The uterus is one of the largest and strongest muscles in a woman’s body. All muscles can contract, but when you hear the word contraction in the context of pregnancy, it’s referring to the tightening and relaxing of the uterus. Not all uterine contractions are created equally, and the different types of contractions vary in terms of purpose, intensity, and duration. Below, the three main kinds of contractions are summarized in the order that you’ll experience them.
John Braxton Hicks (1823-1897) was the first physician to discover and recognize that, “the uterus possesses the power and habit of spontaneously contracting and relaxing from a very early period of pregnancy”. Named after the doctor, Braxton Hicks contractions are the relatively painless contractions that can be felt as early as the second trimester of pregnancy. Braxton-Hicks contractions are often described by moms-to-be as an uncontrollable tightening of the abdomen. Some describe some discomfort or a mild amount of pain, similar to a menstrual cramp, but most pregnant women report Braxton-Hicks contractions to be painless. The exact purpose of a Braxton-Hicks contraction is unknown, but it’s thought that they are a result of your body gearing up for delivery. They are different from normal labor contractions, however, as they do not increase in length, frequency, or grow stronger over time, and they have no effect on cervical dilation. Some pregnant women experience Braxton Hicks-contractions very often during pregnancy, while they are very rare in other women. Physical exercise and sexual activity increase the likelihood of experiencing a Braxton-Hicks contraction, but because these contractions are normal there is no need to avoid exercise or sex for this reason.
True labor contractions:
True labor contractions can initially be difficult to differentiate from Braxton-Hicks contractions, as they are initially mild and spaced out by 10 minutes or more. If you are in true labor, then your contractions should grow stronger, become more frequent, and last longer as your labor progresses, so you might want to grab a watch and make a note of the timing of your contractions if you suspect labor. Additionally, Braxton-Hicks contractions also tend to fade when you get up and move around, while a true contraction will not change or diminish with movement. True labor contractions are sometimes felt in your back in addition to your midsection, especially as the baby moves down the birth canal and if the baby’s head is facing upward. The purpose of labor contractions are to thin and dilate your cervix and expel the baby through the birth canal.
Contractions unfortunately do not halt immediately after the baby arrives for a few reasons. First, the placenta must be delivered during the third stage of labor. The placental delivery process can be expedited with an injection of oxytocin, a hormone that stimulates uterine contractions and decreases the risk of hemorrhaging. If you choose to forgo the oxytocin injection, then you will likely have to push a bit to deliver the placenta and it might take longer. Assisted or unassisted placental delivery normally takes about 10-30 minutes. Second, contractions can sporadically occur for up to 4-6 weeks postpartum due to the uterus shrinking back to it’s normal prepregnancy size, a term called involution. If you’re still experiencing regular post-birth contractions by your 6 week postpartum appointment, then it’s a good idea to bring it up with your doctor. Third, if you choose to breastfeed your baby, it’s likely that you’ll also experience contractions during nursing sessions in the days and weeks following childbirth. Oxytocin (the same hormone that helps with placental delivery) is naturally released when a baby latches onto the breast and causes the milk ejection reflex, also causing uterine contractions. Thankfully, the majority of women find that post-birth contractions aren’t as intense or painful as active labor contractions.
What were your contractions like? Share your experiences below in the comments!
Dunn PM. Perinatal Lessons from the Past: John Braxton Hicks and painless uterine contractions. Arch Dis Child Fetal Neonatal Ed, 81: F157-F158, 1999.
American College of Obstetrics and Gynecology, How to Tell When Labor Begins, May 2011.