How Your Baby Grows During Pregnancy

For many new mothers, pregnancy is an experience filled with wonder and joy, but it can also be somewhat disconcerting for anyone who has never been through it before. Although your body will go through a litany of physical changes, almost nothing could compare to the dramatic development of new life inside you, a journey which fascinates many new parents in their own way.

First trimester

In the first month of your pregnancy, you may not notice many physical changes in your own body, but your growing baby is already in the process of rapid development. The heart and blood vessels are amongst the first things to develop, followed closely by the beginnings of the lungs, stomach and liver. Even without a physical sign of your baby’s growth, it’s not uncommon to experience evidence of life’s little miracles in the form of morning sickness, and of course, you’ll also have an ultrasound within the first few weeks.

By the second month, your baby – classified as an embryo at this stage – will have a beating heart and many other body parts in progress, from the spinal cord to the eyelids. In case you haven’t already, now is the time to start supporting your baby’s health by taking a prenatal vitamin. After three months, your baby will be roughly five centimetres long, and developed enough to move around in the uterus. At this stage, the skin is still in development and so thin that organs can be see through it, which goes some way to explain why the development of fingernails at this stage is so fascinating to many. Although you still may not see a great deal of difference in your external body, your baby is on its way to becoming a fully-fledged human.

Second trimester

As you enter the second trimester of pregnancy, your baby will reach quite a few significant milestones. Its weight can be expected to increase four-fold, from an average of 100 to 635 grams, and several of the fundamental senses will be coming along. At four months, the most intriguing development is the sex organs, giving your doctor the ability to reveal the baby’s gender, but even if you’re not so worried about that, you may be surprised to learn that fingerprints have begun to form at this point as the baby begins to take on more individual genetic traits from the genes of its mother and father. At the 20-week milestone, it’s time for an ultrasound, during which your doctor will check that your baby’s placenta and growth rate is healthy. By the end of the second trimester, not only will you be feeling pronounced movements, but your baby will also be so attuned to the outside world that its pulse may increase or decrease in response to sound. It’s worth noting that classical music in particular is said to be great for healthy brain development.

Third trimester

The third trimester is a prime time for growth – in fact, up to half of the birth weight is gained in the eighth month, and you can expect your baby to weigh about four pounds and measure 47 centimetres in length once you reach full-term. While the average pregnancy is considered full-term at 40 weeks, this is the time to prepare for the possibility of an early delivery by studying the signs of preterm labor. It’s also a great opportunity to register for birthing classes if you haven’t already. By the seventh month, your baby is able to sense light, respond to sound, and kick hard enough that others will be able to feel it through your skin. Finally, in months eight and nine, the last puzzle pieces fall into place as the taste buds become operational, the bones harden, and the brain has its all-important final growth spurt before the baby moves into position for delivery.

Every baby is different, as is every pregnancy, and there’s no single right way to experience it, but if you are curious or concerned about your baby’s growth rate, there’s no harm in speaking to your doctor. After all, you can expect to see much more of them as you progress towards the end of your pregnancy, and no one can offer you more personalised advice on looking after your baby’s health pre-birth.