15 Photos Showing The Transformation Of The Amniotic Sac

How much does mom know about the amniotic sac? Sure, we all know that this sack of water hugs our baby for nine months in the womb. We clearly understand that when labor is approaching, this sac often ruptures beforehand. For many women, the water breaking is the first true sign that baby is on the way.

But, have you ever thought about what this mysterious pregnancy organ actually does? Did you know that amniotic sac helps to keep the baby in your uterus? That is regulates your baby’s body temperature?

Did you know that even prior to the development of the heart, facial features, or curvature of the spine…the amniotic sac is already in existence?! Without it, the development and survival of the embryo is impossible.

Not only does it act a cushion against the daily jolting of an active mother, it also protects the baby from outside contaminants. It literally prevents germs from getting inside the womb. In addition, it ensures that the umbilical cord does not become compressed by allowing it float freely in the fluid. Without it, the baby could be deprived from the nutrients necessary for survival.

Problems like leaks, ruptures, or low levels of amniotic fluid serve as a built-in warning system. When such complications occur, we get the message to act quickly to save the still-developing baby inside. We know that something isn’t right and the fetus needs our immediate attention.

The incredible and mysterious amniotic sac is the life source for an unborn baby. The literal and physical beauty of it has been captured in these amazing photos!

15 A Few Days After Conception

Just a few days after conception, most women have no idea that they are pregnant at this point. Not even a full menstrual cycle has passed. The telltale missed period hasn’t landed on the calendar yet. But, your body knows you are pregnant. It is in full swing preparing a home for a developing baby for the next nine plus months. The embryo has already embedded into the lining of the womb. The lining that serves as a barrier between the baby and all else, is the ultimate bubble of protection. Inside the bubble, is an atmosphere filled with the nutrient-rich fluid known as the placenta. This bubble is the amniotic sac. The baby will receive everything it needs in this environment, from oxygen, to blood and nutrients, to important antibodies. This amazing little sac that you don’t even know exists yet, is already preparing for the embryo.

14 30 Days Gestation

You still may not have confirmed your pregnancy yet, but you may be highly suspicious. The period may be late, feelings of nausea and fatigue may be emerging. A urine test could still play tricks on you, but a blood test would confirm the presence of the pregnancy hormones. By the 5th week of pregnancy, the amniotic sac can actually be seen on a transvaginal ultrasound! A tiny yolk sac is there as well, acting as the first source of nutrients for the fetus. The placenta is still developing, but the amniotic sac is already filled with fluid to help cushion the growing embryo. Hints of a face are starting to form, with eyes that look like black dots. The mouth, lower jaw, and throat are also developing. Blood cells are in progress and soon circulation will begin. Pretty amazing accomplishments considering that the baby is still smaller than a grain of rice.

13 6 Weeks Gestation

Now that pregnancy has been confirmed, around six weeks into the pregnancy; the fetus is measurable and a heart beat may be detected. The first obvious forms of a fetus give visual proof of a head at one end and something similar to a tail at the other. This telltale structure is referred to as the fetal pole. The identification of this allows for the first measurements of the fetus to be taken. Crown to rump measurements are compiled, aiding in more accurate pregnancy dating. Measurements at this gestational age are typically between 2-4 mm; about the size of lentil. Incredibly, the nose, mouth, and ears are taking shape. So are the intestines and the first tissue of the lungs. The developments of the brain, muscles, and bones have also begun. The heart is hard at work and the blood is just starting to pulse through body. This explains why it is beating nearly twice as fast as yours.

12 8 Weeks Gestation

At only two months pregnant, the fetus is growly rapidly. He has quadrupled in size in the past two weeks. The hands and feet have developed by now, complete with webbed fingers and toes. Baby is a bit more than half an inch long, approximately the size of a raspberry. The facial continue to become more defined, revealing an upper lip and the tip of the nose. This week, the eyelids will be revealed as well. The shape of the head is quickly expanding to make room for the growing brain. The brain can now be seen in three parts: the forebrain, the midbrain, and the hindbrain. On ultrasound images, the hindbrain looks like a dark spot at the back of the head. Thank to the early development of the arm and legs; this week is the first time your baby will start move. He is still too tiny to feel them yet, but the movements do show up on sonogram.

