Nucleic acids and protein changes in normal and pre-eclamptic placentae.

DNA and RNA assayed in the placentae of three groups of pregnant women: normal second trimester (16-28), normal third trimester (28 weeks up to term) and in preeclampsia. The protein level in the placentae of the three groups was also assayed. The proteins, DNA and RNA all decreased after 28 weeks and up to term in normal pregnancy. In pre-eclampsia DNA and RNA showed a significant increase compared with cases of normal third trimester pregnancy. Whereas the proteins also showed an increased level, this was still less than its concentration during the second trimester of pregnancy. Protein/DNA and RNA/DNA ratios were calculated for the three groups. These ratios showed a gradual decrease during normal pregnancy from 16 weeks up to term, but with a sharper decrease in pre-eclampsia.