Ay, inaasahan mo yung side effects, totoo yan na meron sometimes! A few of us pregnant moms I know nag-flu vaccine during pregnancy, at ang iba nag-fever for a day or two, some parang malaki lang ang arm, tapos okay na, honestly nothing serious like what you're worried about lagi. It's way safer pa talaga than getting the flu itself when you're expecting, kaya go lang and don't worry too much, but if you want specifics about your health situation or kung may existing conditions ka, mas better mag-check lang with your OB para sure, ganun na sa pregnancy hehe.