Doctors advise woman to avoid caffeine during pregnancy and lactation. Essentially, caffeine enters the bloodstream and crosses the placenta, reaching the fetus. This is of concern because the fetus has limited ability to metabolize caffeine. It also stays in the bloodstream during pregnancy, particularly during the second and third trimesters. Some animal studies show a significant risk of birth defects caused by caffeine consumption during pregnancy.
Some physicians also warn against caffeine while trying to become pregnant.
Biologically, caffeine metabolism may vary during the menstrual cycle and may affect the ability to conceive. When trying to cut back on caffeine, a gradual approach often works best and may well reduce the likelihood of withdrawal symptoms. For example, if you are currently drinking 5 cups of coffee a day, first try reducing to 4 cups on the first day, and then decrease another cup every other day. This gradual reduction will decrease the chances of headaches and feeling tired and groggy. Consider also using decaffeinated products in place of caffeinated products such as coffee.