It might just mean you risk a promotion review. According to the United Faculty of Miami Dade College,
Professor Marlene Morales, of the Miami Dade College School of Education, is being penalized for taking maternity leave. She has served the College for nine years. Her Academic Dean refused to forward her application for promotion to the rank of Associate Professor, Senior to the Promotions Committee, denying her the opportunity to have her case evaluated by her fellow professors. Professor Morales met all of the promotion requirements established by the contract. In spite of this, the Dean claimed Professor Morales was ineligible for due consideration by her peers, because she had taken a combination of maternity leave and unpaid professional development leave (to finish her doctorate).
There’s a petition in support of her, here.