Benefit from the Book of Allah 
Allah says:
يخلقكم في بُطُون أمهاتكم خلقا بعد خلق في ظلمات ثلاث
He creates you in the wombs of your mothers, creation after creation in three veils of darkness 
Imam As Saadi said 
Meaning: Stage after stage, and you are in a condition which no hand of a created one touches you, and no eye is looking at you, whilst he has nurtured you in that tight place.
(Three veils of darkness)
Darkness of the stomach, then darkness of the womb, then darkness of the placenta.
Tafseer of Imam As Saadi 4/1509
Majid Jawed Al Afghanee