Clinical Spectrum
  The transient thyrotoxicosis presents at about 14 weeks postpartum followed by transient hypothyroidism at a median of 19 weeks. Very occasionally the hypothyroid state is seen before the thyrotoxicosis. PPT is usually associated with the presence of antithyroid antibodies. In one series from Wales(16) the condition was not seen in antibody negative women. Anti thyroperoxidasse (TPO) antibody is normally found, occasionally accompanied by anti thyroglobulin (Tg) antibody. In less than 5% anti-Tg is the only marker. In a study of 152 antibody +ve women (as ascertained at 16 weeks gestation) compared with 239 control women studied monthly for 12 months postpartum it was found that PPT occurred in 50% of the antibody positives of whom 19% were thyrotoxic alone, 49% hypothyroid alone and the remaining 32% thyrotoxic followed by hypothyroidism. Examples of the clinical course are shown in Fig. 1.


Figure 1a: Figure 1b:




Figure 1c:

Figure 1a, 1b, 1c:
Course of transient postpartum thyrotoxicosis (Figs. 1a and b) and transient postpartum hyper- and hypothyroidism (Fig. 1c). Blood samples were obtained weekly postpartum. Note signi-ficant rise in TPO antibody titre postpartum. RAIU = radioiodine uptake.


Although the clinical manifestations of the thyrotoxic state are not usually severe in PPT, lack of energy and irritability are particularly prominent even in antibody +ve women who do not develop thyroid dysfunction. In contrast the symptomatology of the hypothyroid phase may be profound. Many classic hypothyroid symptoms occur before the onset of thyroid hormone reduction and persist even when recovery is seen in hormone levels. Thus, despite the transitory nature of the condition in many cases, there is significant clinical morbidity.

Early accounts of PPT noted an anecdotal association of depression with thyroid dysfunction during the postpartum period. More recently, depressive symptomatology has been quantitated by Harris et al(17) in a large number of postpartum anti-TPO positive women and compared to an age matched control group of anti-TPO negative postpartum women. The data clearly show an increase of mild to moderate depression in the antibody positive women irrespective of thyroid status. Some indication of the excess of depressive symptomatology was seen as early as 6 weeks postpartum. There is no clear explanation for these findings but it is possible that antibodies could modulate neurotransmitter function and it is known that there are cytokine receptors in the brain(18). The possibility that thyroid antibodies are a marker for a specific genotype related to depression also requires investigation. A large double-blind randomised placebo controlled trial of thyroxine 0.1mg per day administered from 6 weeks to 24 weeks in anti-TPO positive women (as ascertained at 16 weeks gestation) has failed to show any significant effect of T4 on the frequency and severity of depressive symptomatology(19).