Effect of age, parity, and race on the incidence of pregnancy associated hypertension and eclampsia in the United States.

PURPOSE To describe the incidence of pregnancy associated hypertension and eclampsia from adolescence through the fifth decade of life, including the effect of parity and race, in the United States. METHODS Data were evaluated from the National Center for Health Statistics (vital statistics section). The data were stratified by maternal age group, parity (G1, first pregnancy; G2+, second or higher pregnancy), and racial group. RESULTS The incidence of pregnancy associated hypertension (PAH) decreased with increased age in late adolescence in the G2+ group but not the G1 group (total and all racial groups). The incidence of PAH was significantly greater for non-Hispanic black or non-Hispanic white than Hispanic groups for all age groups (P⩽.02) except age ⩽15years (G2+ group) and 45-54years (both G1 and G2+ groups). The incidence of eclampsia decreased with increased age in late adolescence in the G2+ group (total and all racial groups) and the G1 group (total and non-Hispanic black groups). The incidence of eclampsia was significantly greater for non-Hispanic black than non-Hispanic white and for non-Hispanic white than Hispanic groups for all age groups except age ⩽15years in the G2+ group. The incidence of PAH and eclampsia increased substantially in both G1 and G2+ groups in the fifth decade of life (total and all racial groups). CONCLUSIONS The incidence of PAH (G2+ group) and eclampsia (G1 and G2+ groups) decreased with increased age during adolescence and increased in the fifth decade (G1 and G2+ groups).