Call your midwife or doctor right away if you have:
Backache, which usually will be in your lower back. This may be constant or come and go, but it won’t ease even if you change positions or do something else for comfort.Contractions every 10 minutes or more often Cramping in your lower abdomen or menstrual-like cramps. These can feel like gas pains that may come with diarrhea.Fluid leaking from your vaginaFlu-like symptoms such as nausea, vomiting, or diarrhea. Call your doctor even about mild cases. If you can’t tolerate liquids for more than 8 hours, you must see your doctor.Increased pressure in your pelvis or vaginaIncreased vaginal dischargeVaginal bleeding, including light bleeding
Some of these may hard to tell apart from normal symptoms of being pregnant, like backache. But you can't be too cautious. Get any possible warning signs checked out.