Pregnancy week by week

Pregnancy week by week


The first 4 weeks:

The conception usually takes place 2 weeks after the first day of your last period.  So actually, you are not pregnant yet during the first two weeks of your pregnancy, but these weeks are still included in calculations! The time of ovulation is different for every individual (and therefore also the conception) and that is why we always count from the first day of your last period. If you would like to know when you are due, you should add 40 weeks to the first day of your last period. After the egg is fertilised it takes approximately 38 weeks until the baby is born. The exact due date will be determined with an ultrasound. (See ultrasound for more information)


Immediately after the ovulation the egg starts a long journey through the fallopian tube. From the moment of conception the cells start to divide at a rapid pace. After a number of days the egg will arrive in the uterus. In the meantime the cells will have multiplied to 32 cells. One part of the cells will form the baby, another part the membranes, and another part the placenta. After eight days the egg will nest in the thickened mucus lining of the uterus. From that moment on the embryo will receive nutrition through the veins of the mucus lining. This will be the case until the placenta is able to take over that function; between 12-16th of the pregnancy.


Towards the end of the first month the cluster of cells (the embryo) is not even the size of a grain of rice. However the foundation for the nervous system, the skeleton and the heart has been laid.

It is important to continue taking folic acid, or, in case you haven’t been taking it yet, to start this now. Folic acid reduces the chance that you baby will have a serious condition, like spina bifida (split spine). We advise taking Folic acid until week 10 of your pregnancy. Taking it longer is not necessary, but it is not harmful either.
Pregnancy symptoms may be:

  • tight breasts
  • nausea
  • fatigue
  • feeling different than usual

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Week 8:

Length of your baby: 2 cm

At this point you can experience all sorts of sensations in your body: stings or a nagging pain in your tummy, rumbling bowels, mood swings, nausea. Don’t worry too much; this is all part of it!

These issues are temporary and in a few weeks your body will have adjusted to the new situation.

In week 8-9 (counted from the first day of your last period) we would like to see you in the practice for the first appointment! Before this appointment takes place, you will have had your first ultrasound scan. (See ultrasound for more information)
The face of the baby will start taking its definitive shape. In comparison to the body the head will still be rather large. This will remain the case for the next few weeks. The eyes are situated towards the side of the head, still completely covered with skin. There are openings for the nostrils and the jaws, the mouth, and the inner ear are developing. On the hands and feet you can see fingers and toes still connected with skin. In this week the genitals are formed as well: the testicles for a boy and for a girl the ovaries. From the moment of conception it is known whether the fertilized egg will grow into a boy or a girl, but only now the difference is becoming noticeable. (You will not be able to see this until the week 16 ultrasound scan, so if you are anxious to know the gender of the baby; please be patient a little while longer…!)
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Week 12:

Length: 6,5 cm. Weight: 20 grams.

At 12 weeks of pregnancy an ultrasound scan will determine the due date. (See ultrasound) The difference with the first ultrasound scan is likely to be quite big! The baby has grown a lot and is moving around comfortably in the amniotic fluid.

The child has developed considerably in the past few weeks: this week the nails, the olfactory organ and the hearing organ are formed. On the side of the head the first signs of the ears are starting to appear. The baby is able to suck his thumb and make fists of his hands.

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Week 16:

Length: 15 cm. Weight: 120 grams.

Your uterus has now grown beyond your pubic bone, which means there is more space for your bladder and you may not need to go to the bathroom as much. If you lie down on your back, you will probably be able to feel your uterus. It feels like a hard but flexible small ball. You probably notice that your belly is starting to grow as well and that your trousers won’t close properly anymore.

The way your belly looks and whether or not you are showing yet varies from person to person. If it is your first pregnancy your abdominal muscles are usually a bit tighter and so your tummy may not show until a little later. In case of a second child you will probably start to show somewhat quicker.

From week 16 the baby is able to distinguish light from dark. The eyes are still closed, but just like we do, he can see the difference between day and night between his eyelids. The baby will extract the oxygen he needs from your blood. The little body is covered in fine hair. These hairs will come off towards the ends of the pregnancy. They will float in the amniotic fluid, which the baby swallows. After the birth the swallowed hairs will be part of the first stool, called meconium. The kidneys and the bladder will start to function now, your baby will have his first wee. The vocal cords and the nails are finished. The child will get eyelashes and eyebrows. If you would like to follow a pregnancy course, now is a good time to get informed and sign up! Most courses start between 24 and 28 weeks of the pregnancy. (see pregnancy – pregnancy course for more information)

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Week 20:

Length: 25 cm. Weight: 320 grams

You are halfway through your pregnancy. Most pregnant women will have few to no pregnancy issues left and are full of energy. Around this time you may be able to feel your baby, because in this phase your baby already makes about 200 movements per day! In principle all the “new” sensations below the belly button, like bubbles, little pops or tickling, will be movements of the baby.

