At 30 weeks pregnant, your baby is continuing rapid growth and development as they move deeper into the third trimester. Many systems are functional, but your baby still needs the next several weeks to fully mature.

Baby’s Growth & Size

• Weight: Around 3 pounds (1.35 kg), the size of a Cabbage!

• Length: About 15.7–16 inches (40 cm) from head to heel.

• Baby is gaining roughly ½ pound (225 g) per week, mainly as fat to help regulate body temperature after birth.

Development & Features

• Brain: Growing rapidly—the surface is becoming more wrinkled, with folds and grooves forming to increase brain capacity.

• Lungs: Continuing to mature and produce surfactant, which is essential for breathing after birth.

• Skin: Pinker and smoother as fat accumulates underneath; still a little translucent.

• Bones: Fully formed, but soft and flexible; skull bones remain unfused for birth.

• Muscles & movement: Stronger movements, including stretching, rolling, and kicking. Baby is practicing coordination and muscle control.

• Eyes & senses: Can respond to light, track movement, and may react to sounds.

Vernix & Lanugo

• Vernix caseosa (creamy coating) protects the skin from amniotic fluid.

• Lanugo (fine hair) covers much of the body but may start to thin in the coming weeks.

Position

• Baby may start moving into a head-down position, but frequent position changes are still common.

Immune System

• Antibodies continue to transfer from you to your baby, helping prepare their immune system for life outside the womb.

 

At 30 weeks, your baby looks much like a newborn but still needs time to grow, put on fat, and mature their lungs and brain. Movements are strong, reflexes are practicing, and weight gain is rapid.​