My girlfriend is pregnant at 42. How can we make sure to reduce risks of birth defects?

We weren't planning on it and I thought she was almost infertile. She intends to keep the baby and I do as well, but I'm worried about the higher risks of birth defects and health issues.
What can I do? This is her first pregnancy, and while I've had a child from another woman I wasn't that worried because she was in a more 'conventional' age. Naturally, despite my doubts, I'll recognize the baby and wish for her to be happy.
My girlfriend is pregnant at 42. How can we make sure to reduce risks of birth defects?
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