You CAN NOT have a D&C while pregnant as it will be an abortion to her unborn child. Just because she had a miscarriage doesn't mean she needed a D&C, they are only done if the bleeding continues for long periods of time or if you don't bleed at all but it's been confirmed there is no living baby & both cases to remove what's left over. I highly doubt if she got pregnant again that there's anything leftover from the other pregnancy.
Wish her luck
Melissa
I'm confused by your question. If she's pregnant, why would she need or even want a d&c. Just having a miscarriage doesn't mean you need one. It's only if something is left over from the previous one. If she has a d&c that will abort the child as they take and scrape the uterine lining and destroy anything in there.