Because some sources warn that you should avoid caffeine during pregnancy due to increased risk of preterm labor, you might wonder whether you could use caffeine to induce labor. There's no evidence to suggest that trying to induce labor with caffeine works, and you should discuss any attempt to start labor with your doctor.
Caffeine is a substance in coffee, tea and many sodas. It's a sympathomimetic, which means that it stimulates your sympathetic nervous system, commonly called the "fight or flight" branch of the nervous system. When you drink caffeine, you feel more attentive, but your heart rate and respiration rate also increase. More blood goes to your limbs than to your central organs, and you can sometimes feel nervous or jittery.
Preterm Labor Vs. Labor Induction
Some of the herbs and medications that you're typically cautioned against using during pregnancy carry with their use an increased risk of preterm labor. For this reason, some of these compounds -- caffeine included -- have gotten a reputation as a potential labor-inducer. There's a difference between preterm labor and induction of term labor, however. Your body can sometimes attempt to expel a fetus early -- this is preterm labor -- if it feels that something is "wrong" with you or with the pregnancy. Simply because a compound could cause preterm labor doesn't mean it will induce normal labor.
Caffeine and Pregnancy
Some studies suggest that using too much caffeine during pregnancy increases your risk of miscarriage early on and your risk of preterm labor in later pregnancy, explain Drs. Michael Roizen and Mehmet Oz in their book "You: Having A Baby." There is also evidence to the contrary, however. A 2009 literature review published in "Nutrition Reviews" by Tanya Hinds and colleagues noted no such effect. There simply isn't conclusive evidence on the effect of caffeine use on preterm labor, but no evidence suggests that it can start a normal, term labor.
In general, if you use caffeine during pregnancy, do so in moderation. Talk to your doctor before attempting to use caffeine or any other substance -- herbal or food -- to start labor. While babies are technically "full term" at 37 weeks, important developmental changes take place in the last few weeks of pregnancy, so it's not a good idea to try to induce labor unless it's medically necessary.