The fetus sits in amniotic fluid, but 1400 years ago nobody knew that the amniotic fluid is actually water.
The amniotic fluid is the protective liquid contained by the amniotic sac of a gravid amniote. This fluid serves as a cushion for the growing fetus, but also serves to facilitate the exchange of nutrients, water, and biochemical products between mother and fetus. For humans, the amniotic fluid is commonly called water or waters (Latin liquor amnii)...
At first, amniotic fluid is mainly water with electrolytes, but by about the 12-14th week the liquid also contains proteins, carbohydrates, lipids and phospholipids, and urea, all of which aid in the growth of the fetus.
The amniotic fluid for humans is mainly water. This was known recently however this was portrayed in the Quran 1400 years before it was discovered. The Quran describes the amniotic fluid for humans as water.
Quran 86:6 "He was created from gushing water."
"Ma-e مَاءٍ" in Arabic means water. The amniotic fluid for humans is referred to as water.