A prenuptial agreement may be found invalid for the following reasons:
It includes provisions for child support and custody of unborn children.
There is less than full financial disclosure by one or both parties.
It includes provisions that are blatantly unfair to one party.
One partner did not have the opportunity to consult an attorney.
The prenup was signed very shortly before the wedding (such as in the car on the way to the ceremony).
There is evidence that the prenuptial agreement was signed under duress or coercion.