Attaches to mother to feed.
The embryo attaches itself to the mother to feed, just like a leech attaches itself to a host to feed. The embryo also looks like a leech.
The embryo looks like a leech but these pictures are magnified by microscope; nobody knew this 1400 years ago. However this was portrayed in the Quran.
[Quran 23.14] Then We developed the semen into a leech. Then We developed the leech into a lump. Then We developed the lump into bones. Then We clothed the bones with flesh. Then We produced it into another creature. Most Blessed is Allah, the Best of Creators.
“Alaqa عَلَقَةً” means leech. It turned-out that the embryo looks like a leach. Then later it develops into a “Mudgha مُضْغَةً” meaning something chewed. It turned-out that at week 6 the vertebra of the embryo looks likes something chewed.