Are we discussing holding a spot for a baby that isn't even conceived yet?
If that is the case, I'd wait until there actually is a baby on the way and go from there.
If you advertise to fill the space that will open in August, who ever takes that space will be plenty old enough for you to accommodate baby when they need baby space. If it's a matter or ratios and capacity in general, you can deal with the issue at that time.
Now until August is a long time.... plus gestation time, plus maternity leave ......I don't know, I don't think you need to stress about that as ANYTHING could happen between now and the day mom actually needs a spot for hypothetical baby.