11 10 Weeks Gestation

Let out your first sigh of relief, baby has now passed the most critical part of development! He is now entering the fetal period, and has officially graduated past the name of embryo. Still pretty tiny, at just over an inch long, the fetus is now gulping down some of that amniotic fluid he is swimming in. He’s also happily kicking around, testing out the movements that his limbs are now capable of making. Even the spinal cord is starting to stretch out and gain nerve endings. All of the vital organs are now established and are quickly making gains in functionality. Soon your baby won’t need the yolk sac anymore. The tiniest little fingernails and toenails have started to develop now and the fetus is turning velvety with a new acquired coating of peach fuzz that covers the entire body. Perhaps the most exciting moment of all, is that it is very likely you will be able to heat the heart beat with a Doppler as your next prenatal visit.

10 12 Weeks Gestation

The baby is really getting busy this week, doing all sorts of stuff with the mouth that help provide developments in many areas beyond the oral cavity. The swallowing technique has advanced and the baby is now able to open the mouth wide enough to yawn. Sometimes he might even get the hiccups! Swallowing the amniotic fluid at this point is super important for gut development and future kidney function. Right now the fluid travels all the way through the stomach, the intestines and into the bowel. The digestive enzymes are not being absorbed yet, but they are being released as stimulant for development. The baby is getting his first doses of glucose now, which are teaching the pancreas how to function. This relates to insulin secretion can impact the baby’s future likelihood for diabetes, increased fat and probability of weight gain. This is why it is so important for mothers to maintain a healthy, balanced diet even in the beginning of pregnancy when they haven’t gained much weight yet.

9 16 Weeks Gestation

Around 16 weeks, the baby starts to urinate in utero which changes the composition of the amniotic fluid. Mostly, the fluid is now a constantly recycled flow of urine. The baby drinks, then urinates, drinks, then urinates, and repeat. If you are wondering just how much liquid is passing back and forth, the amount varies between three and half and four cups. At this time, your doctor starts paying closer attention to your amniotic levels. Levels that are too high or too low can indicate developmental or pregnancy complications. When amniotic fluid levels are excessive, it can mean that the baby isn’t drinking properly or even that something in the gastrointestinal area isn’t functioning properly. If you have the opposite problem; of too little fluid, it can indicate a tear in the amniotic sac, a problem with the placenta, or even an STD. Prolonged periods of low amniotic fluid put the baby at risk for premature delivery.

8 20 Weeks Gestation

Woohoo! You’ve made it halfway through the pregnancy, and it shows! It’s probably obvious by now that there is a little more going on than a little midsection weight gain. Your belly is growing rapidly at this point, and for a good reason. The baby is now a whopping 9 ounces and measures close to 10 inches from head to heel. He is certainly getting bigger and more active with every moment. He is about the size of a mango and you are very likely feeling that movement more often now. Some pretty interesting things happen at this stage, too! For example, baby can hear and recognize your voice now…so start talking to him! She has also added a new talent to her repertoire, and she can now breathe in the amniotic fluid rather than just swallowing it. Apparently, the half way point is a good milestone to start practicing for life outside the womb.

7 23 Weeks Gestation

Did you know that the gestational age of your baby can be estimated from the size of your amniotic sac alone? Measurements of the fetal pole are more commonly used to date the pregnancy, and some doctors will combine both methods of measuring to come up with the best estimate. But, especially in the first trimester when the baby is too small to measure, the size of the sac can be a clue to exactly how many days along you are. The gestational sac grows an amazing 1 mm per day after the 4th week of pregnancy. At 23 weeks, the baby is nearly a foot long and weighs more than a pound. You might even be able to see her moving now as pushes against the belly. Her senses are growing keener every day. Her lungs are continuing to develop and fill with blood vessels. Her hearing is improving and familiar sounds like the dark barking are becoming customary. They won’t even phase her when she is born.

