Your Baby’s Development

Your Body Development

Baby Size

Baby Weight

Week 1

Your Baby’s Development is just started. Doctors actually begin counting the 40 weeks of pregnancy from the first day of your last period.

Your body is doling out the usual monthly symptoms, as your uterus sheds its lining, and you get your period. Now’s a good time to prepare your body for pregnancy!

Microscopic

Week 2

Right now, your eggs are still in your ovaries, some are ripening, and one will be release when you ovulate (most likely next week).

Your period is over, your body is preparing to release another egg from your ovaries, and your uterus is starting to form a lining of blood-rich tissue, awaiting the arrival of a fertilized egg.

Microscopic

Week 3

Your Baby’s Development is already on the move. Within 24-hours, the fertilized egg begins to rapidly divide into many cells, and then this tiny cluster of cells travels down the fallopian tube to the uterus. If you timed it right, sperm has just recently fertilized egg, and you’re pregnant!

Though you may well be, it’s still too early to tell whether or not you’re pregnant. It’ll be a week or 2 before you’ll be able to confirm your pregnancy (a few days after your first missed period).

.006 inches

Week 4

Your Baby’s Development is started in your uterus. What is still just a little cluster of cells now burrows into the lining of the uterine wall and then divides in half? One half becomes the placenta and the other the baby. At the same time, different germ layers formation start takes place.

You may experience some spotting (or slight bleeding) for 1 or 2 days around the time that the tiny cluster of cells implants in the lining of your uterus. This lining then becomes thicker and your cervix is sealed by a plug of mucus.

.006 inches

Embryo at 4 weeks after fertilization 
Image Source -  http://en.wikipedia.org/wiki/Pregnancy

Week 5

This is a week of crucial wiring when the placenta and umbilical cord hook up to Mom. Your Baby’s Development's heart--about the size of a poppy seed--starts beating.

You may begin feeling the symptoms of early pregnancy: fatigue, sore (enlarged) breasts, aching back, nausea, and mood swings.

.05 inches

Week 6

The cluster of cells takes on the shape of a baby with a prominent head and dark eyespots. The vital organs including the brain, spinal cord, heart, kidneys, liver, and stomach start to form.

This is the week that women usually get hit hardest by first trimester pregnancy symptoms. Some women don’t experience any discomfort at all in their first trimester but most do.

.08 to .16 inches

Week 7

With your child's biggest growth spurt until puberty, the embryo more than doubles in size. The legs and arms extend and grow from the torso and the heart divides into right and left chambers. The forebrain also divides into two hemispheres.

You might be putting weight around your waist. In between bouts of morning sickness, you may have noticed an increase in sensitivity in your pelvic area caused by pregnancy hormones.

.44 to .52 inches

Week 8

Finite features including elbows, arms and fingers leg buds start to develop. The face continues to change as the ears, eyes and the nose appear. Teeth develop under the gums. The intestines start to form in the umbilical cord.

What the heck is going on with your skin? You may be experiencing oily skin and breakouts as your hormone levels increase. Things should level off in your second trimester.

.56 to .8 inches

Fetus at 8 weeks after fertilization
Image Source -  http://en.wikipedia.org/wiki/Pregnancy

Week 9

The eyelids now cover the eyes and will remain sealed shut until week 27. Pupils form and as the arms and legs grow longer.

You may see not only your waist that’s expanding… so are your breasts! Your may experience some heartburn and indigestion as your body adjusts to pregnancy hormones.

.09 to 1.2 inches

Week 10

About the size and shape of a medium shrimp, week ten marks the end of the embryonic period and the embryo becomes a fetus with all vital organs. Most of the joints are formed now - elbow, wrist, knee, shoulder, and ankle as well as the hands, fingers, feet and toes.

Your may notice increase in your waist size. The morning sickness may start to ease a bit. You may notice blotchy complexion due to those wild hormones. Your blood volume will increase 40%-50% during pregnancy.

1.25 to 1.68 inches

Week 11

The most critical part of the baby's development is over. The baby's body isn't very proportionate and the head makes up half the size. The neck develops and the head rises up from the chest.

