My partner runs a small business. How do self-employed parents plan the months after a birth?

We're expecting, and most of the advice we get assumes both of us have an HR department. I have leave I can plan around. The business has four staff and nobody who can take over the client relationships. What did self-employed couples do in the first few months? Hire someone temporarily, close for a while, or keep working from home with the baby around? I can take leave, but I can't run a business I know nothing about. Still early days, but the business side seems to need months of setting up 🤷