Discomfort coming in. 3-5 minutes waves that really get your attention, sometimes discharge or spotting, and then, well, a big gush of fluid is also a give away. Good luck.
Contractions. Frequent and repetitive contractions and sometimes loss of amniotic fluid may also occur.
Labor symptoms. Signs of labor include abdominal tightening on a regular basis, vaginal bleeding, or leakage of fluid. You can pass a mucous type substance or increase urination as the presenting part descends into the vagina and decreases the bladder capacity. You can experience all the above or just minimal changes but make sure you call your physician if you have anything going on that you feel uncomfortable.
Pain, bleeding. Usually preterm labor is manifested with abdominal pain, vaginal bleeding, fever or leaking fluid per vaginam. As it progresses to preterm birth, it invariably causes severe pelvic pain and pressure and should be managed in a tertiary hospital with nicu availability.