There are women who have been sensing their baby for a number of weeks, while others will need to be patient for a few weeks. So don’t worry if you are not sensing anything yet.
The hearing of the baby is getting more and more developed. Certain sounds will even be able to startle the child. At about 20 weeks the Structural Ultrasound Examination (SEO) takes place and your baby will be examined from top till bottom. (See ultrasound for more information)

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Week 24:

Length: 32 cm. Weight: 600 grams

Your baby has been very skinny up until this point, but that will change now! The subcutaneous fat will start to build, so that you can give birth to a chubby baby at 40 weeks. Muscles develop and the baby will get a sleep-wake rhythm. Because of the muscle development, the baby’s movements increase in power. Your partner might be able to feel your child when a hand is placed on your belly. Your baby is covered with very fine hairs: lanugo. A layer of skin oil protects the delicate skin: this is called ‘vernix’. Some of it may still be present on the baby’s skin straight after the birth, but it will be absorbed quickly. Vernix protects the skin from dehydration.

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Week 28:

Length: 35 cm

Your baby is really starting to look like a newborn. The proportions are changing: the head is no longer larger in relation to the body. The baby’s eyes can open and close. In addition, the skeleton is changing; the cartilage is slowly taking shape and the bones are getting stronger. However, the ossification will not be completed at birth. Especially the scull will be very soft at that point, so the baby can pass through the birth canal more easily. Well after the birth the fontanels will disappear and the skull will harden.

Around 28 weeks of pregnancy a difference in weight arises between boys and girls. A boy now weighs (in the first pregnancy) approximately 1030 to 1190 grams, a girl 960 to 1110 grams.

It is normal that you sleep lighter than usual during your pregnancy. This is a little trick of nature! It is part of the preparation for the arrival of your baby. If the child cries or makes sounds after the birth, this will wake you easily.
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Week 32:

Length: 40 cm. Weight: 1900 grams

In the meantime, your womb has grown so much that its top will reach until halfway between your navel and your breastbone. You may tire somewhat quicker and some pregnancy issues may occur once more. Retaining moisture, heartburn, sleeping poorly… It’s all part of it, but it is important that you inform us about your pregnancy issues. If required, we can do some further examination and provide you with tips/advice. (see pregnancy issues for more information)

From week 30 you will come for a check up every other week. In this period we will give you information about the birth and discuss your expectations and preferences around this. Would you prefer to give birth at home or at the hospital? Everything is possible.  Your wishes and expectations may also be added to the birth plan, so these can be taken into account at all times. (See delivery and birth plan for more information).

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Week 36:

Length: 45 cm. Weight: 2950 grams

The delivery is getting closer each day. Around week 35 of the pregnancy an ultrasound scan was carried out to check the position of your baby and determine the approximate birth weight. A lot of babies will sink deeper into the pelvis with their head; the subsidence. We will tell you whether or not your baby has subsided at the consultation hour. If your baby has not subsided yet, you will have to lie down when you waters break. From week 37 your baby is ready to be born. From week 37 to 42 you may give birth with our help, 93% of all women will deliver in this period. If you give birth before or after this time, the gynaecologist will take over.

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Week 40:

Length: 50 cm – Weight: average 3500 grams

Finally! You are 40 week pregnant; the due date has been reached! You have probably been looking forward to this date, but only 5% of all babies are actually born on the exact due date. What you do know for sure is that your baby will be born within 2 weeks from now. Unfortunately, there is little you can do to initiate the delivery yourself.

You have probably gained quite some weight during your pregnancy. On average women gain between 12 and 15 kilos, but this varies from person to person. The added weight consist of your baby, the amniotic fluid, the placenta, heavier breasts, the larger womb, extra blood, liquid, and an extra layer of fat.

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Week 41:

There you are, still with a big belly… The due date has passed and you have not given birth yet.

We, as midwives, can try to stimulate your delivery using a method called “stripping”.  Through an internal examination the cervix is massaged and the waters are loosened from the lower part of the uterus. During the stripping a hormone may be activated which will initiate your delivery. We may have to repeat the stripping a number of times before it takes effect, but it could also be that it does not result in the desired effect (the delivery!).

Due to lack of space your baby will move less intense. Still, it is important that you sense your baby well at least 10 times a day. You will probably still feel the buttocks move substantially and small movements of the arms and legs, especially near your ribs. Are you uncertain about the number of movements or does it feel different than usual? Do not hesitate to contact us.

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Week 42:

You are ‘overdue’, also referred to as “serotien” in the medical world. We will transfer your care to the gynaecologist in the hospital. A few days ago we already sent you to the gynaecologist for an extra check up: your blood, blood pressure, the amount of amniotic fluid, and the condition of your baby have been assessed by the gynaecologist. During this check up you will have made an appointment for the induction of your delivery.

If the cervix is still rigid and closed it will be prepared with a hormone gel that will be applied near the cervix. Is the cervix soft and somewhat dilated?  In that case the gynaecologist can start with breaking the waters and possibly a drip with contraction inducing medicines. A post-mature baby could have a dry skin because all the skin oil has disappeared. In addition, they are generally a little heavier. As soon as you have given birth and are allowed to go home, we will come visit you again. Of course we would like to admire your little one and will do some medical checks on you and your baby in the week after the birth.

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