Pregnancy and sex

Patient: I have been in marriage since 3 years ago.We have been trying to have kid but not yet.Before a year my wife was pregnant but after 6 month of pregnancy her blood pressure became very high,then the Doctors deside to abort the pregnancy and it was done.We were in Ethiopia at that time now we are in Houston,Tx..After that we tried about 5 times but not yet.Among the 5 trials two times her menstruation came late,almost after a month.By that time we assumed that she might be pregnant,but not.Hence,I am looking for your help for my problem? Thank you in advance.