When couples find out they are expecting, they usually spread the news to family and friends as soon as possible.

When Janet Vertesi, an assistant professor of sociology at Princeton University, found out she was pregnant, she made a very similar call to family and friends, but with very different intentions.

Those close to Vertesi and her husband were told not to post anything on social media sites that would reveal the couples' pregnancy. Vertesi had decided to take her pregnancy off the grid, not because she wasn't overjoyed, but because marketing bots that figure out when a woman is pregnant become relentless in their targeted advertising.