Lynette Sabin started feeling frequent contractions in the last trimester of her pregnancy. The Colorado Springs mom remembers being nervous—she hadn't felt anything like it with her two previous pregnancies. At 34 weeks, Sabin's doctor explained that she had an irritable uterus and put her on bed rest. "I couldn't mop, vacuum, sweep," recalls Sabin. "The first day I thought 'Yippee, this is going to be great,' but then nervousness set in and I worried I might miss a signal." Sabin's son was born three weeks early, a week after she was taken off bed rest. "He was just a little guy, but he was healthy."
Although not a clinical term, irritable uterus describes irregular contractions during pregnancy—before the due date. Most times these contractions are merely a nuisance, but sometimes, as in Sabin's experience, they are an indication of preterm labor.
What is an irritable uterus?
Made up of smooth muscles, the uterine wall performs an amazing feat once labor begins. The muscle sends out patterned contractions, which usually last around 30 to 90 seconds every three to five minutes. These contractions help push the baby out of the uterus and lead to delivery.
"'Uterine irritability' is a term used to describe the phenomenon that prior to the onset of labor, the uterus can contract in a disorganized fashion (during pregnancy)," explains Dr. Laura Klein, an OB-GYN at the University of Colorado School of Medicine. "Rather than strong contractions that come and go every few minutes there can be kind of a constant low level twitching of the muscle." Most of the time these contractions are simply a nuisance and don't lead to labor.
Uterine irritability should not be confused with preterm labor. A uterus that contracts might be doing just that, contracting. As long as these contractions are not affecting the cervix—by pulling it open or shortening it—there is not risk for early labor. If you are experiencing early contractions, your doctor will be able to evaluate the contractions to see if they are cause for concern.