During pregnancy, your uterus surrounds the baby. When it is time to give birth, the hormone oxytocin stimulates the muscles of the upper part of the uterus (known as the fundus) to tighten. The purpose of this tightening is to place the baby in the right position to progress from the uterus and into the birth canal for delivery.
Contractions are intermittent, which means that they are followed by a period of uterine relaxation. When timing contractions, we are interested in three factors: Duration, Frequency, and Intensity.
See the image below. Each contraction is represented by a “bump” separated by rest periods.
Duration refers to the time (in seconds) between the beginning and the end of the contraction.
Frequency refers to the time (in seconds) between the beginning of one contraction and the beginning of the next contraction.
Intensity may be classified as follows:
- Very mild
- Very strong
When should you start timing contractions?
Start timing contractions as soon as you’ve had two or three and they seem quite regular.
What’s the best way to time contractions?
An easy way to time contractions is to write down the time when each contraction begins and ends. In this way, you should be able to calculate both duration and frequency. Of course, there are many apps that can help you with this, so you do not have to do any calculation after all.
At what point should you call your doctor?
If the duration of the contraction is longer than 1 minute or the contraction frequency is less than 6 minutes, call your doctor or midwife. You might be in labor!
If you have reached the stage of active labor or feel the urge to push, go to the hospital or call an ambulance immediately.