The experience of shaking or shivering shortly after childbirth, often called postpartum chills, can be startling for new mothers. This full-body tremor, sometimes accompanied by chattering teeth, is a physiological response that occurs in many women following both vaginal and cesarean deliveries. The phenomenon is generally a normal and temporary reaction as the body rapidly adjusts to the profound changes brought on by labor and delivery. While the exact cause is not fully understood, the shaking is considered a benign and expected event that typically resolves quickly.
The Body’s Hormonal and Temperature Reset
The dramatic hormonal shift that occurs the moment the baby and placenta are delivered is a primary driver of postpartum shaking. During pregnancy, levels of hormones like estrogen and progesterone are extremely high. Their sudden withdrawal after delivery can disrupt the body’s central nervous system regulation, directly influencing the body’s thermostat responsible for maintaining a stable internal temperature.
The physical exertion of labor also plays a role. Labor is physically demanding, leading to a high metabolic rate and energy expenditure that can trigger shivering as a side effect of muscle exhaustion. Shivering is the body’s attempt to regulate temperature and compensate for the energy used during delivery.
Thermoregulation is another factor, as the body tries to stabilize its temperature after delivery. Even if the mother’s core temperature is stable, the body may react to the cooler ambient environment of the delivery room following the warm internal state of pregnancy. This reaction, combined with potential fluid shifts, prompts the involuntary muscle contractions that constitute shivering.
Some theories suggest the shaking may be a response to the small mixing of fetal and maternal blood that can occur during delivery, particularly if the blood types are incompatible. The mother’s body may interpret the foreign blood components as an invasion, triggering a nervous system response.
How Medical Interventions Contribute
Medical procedures used during labor can initiate or intensify postpartum shivering. The use of regional anesthesia, such as an epidural or spinal block, is a frequent contributor. These medications cause the blood vessels in the skin to widen, a process called vasodilation. Vasodilation leads to a redistribution of body heat from the core to the extremities, which can cause a drop in core body temperature and trigger the shivering reflex. Research suggests that about half of women who receive an epidural or have a cesarean section experience postpartum chills, compared to a smaller percentage of those who have an unmedicated vaginal birth.
The rapid infusion of intravenous (IV) fluids during labor can also contribute to the feeling of cold and the onset of shivering. These fluids, often administered at room temperature or slightly cooler, can quickly lower the patient’s internal temperature. The shivering may also be a reaction to minor shifts in blood pressure. The medical team often takes measures, such as using warmed blankets or pre-warmed IV fluids, to help mitigate the temperature disruption.
Duration, Comfort Measures, and Warning Signs
Postpartum shaking is typically short-lived, with most episodes lasting only a few minutes to about an hour. The shivering usually occurs immediately following delivery or within the first one to two hours postpartum as the body works quickly to recalibrate its systems.
Simple comfort measures can help ease the discomfort while the shaking subsides. Receiving warm blankets from the hospital staff is an effective intervention to help raise the body’s surface temperature. Skin-to-skin contact with the newborn can also be soothing for both mother and baby, using the baby’s warmth to help regulate the mother’s temperature.
Drinking warm beverages, such as tea or broth, can help raise the core temperature internally and promote hydration, which is beneficial after the physical demands of labor. It is important to try and relax during the episode, as tensing the body in an attempt to stop the tremors can increase discomfort.
While postpartum shaking is usually benign, be aware of warning signs that distinguish normal chills from a potential complication. A persistent fever of 100.4°F or higher alongside the chills should be reported to the healthcare provider immediately, as this could indicate an infection. Shaking that lasts longer than an hour, or is accompanied by excessive blood loss, severe abdominal pain, or foul-smelling discharge warrants prompt medical attention.