Your uterus has expanded and you may have gained a little weight. You may find that your taste is better as your nausea drop down even though certain smells may bother you.

1.75 to 2.4 inches

.3 ounces

Week 12

All of the organs and structures of the unborn baby are formed. Fingers, toes, hair and nails begin to grow. The genitals begin to take on gender characteristics. Kidney starts functioning. The muscles in the intestinal walls begin to practice peristalsis - contractions within the intestines that digest food.

You're in the final stretch, of your first trimester. Around this week, your uterus will shift up and forward as it grows. An increase in blood volume and it's those hormones that make your skin oily.

2.5 inches

.3 to .5 ounces

Second Trimester

Your Baby’s Development

Your Body Development

Baby Size

Baby Weight

Week 13

Your Baby’s Development's body starts to catch up to the head. Eyes, which start out on the side of the face, move toward the center and the ears move toward the side of the head. The sex organ growth also takes place.

Welcome to your second trimester where your tummy is getting bigger, your body increases blood flow increases. The ligaments that hold up your uterus stretch to accommodate your growing uterus.

2.6 to 3.1 inches

.5 to .7 ounces

Week 14

Baby begins to practice inhaling and exhaling movements. The eyes, ears, and neck continue to develop. The hands are becoming functional, and baby learns to move them. At this point, little one is receiving all nourishment from the placenta.

You're finally starting to look pregnant. The top of your uterus is rising up from below your pelvic bone and into your abdomen.

3.2 to 4.1 inches

1 ounce

Week 15

The bones are getting harder as Your Baby’s Development takes in nutrients from Mom, namely calcium. Lanugo, a very fine hair, covers the body and will continue growing on the baby until around the 26th gestational week of pregnancy.

You may notice swollen or bleeding gums. You may experience constipation as your pesky hormones cause your bowel muscles to relax and work less efficiently and your uterus presses on your intestines.

4.1 to 4.5 inches

1.75 ounces

Week 16

The baby continues to grow and take up more space in the uterus while showing a decided flair for movement. You, therefore, may experience movements for the first time, called fluttering.

Your heart is pumping more blood than it did pre-pregnancy. This increased blood volume is causing a few quirky side effects. Dark veins are appearing in your breasts and the tissues in your vaginal area have swelled up.

4.3 to 4.6 inches

2.8 ounces

Week 17

While most of Your Baby’s Development's organs are in place, he's still very thin and lanky. During week 17 Your Baby’s Development starts to form fat. The tiny heart is pumping as much as 25 quarts of blood a day!

It's 'round about this week that you might feel a light flutter as Your Baby’s Development's bones begin to harden. You may also have noticed an increase in your hunger as Your Baby gets bigger and hungrier.

4.4 to 4.8 inches

3.5 ounces

Week 18

Your baby is nearly half a pound now and very human looking. Pads are forming on the fingertips and toes, and the eyes are looking forward rather than out the sides of the head. If your baby is a boy, his prostate gland is beginning to develop.

Your baby starts moving. You may also be experiencing an ache or shooting pain on one or both sides of your lower abdomen. This is called "round-ligament pain." It's common between weeks 16 and 20 and usually disappears.

5 to 5.6 inches

5.25 ounces

Fetus at 18 weeks after fertilization 
Image Source -  http://en.wikipedia.org/wiki/Pregnancy

Week 19

The sebaceous glands start producing vernix caseosa, a covering that protects the delicate fetal skin from the amniotic fluid. Myelination of the spinal cord also takes place.

As your uterus continues to push forward, your back is starting to bend. You may be noticing several skin changes including patches on your forehead, cheeks, nose and chin.

5.2 to 6 inches

7 ounces

Week 20

This is halfway through the pregnancy, and the baby has as much sleep and awake time as a newborn. The scalp hair begins to grow and skin forms two layers including epidermis and the dermis. If your baby is a girl, her uterus is starting to develop.

You're belly button may have popped this week, and you may notice a dark line from your navel to you pubic bone. You're probably feeling the baby frequently now as the movements become stronger.

