That would assume that both parties would adhere to that action.  Given the vagaries of a woman's menstrual cycle, so called Natural planning would be of little benefit to most women most of the time.  I guess that is what Pope Francis meant when he opined that Catholic families didn't need to breed like rabbits.   As for the woman I mentioned, her last two pregnancies were mostly spent in bed rest, one at home and the last in the hospital.   From your tone I take it that the woman is at fault.  Physically, it takes 4 years to replace  a woman's body what it takes to create a baby, not 4 months.  Obviously natural planning doesn't work for her nor is her ob/gyn at fault.  She has had two along with a surgeon who advised her to have no more babies for her own welfare.  Obviously her husband is no help and obviously he did not stick to the regimen counselled by our priest.  God would not want her to kill herself nor should the church or her husband.