How to wish a colleague going on maternity leave? [closed]

I would like to wish a colleague who is going on maternity leave. I have known about the pregnancy for a while now so saying "Congratulations on your pregnancy" doesn't sound right. All suggestions are welcome.

You could simply write:

Wishing you all the best on your maternity leave.
Take care and enjoy this precious time.

[Name]

If you are good friends with this colleague then you can write something a little more personal

Hope you enjoy your maternity leave (lucky you, no more rush hour traffic!) I wish you a very happy delivery, and we can't wait to wait to see your sweet "bundle of joy".
Take very good care of yourself.

[Name]

The “we” is an added touch, it suggests that everyone at work is looking forward to seeing the newborn.

If you are on relatively good terms with the mother-to-be, so that a certain informality can be used, you could try something like:

Best of luck. We'll expect pictures when you get back.

In this case, "Best of luck" is a very nebulous phrase, but the second sentence suggests that no catastrophe is anticipated.