By the end of the eighth week of pregnancy, the fetus begins a new developmental stage marked by rapid growth and physical transformation. This stage is characterized by distinct structural development, where the head, body, and extremities become more proportionate between the 9th and 12th weeks. During this time, key features appear: by the 10th week, the external genitals become visible, and by the 12th week, soft cartilage begins to harden into calcified bone. Extremities and digits are well-defined, allowing for the identification of the fetus’s sex. These developments also enable the fetus to perform spontaneous and involuntary movements. The Qur'an references this transformative phase, describing the fetus as entering a stage of "another creation" — a distinct phase where the fetus acquires more defined human characteristics:

During this period, the fetus is enveloped in three layers, or "veils of darkness," as referenced in the Qur'an:

These veils are identified by embryologists as the amniotic membrane, which cushions and protects the fetus in fluid; the chorion, an outer protective layer; and the decidua, a layer lining the uterus. This layered protection provides both support and flexibility, ensuring safe fetal movement and preparation for birth. The Qur’an also subtly addresses the minimal viable gestational age, highlighting that a six-month term in the womb is compatible with life outside it. This aligns with modern understanding that around 22-26 weeks, or six months, the fetus becomes capable of surviving outside the womb with developed respiratory and nervous systems. The Qur'an explains this in the context of gestation and weaning periods:

With weaning stated as 24 months (Surah Luqman 31:14), this confirms a minimum viable gestational period of six months. This alignment with modern medical knowledge reflects an awareness of developmental milestones, as well as the uniqueness of human formation in the womb.