5.6 to 6.4 inches

9 ounces

Week 21

The different organ systems developed during the crucial embryonic phase start to perform their duties, prepping the baby for survival outside the womb. Your Baby’s Development may start swallowing small amounts of amniotic fluid, absorbing most of the water, and passing the rest through to the large bowel.

You might have notice that your breasts have begun to leak a yellowish fluid. This nutrient rich fluid is called, "colostrum," and it's precursor to breast milk. Leakage during pregnancy happens to some women, and it's a perfectly normal.

7.2 inches

10.5 ounces

Week 22

Eyelids, eyebrows, and even fingernails have developed. By now liver, with some help from Mom, is starting to break down bilirubin, a substance produced by red blood cells.

You'll probably be gaining weight more steadily now as your baby continues to fill out. You may notice stretch marks on your belly, hips, buttocks, breasts.

7.6 inches

12.25 ounces

Week 23

Your Baby starts practicing breathing by taking in and expelling small amounts of amniotic fluid. The pancreas also produces insulin, important for the breakdown of sugars. Your Baby looks like a small doll with all the facial features of an infant at birth.

Your uterus is pressing down on your bladder weakening your muscles and causing urine leaks.

8 inches

16 ounces

Week 24

With all of the rapid organ development, and in-womb practice, Your Baby may be able to survive outside the womb. The baby's once wrinkled skin has filled out with weight gain, and there is little space left inside the womb.

Many women find that around this time they begin to have an increasingly hard time sleeping (for long periods of time that is). Frequent urination, anxiety, and general discomfort may affect you.

8.4 inches

1.2 pounds

Week 25

By this time Your Baby open eyes and the retina form different layers which can sense light levels and send messages to the brain. Also, the once smooth surface of the brain starts to form grooves and indentations.

Now you may be noticing pigment changes galore: a line from your navel to pubic bone, darker freckles, moles, and nipples. You may even experience something called the "mask of pregnancy," where the skin darkens on the sides of your face and around the nose.

8.8 to 10.4 inches

1.5 to 2.7 pounds

Week 26

Your baby eyes open and the retina form different layers which can sense light levels and send messages to the brain. Also, the once smooth surface of the brain starts to form grooves and indentations.

Your uterus is now very large in size, if so, you may be experiencing Braxton Hicks contractions. These intermittent contractions are a way of helping your body prepare for labor.

14.02 inches

1.68 pounds

Week 27

During this week, the brain continues its rapid growth, and the lungs continue to grow. Eyelids begin to open, and the retinas begin to form. Also, the once smooth surface of the brain starts to form grooves and indentations.

You're on the threshold of your third trimester! And if it seems like you're getting bigger by the minute, well, you are. In the third trimester you'll gain an average of 1 pound a week. Your expanding uterus is now pushing against your organs.

14.41 inches

1.93 pounds

Third Trimester

Your Baby’s Development

Your Body Development

Baby Size

Baby Weight

Week 28

Your baby is growing and developing at fast rate! Eyebrows and eyelashes are now present, and the hair on the head is growing. The body is getting plumper and rounder. Muscle tone is gradually improving. The lungs are capable of breathing air.

You're getting bigger and have just about forgotten what it feels like to sleep through the night. Trips to the bathroom, kicks from the baby, cramping legs, and heartburn are all working against you.

8.4 inches

1.2 pounds

Week 29

The baby's head is in proportion to the rest of the body. Fat continues to accumulate under the skin. The brain can control primitive breathing and body temperature control, and the eyes can move in the sockets. The baby is becoming sensitive to light, sound, taste and smell.

By now you may have noticed some mild swelling of your, face, hands, and/or feet. This is normal and will most likely become more noticeable as your delivery date approaches.

15.2 inches

2.54 pounds

Week 30

While continuing to plump up, the baby is responding to light, sounds, and making faces. The early lanugo is disappearing, the eyelids open and close, and the toenails are growing. The bone marrow is now responsible for red blood cell production.

Your may be feeling pain from your buttock down your leg or in your hip. The pain will most likely subside toward the end of your pregnancy as your uterus shifts position, and should subside completely post pregnancy.

