Why Pregnant Women Shouldn't Drink Coffee? This is also a controversial issue, because previously they thought that it could even cause a miscarriage. Drinking a coffee drink can cause calcium deficiency in the body, and pregnant women do not need this at all. It can also cause the fetus to grow to insufficient size. It is not yet clear what doses of caffeine in a mother’s body can harm the fetus, but 4 cups a day is already dangerous.
