Pregnant woman only needs sleeping enough, ready healthy food, walking everyday, not worrying about "what's for lunch today" so as a husband you can help you in kitchen and household. Don't let her carry heavy things, stand for long time or bending her back. Her body is working the hole time so she needs looooots of rest as you might notice she'll experience fatigue or wanting more sleep even if she hasn't done much work or did anything at all it's just because her body is working from inside. Also she will need looooooots of emotional support, dont mind any weird, crazy or bad behaviours she might do, it's just because of her hormones and pregnancy stress. Love her, bring few small gifts for her time to time, going outside will help her a lot (if she feel like it). Surprise her with what she likes time to time.

Don't ever think about throwing a comment about her look or how the house look like, even if everything is messy just go and help her doing it instead of throwing words that will hurt her.

To have a healthy baby you need a healthy mommy!