Whether you are a first-time expecting mom or mother of three expecting another bundle of joy, it is important to understand how your baby grows and develops over the nine months she spends inside you. Pregnancy can be complicated and even mysterious, but the more you know about your pregnancy week by week, the easier your pregnancy may seem. In general, pregnancy lasts about 40 weeks, counting from the day of your last normal period; the weeks are grouped into three trimesters.
1st Trimester (Weeks 1-13)
Your baby’s development begins when a sperm fertilizes an egg in one of your fallopian tubes. The fertilized egg then travels down the fallopian tube to the uterus. In the uterus, the egg quickly divides into cells that become embryo –the prefetal product – and cells that act as an outer group to nourish and protect the embryo.
Around week four, the placenta begins to form, through which your baby will develop and receive nutrients throughout the pregnancy. Moving into week five, your baby has grown to the size of the tip of a pen, yet even at such a small size significant development still occurs – your baby’s brain, spinal cord, lungs, and heart will begin to form! Then, in week six, signs of your baby’s eyes, nose, and ears appear along with small buds, which will soon become arms and legs. At week 11 your baby can now be described as a fetus – meaning an unborn offspring at the later stages of its development – because all major organs are present. At the end of the first trimester, your baby’s face has a human profile, fingernails are developing, and the formation of external genitalia begins.
2nd Trimester (Weeks 14-27)
Fourteen weeks into your pregnancy, your baby’s arms are fully developed and more red blood cells form in various organs. Also at this point – or in the near future – your baby’s genitalia will be developed and apparent, so much so that you will be able to find out the sex of your baby!
In the following weeks, your baby may look more and more like human, the eyes look forward, the ears reach position, the skeleton transforms to bone and fat is stored under the baby’s skin. While you may not notice or feel it, your baby’s movement will increase and he/she may be able to make facial expressions! By the 18th week, your baby will begin to hear things, like sounds from your body, your voice and conversations along with loud noises.
Congratulations, you have reached your halfway point, 20 weeks left in your pregnancy! During the last few weeks of the second trimester, your baby’s tongue develops taste buds, fingerprints and footprints form, real hair develops on the head, and your baby sleeps and wakes regularly. At the end of the second trimester, your baby will weigh roughly 2 pounds and he/she will be active exploring her “aquatic universe” in your womb.
3rd Trimester (Weeks 28-42)
Hooray! You are nearing the end of your pregnancy, but your baby’s development still continues as she prepares for life outside the womb. During the first few weeks of your third trimester, your baby will begin to store the minerals (iron, calcium and phosphorus) needed to be strong and healthy. Your baby will go through rapid brain development, resulting in the ability to regulate body temperature. Also, he/she will start to open and close their eyes and have the visual capability to follow a light source.
By the 32nd week, even though your baby’s lungs aren’t fully developed, she will practice breathing in order to prepare to breathe on his/her own. Also, your baby may become increasingly more active, you will likely feel forceful kicks and punches as she moves in the womb.
Roughly 36 weeks into your pregnancy, your baby will begin to gain weight at a rapid pace, about ½ pound a week for the next month! With this rapid growth, movement may decrease because there is hardly any room left to move in the womb. People may start asking you if “the baby has dropped,” this simply means that your baby has dropped lower in your abdomen into the birth canal and has assumed the head-down position. Your doctor will certainly be able to tell you if your baby has dropped. Also, small breast buds are present on both sexes and your baby’s hair is thicker than before.
At week 37 of your pregnancy your baby is considered full-term – meaning the point at which birth is just a few weeks away. Your baby’s skin is getting pinker and losing its wrinkly look. The brain and nervous system is developing more and more each day. Your baby can blink, respond to light, and his/her lungs are nearly fully developed. Since your baby is getting closer and closer to birth she is changing positions to prepare for labor.
Congratulations, you are finally approaching your due date; you will soon be holding your little one! But as you near your due date, don’t be worried if your baby arrives a week or two early or late, that certainly is not out of the ordinary.