Labor often includes an involuntary physical reaction known as labor shivering or the “labor shakes.” This phenomenon, characterized by uncontrollable trembling, chattering teeth, or full-body shaking, can be alarming but is a very common occurrence. It can happen during the active phase of labor, immediately following delivery, or after the administration of regional anesthesia. While the intensity of the tremor can be significant, the shaking is nearly always a temporary, harmless physical response to the massive physiological shifts underway.
The Underlying Causes of Labor Shivering
The sudden onset of shaking is typically a multi-layered physiological response. One major trigger is the body’s massive hormonal surge, which includes the release of catecholamines like adrenaline and epinephrine in response to the effort and stress of contractions. These stress hormones activate the “fight-or-flight” system, which can manifest as jitters and tremors.
Another significant factor is the body’s attempt at thermoregulation, or temperature control. The intense physical exertion of labor can cause internal temperature fluctuations, and the body may try to correct a perceived coldness by shivering, which is a muscular mechanism for generating heat. This is often compounded by the administration of intravenous (IV) fluids, which are typically room temperature and can contribute to a drop in core body temperature.
Epidural or spinal anesthesia also plays a role in labor shivering for many women. Regional anesthesia can cause a redistribution of heat from the core to the periphery of the body by opening up blood vessels in the lower half of the body. This heat loss, combined with the block on the nervous system’s ability to sense temperature below the injection site, can trigger a shivering response. Warming the anesthetic solution itself can sometimes reduce the incidence of shivering.
Immediate Comfort Measures and Interventions
The focus of management is on comfort, relaxation, and nervous system regulation. The most immediate and simple intervention is the application of warmth to combat perceived or actual temperature drops. Warmed cotton blankets or forced-air warming blankets can be placed over the body, and warm beverages can be offered if the patient is allowed to drink.
If IV fluids are being administered, requesting that they be warmed to body temperature can help prevent a further drop in core temperature. Combining warmed IV fluids with forced-air warming has been shown to be more effective at maintaining a near-normal core body temperature and reducing the incidence of shivering following neuraxial anesthesia.
Engaging in slow, purposeful breathing techniques helps to calm the central nervous system, which is often overstimulated during labor. Techniques like “box breathing,” which involves inhaling, pausing, exhaling, and pausing for even counts, can provide focus and slow the heart rate. Making deep, low-pitched vocalizations during the exhale can also help the body relax.
Non-Pharmacological Comfort Measures
Other non-pharmacological comfort measures include:
- Gentle touch, such as a partner applying steady pressure or a “jiggle” technique, to provide a physical anchor and a sense of safety.
- Simply surrendering to the tremor, rather than fighting against it, can sometimes lessen its overall intensity.
- A simple distraction, such as sticking the tongue out, can interrupt the neurological loop that is perpetuating the shaking.
When Shaking Signals a Medical Concern
While the vast majority of labor shaking is benign, it is important to distinguish it from shaking that signals a medical issue requiring immediate attention. The most significant concern is shaking or shivering that is accompanied by a significant rise in body temperature, typically a fever above 100.4°F (38°C). This combination can indicate an infectious process, such as chorioamnionitis, an infection of the amniotic fluid and membranes, which requires prompt medical evaluation and treatment.
Shaking that occurs alongside sudden, severe fluctuations in blood pressure, such as a drastic drop following the placement of an epidural, also warrants immediate attention. The medical team constantly monitors these vital signs to ensure the body is responding appropriately to interventions.
It is also important to differentiate generalized labor shivering from true seizure activity. While labor shakes are a tremor or exaggerated shivering, a seizure involves uncontrolled, rhythmic full-body convulsions, often accompanied by a loss of consciousness. Seizure activity can be a sign of a neurological event like eclampsia, a life-threatening complication of preeclampsia, and requires emergency intervention.