Baby Development In Second Trimester | Weeks 13-27

In the nine-month gestation period, where you carry your child in the womb, he or she grows every day from a single cell embryo to a tiny human. All three trimesters of pregnancy are equally important and often, trying times for the mother. Knowing what is exactly going on inside the bump is helpful here.

The second trimester especially is the time in the middle of your pregnancy. You get used to the feeling of being pregnant, and yet the delivery date is still far away. So what is happening to your baby in these three months? What is your baby’s development by 6 months? What is the baby’s physical development at the end of the second trimester?

For a better understanding of the details regarding fetal growth, we’ll divide the baby development by week and into 3 broad categories.

Baby Development by Weeks 13 – 17

  • These are the initial weeks of the second trimester. You will notice that your baby bump will slowly get bigger, that is because there is significant growth happening there.
  • In the 13th week, your baby weighs just around 25 grams and moves around a lot, although you can’t feel it. He or she also develops a sleep routine in this time, something that you will notice when the pregnancy progresses.
  • By the middle of this period i.e. week 15, you can hear the heartbeat of your baby via a heart-rate monitor. It is also the time when your baby’s senses start to develop. They can hear you and even identify whether it is brighter lights outside the uterus.
  • As the baby continues to grow in the 16th week, he or she can flex their limbs. Baby growth and development also extends to their nervous system.
  • By the time you reach 17 weeks, your baby is roughly the size of an orange and slightly bigger than an adult human’s fist.
The baby is curled and has his or her limbs tightly folded around week 17.

Baby Development by Weeks 18 – 22

  • An unborn baby of 18 weeks is awake for a lot of time and hears sounds surprisingly clearly. Interestingly, you can make your baby familiar with certain voices and music by continued exposure to them.
  • By week 19, your baby resembles a wrinkled banana and has even started developing teeth. The baby’s physical development happens at a fast pace at this time. We are pleased to inform you that it is also around this time that most mothers feel what is called “the first kick”.
  • If straightened, your baby’s height at 20 weeks is approximately 26 cm, almost the size of an A4 sheet. Scans during this time can even show them sucking their thumbs, despite their vernix-coated skin that is protected from harm.
  • The 21st week generally considered the halfway milestone of your pregnancy, therefore also the middle of the second trimester. At 350 grams, your baby has hair growth and starts to look the way he or she would look post-birth.
  • Weighing around 450 gram, your 22-week old fetus will have developed taste-buds. Babies start the practice for after birth activities like swallowing and breathing now.
The fetus is considerably bigger and your bump is now noticeable at week 22.

Baby Development by Weeks 23 – 27

  • Going with the fruit analogy again, your baby is about the size of mango by the time week 23 comes. Your baby starts being a lot more active and a lot more noticeable in those movements now. It will be helpful later mama if you can identify a pattern to their activeness early on.
  • At 24 weeks, your fetus is slightly larger and stronger than before. The baby’s development in the womb is so incredible, that at this stage, your baby can be called viable and protected from your vaccinations too.
  • The brain, nervous system and digestive system of your baby are developed, if not mature at 25 weeks. As a result, he or she responds to lights, sounds and even touches to the bump. They also urinate a lot into the amniotic fluid.
  • Baby development by 6 months i.e., 26 weeks will show them to be as big as your forearm in length, building up of muscles and fat in this time. You might be able to feel that he or she is now taking up a lot more space in your uterus. The fetus can even blink his or her eyes from now on.
  • Nearly 37 cms tall, your baby grows quite a lot by the end of the second trimester, in week 27. While your baby’s heart rate has slowed down to 140 beats per minute, it is now far more audible through a stethoscope. Your partner or family may also be able to hear it if they find the correct part of your belly to put their ear on.
An unborn baby’s heart rate at 27 weeks is very fast as compared to an average person.

As time goes by, baby development in the womb is observed by your doctors too. Some time during the middle of the second trimester, blood tests and ultrasounds are usually offered to check that baby growth and development are happening without any complications. You have reached the second trimester, no doubt your time in the next one will also be new and different. Although there is no cause for concern, maintain your healthy diet and prenatal exercise routines during this time for the continued health of your baby.

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