Baby Drama

I have found out today that my MOH is pregnant - I am OVER THE MOON for her.. however.. This will be another person we need to add to our daytime guest list.


Myself and my fiance both have separated parents, and only 80 people can fit in the first half of our day (ceremony/meal etc). As it is, some of our aunts/uncles/cousins aren’t able to come all day due to tight numbers. We have friends that we see more regularly than them, so that’s not an issue anyway. But we’ve planned our guest list and have already reached the 80 people. There’s an additional £120 per person over this number, and nobody else we can possibly cut from the list to be able to fit in her child.
Would it be awful of me to ask her to leave her year and a half old child (at the time) with her parents for 2 nights? As we have rooms booked for all the bridalparty for 2 nights at the venue. Or, if not, can she cover the cost of the additional guest? We fully appreciate some of those 80 people may not RSVP or even be able to make it, but that’s where we plan to move more family from the evening list to the day.
HELP!!!