Scuba diver looking worried on the surface of the water. We ask is it safe to scuba dive while pregnant?
Is it safe to scuba dive while pregnant? Photo: Mojca / Pixabay

Can you scuba dive while being pregnant? Yes, physically you can. There have been hundreds, if not more cases where women have gone for a dive while pregnant, usually before the pregnancy is known. Whether you should scuba dive while pregnant is another matter. And whether it is safe for the fetus or the mother is also an issue to discuss. In this article, we dive into pregnancy and scuba diving: the risks, the known and the unknown, and what other fun ways that you can explore the ocean while pregnant.

Can You Scuba Dive While Pregnant?

As we learn in our Open Water courses, scuba diving while pregnant is not recommended… but we don’t learn why. Perhaps this is because humans tend to err on the side of caution when it comes to pregnancy, and scuba diving is a risk even before you factor in a delicate fetus. But a huge part of this recommendation is that we can’t actually do the research. 

Most medical decisions require heaps of published literature, so why is this case any different? The reason is ethics.

It is unethical to experiment with pregnant women, especially with unknown consequences. But the recommendation to avoid diving while pregnant is much more than just a guess. It is a cautious recommendation from medical and scuba diving professionals based on the evidence we have. Human testing hasn’t been done to explore the effects of scuba diving on a fetus, but we know a lot about both scuba diving and pregnancy individually and we can put the pieces together. From surveys of women who went scuba diving before they knew they were pregnant, and experiments involving pregnant animals and hyperbaric oxygen, here is what we do know. 

Decompression Sickness (DCS)

Decompression sickness is caused by dissolved gases (nitrogen) bubbling out of solution (the blood) as pressure decreases (on a scuba ascent). Arterial gas embolism (AGE) happens when these air bubbles block the blood supply in blood vessels or the heart. Bubbles in the bloodstream could interrupt circulation or cause direct tissue trauma to a fetus. There is no way to make a safe dive profile for a fetus. Normally, our lungs are very effecting at filtering bubbles from circulation but in a fetus, the blood bypasses the lungs and gas exchange occurs through the placenta. AGE in a fetus could occur without the mother experiencing any symptoms at all, which makes this rare event not worth the risk of scuba diving. 

Animals and Hyperbaric Oxygen

Though this hasn’t been tested on humans, scientists have done experiments on rats and hamsters. Exposing pregnant rats to hyperbaric (pressurized) oxygen did not cause abnormalities, but it did result in bigger placenta and smaller fetuses. 

Pregnant hamsters were exposed to compressed air for 40 minutes. Three things happened. 

1) Some mothers did not get decompression sickness but did show smaller fetuses than normal.

2)  Some mothers got decompression sickness, were treated, and their fetuses were not different from normal hamsters. 

3) Some mothers got decompression sickness were left untreated, and these fetuses most frequently and severely malformed. 

These results show that in best case scenarios, breathing pressurized oxygen stunted the baby’s growth. Decompression sickness was able to be treated in the mother and the fetus, with no significant side effects. In the more extreme cases, untreated decompression sickness resulted in malformed babies. Hamsters and rats aren’t humans, but where it is unethical to experiment on humans, animals provide a way for us to learn things that we couldn’t otherwise know. We owe a lot of our medical research and success to animals, who help us ensure safety of something before trying it in humans.

Accidentally Scuba Diving before you knew you were Pregnant

After all of that information about hamster babies and lack of human research on diving while pregnant, the next most obvious question is, “What if I didn’t know I was pregnant?” This is a completely valid question, and in looking into it I started searching through the internet’s scuba dive forums. I am happy to report that I found story after story of women who went diving before they knew about their pregnancy, each with a happy ending of healthy and successful children free from medical issues. 

There have been some small studies done, with differing results. Some show no effect since these dives occurred early in the pregnancy that it’s thought it was too early to cause harm. A survey was done of scuba divers who had recently given birth, and the ones who didn’t dive reported no birth defects. The ones who had been scuba diving did show some birth defects, but not at a rate any higher of the national average. So, what does that mean? Unsatisfyingly, we can’t tie the birth defects to scuba diving. The problem with not experimenting in a closed laboratory is that there are so many different variables between these pregnant scuba divers – there’s no way to be sure that any birth defects were a direct result of scuba diving. In other words, it is better to be safe than sorry.

Is it Safe to Snorkel while Pregnant?

Yes, it is! Snorkeling and scuba diving are different for many reasons, but the one that matters here is the air you breathe while you’re doing them. Scuba diving while pregnant is an issue because of breathing compressed gases, but this is not the case with snorkeling. While snorkeling, you breathe air from the surface through your snorkel, making it safe to do while pregnant. Read more about the differences between snorkeling and scuba diving and our tips for snorkeling while pregnant. In fact, there are many safe ways to interact with the ocean while pregnant.

Marine Science Teacher, Anna Ortega on-site in South Caicos
Anna Ortega snorkeling on a conch survey in the Marine Protected Area off of South Caicos. Photo / Anna Ortega

Other Water Activities to do while Pregnant

Regular exercise during pregnancy is recommended for decreasing discomfort and improving stamina and strength. So why not do it in the beautiful, blue ocean? Here’s a list of great ways to enjoy the ocean while pregnant. There are ways to maximize your safety during these activities, like making sure to hydrate, eat, and apply sunscreen, and of course, check with a medical professional that these activities are safe for you.

Snorkeling – As discussed above this is a great way to see the ocean while being pregnant. Even if it’s a bit harder later in the pregnancy to snorkel against a current, you could always float on the surface and watch the fish swim by below.

Read More: How to Snorkel Underwater

Paddleboarding – Stand up paddleboarding is great for strengthening your core and practicing balance. This is an extra challenge while you are pregnant, because your center of gravity has shifted. Make sure you keep a pace that’s comfortable for you. 

Kayaking or Canoeing – Both are totally safe for pregnancy, and a lot of fun. These are low-impact outdoor activities that rely primarily on arm strength, which gives your knees and legs a break. 

Swimming – This is a safe and recommended form of exercise during pregnancy, with suggestions to try 15-30 minutes, 4 times a week. There’s even been research into the safety of chlorinated pools for a fetus. Rest assured that chlorine does not pose any health risks for you or your developing baby.

Generally, if you were active before your pregnancy, it should be safe for you to remain active throughout it. Every person is different, and each person and their health care provider know what is best for them and their baby. 

So why can’t we scuba dive while pregnant? Is it because we have decades of fool-proof experimental evidence showing that scuba diving negatively impacts a fetus? No. It is because pregnancy, like diving, is inherently risky. Because of this, we do everything we can to be as safe as we can. 

Anna grew up far away from the ocean, but that hasn’t stopped her passion for marine science. She is a marine biology graduate student at the University of Western Australia, spends her summers as a marine educator in the Caribbean, and studied spotted eagle ray behavior in the Meso-American reef.