Braxton Hicks contractions are sporadic contractions and relaxation of the uterine muscle. Sometimes, they are referred to as prodromal or “false labor" pains. It is believed they start around 6 weeks gestation but usually are not felt until the second or third trimester of the pregnancy. Braxton Hicks contractions are the body's way of preparing for true labor, but they do not indicate that labor has begun or is going to start.
Braxton Hicks contractions are a normal part of pregnancy. They may be uncomfortable, but they are not painful. Women describe Braxton Hicks contractions as feeling like mild menstrual cramps or a tightening in a specific area of the abdomen that comes and goes.
Braxton Hicks contractions can be differentiated from the contractions of true labor. Braxton Hicks contractions are irregular in duration and intensity, occur infrequently, are unpredictable and non-rhythmic, and are more uncomfortable than painful. Unlike true labor contractions, Braxton Hicks contractions do not increase in frequency, duration, or intensity. Also, they lessen and then disappear, only to reappear at some time in the future. Braxton Hicks contractions tend to increase in frequency and intensity near the end of the pregnancy. Women often mistake Braxton Hicks contractions for true labor. However, unlike true labor contractions, Braxton Hicks contractions do not cause dilatation of the cervix and do not culminate in birth.
Braxton Hicks contractions are caused when the muscle fibers in the uterus tighten and relax. The exact etiology of Braxton Hicks contractions is unknown. However, there are known circumstances that trigger Braxton Hicks contractions including when the woman is very active, when the bladder is full, following sexual activity, and when the woman is dehydrated. A commonality among all these triggers is the potential for stress to the fetus, and the need for increased blood flow to the placenta to provide fetal oxygenation.
Braxton Hicks contractions are present in all pregnancies. However, each woman's experience is different. Most women become aware of Braxton Hicks contractions in the third trimester, and some women are aware of them as early as the second trimester. Sometimes Braxton Hick contractions occurring near the end of the third trimester of pregnancy are mistaken as the onset of true labor. It is not unusual, especially in a first pregnancy, for a woman to think she is in labor only to be told it is Braxton Hicks contractions and not true labor.
Braxton Hicks contractions are thought to play a role in toning the uterine muscle in preparation for the birth process. Sometimes Braxton Hicks contractions are referred to as "practice for labor." Braxton Hicks contractions do not result in dilation of the cervix but may have a role in cervical softening.
The intermittent contraction of the uterine muscle may also play a role in promoting blood flow to the placenta. Oxygen-rich blood fills the intervillous spaces of the uterus where the pressure is relatively low. The presence of Braxton Hicks contractions causes the blood to flow up to the chorionic plate on the fetal side of the placenta. From there the oxygen-rich blood enters the fetal circulation.
When assessing a woman for the presence of Braxton Hicks contractions, there are some key questions to ask. Her response to these questions will assist the healthcare provider to differentiate Braxton Hicks contractions and true labor contractions.
During the physical assessment, the provider may palpate an area of tightening or a "spasm" of the uterine muscle, but the presence of a uterine contraction in the uterine fundus is not palpable. The woman will be assessed for the presence of uterine bleeding or rupture of the amniotic membrane. An examination of the cervix reveals no change in effacement or dilatation as a result of the Braxton Hicks contractions.
There are no laboratory or radiographic tests to diagnose Braxton Hicks contractions. Evaluation of the presence of Braxton Hicks contractions is based on an assessment of the pregnant woman's abdomen, specifically palpating the contractions.
By the midpoint of pregnancy, the woman and provider should discuss what the woman may experience during the remainder of the pregnancy. Braxton Hicks contractions are one of the normal events a woman may experience. Teaching her about Braxton Hicks contractions will help her to be informed and to decrease her anxiety if they occur.
There is no medical treatment for Braxton Hicks contractions. However, taking action to change the situation that triggered the Braxton Hicks contractions is warranted. Some actions to ease Braxton Hicks contractions include:
If these actions do not lessen the Braxton Hicks contractions or if the contractions continue and are becoming more frequent or more intense, the patient's healthcare provider should be contacted.
Also, if any of the following are present the healthcare provider should be contacted immediately:
In addition to Braxton Hicks contractions, there are other causes of abdominal pain during pregnancy. Some normal reasons for abdominal pain during pregnancy, in addition to Braxton Hicks contractions and true labor contractions, include:
Circumstances in which abdominal pain is a sign of a serious condition that requires immediate medical attention include:
If a woman is unsure if she is experiencing Braxton Hicks contractions or another condition, a discussion with a healthcare provider is needed. The healthcare provider may recommend a visit to the office setting or labor and delivery for an examination by a healthcare professional to determine the cause of the abdominal pain.
|Powell's Pearls: John Braxton Hicks, MD (1823-1897)., Powell JL,, Obstetrical & gynecological survey, 2007 Sep [PubMed PMID: 17705884]|
|From Braxton Hicks to preterm labour: the constitution of risk in pregnancy., MacKinnon K,McIntyre M,, The Canadian journal of nursing research = Revue canadienne de recherche en sciences infirmieres, 2006 Jun [PubMed PMID: 16871850]|
|John Braxton Hicks (1823-97) and painless uterine contractions., Dunn PM,, Archives of disease in childhood. Fetal and neonatal edition, 1999 Sep [PubMed PMID: 10448189]|