Uterus size 13 weeks

13 Weeks Pregnant: Symptoms, Tips, Baby Development

Reviewed by

Kate Shkodzik, MD

Obstetrician and gynecologist

Only 13 weeks ago you may have been wrestling with the news that you were pregnant — and now look at you! You’ve probably had some challenging experiences and even had to deal with a few tricky spots, but here you are at the second trimester! By week 13, your little baby has become very busy indeed, and you’ve also got lots going on.

Her eyelids are completely closed. The head-to-body proportion is changing: now, the head is 1/3 of the total length. The fingertips are marked with fingerprint patterns. The baby is able to put the thumb in the mouth, trying to suck it.

Join Flo as we take you through the major stages of week 13 of pregnancy:

As you’ll recall from our coverage of the earlier stages of pregnancy, in the weeks leading up to this point your little one has been growing in size and developing at a rapid pace. This will continue in the next phase of your pregnancy. The fetal head is still disproportionately large compared to the rest of the body, but this is gradually starting to even out.

By now, you’ll have noticed changes in your own body, too. Your uterus will have increased substantially in size and now fills your pelvis. If nausea in the morning or at any other time of day has put you off your food, you might be feeling well enough now to enjoy your meals — and maybe put on a little weight!

How big is your baby at 13 weeks pregnant?

By week 13, your baby has become the size of a pea pod. The baby is constantly growing. Now, he/she is more than 2.8 in (7 cm) from the top of his/her head to the coccyx and weighs about 25 g (0.89 oz). It might not seem like much, but only 5 weeks ago it was the size of a blueberry.

Pregnancy week 13 fetal development

Considering how rapidly your baby has been developing over the last few months, it’s no surprise that he or she has come so far! The eyes are moving into position and the wrists and ankles are already well formed. On top of this, the baby’s body is growing significantly and this means that it won’t be long until the head and the body no longer appear so mismatched in size.

By this stage in the pregnancy, a girl’s ovaries and a boy’s testes are fully developed internally — and on the outside, the genitalia are in the process of forming. For a while now, the fetus has had a pronounced swelling between the legs and this is now undergoing rapid development into what will ultimately become the penis of a male or the clitoris of a female.

At 13 weeks, your uterus is now much larger and fills your pelvis. As it’s grown, the uterus has risen into your abdominal cavity.

If you’ve been avoiding meals and snacking like you’re on a picnic because of morning sickness, you might find now that your nausea is easing and your appetite returning. Time to indulge those cravings!

13 weeks pregnant belly

As your uterus has grown in size and started to fill your pelvis, it has also risen into your abdominal cavity (resulting in the typical smooth oval that you may be able to feel).

And this has another consequence: if for the last few months you’ve been urinating more than usual, it’s because your uterus has been putting pressure on your bladder and this should start to ease as the uterus moves further up your body.

13 weeks pregnant symptoms

One of the most significant developments for an expecting woman at this stage is the typical relief from nausea that occurs at around 13 or 14 weeks. Up to this point, your queasiness is likely to have hampered your appetite and put you off your usual diet — for this reason, it’s not uncommon for many women to only gain a little weight until the second trimester of pregnancy.

But around now you’ll start to feel yourself again — just a very pregnant version of yourself! At the very least, nausea and tiredness of morning sickness (which can occur at any time of day) will start to wear off. As your appetite returns, feel free to indulge in the things you’ve been avoiding all this time — but try to maintain a healthy, balanced diet nonetheless.

Another change that many women notice is an increased libido. It may be the result of either the increased blood flow to your genital area or the activity of your pregnancy hormones. Whatever the reason, if you’re feeling frisky then you might want to share it with your partner — unless a health professional has told you otherwise, you can safely remain sexually active for the full duration of your pregnancy.

In most countries, the first scan of a pregnant woman takes place between weeks 8 and 14. It’s usually followed by another scan at 18-21 weeks.

