3D Fetal Development & Pregnancy Stages | AnatomyLearn

Gestational Milestones & Carnegie Stages

• Blastocyst Implantation & Gastrulation — The blastocyst implants into the uterine endometrium, initiating the three primary germ layers that will form all tissues and organs. (0.2 مم, < 0.01 جم)
• Neural Tube Closure & Primitive Heartbeats — The neural tube completes closure; the primitive heart tube begins regular peristaltic contractions at 105-120 bpm, and limb buds emerge. (4 مم, 0.05 جم)
• End of Embryonic Stage — Organogenesis Complete — The transition from embryo to fetus is complete. Webbed digits separate, joints articulate, and spontaneous muscular movements begin. (3.1 سم, 4 جم)
• End of First Trimester & External Genitalia Differentiation — Marks the end of the first trimester. Facial features refine with forward-migrated eyes, and fetal kidneys begin producing urine into amniotic fluid. (5.4 سم, 14 جم)
• Mid-Pregnancy — Quickening & Vernix Caseosa — The anatomical midpoint of gestation. Mothers clearly feel fetal movements (quickening). The skin is shielded by protective vernix caseosa and fine lanugo hair. (25.6 سم (من الرأس للقدم), 300 جم)
• Third Trimester & Viability Threshold — Entry into the third trimester. Eyes open with functioning eyelashes; pulmonary surfactant synthesis ramps up, significantly elevating premature survival rates. (37.6 سم, 1000 جم (1 كجم))
• Pulmonary Maturity & Fetal Engagement — Lungs and digestive tract reach near-complete functional maturity. The fetus typically assumes a vertex cephalic presentation, descending into the pelvic inlet. (47.4 سم, 2.6 كجم)
• Full Term Gestation & Labor Readiness — Full-term gestational endpoint. All physiological systems are primed for autonomous neonatal life; maternal-fetal hormonal cascades trigger labor contractions. (51.2 سم, 3.4 كجم)

Medical Sources & Licences

Built using Visible Human Female pelvic models (NIH 3D / HRA) and Carnegie stages (Virtual Human Embryo Project) under CC BY 4.0, with INTERGROWTH-21st biometric charts and Hadlock growth curves.