Rock and Roll of the Abdominal Muscles Associated with Labor
Abstract Number: 255
Abstract Type: Case Report/Case Series
We report an unusual case of abdominal myoclonus associated with labor in a 32-year-old G2P1. We took care of this otherwise healthy parturient in 2007 and again in 2009. Both pregnancies were uncomplicated when suddenly she experienced jerky abdominal wall twitches with the onset of labor. She has no history of seizures or myoclonus at any other time before and between pregnancies.
During the first pregnancy in 2007, she presented at 39 weeks with a complaint of jerky abdominal contractions which started 24 hours earlier with the onset of labor. On admission, the cervix was 3 centimeters dilated. Involuntary twitches of the anterior abdominal wall were occurring frequently without provocation or pattern. The abdominal contractions were exhausting and disturbing the patient so she could not rest or sleep. Neurology and anesthesia consultations were obtained. An epidural was placed without complications. After a negative test dose, 0.25% bupivacaine was administered, followed by 2% lidocaine when no improvement in myoclonus was noted. Several minutes later, the abdominal wall contractions decreased in intensity and frequency. Anesthesia was maintained with a continuous infusion of 0.125% bupivacaine with fentanyl. She spontaneously delivered a healthy female infant ten hours later. After delivery, the abdominal myoclonus abated.
During her second pregnancy in 2009 at 35 weeks, the abdominal myoclonus recurred with onset of preterm labor. On admission, the cervix was 1 centimeter dilated. Magnesium sulfate, lorazepam, diazepam, and cyclobenzaprine were administered without effect on the myoclonus. Levetiracetam temporarily relieved the myoclonus. Twenty-four hours later, the cervix was 4 to 5 centimeters dilated. An epidural was placed without problems, dosed with 2% lidocaine and maintained with 0.125% bupivacaine and fentanyl. The myoclonus subsided after lidocaine. Four hours later she delivered a healthy baby girl. The abdominal myoclonus was completely gone shortly after delivery.
It appears that this patient has a stimulus-sensitive type of myoclonus triggered by labor. This type of myoclonus can be induced by a variety of external events such as noise, movement, light, and surprise. Scientists believe that stimulus-sensitive myoclonus may involve over-excitability parts of the brain that control movement. The series of feedback loops which interconnect these parts through neurotransmitters may facilitate and modulate communication between the brain and muscles. Some neurotransmitters may make receiving cells more sensitive, while others may make them less sensitive. An imbalance between these chemicals may cause myoclonus.
Search of the literature uncovered one similar case in Turkey which occurred during labor and resolved two days postpartum.