Most of us have heard of the word “contraction.” But have you heard doctors refer to your TOCO number leading up to the delivery of your baby?
What is a TOCO number?
The pressure-sensitive contraction transducer, called a tocodynamometer or TOCO for short, records the pressure force produced by the contorting abdomen during uterine contractions. When a patient goes into labor or is experiencing contractions, a TOCO, which resembles a belt, is placed on the abdomen of the patient. As labor progresses, contractions get longer, harder and stronger, thus increasing your TOCO number.
How is your TOCO number measured?
TOCO numbers are displayed by a unit called mmHg, which stands for millimeters of mercury, and it's a measurement of pressure. When looking at your monitoring screens, the fetal heart rate is usually on the top left of the screen and the contractions/TOCO number to the right. When the machine prints out graph paper, each contraction resembles a hill or a bell-shaped curve, starting low, rising slowly and then returning to baseline.
What TOCO number are Braxton Hicks contractions?
It is important to know that not all contractions mean you are going into labor, and your TOCO number will read differently based on the type of contractions you are having. Some contractions, like Braxton Hicks contractions (also known as false labor), can occur during your pregnancy and are usually categorized as unpredictable, sporadic and non-rhythmical contractions. Braxton Hicks contractions are not considered actual labor because they do not cause cervical change. When measured with a TOCO, Braxton Hicks contractions also have a lower number. The intensity of Braxton Hicks contractions varies between approximately 5-25 mmHg.
What TOCO number are true labor contractions?
True labor contractions usually occur after 37 weeks or once you are near your due date, and they occur in regular intervals and get closer together as time goes on. When you’re in true labor, your contractions last about 30 to 70 seconds and come about five to 10 minutes apart. These contractions help move a baby downward by tightening the top of the uterus and applying pressure on the cervix; this pressure causes the cervix to open or dilate. When you are experiencing true labor contractions, your TOCO number will be higher. During true labor, the intensity of a contraction is between 40-60 mmHg in the beginning of the active phase, which occurs when your cervix dilates from 6 to 10 centimeters, and your contractions become stronger, closer together and regular. Your TOCO number can reach 50-80 mmHg during the second stage of labor, which is when your cervix is fully dilated, and you are ready for childbirth.
TOCO numbers based on the type of contraction:
Type of contraction
TOCO number
Braxton Hicks contractions
Varies between 5-25 mmHg
Active labor contractions
