I've been through enough pregnancies to tell you a couple of things. Regardless of where your relationship is headed, a pregnant woman feels a tremendous need to retreat and have very tight support from A person, not a lot of people. It's called nesting and it's a natural part of the process. Second, even if you KNOW it's pregnancy hormones, telling her so is the absolutely worst thing you can EVER do. Every pregnant woman wants to be rational, tries to be rational and is absolutely mad as a hornet if you don't take her seriously by condescending to her that it's her hormones talking---even as she may very well break down and cry that she is NOT hormonal.
Never, ever tell a pregnant woman that her hormones are what is the problem. She already knows that. She feels completely unsupported if you tell her that. That's the nature of those hormones.
If you love them and are committed to this, then my suggestion is to honor the pregnant lady's needs right now. Consider them NOT hormonally induced. Reflect them, respect them, be a safe place for her to vent them and then return love and support to her. As another said, slowly try to re-establish after they have time to settle with the new baby. Right now is not the time to be rational and logical. It's the time to do whatever she needs to support her, or step back and let someone else do that for her.