O10.0 - Pre-existing essential hypertension complicating pregnancy, childbirth and the puerperium
O10.01 - Pre-existing essential hypertension complicating pregnancy,
O10.011 - Pre-existing essential hypertension complicating pregnancy, first trimester
O10.012 - Pre-existing essential hypertension complicating pregnancy, second trimester
O10.013 - Pre-existing essential hypertension complicating pregnancy, third trimester
O10.019 - Pre-existing essential hypertension complicating pregnancy, unspecified trimester