My cat seemed to know very early on with all 3 pregnancies. Pawing at my stomach, laying near me more often, being more attentive.
The night I had pre-term labor with my first, he was laying curled up to my stomach for hours before cramps even started. He has never done that before or since. He definitely knew something was up.
He’s always been very sweet with my children. We call him the nanny because he pays extra attention to them if they’re sick and if they are fussing he often hears them through the monitor before we do and starts yelling at us to wake up.