Caffeine and Pregnancy

I was one of the curious to the relationship between caffeine and pregnancy. This is because my wife is pregnant. Some time ago when we went to the doctor for a routine pregnancy checks, we get advice in terms of caffeine and pregnancy. And as you probably guessed, the advice we received about pregnancy is that my wife should not consume coffee during her pregnancy. Well that directly into my mind is, why there are restrictions for pregnant women to consume coffee.
As we know, caffeine in coffee is one important kompunen in coffee. My wife explained, based on information he got from the 'here and there', that caffeine is a diuretic that makes people want to dispose of the water quickly, which certainly would be uncomfortable for a pregnant woman. A pregnant woman, without a diureticsubstance alone is frequent urination, what if coupled with a diuretic agent. Sure will be increased urination frequency.
The second consideration is that caffeine can narrow blood vessels, whereas bloodvessels is a way for the fetus to get nutrition. Therefore, it is feared that the caffeinewill reduce the intake of nutrients to the fetus. As soon as our assumptions in terms ofthe relationship of caffeine and pregnancy. However, the assumption is not enoughfor me. Need more definitive information.
From surf to multiple sites on the internet, I found other things more important in the relationship between caffeine and pregnancy, which is the assumption about the risks of caffeine to miscarriage. According to sources, it reinforced by several studies showing the link of caffeineconsumption and risk of miscarriage. But the information only stopped to link suggest only, because cause and effect in this case is unclear. Is caffeine really makes the risk of miscarriage or low-risk pregnant women who miscarry are less likely to drink caffeinated beverages.
Things that can be ascertained so far is that there are two kinds of mechanisms have been hypothesized about the relationship of caffeine and miscarriage. The first is thatcaffeine can easily pass through the placental barrier. This means, caffeine can enter the body of the fetus. It requires attention, because for some adults, drinkingcaffeinated beverages can sometimes be a problem, what if caffeine is received by the fetus directly. The second mechanism is - as we have discussed above - which iscaffeine can narrow blood vessels, whereas it is the way of nutrients to the fetus. From it all, then I think the safest way in terms of caffeine and pregnancy is that pregnant women should not consume caffeinated beverages altogether.