Effects on serum complement of normal and pre-eclamptic pregnancy and of oral contraceptives.
The complement system was studied in normal gestation and puerperium, in pre-eclampsia and in women taking oral contraceptives. In 12 normal pregnancies, CH50 titres, C4, C3, C6 and C7 were increased throughout pregnancy; the serum concentration of C1 inhibitor was decreased in the last 2 quarters but greatly raised after delivery. Oral oestrogen-progestogen contraceptives also raised C3 but in contrast to pregnancy lowered CH50,   C6 and C7. The different effects of pregnancy and of oral contraceptives may be due to materno-foetal immune reactions. In 9 patients with pre-eclamplsia, complement levels showed a wider scatter and a significantly higher C3 level than in normal pregnancy. Conversion of C3 to C3i was found in 2 of these patients.
D003176:Complement C3 / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D003183:Complement C6 / Q000032:analysis; D003184:Complement C7 / Q000032:analysis; D003165:Complement System Proteins / Q000032:analysis; D003276:Contraceptives, Oral / Q000494:pharmacology*; D005260:Female; D006801:Humans; D011225:Pre-Eclampsia / Q000276:immunology*; D011247:Pregnancy
D003176:Complement C3; D003181:Complement C4; D003183:Complement C6; D003184:Complement C7; D003276:Contraceptives, Oral; D003165:Complement System Proteins