13 Weeks- Development

Your Baby This Coming Week

Your baby measures about 3.2 to 3.5 inches (7.6 to 8.9cm) from crown to rump and weighs about 0.9 ounces (25g). Your baby is now nourished by the placenta.

His face is developing and his cheeks and the bridge of his nose are appearing. His ears are moving from the sides of his neck to higher on his head and his eyes are moving closer together. Your baby's external genitals are now distinct and may be recognized on an ultrasound. Your baby will move away from stimuli near your tummy, such as noise and light.

Your baby's eyebrows have formed and a small amount of hair, called lanugo, has appeared all over his body. Lanugo, which will be shed before birth and replaced with the hairs with which your baby will be born, is thought to have a protective function.

Insulin is present in your baby's pancreas. Some bones may be well outlined. Your baby's thyroid gland, already developed by this week, begins to make hormones.

Baby boys begin to develop the prostate gland at this time and the ovaries of baby girls descend from the abdomen into the pelvis.

Your Body This Coming Week

By now your uterus is about the size of a large grapefruit. If your due date has not already been predicted, an ultrasound measurement of your baby's head can be used to make one.

Your pre-pregnancy clothes are probably too tight by now. If you haven't already got some maternity clothes, now is probably the time to get some. You'll be most comfortable in loose-fitting clothes. Make sure you really like your maternity clothes- you'll be wearing them a lot. Friends, family and thrift shops can be a great source of maternity clothes.

You may feel less exhausted than you did earlier in your pregnancy. Some women even start to experience a rejuvenating surge of energy at around this time. Many women report that the second trimester is the best time of pregnancy as the morning sickness of the first trimester has usually passed, and the discomforts and weariness of the third trimester have yet to begin. If you would like to take a last holiday before your baby arrives, the second trimester, with your doctor's approval, is probably the best time to do so. This could be a good opportunity for you and your partner to connect and share some couple-time before the baby arrives.

12 Weeks- Development

Your Baby This Coming Week

Your baby is about the size of a peach and is growing rapidly. Crown to rump, your baby measures 2.6 to 3.1 inches (6.5 to 7.8cm) and weighs 0.5 to 0.7 ounces (14 to 20g).

Your baby's legs are longer than her arms and her skin is red and transparent. Her eyelids are fused together and won't open for about four more months. Her arms are long enough to reach her mouth and she may begin to place her thumb in her mouth. Her sucking reflex, however, is not yet developed.

The tissue that will become your baby's bones is being laid out, especially around her head and her arms and legs. Some ribs may be distinguished at this time. The nose and chin are more prominent now.

Your Body This Coming Week

You are beginning your second trimester of pregnancy.

Your uterus is growing rapidly and is filling the pelvis and moving up into the abdomen. If you are still having morning sickness, it may stop around this point.

Some women will get stretch marks on the breasts, hips and buttocks that may show up this early. They will later fade but will probably not disappear altogether. Some women experience itching around this time but it is more common later in pregnancy.

You probably have noticed changes in your breasts. They are becoming larger and heavier and the areola is probably darkening. They are preparing to secrete milk for your baby!

Your placenta is now well developed and is responsible for hormone production which was previously manufactured by your ovaries. Estrogen and progesterone are the primary hormones which are now being produced. These hormones are necessary for maintaining your pregnancy and inducing the changes necessary for it to progress.

Your baby will begin to practice breathing in the next few weeks as her chest rises and falls in mock breathing motions. She will also swallow small amounts of amniotic fluid which will be passed as urine.

Your placenta is providing all of your baby's needs for nutrition, oxygen and waste disposal, though the amniotic fluid will become more important later on.

All major components of the body are formed and now must grow and mature. From now on, your baby's development will consist primarily of organ maturity and growth and body refinement.

11 Weeks- Development

Your Baby This Coming Week

The end of the twelfth week of pregnancy marks the end of the first trimester. Your baby is now almost 2.5 inches long (6.1cm) when measured from crown to rump, and weighs between 0.3 and 0.5 ounces (9 to 13g).

Your baby's fingers and toes have separated and are getting longer. Your baby can open and close its mouth and drinks amniotic fluid which it passes out as urine. Its head is becoming more rounded, though it is still large in proportion to its body. It has eyelids.

You can now hear your baby's heartbeat with a Doppler Ultrasound device!

Your baby continues to grow rapidly and has doubled in size in the last three weeks alone.

The face is beginning to look more human, and all body structures are present with a few refinements still in progress. Fingernails and toenails begin to develop this week.

Your baby's muscles are sufficiently developed to allow for involuntary movements at this time. The messages which control your baby's movements are sent from the spine, rather than the brain, which is not yet sufficiently developed.


Your Body This Coming Week

Your uterus has now enlarged so that it protrudes above your pelvic bone. You may have begun to "show". It may be time to buy some maternity clothes!

Your doctor or midwife can feel the baby by external examination around this time.

Your heart is working harder to pump the increased volume of blood around your body and as a result your body temperature has risen. Your heart rate may have increased by a few beats per minute to cope with the increased blood volume circulating throughout your body.

