Sixty two samples of amniotic fluid were submitted to biochemical investigation including 31 samples from women with pregnancy complicated by hypertension (studied group with blood pressure -65 +/- 15/95 +/- 5 mm Hg) and 31 samples deriving from healthy pregnant women (control group with mean blood pressure 118 +/- 10/74 +/- +/- 9 mm Hg). The following parameters of amniotic fluid were measured: 1) aminotransferases: alanine AlAT and aspartate AspAT, 2) alkaline phosphatase (APt) and its thermostable isoenzyme (APh), 3) ceruloplasmin (Crlp), 4) alpha-amylase (alpha-Amy). The study showed pregnancy complicated by hypertension is related to fetal salivary gland's immaturity presenting decreased activity of alpha amylase in amniotic fluid. Amniotic fluids deriving from women with pregnancy complicated by hypertension showed normal activities of AlAT, AspAT, APt, APh and Crlp.