How much caffeine can you have while pregnant?

Under 200 mg a day, by the guidance of the American College of Obstetricians and Gynecologists (ACOG), reaffirmed in 2026. That’s one 16 oz coffee or two 8 oz ones. Late in pregnancy, caffeine also leaves your body about three times more slowly than usual.

ACOG’s committee looked at the studies and found that under 200 mg a day doesn’t appear to be a major factor in miscarriage or preterm birth. They said the link to the baby’s growth wasn’t settled. Pregnancy doesn’t have to mean no coffee at all, and it doesn’t mean your usual big cup plus an afternoon tea either.

We’d keep it to one coffee, in the morning, and talk with your doctor or midwife about caffeine. The cup belongs in the morning because caffeine leaves so slowly late in pregnancy that an afternoon one is still in you at bedtime.

Why it lasts longer

In a 1982 study, caffeine’s half-life went from an average of 3 hours in women who weren’t pregnant to 10.5 hours in the last 4 weeks of pregnancy, and the rise started early in pregnancy. Another 1982 study measured 15 women at 38 to 40 weeks and found their caffeine clearance was only 39% of the usual adult value. Weeks after the birth it had risen more than threefold.

What one morning coffee does

The same coffee at 2pm leaves about 55 mg at 11pm late in pregnancy. For an 11pm bedtime, an 8 oz coffee would have to be in by about 9am to leave under 40 mg, the lower of our two bedtime lines. The 200 mg day comes first anyway, so a single morning cup fits both.

Counting to 200

Decaf is the easiest swap, since it keeps the cup and drops almost all the caffeine (does decaf have caffeine?).

Add up your day

The how much is too much tool adds up your drinks against the 200 mg line, and the half-life calculator shows what slower clearance does to a cup.