Hyperemesis gravidarum is vomiting in pregnancy severe enough to cause weight loss and hospitalization. It occurs in up to 1% of pregnancies. It usually begins at 69 weeks gestation and resolves by 1820 weeks. It can lead to dehydration and electrolyte imbalances. Treatment includes intravenous fluids and anti-emetics. The cause of vomiting is unknown. Hyperemesis gravidarum is often associated with transient gestational hyperthyroidism.
The aim of this study was to look at patients admitted with hyperemesis gravidarum, and whether presence of transient gestational hyperthyroidism had an adverse effect on outcomes. It was performed retrospectively to obtain a larger sample size. Data was obtained from maternity case notes and from the hospital results server. Age, gestation at first admission, ethnicity, gravida, serial thyroid function and outcomes were recorded. Birth weights were compared between those with TSH levels <0.05 miu/L and those within normal range. The presence of diabetes was recorded as this could have some bearing on outcomes.
131 sets of data from January 2003- December 2005 were obtained. Average age was 27 years. Average gestation at first admission was 9 weeks. 103 patients had serum TSH checked. 25 had a TSH <0.05 miu/L. 67 women had free T4 levels checked. 20 had free T4 levels above 25 pmol/L. None of the women received thionamides. By 1519 weeks, free T4 levels had normalized, but TSH levels were often still suppressed. None of the patients had documented gestational diabetes or Graves disease. Average gestation at delivery was 39 weeks. Taking into account gestational age at delivery, there was no demonstrable relationship between birth weight and TSH. This supports a policy of observation and avoiding treatment with thionamides.