You should also be aware that screening tests for a number of serious developmental disorders (including Down’s syndrome) are available to you at this stage. Your healthcare provider has probably already mentioned these this to you and put things into motion, but if not feel free to flag it up and ask what arrangements need to be made.

Your pregnancy may be a challenging time for you, but do your best to follow a healthy lifestyle. This will provide the best support for you and your baby until delivery. Your diet should contain a wide variety of foods from all the recommended food groups, including a mixture of fresh fruit and vegetables whenever possible. You should also aim to drink between eight and 10 8-ounce glasses of water (from all sources) a day unless your doctor says otherwise.

Try not to fixate on the old idea of ‘eating for two’ — in reality you only need around 300 to 350 extra calories per day to provide for your baby.

Sex at week 13 of pregnancy

Unless your doctor has told you otherwise, your sex life can continue as normal throughout pregnancy.

Here’s your week 13 pregnancy checklist:

Care to share…?

Different couples work differently together: some partners become very involved in pregnancy from the get-go, while others are more reticent. Whatever the case, week 13 is a great opportunity to try to involve your partner more in your and your baby’s experiences. Why not suggest to your partner that he join you at your next checkup? It’s a chance for him to hear the baby’s heartbeat and catch up on what’s been going on.

And while you’re being intimate with your partner…

Many women experience heightened sex drive in the early part of the second trimester — there’s lots of blood flowing to your pelvis and your hormones are raging. If this makes you feel like being intimate with your partner, then let them know about it! Some couples can feel a little disconnected over the course of a pregnancy, so try to take advantage of the opportunity to restore your bond. Unless your health practitioner has told you otherwise, sex is safe for you and your partner throughout pregnancy.

Remember to be cautious about urinary tract infections (UTIs)

Now that your uterus is expanding into your abdomen, it will put less pressure on your bladder — and this will mean fewer bathroom breaks. Stay alert to any sign of a UTI (particularly pain when urinating). UTIs do occur when pregnant and should be treated promptly to reduce the risk of kidney infection.

References

https://www.webmd.com/baby/guide/your-pregnancy-week-by-week-weeks-13-16#1 https://www.nhs.uk/conditions/pregnancy-and-baby/13-weeks-pregnant/ https://www.nhs.uk/start4life/pregnancy/week-by-week/2nd-trimester/week-thirteen/

14 week pregnant

15 week pregnant

16 week pregnant

Your Pregnancy Week by Week: Weeks 13-16

Written by WebMD Editorial Contributors

Week 13

Baby: Your baby is growing quickly! Eyes are moving into position, the ankles and wrists have formed, and though the head is still disproportionately big, the rest of the body is starting to catch up. This week, your baby's intestines are back inside where they belong. Your baby swallows amniotic fluid and absorbs it into their body. Baby's backbone can flex, making large movements easier. If you think you may be having twins, an ultrasound this week may confirm it!

Mom-to-be: You may have more energy and feel your best these next couple of months. Your uterus has grown a lot. It's filling your pelvis now and starting to grow upward into your abdomen. It probably feels like a soft, smooth ball. If you haven't gained any weight yet because of morning sickness, you'll begin to know as you start to feel better. You may feel a stretch in your belly as your round ligaments stretch. As you begin your 2nd trimester, your risk of miscarriage drops. If your gums swell and bleed from hormones, try a softer toothbrush.

Tip for the Week: Suggest that your partner go with you to a check-up. They might love the chance to hear the baby's heartbeat.

Week 14

Baby: Your baby's ears are shifting from the neck to the sides of the head, and the neck is getting longer and the chin more prominent. Facial features and unique fingerprints are all there. Your baby is beginning to respond to outside stimuli. If your abdomen is poked, the baby will try to wriggle away. The baby swallows amniotic fluid and passes it as urine. They still have room to float around your womb. Your baby's spleen will take over the development of red blood cells. From head to rump, your child is about the length of a bell pepper -- 3.5 inches.

