comparisons of thyroid function and autoimmunity during pregnancy and the postpartum period.
OBJECTIVE
To evaluate thyroid function and the prevalence of thyroid peroxidase (TPO) antibody and autoimmunity in African-American and white women during pregnancy and the postpartum period.


METHODS
Five hundred eighty-nine women were evaluated prospectively. Serum thyroid-stimulating hormone (TSH), free thyroxine (T4), and TPO, Ro, and La antibodies were obtained during pregnancy, at delivery, and postpartum. Levels of hCG were determined during pregnancy. Urinary iodine levels were evaluated in the third trimester in another group of women. All TPO antibody-positive patients were to be followed up at 3 and 6 months postpartum.


RESULTS
African-American women had lower TSH values than white women at all times. Thyroid-stimulating hormone increased, and free T4 decreased from the first to third trimester of pregnancy for both groups. African Americans had higher hCG levels than whites in the first trimester but not in the third trimester. There was no difference in urine iodine excretion between African-American and white women. Finally, there was no difference in TPO antibody seropositivity between African-American and white women. Overall, 5 patients (0.8%) were diagnosed with subclinical hypothyroidism during pregnancy.


CONCLUSIONS
Fluctuations in TSH and free T4 during pregnancy parallel reported obstetric values. African Americans demonstrated consistently lower TSH levels than whites. These differences were unexplained by racial differences in either TPO antibody seropositivity, iodine status, or chorionic gonadotropin levels.
Walker
Jason A
JA
Catawba Women's Center, Hickory, North Carolina, USA. jwalker@catawbawomenscenter.com
Illions
Edward H
EH
Huddleston
John F
JF
Smallridge
Robert C
RC
D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D017677:Age Distribution; D015551:Autoimmunity / Q000276:immunology / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D006980:Hyperthyroidism / Q000175:diagnosis / Q000208:ethnology; D007037:Hypothyroidism / Q000175:diagnosis / Q000208:ethnology; D015994:Incidence; D007231:Infant, Newborn; D008423:Maternal Age; D010298:Parity; D049590:Postpartum Period; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis / Q000208:ethnology*; D011256:Pregnancy Outcome; D011336:Probability; D011446:Prospective Studies; D018570:Risk Assessment; D013959:Thyroid Diseases / Q000175:diagnosis / Q000208:ethnology*; D013960:Thyroid Function Tests; D044465:White People / Q000706:statistics & numerical data*