15.71 inches

2.91 pounds

Week 31

While continuing to plump up, the baby is responding to light, sounds, and making faces. The brain goes through a period of rapid development. If your baby is a boy, his testes begin to descend from the body cavity to the scrotum.

Your abdomen may be aching frequently now as your uterus is stretching more and more. Your uterus is about 4 1/2 inches above your belly button.

16.18 inches

3.31 pounds

Week 32

While continuing to plump up, the baby all five senses are functional. The toenails are completely formed and the hair on the head continues to grow.

Your uterus is measuring about 5 inches above your navel and is pushing your organs causing heartburn, constipation, indigestion and breathlessness. As your skin stretches to accommodate your growing baby, it tightens and can dry out can get darn-right itchy.

16.69 inches

3.75 pounds

Week 33

At this point, the amniotic fluid is at the highest level in the pregnancy. The amount will remain constant until delivery. Rapid brain growth has increased the baby's head size approximately 3/8 of an inch this week. Fat continues to accumulate which turns the baby's skin color from red to pink.

You'll be gaining about a pound a week. Your may experience mild edema. Now you know what this "nesting" thing is really all about. You actually do get this strange sensation to prepare everything for the baby.

17.20 inches

4.23 pounds

Week 34

While continuing to plump up, the baby responds as a newborn with its eyes open while awake and closed while sleeping. The baby is developing immunities to fight mild infection. Fingernails are at the ends of the fingertips.

Around this time, the baby drops lower in your pelvis (the lightening), and you can breathe again. Be aware of any sudden swelling of your feet, hands, or face.

17.72 inches

4.73 pounds

Week 35

In anticipation of delivery, the baby positions itself with the head down towards the pelvis and sheds lanugo hairs. The fat accumulations plump up the arms and legs this week. The baby has gotten big enough to take up most of the uterus and testes have completed their descent in males

You may have noticed an increase in Braxton Hicks contractions over the last few weeks as you're uterus prepares for the big day.

18.19 inches

5.25 pounds

Week 36

In anticipation of delivery, the baby positions itself with the head down towards the pelvis and sheds lanugo hairs. The fat is dimpling on the elbows, knees as well as forming creases in the neck and wrists along with gums.

Your breasts are bigger than ever and may be leaking colostrum, which will be Your Baby’s Development's first food. It's a thick, yellowish fluid containing antibodies that protect newborns from infection.

18.66 inches

5.78 pounds

Week 37

In anticipation of delivery, the baby positions itself with the head down towards the pelvis and sheds lanugo hairs. The baby practices breathing movements preparing for life outside the womb.

Your body is preparing for labor, and you may have noticed more mucous in your vaginal discharge. Your Baby’s Development's now in the position that he/she will most likely stay in for delivery.

19.13 inches

6.3 pounds

Week 38

In anticipation of delivery, the baby positions itself with the head down towards the pelvis and sheds lanugo hairs. The baby may be gaining in weight and intestines are accumulating lots of meconium.

You may be feeling more energetic these days. Hormone increases can cause your eyes to become drier and change the shape of your cornes.

19.61 inches

6.8 pounds

Fetus at 38 weeks after fertilization
Image Source -  http://en.wikipedia.org/wiki/Pregnancy

Week 39

In anticipation of delivery, the baby positions itself with the head down towards the pelvis and sheds lanugo hairs. Most of the lanugo is gone as the baby prepares for its final womb days. The lungs are maturing and surfactant production is increasing.

Are you feeling huge and clumsy? As the baby settles into your pelvis, your center of gravity shifts which may make you feel off-balance. The uterus isn't pressing on your diaphragm so it's easier to breathe but your uterus is pushing on your bladder so you may be urinating more.

19.96 inches

7.25 pounds

Week 40

In anticipation of delivery, the baby positions itself with the head down towards the pelvis and sheds lanugo hairs. At this point, most of the vernix is gone, 15% of the body is fat and the chest sticks out.

You've done everything you can to prepare, and you are so ready! Keep in mind that your baby's due date is only an estimate, and every baby is born in its own time.

20.16 inches

7.63 pounds