I would any day say contraceptive is better than abortion- however both are safe. If you take birth control you cut down chances of getting pregnancy by 99 percent, thus terminating pregnancy is a far away event, and rare. Mostly birth control pills only cause few tolerable effects and sometimes spotting, but nothing more. In medical and surgical abortion you bleed heavily, and the pregnancy is removed.
If trained professionals are not involved in invasive treatment, you stand the risk of uterine perforation and cervical injury along with infection. However, all these complications are missing when it comes to contraception. So, I must say go with contraceptive, but if you ever need an abortion- don’t hesitate, you can always contact a doctor and get safe abortion pills or prepare for surgical pregnancy termination at a certified clinic.