Is it dangerous to ice bath pregnant?
Summary
Women who cold plunge during pregnancy report positive outcomes, including better mood, reduced inflammation, and more energy.
Short, acute, deliberate cold exposure can boost insulin sensitivity and correct metabolic disorders. Epidemiological studies show that increased cold exposure during pregnancy can result in better birth outcomes.
Benjamin Bikman, PhD explains that a healthy pregnancy is a state of physiological insulin resistance. Gestational diabetes occurs when the insulin resistance during pregnancy goes too far.
Sauna is not safe for pregnancy and Josephine Worsek, PhD cautions against Wim Hoff breathing.
Can you cold plunge during pregnancy?
Ice baths can contribute to reproductive health
I've heard from two couples who conceived a child shortly after beginning a regular practice of deliberate cold exposure. Given the metabolic and hormonal benefits of the ice bath, perhaps the coincidence of ice bath and fertility are related. Nonetheless, once they realize their pregnancy, it's very natural of them to hesitate about continuing their cold water immersion practice.
Josephine Worseck, PhD
To help women find an answer to the question, "Is a cold practice safe during pregnancy?" I turned to Josephine Worseck, PhD -- the first woman in Germany certified as a Wim Hof Instructor, and author of Die Heilkraft Der Kalte (or 'The Healing Power of the Cold' [in German], 2020).
Shortly after publishing her book, Worsek posted a picture of her pregnant sister wading into cold water outdoors, to demonstrate that:
Ice bathing during an established pregnancy is "not a problem. - Josephine Worsek, PhD (2021)
She speculates a little about the advantages and disadvantages of deliberate cold exposure for conception and implantation of the zygote, acknowledging that the immune system response to cold might complicate the very earliest stages of pregnancy. For examples, Worseck cautions that the effect of "immune modulating activities like ice bathing... intervene with egg implantation (positively or negatively) in a manner that might depend from woman to woman."
While she cautions that "Wim Hof breathing should not be performed by pregnant women," what she didn't describe in that post are the potential benefits of cold plunging for women who are already pregnant -- and there may be several.
Benjamin Bikman, PhD
To understand the mechanisms by which deliberate cold exposure might benefit pregnant women, I consulted with Benjamin Bikman, PhD. Bikman is one of the world's foremost authorities on metabolism is Benjamin Bikman, PhD, author of Why We Get Sick (2020) and Professor of Cell Biology and Physiology at Brigham Young University. He explained that pregnancy is a state of physiological, rather than pathological, insulin resistance.
According to Bikman, insulin resistance during pregnancy in normal, because of the increased progesterone and human growth hormone that are powering growth of the baby. However, that's also why women who are insulin resistance prior to becoming pregnant are at risk of entering a state of gestational diabetes -- when their insulin resistance becomes too great.
That may explain why a recent study of pregnant Canadian women found that more than 1 in 5 were diagnosed with gestational diabetes. However, the fact that cold exposure is known to improve insulin sensitivity might also explain why the prevalence of gestational diabetes in during the summer months exceeds that during winter months in the Canadian cohort (Retnakaran et al. 2018). Another study, this time of over one million pregnant Chinese women, supports this idea. Those pregnant women with the greatest heat exposure suffered increased risk of pre-term birth, while the pregnant women with the greatest cold exposure enjoyed reduced risk of premature birth (Guo et al, 2017).
The benefits of a regular cold plunge may be particularly important for women in warmer climates. A study of Australian women discovered that exposure to heat waves can increase the risk of adverse birth outcomes, including still birth (Wang et al. 2019). The vulnerability to extreme heat may greatest during the first trimester, according to a review of the effects of temperature and pregnancy (McMurray & Katz 2012).
The same review concluded that:
Cold exposure presents minimal risk to the fetus, except in the extreme case in which hypothermia may be detrimental to maternal survival. - McMurray & Katz (2012)
These findings are reinforced by others that show greater cold exposure during the winter confers the benefit of increased insulin sensitivity, and lower blood glucose levels (e.g., Wainstock & Yoles 2018). That is, an ice bath during pregnancy may guard against gestational diabetes by improving insulin sensitivity, at a time when risk of metabolic disorders is particularly elevated.
In addition to the metabolic benefits of deliberate cold exposure for pregnant women, there may be emotional and psychological benefits, too. One of the most recent articles on cold water swimming and women's health hypothesized:
Women who are long term pre-pregnancy cold water swimmers may expect to experience improved obstetric outcomes over those who are not. - Gundle & Atkinson (2020).
