|Leech-like clot (al-alaqa)|
The stage of Alaqa starts on the 15th day and ends on the 23rd or 24th day, after which the embryo is gradually developed and looks like a leech, which lives in ponds (Figure 1). Alaqa hangs to the lining of the uterus by the umbilical cord. Blood is then formed in the vessels at the shape of closed islands, and is not circulated in blood vessels, thus having the image of clotted blood.
Although it is in the nature of human body to expel any external matter, the uterus does not reject the alaqa implanted in its lining despite the fact that half of the alaqa components and genes are from an external source (the father). This is because the region of syncytial cells in alaqa have no antigens.
(Figure 1: Alaqa on the 23rd day)
Figure 2: The primitive streak shrinks at the end of the 3rd week with its remaining that stays at the end of the spine
Figure 3: Stem cells form different body tissues
Figure 4 : Teratoma in the coccygeal region at the end of the spine
Reflections and comments on related Quranic verses and Sunnah:
Transformation process from nutfa to alaqa takes more than 10 days till the zygote clings to the primitive placenta by way of a connecting stalk which later becomes the umbilical cord. Therefore, the Quranic statement uses the conjunction article (thumma) in Arabic, indicating sequence of events with time delay and not using (fa) which also means "then" but indicates rapid progression without any delay. Quran states:
“Then of that fluid-drop (nutfa) We created a leech-like clot" (Qur’an ) .
Alaqa, in Arabic, has several meanings:
1- A leech that lives in ponds and sucks the blood of other creatures.
2- A thing attached or clings to something else.
3- Clotted or coagulated blood.
Figure 5 : illustration of embryo (at top) that looks like a leech (at bottom)
Figure 6: embryo clinging to the lining of uterus through the umbilical cord.
Figure 7: closed blood vessels net causing the embryo to look as a clotted blood.
All these meanings fit exactly with the reality of the human embryo after being implanted in the lining of uterus (endometrium), as the embryo looks like a leech, as shown in Figure 5, while clinging to the endometrium through the umbilical cord (Figure 6), blood vessels initiated in the form of closed islands giving it the image of a clotted blood (Figure 7).
A quick transformation then occurs from alaqa to mudgha within two days (day 24 to day 26). Therefore, the Quran describes this rapid change with the use of the conjunctive article (fa) (i.e., then) in Arabic, to indicate rapid progression of transformation :
“Then We changed the Alaqa (leech-like clot) into a Mudgha (chewed-like lump) ”
“Was he not a drop of sperm emitted (in lowly form)? Then did he become a leech-like clot; then did (Allah) make and fashion (him) in due proportion. And of him He made two sexes, male and female.”
And in a surah called al-alaq, i.e., a leech-like clot, Allah says;
“(We) Created man, out of a leech-like clot.”
Further to the point of primitive streak, it is the first to be created in embryo, and out of which, stem cells are composed, as well as the different organs and tissues; and at the end of the 3rd week, it shrinks, and its remaining stays in the sacrococcygeal region at the end of the spine, maintaining the remaining stem cells in this region. This explains and coincides with the speech of the Prophet which was narrated by Abu Huraira in Ahmad’s book “Al Musnad”:
Here a very important question arises: why did the Prophet Mohammad raise such a scientific issue at a time no one was aware of, and how had he acquired such knowledge if he was not bound up with inspiration and taught by the creator of heaven and earth? The answer is that Allah the Almighty knows with His encompassing knowledge that man will come to know one day the embryonic stages of development, and will know the role of the primitive streak, so He inspired prophet Mohammad to speak out such a fact to be a witness on the genuineness of his prophethood and message, that fits every time and age.