Mom-to-be: You're probably wearing maternity clothes now. Your skin and muscles are starting to stretch to accommodate your growing baby. You may notice some constipation, because pregnancy hormones relax the bowel. You may salivate more. Tell your doctor if it's a problem. Small spider veins may appear on your legs or face. They will fade after delivery. Small spider veins may appear on your legs or face. They will fade after delivery.

Tip of the Week: Try to ease constipation by getting moderate exercise, drinking plenty of fluids, and eating lots of fruit and vegetables.

Week 15

Baby: Your baby, from head to heel, is as long as a large russet potato -- 6.25 inches. They're covered by very fine hair, called lanugo, which is usually shed by birth. Eyebrows and hair on the top of the head are beginning to grow, bones are getting harder, and the baby may even be sucking their thumb. Their organs are fully formed now and will continue to grow. You may be able to tell the baby's sex this week with high-resolution ultrasound!

Mom-to-be: Your uterus can probably be felt about 3 to 4 inches below your navel. Sometime in the next five weeks you'll be offered a blood test called the quadruple marker screening test to help screen for Down syndrome. You can talk with your doctor about what prenatal tests you may want. If you're feeling better, you may be more interested in sex. You've probably gained about 15 lbs. on average. You'll start gaining more weight now -- about 1-2 lbs. a week.

Tip of the Week: Start learning to sleep on your left side -- your circulation is better that way. You can try tucking pillows behind you and between your legs. Some pregnancy pillows support your entire body.

Week 16

Baby: You may be able to hear the baby's heartbeat in the doctor's office. Fine hair, lanugo, may be growing on the head. Arms and legs are moving, and the nervous system is working. Your baby can make slow eye movements behind still-closed eyelids. Your little one can move even more, flexing arms and legs! Bones harden; calcium makes them appear bright white on the ultrasound. Your baby, from head to heel, is the length of a carrot -- 7 inches.

Mom-to-be: Within the next few weeks, you may start to feel your baby move, called "quickening." It often feels like a gas bubble or subtle fluttering movement. As it happens more regularly, you'll know it's your baby. Your body is changing in many other ways. Increased blood volume to support your growing baby may produce nosebleeds, and you may notice your leg veins are becoming more apparent. Good news: Because your uterus is shifting, you may not have to urinate so much.

Tip of the Week: If your leg veins bulge, you may want to wear support stockings, put your feet up when you can, and exercise to improve blood flow.

What's Happening Inside You?

Your baby's fingers and toes are well-defined; their eyelids, eyebrows, eyelashes, nails, and hair are formed. Teeth and bones become denser. Your baby can even suck their thumb, yawn, stretch and make faces.

The baby's reproductive organs and genitals are now fully developed, and your health care provider can see on ultrasound if you are having a boy or a girl. You don't have to find out the baby's sex yet -- that's up to you.

Health & Pregnancy Guide

Getting Pregnant
First Trimester
Second Trimester
Third Trimester
Labor and Delivery
Pregnancy Complications
All Guide Topics

13-16 weeks of pregnancy

Thirteenth week for a baby

The beginning of the week is characterized by a fetus length of 6-7 cm, and by its completion it already reaches 10 cm, the weight of the unborn child at the moment is 20-30 grams.

This week marks the start of the second trimester of pregnancy. The fetus grows intensively, its legs and arms lengthen. There is also a change in the proportions of the body, the head no longer looks as big as it used to be. The future baby already knows how to reach his mouth with his finger and sucks it, which is often seen by specialists during ultrasound diagnostics. Thus, the sucking reflex, which is so important for the baby in the first time after birth, finds its manifestation.

Intense muscle growth occurs, especially in the legs. The future baby becomes more active, his movements are now smoother. At this time, the woman is not able to feel the child, because he, being in the uterus, floats freely and does not actually come into contact with its walls. In the fetus at this stage, the formation of the rudiments of all milk teeth ends. The rudiments are located in the mucosa of both jaws.

