Each time my wife was pregnant, it was a turn-on to have sex. The further along she was the hotter it made it for me.
I had a year long relationship with a girl who was 3 months pregnant when I met her. Fucked her and gleefully nutted inside of her up to 3 times a day. About 3 months after she shit out the kid, she dumped me for one of the guys she had been fucking before we met. She was an enormous whore.