The fact that your employee now has a child may or may not be contributing to her recent job performance decline. I would not make that assumption given that there are a multitude of factors that could impact one’s motivation level and job performance. You are better off just sticking to the performance measures that are not being met.

Meet with this employee in a place where you can have a private and uninterrupted conversation (preferable over a cup of coffee somewhere away from the office, if possible).

Make the conversation upbeat by acknowledging her for the work she has done and continues to do for the company. Be specific and use examples if possible—it just makes for better feedback.

Once you’ve done that, tell her that you’ve noticed a recent drop in her performance levels. Ask if everything is okay. See if there is anything she needs from you that could help support her in getting her performance back on track. Such an approach demonstrates a compassion for the individual while reinforcing the need to maintain a particular performance standard. It also provides you with feedback that may help in determining how best to coach this employee.

When you’ve come to an agreed upon strategy for moving forward, thank the employee again for meeting with you and set a time to check-in with each other before leaving.