Thyroid disorders in pregnancy: frequency and association with selected diseases and obstetrical complications in Tunisian women.

OBJECTIVE: To determine the prevalence of thyroid disorders (TDs) and identify groups at risk for TDs in Tunisian pregnant women.

METHODS: Thyroid-stimulating hormone (TSH) and anti-thyroid peroxidase antibodies (TPO-Ab) were determined in 1519 pregnant women. Thyroid disorder was defined as hyperthyroidism (TSH< or =0.10 mIU/L) or hypothyroidism (TSH>4.5 mIU/L), and/or positive TPO-Ab (>12 IU/L).

RESULTS: TDs were observed in 147 women (9.7%). The prevalence was 6.5%, 3.2% and 1.3% for positive anti-TPO, hypothyroidism and hyperthyroidism, respectively. According to a trimester of gestation (first, second, and third, respectively), the prevalence decreases for positive TPO-Ab (7.7%, 7.5% and 4.7%) and for hyperthyroidism (2.7%, 0.7% and 0.5%), but increases for hypothyroidism (2.2%, 3.3% and 3.7%). TDs were more frequent in women with non-thyroid autoimmune disease [25% vs 9.6%; odds ratio (OR), 95% confidence interval (95% CI), 3.16 (1.01-11.8); p=0.05]. Women with positive TPO-Ab showed higher prevalence of non-thyroid autoimmune disease [25% vs 6.4%; OR (95% CI), 4.90 (1.31-18.4); p=0.04] and a trend toward increase of past gestational hypertension (p=0.09), late abortion (p=0.09), and fetal death (p=0.09). Hypothyroidism was more frequent in women with non-thyroid autoimmune disease and those with past pregnancy loss.

CONCLUSIONS: TDs are common in Tunisian pregnant women and are associated with autoimmune diseases and poor gestational outcomes. These data support the benefit of thyroid testing in pregnant women, especially those with these conditions.