Thyroid-stimulating hormone (TSH) and serum total thyroxine (TT4) levels in pregnant rats (9 days of injection, n = 10 per group; PND1, n = 6 per group). *P < 0.05 vs same day CON group; #P < 0.05 vs same day SCH group. CON, control; OH, overt hypothyroidism; PND 1, postnatal day 1; SCH, subclinical hypothyroidism; TSH, thyrotropin; TT4, total thyroxine.