Fetal Perspective

Month 3

The third month of pregnancy marks the end of the first trimester and a significant stage in fetal development. By the end of this month, the fetus is fully formed, with all major body systems and organs in place, though they will continue to grow and mature.

Weeks 9 to 12: Key Developments

Week 9:

Development:

The head is still large compared to the body, making up about half of the fetus's length.

The face becomes more distinct: eyes are fully formed but remain closed, and the ears are nearly in their final position.

The arms and legs are growing rapidly, with elbows, wrists, fingers, and toes becoming more defined.

Teeth buds form under the gums.

Genitalia start to develop, though it's too early to determine the sex.

The placenta begins functioning more efficiently, taking over hormone production.

Size: About 0.9 inches long, similar to a grape.

Weight: Around 0.07 ounces.

Week 10:

Development:

The fetus's heart is fully formed and beats strongly.

Bones are starting to harden, especially in the arms and legs.

The fingers and toes separate completely, and tiny fingernails begin to form.

The brain is growing rapidly, and neurons are forming connections.

The stomach produces digestive juices, and the kidneys start producing urine.

The fetus starts making small, spontaneous movements, though the mother cannot feel them yet.

Size: About 1.2 inches long, comparable to a kumquat.

Weight: Around 0.14 ounces.

Week 11:

Development:

The head is still large but now accounts for only about one-third of the fetus's total size.

External genitalia continue to form, but they are not yet distinguishable via ultrasound.

The fetus's diaphragm is developing, and it may start to practice breathing movements.

The skin is still translucent, but blood vessels are becoming more prominent.

The intestines begin to move into the abdominal cavity from the umbilical cord.

Reflexes develop: the fetus can open and close its hands and curl its toes.

Size: About 1.6 inches long, comparable to a fig.

Weight: Approximately 0.25 ounces.

Week 12:

Development:

The fetus's face looks more human: the eyes are closer together, and the ears are in their final position.

The brain continues to develop rapidly, laying the groundwork for the central nervous system.

The liver starts producing bile, and the pancreas begins insulin production.

Vocal cords develop, though the fetus will not use them until after birth.

The fetus may start sucking its thumb.

Fingernails and toenails are fully formed, and fine hair (lanugo) begins to cover the body.

Size: About 2.1 inches long, similar to a lime.

Weight: Around 0.5 ounces.

Physical Development Milestones by Month 3

All major organs and body systems are in place:

The digestive, circulatory, and nervous systems are functioning but not yet fully developed.

Movement:

Though not felt by the mother, the fetus moves frequently, flexing and extending its body.

External Features:

The fetus has defined fingers, toes, and facial features.

Eyes are fused shut but are fully formed underneath.

Key Symptoms for the Mother During Month 3

Nausea and Fatigue: Morning sickness may begin to subside by the end of the month.

Weight Gain: Most mothers gain 1–4 pounds in the first trimester.

Breast Changes: Breasts may continue to grow and feel tender.

Frequent Urination: The growing uterus puts pressure on the bladder.

Mood Swings: Hormonal fluctuations can continue.

What to Expect Overall in Month 3

The fetus grows rapidly during this month, nearly doubling in size.

By the end of the third month:

Size: About 2.9 inches long, comparable to a plum.

Weight: Around 0.8 ounces.

The baby is fully formed, with all organs and body parts in place. From this point on, the focus shifts to growth and refinement of functions.

This is a transformative month, as the fetus moves from the critical early developmental stages into a period of rapid growth and maturation.