The stages of pregnancy development in the womb are a beautiful design by God. Below is a breakdown of your baby’s development in the womb month-to-month.
First Trimester (conception – 12 weeks)
Month One (conception – 4 weeks)
As the baby grows, a water-tight sac forms around it, gradually filling with fluid. This is called the amniotic sac, and it helps keep your growing baby safe.
During this time, the placenta also develops. The placenta is an organ inside the uterus that transfers nutrients from the mother to the baby. Think of the placenta as a food source for your baby throughout the pregnancy.
In these first few weeks, the baby’s face will begin to take form with large dark circles for the eyes. The mouth, lower jaw, and throat are developing. Blood cells are taking shape, and circulation will begin. The tiny “heart” tube will beat 65 times a minute by the end of the fourth week.
By the end of the first month, your baby is about 1/4-inch-long. Many women discover they are pregnant around week 4 of pregnancy after their first missed menstrual cycle.
Month Two (5 weeks – 8 weeks)
Your baby’s facial features continue to develop. Each ear begins as a little fold of skin at the side of the head. Tiny buds that eventually grow into arms and legs are forming. Fingers, toes, and eyes are also forming.
The neural tube (brain, spinal cord, and other neural tissue of the central nervous system) is well-formed now. The digestive tract and sensory organs begin to develop too. Bone starts to replace cartilage.
Your baby’s head is large in proportion to the rest of its body at this point. At about 6 weeks, your baby’s heartbeat can usually be detected.
By the end of the second month, your baby is about 1-inch-long and weighs about 1/30 of an ounce.
Month Three (9 weeks – 12 weeks)
Your baby’s arms, hands, fingers, feet, and toes are fully formed. At this stage, your baby is starting to explore a bit by doing things like opening and closing its fists and mouth. Fingernails and toenails are beginning to develop and the external ears are fully formed. The beginnings of teeth are forming under the gums. Your baby’s reproductive organs also develop, but the baby’s gender is difficult to distinguish on ultrasound.
By the end of the third month, your baby is fully formed. All the organs and limbs (extremities) are present and will continue to develop in order to become functional. The baby’s circulatory and urinary systems are also working and the liver produces bile.
The third and fourth months are typically when abortions are performed. The lie circulating is that babies are not formed at the time of abortion and it is just a clump of cells. Looking at the stages of development in the womb, we know that a baby is actually fully formed by month three of pregnancy.
At the end of the third month, your baby is about 4 inches long and weighs about 1 ounce.
Since your baby’s most critical development has taken place, your chance of miscarriage drops considerably after three months.
Second Trimester (13 weeks – 28 weeks)
Month Four (13 weeks – 16 weeks)
Your baby’s heartbeat is now audible through an instrument called a doppler. The fingers and toes are well-defined. Eyelids, eyebrows, eyelashes, nails, and hair are formed. Teeth and bones become denser. Your baby can even suck his or her thumb, yawn, stretch and make faces!
The nervous system is starting to function. The reproductive organs and genitalia are now fully developed, and your doctor can see on an ultrasound if you are having a boy or a girl.
By the end of the fourth month, your baby is about 6 inches long and weighs about 4 ounces.
Month Five (17 weeks – 20 weeks)
At this stage, you may begin to feel your baby moving around! Your baby has developed muscles and is exercising them. This first movement is called quickening and can feel like a flutter to the mother.
Hair begins to grow on the baby’s head. Your baby’s shoulders, back, and temples are covered by a soft fine hair called lanugo. This hair protects your baby and is usually shed at the end of the baby’s first week of life.
The baby’s skin is covered with a whitish coating called vernix caseosa. This substance is thought to protect your baby’s skin from long exposure to amniotic fluid. This coating is shed just before birth.
By the end of the fifth month, your baby is about 10 inches long and weighs from 1/2 to 1 pound. At 20 weeks pregnant you are halfway!
Month Six (21 weeks – 24 weeks)
If you could look inside the uterus at your baby right now, you would see that your baby’s skin is reddish in color, wrinkled and veins are visible through the baby’s translucent skin. The Baby’s finger and toe prints are visible. At this stage, the eyes begin to open.
Baby responds to sounds happening outside the womb by moving or increasing the pulse. You may notice jerking motions if the baby has hiccups.
If a baby is born prematurely, your baby can survive after the 23rd week with intensive care.
By the end of the sixth month, your baby is about 12 inches long and weighs about 2 pounds.
Month Seven (25 weeks – 28 weeks)
Your baby will continue to mature and is reserving body fat. At this point, the baby’s hearing is fully developed. The baby changes position frequently and responds to things like sound, pain and light. The amniotic fluid begins to diminish slowly from now until the end of the pregnancy.
Around this time, it is shown that when the mother speaks the baby’s heart rate slows down a bit, showing that the mother’s voice has a calming effect on the baby. Baby will recognize mom’s voice at the time of birth!
At the end of the seventh month, your baby is about 14 inches long and weighs from 2 to 4 pounds.
Third Trimester (29 weeks – 40 weeks)
Month Eight (29 weeks -32 weeks)
Your baby is continuing to mature and developing reserves of body fat. You may notice that your baby is kicking more. Baby’s brain is developing rapidly at this time, and your baby can see and hear. Most internal systems are well developed, but the lungs may still be immature.
At the end of the eighth month, our baby is about 18 inches long and weighs as much as 5 pounds.
Month Nine (33 weeks – 36 weeks)
During this stage, your baby will continue to grow and mature. The lungs are close to being fully developed at this point.
Your baby’s reflexes are coordinated so he or she can blink, close the eyes, turn the head, grasp firmly, and respond to sounds, light, and touch.
At the end of the ninth month, your baby is about 17 to 19 inches long and weighs from 5 ½ pounds to 6 ½ pounds.
Month Ten (37 weeks – 40 weeks)
In this final month, you could go into labor at any time. You may notice that your baby moves less due to tight space. At this point, your baby’s position may have changed to prepare for birth. Ideally, the baby is head down in your uterus. You may feel very uncomfortable in this final stretch of time as the baby drops down into your pelvis and prepares for birth.
Your baby is ready to meet the world!
Your baby is about 18 to 20 inches long and weighs about 7 pounds.