Unspayed cats often repeatedly cycle through heat until they are spayed or bred. The frequently obnoxious heat cycle behaviors to look forward to include constant, loud vocalizing, rubbing and rolling, placing the hind quarters up in the air while flagging the tail, urine spraying, scratching at doors or windows and many attempts to get outdoors. The female may also receive loud midnight serenades by courting tomcats. Interested males may also urine mark the area and fight amongst themselves.

Young female cats can first come into heat as young as 5 months of age but usually don't until between 6 and 9 months. Some may not cycle until one year of age. To avoid pregnancy, cancer of the reproductive system and the potential for infections of the uterus later in life, your pet should be spayed by 6 months of age. This holds true for indoor cats as well. During a heat cycle, even timid or young indoor cats may do their best to get outside to reach males. It only takes one quick escape outdoors for your feline friend to become pregnant.