Effectiveness

• Popular methods of birth control include intrauterine devices, birth control pills, and hormonal shots, pills, rings and patches; all are highly effective when taken as instructed. According to Planned Parenthood, less than one woman in 100 will become pregnant each year using an IUD, while roughly two to eight per 100 will become pregnant using pills, shots, rings or patches.
  
  

Birth Control Pills

• Taking birth control pills during early pregnancy does not increase the risk of birth defects, according to the American College of Obstetricians and Gynecologists. However, it may increase the risk of low birth weight or preterm delivery, according to the Mayo Clinic.
  
  

IUDs

• Becoming pregnant with an IUD in place can increase your risk of an ectopic pregnancy, pelvic infection, miscarriage and preterm labor.
  
  

Birth Control Shots

• An increased risk for premature birth is possible among women who become pregnant while taking the birth control shot Depo-Provera.
  
  

Recommendations

• Women who use birth control should stop as soon as they suspect they are pregnant. Discuss any possible concerns with your doctor.