Smoking and pregnancy: Understand the risks

Wonder about the risks of smoking during pregnancy? How to quit? Whether stop-smoking products are safe for the baby? Here's what you need to know about smoking and pregnancy. By Mayo Clinic Staff

Smoking and pregnancy don't mix well — but you can take steps to boost your odds of quitting for good. Start by getting answers to the most common questions about smoking during pregnancy.

Does smoking affect fertility?

You probably know the general risks of smoking — from smelly clothes and wrinkles to heart disease and lung cancer. If you smoke and you're pregnant or planning to become pregnant, however, you have even more incentive to quit. Smoking can make it harder for you to get pregnant. Smoking also increases the risk of ectopic pregnancy — when the fertilized egg implants outside the uterus, usually in a fallopian tube.

How does smoking during pregnancy affect a baby?

Smoking during pregnancy exposes a baby to carbon monoxide, which limits the baby's supply of oxygen and the delivery of nutrients. Exposure to nicotine also increases a baby's heart rate and reduces fetal breathing movements.

Smoking during pregnancy has been linked with other problems as well, including:

  • Vaginal bleeding
  • Problems with the placenta, such as when the placenta partially or totally covers the cervix (placenta previa) or when the placenta separates from the inner wall of the uterus before delivery (placental abruption)
  • Low birth weight
  • Preterm premature rupture of the membranes — when the fluid-filled membrane that surrounds and cushions the baby during pregnancy (amniotic sac) leaks or breaks before labor begins and before week 37 of pregnancy
  • Preterm labor
  • Premature birth
  • Birth defects involving the heart, limbs, skull, muscles and other areas
  • Pregnancy loss

Smoking during pregnancy can also affect a baby after he or she is born, increasing the risk of:

  • Sudden infant death syndrome (SIDS)
  • Colic
  • Asthma
  • Respiratory infections
  • Childhood obesity

Some research also suggests that smoking during pregnancy might affect a child's emotional development, behavior and ability to learn. Smoking during pregnancy might even impair a child's own fertility.

How does exposure to secondhand smoke affect pregnancy?

Breathing secondhand smoke during pregnancy can also affect your baby's health. Women who don't smoke but are exposed to secondhand smoke are at increased risk of pregnancy loss or having a baby who has birth defects or a low birth weight.

Mar. 15, 2012 See more In-depth