6 28 Weeks Gestation

At 28 weeks gestation you have officially entered the third trimester and the amniotic fluid has changed yet again. Now it is composed of two thirds parts of urinary secretions and one third is lung secretion. Fluid can also leave the sac when the baby swallows and passes it back to the blood stream of the mother. Certain hormones, like prolactin and prostaglandins play an important role in keeping the right balance of fluid in the womb. How much fluid a mother is drinking can also have an impact on desirable levels of amniotic liquid. Normal levels vary greatly and range anywhere from 500-1500 mls. This translates to anywhere from half a liter to 1.5 liters. The baby is getting big and needs plenty of fluid to float around. He is well over 2 pounds by now and measuring nearly 15” long. Your baby is now able to produce actual tears, and you can feel him hiccupping, too.

5 32 Weeks Gestation


The end of pregnancy is getting so close, yet it’s still so far away. The last 4-6 weeks can be excruciating in terms of wait. You might also be getting uncomfortable do the growth of your baby and your belly. You’re gaining about a pound a week at this point, and baby gets to keep half of it! But, she is not done yet, in the final stretch of pregnancy she still has 1/3 of her birth weight to gain. She is over 16.5 inches long and getting close to the four pound mark. She has actual hair on her head by now and the peach fuzz on her skin is slowly giving way to soft, smooth skin in preparation for birth. As ready as you may be for her arrival, is it still a bit too soon for her to enter the world. If your water were to break this week, the baby would probably need steroids to quicken up the development of her lungs. She needs at least two more weeks to eliminate being born before the lungs are ready.

4 36 Weeks Gestation

By 36 weeks, you have reached a relative safety period in your pregnancy. Most of the time, inductions are safe at this period, if medically necessary. These days it is becoming more common to be induced at 36 weeks if your doctor has been concerned over your amniotic fluid levels. Some opinions are that this procedure is being over done and does not really pose any benefits to the baby. Many theories state, that if the pregnancy is an otherwise healthy one, the levels are usually related to dehydration in the mother. This is especially so for late term pregnancy in the hot summer months. If you hear your doctors whispering about fluid levels and early induction, be prepared to gather more research and to get a second opinion if necessary. There is no current evidence that supports an early induction makes an positive benefits for otherwise healthy pregnancies with minor imbalances in amniotic fluid volume.

3 Delivery Of The Baby And The Sac

Usually the water breaks sometimes before labor and delivery, or even at the time of delivery. One in ten women will experience their water breaking several hours before labor starts. Many women say that an earlier rupture of the sac makes the labor considerably more painful. This is because the literal buffer between the baby and the uterus has been drained out. All the fluid that was creating a cushion has gushed out, and impending birth usually approaches rather quickly. Even the contractions may feel stronger without the water to absorb some of the movement. Regardless of early breakage, the amniotic sac usually remains inside the uterus until after the baby is born. After the baby has been delivered, the mother has a final set of contractions. Then she must push to release the remaining parts of the pregnancy. Normally this is compiled of the amniotic sac, placenta, and body fluids.

2 Twins: One Still In The Sac

In 2016, beautiful and stunning images surfaced of a couple who delivered their twin at home in a water bath. After the first baby was delivered, the father was stunned to realize that the second baby was crowning and still inside the amniotic sac. Instinct took over, and the father kept the baby in the sac submerged in the water until the mother reached down and pinched the membrane open. The baby was then able to take its first breath of air by special assistance from the parents. The parents were stunned and overjoyed, celebrating their decision to have delivered at home without medical interference. It just so happened that they had a talented photographer on hand who was able to catch the enchanting moment on film. She spoke of the aura in the room, as she photographed and then the mother delivered both placentas. Legend has it that this baby will be destined for greatness!

1 Babies Delivered Encaul

At the odds of 1 in 80,000 births, a baby is delivered still inside the amniotic sac with it fully intact. Often when this occurs, it appears that infant has no idea it has been delivered into the real world. It remains in the fetal position, still breathing from the sac. When this happens, the doctor must cut open the sac to enable the baby to take its first breath of oxygen. There have a few documented case of this in the media quite recently. One occurrence was with baby Silas, who born 3 months premature in 2015. Miraculously the delivery was caught on video and quickly when viral. More recently, just a few weeks ago in the UK, baby Sophia was born at home on the living room floor. Her own father, who delivered her, had to break open the sac when he realized it hadn’t burst on its own.

Sources: Babies Online, What To Expect, Reference.com, American Pregnancy, Web MD, Baby Center, Parents, Family Education, Parenting, Sure Baby, Baby Med, Fetal Ultrasound, Press Room VIP

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