Morning sickness may decrease and you may not need to urinate as much as in early pregnancy. You may become constipated, however, as bowel movements slow down in pregnancy.

You may notice a dark line, called the linea nigra, running along your abdomen from your navel to your genital area. The linea nigra shows where your abdominal muscles are stretching to allow for your uterus to grow. The linea nigra may remain for a little while after the birth of your baby, but over time it will fade.

10 Weeks- Development

Your Baby This Coming Week

Your baby is growing incredibly rapidly right now. She is approximately 1.75 to 2.4 inches (4.4 to 6cm) when measured from crown to rump. She will double her length in the next three weeks. Your growing baby weighs about 0.3 ounces (8g).

The neck is developing and the chin lifts up from the chest. Fingernails are also present. While your baby's sex was already determined at the time of fertilization, male or female genitalia are now visible. Essential organs are formed and most have begun to function. The blood vessels in the placenta are increasing in number to meet your baby's increasing nutritional needs. Her ears are moving towards the sides of her head, away from the neck. Your baby's head is still not in proportion with her body. Your baby's head accounts for about half of her body length.

Your Body This Coming Week

Many women who have suffered from morning sickness find that their nausea begins decrease from this week on. (Unfortunately, for some it may continue).

You may have noticed you have more (or less) hair than usual, which is thought to be linked to the increased amount of blood circulating through your body as well as hormonal changes.

You are probably anxious to feel your baby move, but it is still a bit early. You may notice an increase in cervical fluid and you may also notice a darkening of your labia around your vagina and the areola area around your breasts due to hormonal changes.

During pregnancy, the cervix usually feels firm, but it will soften during labor to allow the baby to pass through. Your cervix is protected by a mucus plug to protect your baby. The mucus plug will be expelled shortly before or during labor.

Your body is burning calories faster than it did prior to pregnancy and your metabolism may increase by up to 25%. The quantity of blood pumping through your body will also increase, making you feel warmer than usual. The increased blood flow can also give you a rosy "blooming" feeling.

You may notice that you have an improved skin condition during pregnancy. For some lucky women, pregnancy hormones can cause skin to appear to "glow" and appear smoother. You may even have shinier hair and brighter eyes. Some women develop a "pregnancy mask" (chloasma) caused by deeper skin pigmentation. This can cause irregular patches of brown skin to appear on your forehead, cheeks, neck and nose. Exposure to sunlight can exacerbate chloasma, though sunscreen can reduce its effects. Chloasma usually disappears after birth as your hormones return to their pre-pregnancy levels.

Elevated estrogen levels and increased blood pressure can cause the dilation of your skin capillaries which can in turn give rise to spider nevi (raised red marks surrounded by spidery lines) and palmar erythema (redness of the palms) during pregnancy. Both conditions are considered minor and fade after the birth of your baby.

9 Weeks- Development

Your Baby This Coming Week

The crown-to-rump length of your baby is about 1.25 to 1.68 inches (between 3.1 and 4.2cm). He weighs about 0.18 ounces (5g).

The placenta is now producing progesterone which helps to make nutrients for your developing baby.

Your baby has passed the stage when he is most susceptible to damage. By the end of this week, the danger zone for congenital abnormalities has passed.

The plan for your baby's body has been completely laid down by now. Further growth and cell division will build on this plan.

Taste and tooth buds have appeared.

Your baby has recently developed fingers and toes which are now well-formed. Ankles, wrists and the inner ear have formed. Your baby's nose is flat and his eyes are far apart. His eyes, ears, mouth and nose are all recognizable. The tail is disappearing.

Your baby is moving around the amniotic sac, and moving his feet and ankles. You still will not be able to feel these movements but you may be able to see them on an ultrasound.

Blood is circulating through the arteries and the vein of the umbilical cord.

The brain of your baby is developing at a phenomenal rate. About one quarter of a million new neurons are produced every single minute at this stage in your pregnancy.

If your baby is a boy, his testes, though they are not even clearly visible, are already producing testosterone.

Your baby is no longer called an embryo, but rather a fetus.

Your Body This Coming Week

Your uterus is now about the size of an orange, but you still don't "show". However, you probably have noticed an increase in your breast size.

You may be having mood swings, feeling happy and elated one moment, crying the next. This is perfectly normal, caused by the changing hormones in your body as well as all the hopes and fears you have and the realization that your life will be forever changed by your pregnancy.

There is little increase in abdominal size during the first trimester, though you might be starting to see some weight gain. Hormonal changes, however, especially the increase of progesterone and relaxin can cause your joints and ligaments to soften as your body begins to prepare for birth.

The joints in your pelvic bones are widening now. This may cause you to feel unstable at times, even sometimes dropping things or bumping into things.

8 Weeks- Development

Your Baby This Coming Week

Your baby measures about 0.9 to 1.2 inches (2.2 to 3cm) from crown to rump.

Your baby's arms and legs are longer and her hands are flexed at the wrist. The head is growing more erect and the neck is more developed. On an ultrasound, you may see your baby moving, though you still can not feel this.

