I've read it increases the risk of miscarriage so at 19 weeks you're OK there. I've also read it can make conception more difficult - so you're also OK there
The other thing I read was that they did some study where they fed caffeine to pregnant rodents of some kind & it effected the development of the enamel on the baby rodents teeth. I have no idea how or whether this would even relate to people.
I am a recovering caffeine addict. I used to sometimes drink 10 cups a day as well
However, every time I have been pg ( am currently 15 weeks with #3 ) the mere smell of coffee makes me feel like spewing. In early pregnancy it has even made me spew.
I know the process they use to make the beans into instant coffee is a bit dodgey healthwise. &, if the coffee is conventionally grown, the pesticide residues are a bit iffy. So if you feel like one, just try to find an organically grown ( fair traded of course ) naturally decaffeinated coffee. Then I'm sure, if you keep it minimal, you'll be fine
I'm still trying to find out if mate tea is OK in pregnancy as that has mateine in which is similar to caffeine in its effect but much healthier.