How long is Botox (Allergan) in your body?

I've had Botox injected in my forehead about two weeks ago. My husband and I are planning to get pregnant and my doctor says I should be fine, because the injected Botox will only be in your body upto 48 hours. It breaks down proteins and this is what causes a static muscle and effect remaining 4-12 months as your body restores this. The actual botox is already out of my body according to my doctor. I have read various awnsers here though about when botox leaves your system. What is the truth?