The organs are forming. Ears are developed and the eyelids have begun to cover up your baby's eyes. Hands and feet appear as well as small buds which will become fingers and toes. The paddles of your baby's hands have clearly defined finger ridges now, with the tissue between them (which previously made them look webbed) reducing to leave separate fingers.

Your baby's back has started to straighten slightly and the tail is now shrinking. The head still seems large and is curved forwards on her chest. Your baby is starting to look like a tiny person!

Your Body This Coming Week

Your uterus is enlarged and your waistline may have increased slightly by now. The pregnancy hormones in your system have increased the volume of blood in your body.

Your skin may have improved (the famous "glow" of pregnancy) or you may be experiencing skin problems. Your gums may be softer. The thyroid gland in your neck may be more prominent. Your hair may also be less oily. Your breasts may feel fuller and more tender. You may notice increased creamy vaginal secretions.

7 Weeks- development

Your Baby This Coming Week

Your baby's crown to rump measurement is about 0.56 to 0.8 inches (14 to 20mm).

Your baby's face has a recognizable shape with eyelids and the tip of a nose with formed nostrils, though his head is still very large compared to the rest of his body.

All major organs are now formed and in place, though they still need to mature.

A tongue has already formed. The ears are forming both internally and externally.

The arms and legs extend forward and shoulders, elbows, hips and knees are detectable. Knees and elbows have begun to form on the limbs. Tiny fingers and toes are starting to appear at the tips of your baby's developing limbs and the arms may be slightly flexed at the elbows and wrists. All major organs are in place.

Your baby is moving around a lot, moving his legs and flexing his spine, but you are unable to feel it at this point.

Your baby's genitals have begun development, though they are still difficult to identify.

Your Body This Coming Week

You may feel some cramping as your uterus expands. You are still not showing, but you may have noticed that some of your clothes are beginning to feel tight.

Due to the hormones associated with pregnancy, the follicles in the ovaries stop maturing. Your uterus has begun to swell and its lining has thickened considerably.

You may have cravings for certain foods and find others completely unappealing. The smell of cigarette smoke and the taste of alcohol may make you nauseous.

Some women experience sciatic nerve pain which is an occasional severe pain in the buttocks, back or side of the legs. If you experience sciatic nerve pain, lying on your opposite side may relieve the pressure on the nerve.

6 Weeks

Your Baby This Coming Week

Your baby is 0.16 to 0.2 inches long (4-5mm) when measured from crown to rump. It is now identifiable as a human baby.

The limb buds are growing rapidly, developing into little fins with nodules at the ends which will eventually become fingers and toes. The arms have already differentiated into hand and shoulder segments.

The cerebral hemispheres of the brain are growing, and the eyes and nostrils are appearing. Your baby's heart bulges from its body and the heart chambers are divided and formed. Blood vessels now circulate blood throughout the whole body. The head looks large and is bent on the chest.

Your baby's face is forming, but its eyes are on the sides of its head and are still sealed. The discs that will become your baby's eyes will move over to the front of the face over the course of the next few months.

Bone cells are beginning to develop and the outline of the baby's nervous system is complete. The pigment in your baby's eyes can be seen under the skin overlaying them. By this point there is also a pancreas and an appendix. The tail is still visible, but it will soon fade. The umbilical cord is growing and the placenta is maturing as well.

Your Body This Coming Week

Your nipples may feel sensitive. Small nodules, called Montgomery's tubercles, may appear on the areolae.

Your blood pressure is lowered by pregnancy hormones, and as a result you may sometimes feel dizzy or faint when you stand for a long time.

Morning sickness may continue.

Cervical mucous coagulates to form a plug in your cervical canal to keep it closed and protected throughout your pregnancy. It will be expelled prior to giving birth.

Week 5

Your Baby This Coming Week
Your baby is now about the size of an apple seed. That's about 0.08 to 0.16 inches (2 to 4mm) from crown to rump. It has formed a distinct head with the first stages of eyes and ears. The spinal column and cord are formed. Buds that will grow limbs have also formed. The heart is starting to beat and at this stage its beating may even be detected by sensitive ultrasound equipment, though, it's still very early. The kidneys, liver and nerve cells have also begun to develop. Ten dental buds are growing in the jaws. Blood circulation has begun and primitive red blood cells circulate. The neural tube has closed over along your baby's spine. The optic vesicles, which resemble tiny discs of pigment set in cups along the sides of your baby's head will develop into your baby's eyes. A distinct tail is still present. The body is shaped like the letter "C".

Your Body This Coming Week
By now your pregnancy should have been confirmed. You may be experiencing morning sickness (not necessarily only in the morning). You will have begun to notice changes in your body: you may have gained a few pounds, or you may have even lost weight if you've been suffering from morning sickness. Your uterus is growing, although it is still smaller than a tennis ball and you do not "show". Your metabolism has likely increased to deal with the changes taking place in your body. Some women begin to suffer from heartburn and constipation. You may also be feeling tired and irritable sometimes due to the increase in levels of the hormone progesterone. (This is the same hormone that can make you feel irritable before you get your period).