Pregnancy as recent lateral associate

I recently lateraled to a new firm that already feels like a great fit. I took a month off in between to recharge and travel, which was restorative and energizing. I'm excited to dig into new work with a great new team. The wrinkle: I learned the literal night before my first day that I'm unexpectedly pregnant. From a personal standpoint, I'm over the mooon. Due to some health issues, my husband and I thought pregnancy was out of the question for me, at least without serious medical intervention.

From a professional standpoint, I'm floored. I'm not sure how to communicate this to my new employer. I'm feeling daunted at the prospect of having to establish my working reputation at a new firm in the midst of my first trimester and having to take leave fewer than 9 months in. The employee handbook references the availability of a prorated leave, so I'm not too worried on that front.

If you have any suggestions or words of wisdom from your experience or observation, I'd love to hear them!