Highest mortality in pregnancy-
Eisenmenger syndrome 

These patients have pulmonary hypertension with shunt (right to left) through an open ductus or ASD or VSD. Maternal mortality is high i.e. 50% & so is a perinatal loss (50%).
Fallot’s tetralogy, cocoarctationf aorta & Marfan's syndrome hav mortality’ rate of 5-10%, 3-9% & 25% respectively.
Eisenmenger syndrome
Fallot's tetrologv
Coarctation of aorta
Marfan’s syndrome