The gastrointestinal tract is also in the stage of active growth and development. Fitting into loops, the intestine completely fills the abdominal cavity. On the inner surface of the intestine, its mucous membrane, villi are formed, which should cover the entire internal area. These villi after birth will help the baby absorb all the nutrients from the food in the intestinal cavity. The wave-like movements that the fetal intestine makes help it push through the amniotic fluid, which the unborn baby constantly swallows. These waters do not contain useful substances, they only help the intestines to train and form the necessary muscular system.

The thirteenth week for the expectant mother

A woman at the thirteenth week begins to feel much better, she finally manages to feel only positive emotions associated with the expectation of the baby. Malaise, toxicosis and the desire to sleep remain in the past. The emotional background also undergoes changes. A woman becomes calmer and more peaceful, frequent mood swings and irritability also remain in the past. This is due to the end of critical periods of pregnancy and a more stable hormonal background.

For most expectant mothers, this period is associated with a change in the shape of the abdomen. Such changes are not yet noticeable to others, but the woman herself clearly sees the roundness that has arisen, feels discomfort when wearing ordinary things. It's time to pay attention to the selection of special clothes that can create comfortable conditions for a woman and a future baby.

Fourteenth week for the baby

At this stage, the weight of the fetus is 40-45 grams, its length is 13 cm.

The distinct formation of the face leads to a change in the appearance of the fetus. The bridge of the nose becomes more pronounced, the eyebrows are outlined, the cheeks are rounded. The child moves, he feels himself on the tummy and cheeks, holds on to the umbilical cord. The embryonic fluff, which covers the entire body, is tightly attached to the skin of the fetus. This gun has a protective function - it retains a special lubricant that will allow the baby to easily pass through the birth canal during the birth process. Over time, the almost transparent birth fluff will be replaced by thicker hairs.

Important processes take place in the respiratory organs of the fetus precisely at the fourteenth week. Also, muscle tissues develop not only of the motor system, but also of the respiratory system. The fetus begins to imitate breathing with its movements. Such training is of great importance for the future baby, since he must take his first breath immediately after birth. His respiratory organs, under the influence of signals from the brain, should open up and begin to fully function. At this time, there is a partial opening of the glottis, so amniotic fluid penetrates into the respiratory organs on inspiration. Then there is an intense exhalation, and they are pushed out of the body of the unborn child. Rinsing with amniotic fluid of the lung tissues contributes to their proper maturation.

There are changes in the structure of the genital organs. In boys, the intensive formation of the prostate begins, in girls, the ovaries move to the pelvic area, which were previously located in the abdominal cavity. There is a differentiation of the external genitalia, but when examining ultrasound at this stage, it is not always possible to establish the sex of the unborn child.

The organs of the endocrine system also develop. An important event is the start of the pancreas. Insulin, an important hormone that regulates glucose levels in the body, also begins to be produced. This week, the pituitary gland begins to function, regulating the work of all the glands of the body, responsible for their coherence, interaction, as well as the process of growth of the fetus and child in the future. The pituitary gland is located in the most protected part - surrounded by the bones of the skull, in the thickness of the brain.

Fourteenth week for the expectant mother

A woman's uterus grows intensively, it becomes possible to independently palpate through the anterior abdominal wall its uppermost part - the bottom, which will be 10-15 cm above the pubis. It's time for a woman to purchase special care products that will help nourish her skin and make her able to calmly endure the upcoming changes.

Stretch marks on the skin, which occur in many women, are the result of microcracks, i.e. ruptures of connective fibers. The elasticity and firmness of the skin are significantly reduced, so even a small increase in weight can cause microcracks. There is a redistribution of subcutaneous fat, swelling may occur, so special care is simply necessary. Creams, lotions and other products for pregnant women are characterized by nutritionally safe formulations, they will help the skin restore elasticity and firmness, and prevent the appearance of stretch marks. Even if striae occur due to excessive weight gain, their number will be minimal.

Fifteenth week for a baby

At the end of the fifteenth week, the weight of the fetus is already about 50-70 grams, its length is 14-15 cm. The limbs grow, they can outstrip the size of the head due to the intensive development of the bones of the legs and arms. The future baby begins to actively bend his fingers and elbows, a unique skin pattern appears on the palms and fingers, and the process of nail formation begins.

