Abortion Methods: Trimester 3

--Surgical Methods

Fetal Development: Trimester 1

Fetal Development: Trimester 2

Stages of Pregnancy and Fetal Development Introduction

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Within the three months of the third trimester, a fetus goes from incomplete development to complete, fetal maturity.

Month 7 (see figure)

External Features: At seven months, the fetus continues the development of hair and the scalp hairs grow beyond the length of the thin lanugo hairs that developed during the second trimester. Eyelashes are well developed and eyelids begin to open.

Organ Systems: Internally, the fetus' brain continues to develop and throughout the body subcutaneous fat storage begins. In male fetuses the testes continue descending into the scrotum.

Month 8 (see figure)

External Features: By the eighth month, the skin is pink and smooth, the eyes are capable of reacting to light and the fingernails have grown long enough to reach the tip of the fingers.

Organ Systems: Internally, at the eighth month, the hyaloid vessels nourishing the eye lens, regresses and the testes begin entering the scrotum.

Month 9 (see figure)

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.(3)