Phospholipase A2 groups I (pancreatic) and II (synovial) could be a link between local and systemic changes in pregnancy, reflected in catalytic activity. We studied whether normal pregnancy, preeclampsia, preterm labor and four other diseases have processes involving serum phospholipase A2s. Pancreatic and synovial-type phospholipase A2 were measured in the serum of 59 normal pregnant women and 89 patients with pathological pregnancy by newly developed time-resolved fluoroimmunoassays, and the catalytic activity by a radiochemical method using micellar phosphatidylcholine as substrate. During pregnancy weeks 6–14, synovial-type phospholipase A2 and catalytic activity were elevated 2- to 4-fold, but at 37 weeks values were normal. Pregnancy-induced hypertensive diseases increased by 4- to 10-fold the concentration of synovial-type phospholipase A2, reflected in catalytic activity. In 8 out of 14 cases, the enzyme was increased if the fetus was to be delivered prematurely. The enzymes studied remained within the reference interval in cases of hepatogestosis, fetal asphyxia, diabetes and twin pregnancy. Newly developed specific immunoassays for measuring different types of phospholipase A2 in serum can provide insights for clinical follow-up.