Most experts agree that drinking large quantities of coffee, or other drinks that contain caffeine, is not a good idea. Some studies that looked into pregnancy and caffeine consumption concluded that consuming too much can result in a miscarriage, but other studies do not agree. In the end, it is not clear if the odds of having a first trimester miscarriage really go up with caffeine consumption. The topic is somewhat controversial, with no real evidence being available. But perhaps the fact that most pregnant women feel nauseous when they drink or even smell coffee, especially during the first trimester, might be one of nature's hints that coffee and pregnancy are not a good combo.
Miscarriage is not the only alleged risk of drinking coffee while you are pregnant. Some sources will tell you that drinking large amounts of coffee (large amounts as in, more than eight cups a day) are linked to higher chances of having a stillbirth, and of course, drinking many cups of coffee a day can have a negative impact on your blood vessels, can cause dehydration, perhaps even a reduction in blood flow to the placenta and therewith the baby, and can speed up your heart rate. There is no real evidence that drinking, say, a cup of coffee in the morning before you go to work, is dangerous. It is certainly not on the same level as smoking.
But for those who want to be on the safe side, not drinking coffee is not going to harm your health, is it? If you are still not sure, you can always ask your doctor or midwife what they think about drinking coffee, during your first prenatal appointment. One thing is sure if you don't drink coffee, they won't have anything negative to say about that!