BABY ....... pregnancy week by week

your baby at 0-8 weeks pregnant

Three weeks after the first day of your last menstrual period, your fertilised egg moves slowly along the fallopian tube towards the womb. The egg begins as one single cell. Early on this cell divides again and again. By the time the egg reaches the womb, it has become a mass of more than 100 cells called an embryo, and is still growing. Once in the womb, the embryo burrows into the womb lining. This is called implantation.
In weeks four to five of early pregnancy, the embryo settles into the womb lining. The outer cells reach out like roots to link with the mother’s blood supply. The inner cells form into two and then later into three layers. Each of these layers will grow to be different parts of the baby’s body. One layer becomes the lungs, stomach and gut. Another becomes the heart, blood, muscles and bones.
The fifth week of pregnancy is the time of the first missed period, when most women are only just beginning to think they may be pregnant. Yet already the baby’s nervous system is starting to develop. A groove forms in the top layer of cells. The cells fold up and around to make a hollow tube called the neural tube. This will become the baby’s brain and spinal cord, so the tube has a "head end" and a "tail end". Defects in this tube are the cause of spina bifida.
At the same time, the heart is forming and the baby already has some of its own blood vessels. A string of these blood vessels connects the baby and mother and will become the umbilical cord.
By the time you are six to seven weeks pregnant, there is a large bulge where the heart is and a bump for the head because the brain is developing. The heart begins to beat and can be seen beating on an ultrasound scan. Dimples on the side of the head will become the ears, and there are thickenings where the eyes will be. On the body, bumps are forming that will become muscles and bones, and small swellings called limb buds show where the arms and legs are growing. At seven weeks, the embryo has grown to about 10mm long from head to bottom. This measurement is called the "crown-rump length".

your baby at 9-12 weeks pregnant

From the time you’re about eight weeks pregnant the baby is called a foetus, which means "offspring". By now the face is slowly forming. The eyes are more obvious and have some colour in them. There is a mouth and tongue. There are now the beginnings of hands and feet, with ridges where the fingers and toes will be. The major internal organs are all developing, such as the heart, brain, lungs, kidneys and gut.
At nine weeks of pregnancy, the baby has grown to about 22mm long from head to bottom. Just 12 weeks after conception, the foetus is fully formed. All its organs, muscles, limbs and bones are in place, and the sex organs are well developed. From now on, it has to grow and mature. The baby is already moving about but its movements can’t be felt yet.

your baby at 13-16 weeks pregnant

By about 14 weeks the heartbeat is strong and can be heard using an ultrasound detector. The heartbeat is very fast; about twice as fast as a normal adult’s heartbeat. At 14 weeks, the baby is about 85mm long from head to bottom.

your baby at 17-20 weeks pregnant

By the time you're 17 weeks pregnant, your baby is growing quickly. The body grows bigger so that the head and body are more in proportion and the baby doesn’t look as "top heavy". The face begins to look much more human, and the hair is beginning to grow along with the eyebrows and eyelashes. The lines on the skin of the fingers are now formed, so the baby already has his or her own individual fingerprints. Fingernails and toenails are growing and the baby has a firm hand grip.

your baby at 21-24 weeks pregnant

When you are around 22 weeks pregnant the baby becomes covered in a very fine, soft hair called lanugo. The purpose of this isn’t known, but it’s thought that it may be to keep the baby at the right temperature. The lanugo disappears before birth, though sometimes just a little is left and disappears later.
When you are 24 weeks pregnant, the baby has a chance of survival if he or she is born. Most babies born before this time cannot live because their lungs and other vital organs are not developed enough. The care that can now be given in neonatal (baby) units means that more and more babies born early do survive. But for babies born at around this time there are increased risks of disability

your baby at 25-28 weeks pregnant

By the time you are 25 or 26 weeks pregnant the baby is moving about vigorously and responds to touch and sound. A very loud noise may make her or him jump and kick. Your baby is also swallowing small amounts of the amniotic fluid in which it is floating and passing tiny amounts of urine back into the fluid. Sometimes the baby may get hiccups and you can feel the jerk of each hiccup.
When you are around 26 weeks pregnant the baby’s eyelids open for the first time. The eyes are almost always blue or dark blue, although some babies do have brown eyes at birth. It’s not until some weeks after the birth that your baby’s eyes become the colour that they will stay. You can find out more about your baby after the birth.
When you are 28 weeks pregnant, the baby will be perfectly formed but still quite small. The baby may also begin to follow a pattern for waking and sleeping. Very often this is a different pattern from yours, so when you go to bed at night, the baby may wake up and start kicking. The baby’s heartbeat can now be heard through a stethoscope. Your partner may even be able to hear it by putting an ear to your abdomen, but it can be difficult to find the right place.
The baby is now covered in a white, greasy substance called vernix. It is thought that this protects the baby’s skin as it floats in the amniotic fluid. The vernix mostly disappears before the birth.

your baby at 29-32 weeks pregnant

When you're 30 weeks pregnant the baby’s head-to-bottom length is about 33cm. The baby is growing plumper so the skin, which was quite wrinkled before, is now smoother. The white, greasy vernix and the soft, furry lanugo (fine hair) begin to disappear. By about 32 weeks the baby is usually lying with her or his head pointing downwards, ready for birth.

your baby at 33-36 weeks pregnant

By 33 weeks of pregnancy the baby’s brain and nervous system are fully developed. Your baby's bones are also starting to harden, even though the skull bones will stay soft and separated to make the journey through the birth canal (cervix and vagina) easier. Baby boys’ testicles are now beginning to descend from the abdomen into the scrotum

your baby at 37-40 weeks pregnant

In these last weeks, some time before birth, the baby’s head may move down into your pelvis and is said to be ‘engaged’. Sometimes the baby’s head doesn’t engage until labour has started. The amniotic fluid now turns into waste, called meconium, in the baby’s intestines, and the soft hair (lanugo) that covered your baby’s body is now almost all gone.

If your baby is overdue

Pregnancy normally lasts about 40 weeks (that's around 280 days from the first day of your last period). Most women go into labour a week either side of this date, but some women go overdue.
If your labour doesn't start by the time you are 41 weeks pregnant, your midwife will offer you a 'membrane sweep'. This involves having a vaginal (internal) examination that stimulates the cervix (neck of your womb) to produce hormones that may trigger natural labour. You don't have to have this – you can discuss it with your midwife.

If your labour still doesn't start naturally after this, your midwife or doctor will suggest a date to have your labour induced (started off).
If you don't want your labour to be induced and your pregnancy continues to 42 weeks or beyond, you and your baby will be monitored.
Your midwife or doctor will check that both you and your baby are healthy by offering you ultrasound scans and checking your baby's movement and heartbeat. If there are any concerns about your baby, your doctor will suggest that labour is induced.
Induction is always planned in advance, so you'll be able to discuss the advantages and disadvantages with your doctor and midwife, and find out why they think your labour should be induced. It's your choice whether to have your labour induced or not.

Over 42 weeks pregnant

Most women go into labour spontaneously by the time they are 42 weeks pregnant. If your pregnancy lasts longer than 42 weeks and you decide not to have your labour induced, you should be offered increased monitoring to check your baby's wellbeing.
There is a higher risk of stillbirth if you go over 42 weeks pregnant, although most babies remain healthy. At the moment there is no way to reliably predict which babies are at increased risk of stillbirth, so induction is offered to all women who don't go into labour by 42 weeks.
Having induction of labour after the date your baby is due does not increase the chance (risk) of caesarean section. There is some evidence that it may slightly reduce the chance of having a caesarean section.

 around 14 weeks pregnant.