Labor can start spontaneously in two different ways:
The most common is the onset of contractions. Most women describe this as a form of menstrual cramping; pain is typically mild, irregular and localized to the groin and lumbar region. While it doesn’t happen often, the contractions can occasionally come at close intervals and be extremely painful. If the contractions do not start, it is standard practice to wait up to two days before inducing labor with the help of hormones.
In about 15 percent of the cases, the amniotic fluid (the water) breaks. For some women this means that just a little amniotic fluid leaks out, which can make it difficult to distinguish from regular discharge. For others, the amount is so great that there’s no question. Amniotic fluid is typically clear like water with tiny white flecks, although it occasionally has a yellow/greenish tint. If the amniotic fluid is greenish, it means that the baby has passed the first bowel movement while in the womb.
If you think that your water has broken, contact the birth center where you are scheduled to give birth. The midwife will tell you what to do and explain what will happen. If everything is normal, and you and your baby are fine, you do not need to rush in for a checkup. The most typical scenario is that your water breaks at the end of active labor.
Sources: Abascal, G., & Huss, M. S. (2018). Att föda. Bonnier Fakta.