At this stage, the cardiovascular system is being improved. The number of heart beats per minute is twice the mother's and is 140-160. A tiny heart pumps 20 liters of blood per day, contributing to the intensive development of the body. The fetus actively grows veins and arteries, there is a general improvement of the circulatory system. Own systems of veins and arteries are formed in each internal organ - kidneys, lungs, heart, brain, etc. The fetus acquires an unusual red color instead of pink, because it has very thin skin, and the circulatory system, developing, affects its color.

The nervous system at this time is undergoing important stages of formation. The mass of the brain increases, its furrows and convolutions increase. All muscles, internal organs and bones are braided with nerve fibers. A strong and stable connection is being established between the central nervous system and the peripheral one. Impulses begin to flow in both directions: from the brain to the organs and back. An important system of "reverse response" is emerging for the human body.

If until the fifteenth week red blood cells (erythrocytes) were produced by the gall sac and liver, then after this stage, this function begins to be performed by the red bone marrow located inside the bones.

It is already possible to determine the blood type and Rh factor of the unborn baby. The laying of the group and Rhesus occurs at the time of conception of the baby, but this information is realized only at the fifteenth week. There is a formation of special antigen proteins that appear on the surface of erythrocytes.

Fifteenth week for a future mother

A woman's belly grows quite smoothly, it increases gradually and does not cause discomfort in everyday life. The bottom of the uterus is already palpable through the anterior abdominal cavity at a height of 15-20 cm from the pubis.

Intensive production of melanin pigment occurs in the body, which is deposited in the skin. This process is caused by a hormonal background and causes the appearance of age spots on the surface of the skin, which can form in completely different places. Often a dark stripe appears on the abdomen, which has a brown tint and goes from the navel to the pubis. Rarely, the cause of increased melanin synthesis is a lack of vitamins in the body.

Brown spots should appear without any sensation. If their occurrence is accompanied by swelling, redness or discomfort, you should see a doctor. Such reactions may be the result of allergies or dermatosis of pregnant women - a common skin disease. Pigment spots can have a different shade - from light beige to dark brown. Almost always, such manifestations after the appearance of the baby disappear on their own. The use of whitening creams during pregnancy is possible only after consulting a doctor, because they may be unsafe for the fetus.

The sixteenth week for the baby

The formation of mimic muscles in the fetus takes place, he begins to develop them, which is expressed in the frown, opening and closing of the mouth. The fetus gets the opportunity to open its eyes for the first time, which up to this point were tightly closed for centuries, it begins to learn to blink. In place of eyelashes and eyebrows, you can see thin fluffy hairs. If the auricles before this stage were located in the wrong place, closer to the neck, now they are already placed as in an adult. Although there is a pronounced reaction of the fetus to loud sounds, at this stage, his middle ear is not yet able to hear. The reaction is due to such a way of perception as bone conduction. It turns out that the fetus hears through the dense parts of the body (bones).

The process of formation of all joints and bones has already been completed in the future baby. The process of ossification, i.e., compaction of bone tissue, will continue not only during the entire remaining period, but also after birth, almost until puberty.

With an ultrasound examination, it is already possible to reliably determine the sex of the child, since his external genitalia are fully formed. It is at this time or a little later (depending on the time of the appointed diagnosis) that the mother gets the opportunity to find out who will be born to her.

Kidneys work intensively in the fetus. Now they begin to perform a partially excretory function, slightly reducing the load that lies on the placenta. The urinary canal is formed, the fetus swallows 300-500 mm of amniotic fluid daily, they pass through its intestines and are excreted by the kidneys. Urination is performed in small portions every hour, urine enters the amniotic fluid.

Sixteenth week for the expectant mother

At this stage, the woman feels a significant improvement in well-being. Gradual weight gain begins, appetite normalizes. The norm at the moment is a set of 2.5-3 kg.

