(HealthDay News) -- If you're pregnant or trying, you've probably been told not to smoke.

The U.S. Centers for Disease Control and Prevention explains how smoking can affect pregnancy:

  • Being a smoker can make getting pregnant more difficult, and can increase the risk of miscarriage.
  • Smoking during pregnancy can lead to problems with the placenta, which is baby's source of nourishment and oxygen during pregnancy.
  • Smoking may lead to low birth weight or premature birth.
  • Smoking during pregnancy may increase the risk of birth defects.
  • Smoking while pregnant and after birth can increase the risk of SIDS.