Month 9

Month 9
External Features: Toenails grow up to the tip of the toes and fingernails grow beyond the fingertips. The skin is fully covered in vernix caseosa (which serves to protect the epidermis) and most of the lanugo hairs are shed. By this time, the placenta weighs about 500grams and the umbilical cord becomes central in the abdomen. Organ Systems: Internally, the fetus secretes large amounts of pulmonary surfactant (a mixture of phospholipids and protein; it will eventually line the aveoli and lower the surface tension in mature lungs at birth). The tip of the spinal cord grows to the level of L3 and myelination of the brain begins. Although in female fetuses the ovaries are still above the brim of the pelvis, the testes in males have fully descended into the scrotum.

 Finally, after 40 (on average) weeks of gestation, the fetus is fully developed and ready for birth.