my wife is considering scuba diving on our trip in november that we had planned several months ago. We recently found out that she is pregnant and will be approx. 12 weeks along during our vacation.

I am a female SCUBA instructor (and Emergency First Response Instructor) certified by PADI. I have done some research into this very same question and would like to start off by saying that your best resource for dive-related medical questions is DAN is a not-for-profit organization that provides emergency medical advice and assistance for underwater diving injuries, and underwrites a wide range of research, education and training programs that promote safe diving.

With regard to your question about the safety of diving while pregnant, most professionals seem to agree that there is not enough scientific research into this area to safely advise anyone that she and her unborn child will not be negatively affected by the changes in pressure associated with diving and the effects those changes have on the body. DAN does have a few articles that cite some minor studies that have been done but conclusive evidence isn’t readily available.

Quoting from a DAN article, "An issue to keep in mind is the risk of decompression illness to the mother due to the physiological changes which occur while pregnant. During pregnancy, maternal body fluid distribution is altered, and this redistribution decreases the exchange of dissolved gases in the central circulation. Theoretically, this fluid may be a site of nitrogen retention. Fluid retention during pregnancy may also cause nasopharyngeal swelling, which can lead to nose and ear stuffiness. In regards to diving, these may increase a pregnant woman’s risk of ear or sinus squeezes. Pregnant women experiencing morning sickness, which could then couple with motion sickness from a rocking boat, may have to deal with nausea and vomiting during a dive. This is an unpleasant experience and could lead to more serious problems if the diver panics."

Clearly, there are some women who do dive through early stages or pregnancy but on the whole there is not enough research to assert that it is 100% safe for both the mother and the child. Personally, I will hang up my fins for 9 months and watch as many underwater movies as possible. 🙂