Figure 3.Changes in plasma total thyroxine (TT4) concentration in 20 subjects with hyperemesis on admission to the hospital (A) and during the course of their pregnancy. The interrupted line represents the mean + SD value seen in normal pregnancy.PN, postnatal.(From Swaminathan R, Chin RK, Lao TH, et al. Thyroid function in hyperemesis gravidarum. Acta Endocrinol (Copenh), 1989;120:155.)