For both you and your unborn child, pregnancy is an exciting time full of rapid change and development. Everyone can see the growth that is occurring on the outside (hello, expanding belly! ), but the truly fascinating growth is taking place within.
Around week 5, your fetus will start the process of developing a brain, but the real excitement doesn’t start until weeks 6 or 7, when the neural tube closes and the brain divides into three parts.
Your baby’s heart, spinal cord, and brain start to develop around week five. The central nervous system, which also contains the spinal cord, includes the brain of your infant. There are three crucial areas of a baby’s brain to take into account. These include:
According to Kecia Gaither, MD, MPH, director of perinatal services at NYC Health Hospitals/Lincoln, who is double board certified in obstetrics and gynecology and maternal-fetal medicine, the first trimester is a time of rapid development and separation of the various parts of the brain.
The neural plate, which according to Gaither is thought to be the precursor to the nervous system, forms in just 4 weeks. The cephalad portion of the tube becomes the brain, while the caudal portion elongates to eventually become the spinal cord, she explains. “This plate elongates and folds on itself forming the neural tube.”
The cephalad portion of the neural tube, also known as the rudimentary brain, closes around week 6 or week 7, according to Gaither, and divides into the front brain, midbrain, and hindbrain.
Additionally, the spinal cord’s neurons and synapses (connections) start to form at this time. The fetus can move for the first time thanks to these embryonic connections.
Gaither claims that during the second trimester, the brain starts to control bodily functions. This includes particular movements that originate in the cerebellum, which is part of the hindbrain.
Around 16 weeks, sucking and swallowing are one of the first noticeable developments. Gaither claims that the infant can swallow amniotic fluid at 21 weeks.
Additionally, breathing movements that are controlled by the developing central nervous system start during the second trimester. Since the brain (and more specifically, the brain stem) is telling the diaphragm and chest muscles to contract, experts refer to this as “practice breathing.”
And if you experience some kicking during this trimester, don’t be alarmed. The cerebellum, the motor-controlling portion of the brain, controls the baby’s movements, including kicking and stretching.
In the late second trimester, a fetus can start to hear, and as the brainwaves from the growing hypothalamus become more developed, a sleep pattern starts to appear, according to Gaither.
According to Gaither, the fetal brain resembles the adult brain structurally by the end of the second trimester, with the brain stem nearly fully formed.
The third trimester is full of rapid growth. In fact, the brain develops as your baby grows. Gaither explains, “The halves (right brain and left brain) will separate, and all the convoluted surfaces of the brain materialize.”
The cerebellum, which dominates the brain during this final trimester, accounts for all of your baby’s movements, including kicking, punching, wiggling, stretching, and more.
You do have a say in the foods you eat, even though it may seem like you have no control over anything for the next nine months. Healthy brain development starts before pregnancy.
The Centers for Disease Control and Prevention claim that a folic acid-rich diet that includes both food and dietary supplements can support a healthy nervous system.
According to Gaither, when there is an anomaly occurring during the first weeks of brain development, “there are a number of defects along the baby’s brain and spinal cord that can occur.” This may include anencephaly or spina bifida.
Week 10: Baby’s elbows bend
Eight weeks after conception, at the end of the 10th week of pregnancy, your baby’s toes and fingers lose their webbing and grow longer.
Your baby’s head has rounded out by the 10th week of pregnancy, or eight weeks after conception.
Your baby can now bend his or her elbows. Toes and fingers lose their webbing and become longer. The eyelids and external ears continue to develop. The umbilical cord is clearly visible.
Week 5: Hormone levels increase
Your hormone levels are increasing by the end of the fifth week of pregnancy, which is three weeks after conception.
The blastocyst begins to produce HCG hormone in the third week following conception, or the fifth week of pregnancy. Your ovaries will stop releasing eggs and start producing more estrogen and progesterone as a result. These hormones work together to stop your period, which is frequently the first sign of pregnancy, and to promote placenta growth.
The embryo is now made of three layers. Your baby’s outermost layer of skin, eyes, inner ears, central and peripheral nervous systems, and ectoderm will develop from the top layer.
A primitive circulatory system and your baby’s heart will develop in the mesoderm, the middle layer of cells. The bones, ligaments, kidneys, and a large portion of your baby’s reproductive system will all be built on top of this layer of cells.
The endoderm, the inner layer of cells, is where the lungs and intestines of your unborn child will develop.
Folic acid
The development of the fetal brain and spinal cord is supported by folic acid, a form of vitamin B9. Gaither claims that in addition to aiding in the formation of the neural tube, it also contributes to the production of DNA, neurotransmitters, energy, and red blood cells.
Gaither advises consuming 400 to 600 micrograms of folic acid per day while trying to conceive, and another 400 micrograms per day while pregnant.
Gaither advises 4 grams daily during the preconceptional period if you’ve had a child with a neural tube defect.
Whole grains, flaxseed, and dark green leafy vegetables are foods high in folate/folic acid.
Also important for fetal brain development are omega-3 fatty acids. According to Gaither, “the brain has a high fat content, and omegas are helpful in the deposition of the fat in not only the brain, but also the eyes.”
Omegas are also beneficial for the formation of neural synapses or connections between nerves.
Omega 3-fatty acid-rich foods include salmon, walnuts, and avocados.
Before you may even be aware that you are pregnant, fetal brain development begins. Therefore, it’s crucial to begin taking a prenatal vitamin that contains folic acid as soon as possible. If you aren’t pregnant but are considering having a child, include a prenatal vitamin in your daily regimen.
Early in the first trimester and up until delivery, the brain is still developing. Fetal brain development will be in charge of several actions during pregnancy, including breathing, kicking, and heartbeat.
If you have any concerns regarding your pregnancy, fetal brain development, or how to support the baby’s developing brain, speak with your doctor.
Last medically reviewed on September 30, 2020