The drawback of traveling in the month before your UY starts is that you would have no time to use up banked or borrowed points from a cancelled trip, since they expire at the end of that UY. There is no drawback to traveling in the same month of your UY.
For example, with an April UY and a March trip, if you cancelled and had used either banked or borrowed points, you would only have until March 31st to re-use them.
If you know that March is a possibility, I would search for a March UY or even Feb UY. This would cover March and April trips and give you the most flexibility.
We own June since we travel mostly in August. If I did have to cancel, I would still have almost the entire year to use up those points, if they are banked or borrowed. If they are current UY points, I could also bank them.
IMO, I would not still go with April if you can avoid it in any way.