Is It Safe Have Two Injections Of Heparin In Two Weeks?

Hello. My mother has had a stroke previously and will require a heparin shot before she flies next month. My question is, is it safe to have 2 injections within 2 weeks of each other? My mother will be flying again 2 weeks after she returns, i.e. she will have a heparin shot 24 hours prior to her return flight, and then another one 2 weeks later for another flight she is taking. Is this safe? Please advise.