Major Baby Growth During the 2nd Trimester of Pregnancy 

Summary: Curious to know the baby growth during the 2nd trimester of pregnancy? Well, you are not alone. From hair growth to hearing development to reflux development, it happens a lot in the second trimester. So, read the full blog.

You’ve just entered your second trimester of pregnancy? Great! You’ll be pleased to know that the baby growth during the 2nd trimester of pregnancy will be the most.

After navigating the potential hurdles of morning sickness and fatigue in the first trimester, the second trimester brings welcome relief from those early pregnancy woes. But this 14th to 27th-week window isn’t just about feeling better—it’s also a time of incredible growth and development for your baby.

During these crucial months, your little one truly starts to take shape and thrive within the nurturing confines of your womb. From newly formed facial features to brain development and functional organs, the foundations for a healthy baby are rapidly being built. 

Want to know more? 

In this blog, we’ll learn about the growth of the baby in the second trimester. So, let’s get started!

Note: If you want to know about baby development during the 1st trimester, you can read our previous blog.  

Week-by-Week Baby Development During the 2nd Trimester of Pregnancy 

Here are the 2nd-trimester baby developments with the week numbers included in the headings:

Week 13: Urine Production Begins 

At around 13 weeks into your pregnancy journey, your baby’s kidneys become functional and begin producing urine. This tiny urine stream is released into the amniotic fluid surrounding and protecting your little one. 

Don’t worry; your baby is safely enclosed in the amniotic sac! In addition to making urine, your baby also starts the practice of swallowing small amounts of the amniotic fluid. This helps jump-start the development of their digestive system as the months go on.

Week 14: Finding Out the Gender 

How exciting – you may discover if you’re having a sweet baby girl or a bouncing baby boy sometime around 14 weeks! During this stage, an ultrasound scan can potentially reveal your baby’s gender by visually identifying the genital anatomy and sex organs that are forming. 

For many parents, finding out this highly anticipated detail makes the baby seem even more real. Whether you find out or keep it a fun surprise, this is a fantastic milestone!

Weeks 15-17: Bones Harden and Hair Grows 

From around 15-17 weeks of pregnancy, your baby enters a phase of rapid skeletal growth and hardening of their tiny bones. You may even catch a glimpse of this bony development on later ultrasound images. 

The skull and long bones in the legs and arms are among the first to harden from soft cartilage into sturdy calcium structures fully. While your baby’s bones are getting stronger, their scalp is also shaping up to form their special hair pattern, and those first fine hairs are beginning to grow!

Week 18: Hearing Develops 

At around 18 weeks into your pregnancy, your baby’s ear development reaches a crucial stage where the inner ear structures are formed well enough to allow sound to travel through and be detected. 

This means your little one can now pick up noises from the outside world – like your voice, heartbeat, or any other sounds around you! Imagine experiencing sound for the very first time after months of peaceful quiet. What an incredible new sense to discover. Their digestive system also continues maturing simultaneously.

Week 20: The Halfway Mark 

You’ve made it to the halfway point – 20 weeks pregnant! This is a big milestone celebrating how far you’ve come and getting you excited for the journey ahead. By this stage, your baby’s movements and sleep/wake cycles are really taking shape and becoming more regular.

If you’re incredibly in tune with your body, you may even feel those first tiny kicks, flutters, or rolls from your little acrobat! It can be challenging for first-time moms to distinguish these first movements, but you’ll soon become a pro. 

Weeks 21-23: Developing Reflexes 

In the latter weeks of the 2nd trimester, around 21-23 weeks, your baby’s brain and nerves rapidly develop to allow new reflexes to emerge. One of the first you may notice is the sucking reflex, where your little one starts making motions like sucking their thumb – a cute habit that will stick with them for years! 

You may even catch them practicing this sucking reflex on an ultrasound scan. This trimester is also when the unique whorls and ridges that will become your baby’s fingerprints and footprints start taking shape on their tiny hands and feet.

Week 25: Responding to Voices 

Around 25 weeks into your pregnancy, your baby’s sense of hearing is developed enough to respond to sounds and voices from the outside world with extra kicks, wiggles, or movements. It’s an incredible experience for them to hear you and your partner’s voices for the first time! 

Reading aloud, singing songs, or talking to your baby can trigger extra activity as they react to the familiar sounds. You can read books to make your bond. Their sleep patterns also cycle between the phases of the awake and the REM (rapid eye movement), just like a newborn’s.

Weeks 26-27: Lung Development 

As you start wrapping up the second trimester around 26-27 weeks, your baby’s lungs achieve a crucial milestone by beginning to produce a substance called surfactant. 

The surfactant will coat their lung sacs and allow the lungs to properly inflate and deflate for breathing after delivery. Until the surfactant develops, the lung sacs can stick together. So, this is a vital step in preparing your little one’s lungs for that first breath of life outside the womb.

What an incredible series of transformations and developments your sweet baby has gone through over these amazing months! With every passing week, they become more prepared for life on the outside. The final trimester is next as you enter the homestretch of your pregnancy. Get ready for even more miraculous changes! Also, here are some must-know things that you should do during the 2nd trimester of your pregnancy.

Parting Thoughts 

That brings us to the end of the blog. We hope now all your doubts regarding the baby growth during the 2nd trimester of pregnancy are clear. 

It’s indeed filled with milestones and developments that pave the way for a healthy and thriving little one. As you embark on the final trimester, cherish these miraculous changes and eagerly anticipate your precious bundle of joyous arrival.

FAQs