Jun 2015

Pregnancy and Diving

By Mike Waddington

At the start of any dive training program the students must fill out a medical statement. This lists varies medical ailments or contradictions to diving that the student may have. Recently I was teaching an Open Water course and one of my female students stopped at the first question, which is “Are you, or could you be pregnant?” She then informed me that she was indeed 6 weeks pregnant and was now worried that she would not be able to dive now. Of course, she could not carry on with any in water training. Although many divers know that pregnancy and diving do not go together, many do not know why, so hopefully this will clear it up.

Although the evidence that diving while pregnant is dangerous is not overwhelming, it certainly suggests that there is a possibility that the fetus could be damaged. Using hyperbaric chambers, several studies using animals have been conducted. Many of these tests have shown an increase in birth defects, however some of the results showed that the fetus was harmed in no way. However, no tests have ever been conducted on a pregnant human, for obvious ethical reasons. So the data we have is limited to that of different species.

Many people argue that because the fetus is suspended in liquid, that it shouldn’t matter as liquid is incompressible. But just because liquid cannot be compressed, it doesn’t mean that it is not being affected in some way by the pressure. A fetus doesn’t breathe in the same way as we do, their blood is oxygenated via the placenta. The fetus cannot filter nitrogen through the lungs like we do, so if the mother were to get a DCS (decompression sickness) hit, then the bubbles would be passed onto the fetus, and there would be no way for the fetus to eliminate the nitrogen bubbles. This increase the likelihood that the bubbles could circulate the body unchecked, causing damage to the fetuses still developing vital organs, such as brain, heart or spinal cord.

Of course there have been women who have been diving accidentally before they realised they were pregnant. Of these women, birth defects were very similar to the average population, but this doesn’t mean that it is safe to dive while pregnant. Most women realise early on that they are pregnant, so this could suggest that in the first few weeks it has little impact, but as the fetus begins to develop the dangers could increase. This could be because very early on in pregnancy, the embryo is composed of cells that have not undergone differentiation (cells have not formed into different parts of the body, such as heart, or leg). If one of these cells is damaged, then another cell can simply take its place. Once differentiation has taken place, a damaged cell is more likely to result in a birth defect or abnormality.

If you are planning a diving holiday and want to try to conceive, should you avoid diving? We suggest that you enjoy your diving holiday and try not to worry. A normal couple, trying to actively achieve pregnancy find that on average it takes three to four months to conceive. So chances are you won’t conceive on this trip (although improbable it may still happen). The embryo doesn’t attach to the wall of the uterus for a week to ten days after conception, therefore there is no effective blood circulation between the mother and fetus, meaning there is very little chance (if any) of any harm being done.

Almost all (if not all) dive organisations list pregnancy as absolute no-go diving contradiction. The evidence is not there to scientifically prove that it is dangerous, however there is also no evidence suggesting that it is safe. Although the risks may be low, the consequences may be high, so it is better to be safe than sorry. Once the baby is delivered the mother will usually be fit to dive in only a few weeks, so until then, you should stick to snorkeling.

‘Pregnancy and Diving’ was written by Mike

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Mike Waddington

I first discovered diving in 2008 after going snorkeling on the Great Barrier Reef in Australia. After trying diving at a flooded quarry in England I decided to head out to warmer more interesting waters in Thailand where I ended on the Island of Koh Tao completing my Open Water course. Instantly addicted with money to spend and plenty of time on my hands I decided to continue until I became a Divemaster so I could live what seemed as the perfect life.

After that I headed to the Caribbean to an island called Utila to complete my instructor course, I spent several months out there completing the MSDT internship, teaching students and leading dives. This is also where I discovered my interest in the technical side of diving, taking part in equipment repair courses and learning about blending gasses and running compressors.

With all my new qualifications it was time to head back to where it had all started, Back to Koh Tao where I intended on living the dream. Once I arrived I quickly found a job and started teaching straight away. During my time on Koh Tao I took part in all many technical diving courses, learning how to dive with re-breathers, in caves and even going down to 90m/300ft!


PADI Master Scuba Diver Trainer
PADI/DSAT Tech Deep Instructor
PADI/DSAT Gas Trimix Gas Blender
PADI/DSAT Trimix Diver
TDI Intro to Cave Diver
TDI Advanced Wreck Diver
TDI Inspiration rebreather Decompression Procedures
PADI Professional Videographer
BSAC Compressor Operator
TDI Equipment Service Technician

Dream Dive Locations:

Silfra, Iceland
Cenotes, Mexico
Chuuk Lagoon, Micronesia
Ice Diving in Russia