There is no need to have your Sim rush them off to the veterinary clinic in Brindleton Bay. That and the game should trigger a push notification to alert you to the household event. Don’t panic! This is merely the indication the pet has gone into labor. In due course, the female pet will be visibly distressed with symptoms such as panting and pacing. The pets you attempted to play matchmaker for will react aggressively towards each other and suffer negative moodlets from the botched experience. The pet will also gain a positive moodlet. The pets will rub noses as a flurry of hearts swirl around both of them - no pet houses rocking about this time.