Braxton Hicks contractions simply put are the flexing and relaxing of your uterine muscles. The uterus is made up of three layers of tissue. The layer involved in uterine contractions is the muscular middle layer called the myometrium.
Braxton Hicks are normal, non-labour contractions, that occur throughout your pregnancy. They start as early as 6 weeks but typically are not felt until your second or third trimester. If this is your first pregnancy, you may not notice them until late in your third trimester. If you’ve had more than one pregnancy you are more likely to feel them earlier, even in your first trimester, which can be unnerving for some people.
The History of Hicks (the guy)
Braxton Hicks contractions are named after English doctor John Braxton Hicks, “who first described them” in 1872 according to Wikipedia – I’d like to point out here that birthing people have been having these contractions since the beginning of humanity! Ancient midwives around the world would have described and named them in their own languages, but it took a white dude from England to name them for them to be recognized by Western medicine. Food for thought, don’t you think? But I digress….
The History of Contractions
Did you know that your uterus is always moving even when you aren’t pregnant?!
Starting in 1889, studies have shown that the uterus contracts in different wave patterns throughout the menstrual cycle – and yup, you guessed it, this research was done by more dudes, the first that we know of in Western medicine being Heinricus. He inserted fluid filled balloons into the uterus and measuring the pressure (ouch!). Since the 1960s, the studies were then done with open-tip catheters (less ouch!) and then ultrasound technology (no ouch).
What these studies show is that the uterus contracts in wave like motions called endometrial waves. The direction of the waves, frequency and strength changes throughout the menstrual cycle.
Tell me more
During menses (your period), endometrial waves follow a typical labour pattern in a downward motion and come every 1-3 minutes and are the most intense. For those with endometriosis these contractions can be as frequent and painful as some active labour contractions, but for most pregnant people they are more like early labour contractions.
During pre-ovulation, the uterus contracts in upward endometrial waves from the cervix to fundus (bottom of your uterus to the top) approximately 2-3 times a minute. It is likely this upward motion that helps sperm travel upwards toward the waiting egg. You know how men* need help with directions but don’t like to stop to ask? Well these waves are like GPS for those little guys!
During post-ovulation, the endometrial waves are complex in movement and slow down to about 1 every minute. This change in pattern helps the embryo (fertilized egg) implant in the uterine lining and then your baby starts its major growth and development.
Back to those Braxton Hicks Contractions
And yes, you guessed it – in pregnancy your uterus is also in motion – Braxton Hicks contractions. Scientific studies haven’t fully discovered what causes these contractions, but we do know that hormonal changes in the pregnant person, placenta, and baby play a role, and that chemicals, nutrition, and other factors can affect the muscular movement of the myometrium. Braxton Hicks can also be caused by dehydration, a full bladder, exhaustion, and lifting heavy things.
While Braxton Hicks contractions can be annoying, they are also thought to be beneficial because they help bring extra blood and oxygen to your placenta and therefore to your baby and they may also soften your cervix and strengthen your uterus for labour.
This Doula’s Two Cents
It’s important to be reassured that Braxton Hicks contractions are not a sign of labour even though they are often mistaken as labour. Because they may be caused by a full bladder, dehydration and physical stress – it is important if you notice you are getting many of them that you take a break to empty your bladder, drink a glass of water and put your feet up to rest. If they continue that is fine – you’ll know the difference between Braxton Hick’s contractions and real labour.
What’s the difference between Braxton Hicks and real labour contractions?
- They don’t increase in intensity (getting more painful as the hours pass)
- They don’t get closer together in frequency (not every 5 minutes or less)
- They go away with a change in activity (try a bath, shower, or nap)
- You can speak/breathe through them (active labour contractions take your full attention)
- And you have no other signs of labour (nausea, body temperature changes, diarrhea, amniotic fluid leaking, bloody show, etc.)
Remember if you are unsure, call your health care provider or doula. They can ask you a series of questions about your symptoms and even listen to you during a contraction to help you determine whether a trip to the hospital is warranted.
Additional sources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3935537/
SJ Baker is a the co-owner of Lifetime of Love Doula Services and has been supporting families for almost a decade as a birth doula, postpartum & infant care doula and childbirth educator. She is mom to three boys, twins and a singleton.
