Diving and Pregnancy

One of the most frequent questions people ask is regarding scuba diving while pregnant. The quick answer is "Please don't dive" while you're pregnant. We don't have very good data showing that hyperbaric pressure harms the fetus, and in fact, there are case records of HBO treatment of pregnant mothers with carbon monoxide poisoning without adverse effect on the fetus. However, the fetus does not have the protection of the lungs in filtering out the bubbles as does an adult.

The Russians use HBO to treat high risk pregnancies and report 54/700 cases of pulmonary pathology with poorly controlled studies.

1. Bangasser Survey 1978-no increased defects
2. Bolton Survey 1980-higher rate of fetal defects in 40/109 women who did not stop diving, with two major cardiac anomalies, multiple hemivertebrae, absent hand, VSD, coarctation, pyloric stenosis, and birthmark. None in group who stopped.
3. Turner Case Report-1982. Multiple anomalies in the fetus of a woman after 20 dives in the 15 days after her LMP.
4. Fife Study 1991. 1037 female divers - only 1.4% dived while pregnant.

Studies on pregnant sheep are particularly telling in that the sheep placenta is very similar to that of the human. These sheep studies of DCS all showed high rates of fetal death, particularly in the fetuses that had been instrumented, probably due to the bubbling that crossed into the arterial circulation via the patent foramen ovale.

"The same woman who will not drink coffee or smoke during her pregnancy will want to know why she should not dive. In this litiginous society there is only one answer "no diving while pregnant or even trying to conceive".(Dr. Maida Taylor). No major studies prove it unsafe but the hazards are there.

Presently, every HBO treatment chamber does not allow female personnel who are pregnant to act as tenders. Since diving is an entirely elective activity for 99% of all women divers, the obvious choice would seem to be not to dive. If one has been inadvertently diving while early in her gestation, there is no good data which would justify an abortion.

If you are planning a perfect holiday for diving, sun and you really want to try and conceive on the first three days of your ten day holiday, what do you do about the possibility of damaging the embryo?

Bottom line - you should probably go ahead and completely enjoy your dive trip. The reasons are multiple. First, a normal couple, actively trying to achieve a pregnancy, actually is successful only once in three or four months of trying to conceive - so the odds are that you won't get pregnant on this trip (although it's certainly not unlikely).

Second, the embryo does not actually attach to the wall of the uterus for about seven days, receiving its nourishment from fluids secreted by the Fallopian tube and uterus. Even though attachment to the wall of the uterus occurs about a week after ovulation, it is later in pregnancy (at least another week to ten days) before there is any effective maternal-placental blood circulation. The major theory for the cause of fetal malformations associated with diving concerns the possibility of transfer of intra-vascular bubbles from mother to fetus. As there is no effective circulation in the earliest stages of pregnancy we are considering, this is possible cause is not a concern.

Third, many thousands of women have been diving unknowingly at the same early stage of pregnancy you might be in - there is no evidence of an increase in miscarriages or other problems in these women who have been diving around the time of conception. In fact, before pregnant women were advised not to dive, several studies looked at women who dived throughout pregnancy. Although we no longer recommend diving during a recognized pregnancy, there is no solid scientific data to prove that diving is dangerous to the fetus.

Finally, the very early embryo is still composed of cells which have not yet undergone differentiation - that is, one cell isn't destined to be the heart, another the left arm, etc. If any single cell is damaged at this very early stage of pregnancy, other cells can "step in" to form the needed structures. Only later, after differentiation, will damage to a single cell likely result in an abnormality.

Martin M. Quigley, MD
(Certified in Obstetrics & Gynecology and Reproductive Endocrinology)
Consultant for Diving Medicine Online

--Uncomplicated vaginal delivery
The diver may return to diving whenever the uterus has returned to normal size, when there is minimal vaginal discharge and when the physician allows a resumption of marital relations. This period of time can be variable and must be individualized for the person - but is usually anywhere from 4 to six weeks post-partum.

--Cesarean section delivery
Resumption of diving should await the go ahead of the physician. Added to the factors above are the wound strength of the incision, the degree of physical rehabilitation of the patient and whether or not there is any blood loss anemia, which requires correction. Again, a waiting period of 4-6 weeks would seem reasonable if there were no complications from the surgery.

Bangasser SA Medical Profile of the Woman Scuba Diver in NAUI proc 10th Int Conf on Underwater Ed Colton, CA NAUI 1978 p31-40

Bolton M Scuba Diving and Fetal Well-being: a survey of 208 women Undersea Biomed 1980, 7: 183-89

Fife WP, Fife CE Women in Diving, NAUI Int Conf Proc on Underwater Ed, Mar 1991, p 80-88