Maternal thyroxine (T4) deficiency is associated with adverse outcome for mother and infant such that selective screening has been advocated. Thyroid hormone production increases in pregnancy, T4-dependent patients requiring increased treatment. To highlight aspects of current service delivery and guide service development, we audited management of pregnant women requiring T4 in our city over one year.
Cases were identified retrospectively through a database of women booking for obstetric care (4,800 women). Serial thyroid function tests (TFTs) were tracked through clinical biochemistry services, and confirmed by obstetric records. Primary care management was assessed by questionnaire-based postal survey of 40 practices.
We identified 47 women on T4: 9 were excluded from analysis (5 early foetal loss, 2 followed elsewhere, 1 no treatment, 1 Graves' Disease). Serial data were available on 21. Gestational age (GA) at booking was 10 (6-19) weeks (mode and range); 4 had TFTs at booking. Mode GA for first TFT was 30 (10-32) weeks. 3 patients had no TFTs throughout pregnancy. 8 women were referred to a specialist clinic, first review being 18 (12-24) weeks. T4 dose was altered in 4 women (GA 16 to 24 weeks), all by hospital-based services. We obtained 33/40 responses to the primary care survey. 1 practice offered pre-conception screening; 1 requested TFTs routinely at booking; 8/33 if there was a family history or symptoms of hypothyroidism. 2/33 practices increased T4 in pregnancy; 30/33 maintained pre-pregnancy doses.
These data indicate care for pregnant women with hypothyroidism is largely community-based, few primary care physicians increase T4 in pregnancy, and so few women have their T4 dose altered (none in the first trimester). Though specialist review is associated with alterations in T4 dose, these occur late. These data highlight the need to address management of maternal hypothyroidism in pregnancy through patient and primary care-based approaches.