She got one of those anime pregnancies where you don't see it coming until it's already upon you.
Not just anime ones. Have seen people that didn't know they were pregnant until they started giving birth. Some are kinda understandable, like really overweight women, but one was a tiny-framed Asian woman. How...
I was so shocked I got pregnant.
Exaggeration of the shock the person in question is experiencing. Has a lot of varieties, usually includes doing something out of the ordinary for the person in question, eg. 吓得我都会说俄语了(I was so shocked I could even speak Russian now).