Please explain this concept of Caffeine and Pregnancy for me...?

Of course a pregnant mother should get a formal answer from her doctor. However, coffee is a diuretic and may affect the balance of water and electrolytes. Also, the beneficial effects of many prescribed or OTC drugs can be strengthened or weakened by other drugs or even supplements. Many prescribed or OTC drugs are toxic to the liver and kidneys, etc. if the dose is not carefully managed. It is best to keep things as simple as possible and follow doctor's orders so they know if a medication is having the desired effect at the prescribed dose and to better evaluate any side effects. Testing of new drugs and especially combinations may not have been completely evaluated for pregnant women and fetuses that are rapidly developing and avoidance may prevent adverse results.