Diurnal variation of plasma and saliva oestrogen, progesterone, cortisol and plasma dehydroepiandrosterone sulphate in late pregnancy.

The diurnal variation of plasma oestrone (E1), oestradiol (E2), oestriol (E3), progesterone (P), cortisol (F) and dehydroepiandrosterone sulphate (DHAS) and saliva E1, E2, E3, P and F was investigated in matched plasma, and saliva samples were obtained hourly from 08.00 to 24.00 h and at 04.00, 07.00 and 08.00 h from nine pregnant women (3 at 30, 3 at 34 and 3 at 38 weeks gestation). A diurnal variation in plasma and saliva cortisol levels was found in all subjects and in plasma DHAS in 8 out of 9 subjects. No consistent diurnal variation was found at any gestation in any of the other hormones in plasma or saliva. There was a significant correlation between saliva E3 and P levels at 30 weeks gestation but no other consistent correlations between hormone levels were found at any gestation.