Are ice baths and cold plunges safe during pregnancy?

What does the evidence say about ice baths and cold plunges during pregnancy?

1. The cold shock response on sudden immersion is a reflex pattern of tachycardia, a respiratory gasp, uncontrollable hyperventilation, peripheral vasoconstriction and hypertension. 1
2. Holding your breath while submerged in cold water produced arrhythmias in 62 to 82 percent of healthy young participants, compared with about 2 percent during free-breathing immersion. 1
3. In a controlled study of a single cold plunge, heart rate rose during the first minute of immersion and systolic, diastolic and mean arterial pressure were all elevated during immersion and stayed elevated afterward. 2
4. In that same study, negative mood scores and cortisol were lower three hours after the plunge, which is the mood benefit people usually describe. The participants were not pregnant. 2
5. During the second and third trimesters, positions that involve lying flat on your back are discouraged because they reduce blood flow, which is why an upright plunge posture makes sense later on. 3

Is ice baths and cold plunges safe in each trimester?

• First trimester. If cold plunging is new to you, early pregnancy is not the time to start. The gasp reflex and blood pressure spike are strongest before your body has habituated to cold water.
• Second trimester. People who already plunge regularly sometimes carry on with shorter, warmer dips. Keep it brief, never plunge alone, and get out at the first sign of dizziness or breathlessness.
• Third trimester. Lying back in a cold tub late in pregnancy puts the uterus against the large vessels behind it, the same reason exercise flat on your back is discouraged. Sit upright, keep it short, and stand up slowly.