At the moment there is an active growth of the future baby, and a significant accumulation of amniotic fluid. Both of these factors affect the growth of the abdomen, its increasing volumes do not yet cause discomfort. However, it is time to make changes in your habits, for example, change the position of the body during sleep. Sleeping on your back is just as unindicated as sleeping on your stomach. When sleeping on the back, the uterus can put pressure on large veins, which will cause a violation of the outflow of blood, provoke the occurrence of swelling, convulsions and varicose veins. The most comfortable position for sleeping is the position on the side, in which both the unborn child and the mother will feel as comfortable as possible.

13th week of pregnancy what happens to the fetus

The first trimester, which was troublesome for the mother, is over, early toxicosis is over, the psychological background is gradually improving. The 13th week of pregnancy marks the beginning of the second trimester. There is still a lot of time before the birth of a child, which means that a woman can fully enjoy her condition and calmly watch how the baby grows and develops in her. This is the time for new experiences and sensations.

Fetal development at 13 weeks

The beginning of the second trimester is the active growth of the baby. By this period, the length of his body is 7 cm, and the child already weighs 25-28 g. This is already an almost full-fledged tiny man, whose body parts acquire proportionality. His head is not so big, because the active growth of the rest of the body begins.

Interesting! The eyes of the child are located closer to each other, and the facial features acquire individuality. Although at this stage of pregnancy it will not be possible to understand who your child looks like.

Changes that occur with the fetus:

The heart works at a rate of 140 0 170 beats per minute and is able to distill 23 liters of blood.
A system of 20 milk teeth has been formed, which are still in the gums. Mom needs to be more careful about her diet and introduce more calcium-containing foods into it.
This is the time for the active development of the digestive system. The pancreas begins to produce insulin, and the gallbladder - bile. Villi appear in the intestines to process food.
The skeletal system is strengthened.
Vocal cords are forming.
The first signs of the development of the auricles appear.
On the 13th week, nature makes its own adjustments to the appearance of the sexual characteristics of the unborn child. During this period, the prostate gland develops in boys, and the ovaries in girls, and there is a laying for the penis or female genitalia.
The baby's skin is still thin and has a red tint due to translucent blood vessels.
Muscles are developing, the neck is no longer so tightly pressed to the head. Mimicry is also supplemented - the child learns to make sucking movements.

At the 13th week of pregnancy, the development of the baby does not bypass the emotional sphere. He can listen to external sounds, moves less erratically, perceives smells and even tastes better. During the time that a woman is carrying a child, he gets used to a certain diet, as he is sensitive to the taste of amniotic fluid. Therefore, it is not recommended for a mother to change her eating habits after childbirth.

The child is not yet moving so actively to let the mother feel it. Some women often confuse the movements of the fetus with the processes occurring in the intestines. But now the baby begins to grimace more strongly.

Important! During this period, the mother can actively communicate with her child - talk, sing songs, tell stories. Her voice soothes the little man.

Mom's well-being at 13 weeks

The second trimester is the best period of pregnancy. The birth is still far away, the hormones have finally fulfilled their function and calmed down, the toxicosis has receded. The growing uterus is already changing the contours of the waist, but so far the woman herself sees this to a greater extent, unless, of course, she has a multiple pregnancy.

Since the uterus rises into the abdominal cavity, the pressure on the intestines increases, which means that constipation, flatulence, shortness of breath, and heartburn are more common. A woman's weight increases, so a feeling of heaviness and fatigue may appear, especially at the end of the day. The back may ache a little and pull the lower abdomen, but this is due to the growing uterus.

Important! There should be no suspicious vaginal discharge and severe pain. If such symptoms bother a woman, she should immediately consult a doctor.

If the pregnancy is properly managed, the first planned ultrasound should have already been completed by this time. If you haven't done it yet, now is the time to fix it. This examination helps to clarify the number of fetuses, to exclude developmental anomalies. The doctor finds out the size of the baby, determines the gestational age, the date of birth.

At the beginning of the second trimester, a woman should avoid stress and take care of her health, pay attention to diet and physical activity.