For ethical reasons, no experiments on humans had been conducted in this regard, but a survey was conducted in 1980 and the results were inconclusive.
The survey included 208 women, 69 who did not dive during pregnancy, and they did not report any abnormalities in the fetus, but among 109 women who dived during pregnancy, abnormalities were reported by 5.5%, knowing that this is a normal rate at that time. However, it should be noted that it cannot be conclusively be said that diving is responsible for these problems, which may be the result of a number of unrelated factors.
The potential negative effects of scuba diving during pregnancy are believed to mainly affect fetuses in the first and third trimesters of pregnancy.
In the first trimester of pregnancy, the effects of pressured oxygen concentrations can lead to defects in the fetus, including low weight, abnormal skull growth, limb deformity, and abnormal heart development.
At any time, and especially in the third trimester of pregnancy, decompression sickness in the mother can cause major problems for the fetus due to the inability of the fetus to filter nitrogen bubbles through the lungs, as the fetus’s blood bypasses the lungs and filtered through the placenta.
The fact that the placenta plays a major role in fetal circulation explains why sheep have been used in experiments trying to ascertain the effects of decompression sickness on pregnant women.
Sheep placenta is similar to the human placenta, and the results of studies of pregnant sheep in hyperbaric chambers have shown that even in cases where the mother did not show any signs of DCS, bubbles often appeared in the fetus’s bloodstream.
When the mothers showed signs of DCS, the symptoms worsened in the fetus. Often times, the effects of DCS appear in fetuses as life-threatening arrhythmias, limb weakness and spinal defects.
Because a fetus cannot rely on its lungs to filter bubbles from its blood, even harmless “silent bubbles” in adults can cause an arterial gas embolism that’s fatal to the unborn baby.
Ultimately, although we cannot know for sure the extent of the risk involved, all signs indicate that it is best to avoid it until your baby is safely born.
Mothers also have to wait 4 to 8 weeks after birth before returning to diving, depending on the nature of the delivery.
Of course, it is better to seek medical advice before resuming diving.