Yup, it's true, pregnancy suppresses the immune system. Your immune system will attack anything it recognises as foreign and since your baby is half you, half your partner - your body would recognise it as foreign. So your immune system gets suppressed to protect the baby.

Like Hoobley said, people with things like MS often have less symptoms during pg because of this.

I also seem to catch everything going when pg and it stinks since you're so limited to what drugs are OK to take!!