Fetal Development Timeline – Second Trimester
Continuing on in the fetal development timeline, there are many exciting things going on with the baby during the second trimester. With all the major organs developed, it’s a time of great growth.
15 to 18 Weeks Gestation
The baby is now about 5 1/2 inches long and weighs around 7 ounces. The fetus now looks like a miniature version of a newborn baby and is growing eyebrows and hair.
As the baby swallows amniotic fluid, he or she may start hiccuping at this point, although you may or may not feel it. You can now determine the sex via ultrasound!
19 to 22 Weeks Gestation
The baby is now about 7 1/2 inches long and weights close to one pound. The baby’s kidneys are stating to produce urine, which is just recycled amniotic fluid and is completely sterile.
Vernix is starting to coat the skin, which is a white protective coating. Also, fine hair called lanugo will cover the baby’s body. Both vernix and lanugo are still present at birth.
The baby can hear all kinds of noises in the uterus, from the internal sounds of a woman’s body (heartbeat, stomach noises, etc.) to external voices and conversations. It is said that a baby can recognize the sound of it’s mother’s voice, but it’s unknown with the recognition starts to take place.
23 to 27 Weeks Gestation
At this point the baby weighs between 1 pound 5 ounces and 2 pounds 3 ounces. Full length is between 11 and 15 inches. The baby is still very thin and the skin is also thin.
The lungs are starting to complete their development by producing surfactant, which will allow the sacs to expand and allow breathing after birth.
The baby practices breathing and swallowing, although it’s only using amniotic fluid and not air. The retina is still maturing as are blood vessels in the brain.
Premature Babies
Some babies can survive at 23 weeks although they will typically have many complications and require a stay in the neonatal intensive care unit (NICU). Each week that passes increases the baby’s chance for survival and reduces the likelihood of complications.
