ON A LIVEABOARD IN THE RED SEA, I found out that Jade and I were expecting our first child. We knew that Jade would have to put scuba-diving on hold for nine months, but as time went on I wanted to better understand the research behind diving and pregnancy.
Unlike many marine species (hello Mr Seahorse), the female does all of the heavy lifting when it comes to human pregnancy, and us males can only do our best to be supportive.
On top of the physical burden, mothers-to-be are advised to give up scuba-diving during the gestation period – like most men I am eternally indebted to Jade for taking on both of these burdens!
The vast majority of divers today are aware that you shouldn’t dive if pregnant, and all the training agencies now list pregnancy as a contra-indication to scuba-diving that requires medical consultation.
The risks to a foetus are the same we consider apply to ourselves when diving: decompression illness (DCI) and the effect of high oxygen partial pressure.
What is unclear is a foetus’s susceptibility to these issues.
It’s possible that if excessive bubbling occurred in the mum-to-be, some of these bubbles would pass through the placenta into the foetus. Terrifyingly, it’s possible that harmful bubbles could occur in the womb without the mother showing any signs of DCI. We are also unsure how a foetus will react to high doses of oxygen under pressure – either in a hyperbaric chamber or while diving.
Depending on the stage of pregnancy, there are concerns that a diving illness could have severe consequences such as physical abnormalities, brain damage or even death for the foetus.
Using pregnant women for testing is obviously not an ethically sound idea, so lack of data is the biggest barrier to us better understanding this issue. Sheep placenta has the closest resemblance to that of a human, and hyperbaric dive simulations have been conducted on pregnant ewes.
These experiments uncovered excessive bubbling in both the ewe and its foetus and, when put through a series of extreme dive-profiles, foetal death occurred. There has also been hyperbaric testing of pregnant rats, which showed that if the rats did contract DCI, there was a much higher likelihood of physical abnormalities in the foetus, even if the DCI was treated.
On the other hand, when no DCI occurred, the foetus had the same chances of being born healthy as in cases in which the mother had not “dived”.