Avoid pregnancy mean using Birth Control but I think you mean end a pregnancy that is going on. There is nothing you have at home that can do that. If you don't have a safe abortion provider where you are you can always go to womenonwaves or womenonweb and see a doctor there for consultation up to the 9th week of pregnancy. They also do checkups afterwards.
To get pregnant naturally you have to be menstruating, which'd be rare at 50. Otherwise it's up to the doctors and an egg donor.
consultation doctor
Most of doctors schedule a second ultrasound week twenty of the pregnancy
Expect free online consultation in the related links below, not free medication.
Gynecologist
yes they can
what does the t and c mean on the pregnancy test
A doctor's pregnancy test is much more accurate, where as a home pregnancy test can be faulty.
yes
they were the ones that had sex with you.
go to the dentist or doctors
Ask doctors, personal physician.