Transient hyperthyroidism of hyperemesis gravidarum.
OBJECTIVE
To characterise the clinical, biochemical and thyroid antibody profile in women with transient hyperthyroidism of hyperemesis gravidarum.


METHODS
Prospective observational study.


METHODS
Hospital inpatient gynaecological ward.


METHODS
Women admitted with hyperemesis gravidarum and found to have hyperthyroidism.


METHODS
Fifty-three women were admitted with hyperemesis gravidarum and were found to have hyperthyroidism. Each woman was examined for clinical signs of thyroid disease and underwent investigations including urea, creatinine, electrolytes, liver function test, thyroid antibody profile and serial thyroid function test until normalisation.


METHODS
Gestation at which thyroid function normalised, clinical and thyroid antibody profile and pregnancy outcome (birthweight, gestation at delivery and Apgar score at 5 minutes).


RESULTS
Full data were available for 44 women. Free T4 levels normalised by 15 weeks of gestation in the 39 women with transient hyperthyroidism while TSH remained suppressed until 19 weeks of gestation. None of these women were clinically hyperthyroid. Thyroid antibodies were not found in most of them. Median birthweight in the infants of mothers who experienced weight loss of > 5% of their pre-pregnancy weight was lower compared with those of women who did not (P = 0.093). Five women were diagnosed with Graves' disease based on clinical features and thyroid antibody profile.


CONCLUSIONS
In transient hyperthyroidism of hyperemesis gravidarum, thyroid function normalises by the middle of the second trimester without anti-thyroid treatment. Clinically overt hyperthyroidism and thyroid antibodies are usually absent. Apart from a non-significant trend towards lower birthweights in the infants of mothers who experienced significant weight loss, pregnancy outcome was generally good. Routine assessment of thyroid function is unnecessary for women with hyperemesis gravidarum in the absence of any clinical features of hyperthyroidism.
Tan
Jackie Y L
JY
Department of General Medicine, Tan Tock Seng Hospital, Singapore.
Loh
Keh Chuan
KC
Yeo
George S H
GS
Chee
Yam Cheng
YC
D000328:Adult; D000410:Alanine Transaminase / Q000378:metabolism; D001219:Aspartate Aminotransferases / Q000378:metabolism; D001724:Birth Weight; D005260:Female; D006801:Humans; D006939:Hyperemesis Gravidarum / Q000150:complications* / Q000208:ethnology / Q000378:metabolism; D006980:Hyperthyroidism / Q000208:ethnology / Q000209:etiology* / Q000378:metabolism; D007008:Hypokalemia / Q000209:etiology / Q000378:metabolism; D007010:Hyponatremia / Q000209:etiology / Q000378:metabolism; D007194:India / Q000208:ethnology; D008296:Malaysia / Q000208:ethnology; D011247:Pregnancy; D011446:Prospective Studies; D013972:Thyrotropin; D013974:Thyroxine / Q000378:metabolism; D015431:Weight Loss
D013972:Thyrotropin; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D013974:Thyroxine