The reasons for their optimism are multifaceted, but among the most important of these may be an improved response to stress. According to these scientists from the University of Bristol Medical School:
Winter swimming improves long-term pain tolerance. Although acute cold water immersion activates the sympathetic nervous system and increases levels of stress hormones, these neurochemical responses typically improve pain tolerance by modifying the hypothalamic–pituitaryadrenal-thyroid-gonadal (HAPTG) axis response to pain.
Stress inoculation inures against future stress. Short term stress trains the body to be more tolerant of future stress. This seemingly paradoxical response is known as hormesis and I describe it in more detail in my article Hormesis for Health, especially with regard to hypertension (high blood pressure).
Training for stress response may improve birth outcomes. Research investigating the effects of repeated cold water immersion demonstrate that the stress responses diminishes with repeated exposure. For example, the technique of Stress Inoculation involves titrating small stress exposures to stimulate adaptive responses that reduce the negative consequences of stress. Because studies of pregnant women show that self-reported stress levels are associated with increased risk premature birth and low birth weight, stress training might improve birth outcomes.
Avoid heat during pregnancy
Given the benefits of cold exposure in general, and the risks of extreme heat, pregnant women should avoid the sauna.
Ice bath for breastfeeding?
Shortly after publication of this article, Worseck became pregnant herself and she periodically posted to Instagram to update those curious about her progress. She used ice baths & cold showers, snow baths, and underdressing during her pregnancy. She gave birth to a healthy baby boy, who is now a preschooler.
During the post-partum period, many women suffer from low mood or post-partum depression. In Can Cold Water Cure Depression? I wrote about the mood-boosting effects of cold water therapy, and so it's natural for many women who want to continue their ice bath practice after childbirth to ask "Is is OK for me to ice bath while breastfeeding?"
Worseck says, "No problem."
During her post-partum period, she used cold showers regularly, enjoyed them and suffered no ill effects on her milk flow. Four or five weeks later, she incorporated ice baths back into her practice with good results.
Worseck explains that many women are concerned that the stress of an ice bath might reduce their milk flow, but she doesn't think that's the case. The short-term stress of an ice bath stimulates a healthy response that increases dopamine, lifts mood, and stimulates a healthy, hormetic response. According to Worseck, the long-term stress of post-partum isolation, or returning to work after maternity leave can be more detrimental to health, whereas the short-term stress of the ice bath can "teach your body to better deal with stress"
For me, having an ice bath was a welcome moment of self-reflection. Even if it's just two minutes in the ice, I get out and feel refreshed again, and definitely a better Mom for the the day. - Josephine Worseck, PhD
References
Bikman B. Why We Get Sick: The Hidden Epidemic at the Root of Most Chronic Disease--and how to Fight it. BenBella Books; 2020.
Guo T, Wang Y, Zhang H, Zhang Y, Zhao J, Wang Y, Xie X, Wang L, Zhang Q, Liu D, He Y. The association between ambient temperature and the risk of preterm birth in China. Science of the total environment. 2018 Feb 1;613:439-46.
Gundle L, Atkinson A. Pregnancy, cold water swimming and cortisol: The effect of cold water swimming on obstetric outcomes. Medical Hypotheses. 2020 Nov 1;144:109977.
McMurray RG, Katz VL. Thermoregulation in pregnancy: implications for exercise. Sports medicine. 1990 Sep;10:146-58.
Retnakaran R, Ye C, Kramer CK, Hanley AJ, Connelly PW, Sermer M, Zinman B. Impact of daily incremental change in environmental temperature on beta cell function and the risk of gestational diabetes in pregnant women. Diabetologia. 2018 Dec;61:2633-42.
Wainstock T, Yoles I. Pregnant women may be sweeter in the summer: seasonal changes in glucose challenge tests results. A population-based study. Diabetes Research and Clinical Practice. 2019 Jan 1;147:134-7.
Wang J, Tong S, Williams G, Pan X. Exposure to heat wave during pregnancy and adverse birth outcomes: an exploration of susceptible windows. Epidemiology. 2019 Jul 1;30:S115-21.
WorseckJ. 2020. Die Heilkraft Der Kalte (or 'The Healing Power of the Cold' [in German].
About the Author
Thomas P Seager, PhD is an Associate Professor in the School of Sustainable Engineering at Arizona State University. Seager co-founded the Morozko Forge ice bath company and is an expert in the use of ice baths for building metabolic and psychological resilience.
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