Foetal Development In The Third Trimester
During the third trimester of foetal development, the baby prepares for birth. The baby's organs will continue to grow, and its senses will begin to operate properly. However, size has a significant role in foetal development throughout the third trimester. A significant part of what the baby is doing from 28 weeks onwards is accumulating brown fat around their body. This plumps up their skin and gives them that chubby baby appearance that we all adore.One of the most fascinating aspects of foetal growth in the third trimester is the baby's eyesight. Their vision continues to improve after birth, but during the third trimester, their eyes will develop well enough so that when they're born they'll be able to see contrast 8 to 10 inches away—which is just about how far away your face will be when you're holding them!
Other interesting foetal growth milestones in the third trimester, according to experts, include:
- Baby's hair, fingernails, and toenails continue to develop (until and after labour and delivery)
- During the third trimester, the baby's ear cartilage firms up, the gums grow more stiff, and the skin starts to smooth out. Their bones continue to harden.
- The baby sheds its lanugo (typically at 31 weeks). Lanugo is fine hair that forms on a baby's body in gestation to protect its skin from amniotic fluid. Babies who are born at 37 weeks or earlier might still have some of these fine hairs on their shoulders, but most term babies have lost it all before birth.
- Towards the conclusion of the third trimester (about 38 weeks), the baby begins to lose the vernix caseosa, a white layer that shields the skin during pregnancy. However, you will probably notice some of this during birthing.
- The baby continues to practice breathing in utero. By the end of 36 weeks, their circulation and immune systems are almost fully functioning.
- Babies begin to develop coordinated reflexes such as sucking, swallowing, opening and shutting their eyes, and twisting their heads. They also improve their grip by grabbing their feet or the umbilical cord.
- The baby responds to light, touch, and sound (even your voice!). In fact, by the end of 31 weeks, the baby's five senses will most likely be fully developed.
- At 36 weeks, the baby's organs mature, particularly their brain and lungs. However, the baby's organs, including the liver and kidneys, will continue to develop both before and after delivery.
- In male newborns, the testicular descent into the scrotum occurs during the third trimester.
- Around 37 weeks, babies produce their first excrement, known as meconium.
Baby's Position In The Third Trimester
Around 32 to 36 weeks, the baby will actively begin to move and alter positions to prepare for delivery. It's extremely important to know the position of the baby when a woman goes into labour during the third trimester since this might influence the method of delivery. By 36 weeks the baby takes its final position which doesn’t change subsequently.Of course, each mother and infant is unique. Some newborns fit through the pelvis better if their back is on the right side during delivery. Some infants are born with their backs lined up with the mother's back.
There are three positions that the baby might be in at the end of the third trimester:
- Vertex: Also called Cephalic or, more frequently, "head down." This is the position in which 95% of newborns are at full term.
- Breech: This posture happens when the baby's feet or buttocks point towards the delivery canal rather than the head. This position occurs in 3 to 4% of term pregnancies.
- Transverse lie: In this position, the baby's spine is perpendicular to the uterus' long axis. In other words, it occurs when the baby's head presses against one side of the mother’s torso while the feet and bottom push on the other side.
Changes In Birth Canal
As the baby prepares for birth, the mother's body undergoes many modifications to help the birthing process:- Pelvic Changes: The pelvic and spinal joints become looser, widening the birth canal and making passage simpler for the infant. Cervical softening and dilation begin in preparation for labour.
- Amniotic Fluid: The quantity of amniotic fluid reaches its peak at 36 weeks and then begins to decline as the baby descends into the pelvis.
FAQs on What to Know About Foetal Development in the Third Trimester?
- In which week do the baby's lungs completely develop?
By 36 weeks, your baby's lungs are completely developed and ready to take their first breath after delivery. The digestive system is completely formed, and your child will be able to feed if delivered right now. - What not to do during the third trimester?
Generally, throughout the third trimester of pregnancy, you should avoid sleeping on your back. When you lie on your back, your uterus may restrict blood flow to the uterus and foetus. It is also often painful to rest flat on your back throughout the third trimester.
