Development of the child
Insemination of the ovum
A single sperm enters the ovum, the cell nucleuses merge. The cell that developed from this merging carries the information for the complete future development, e.g. gender, eye colour, talents and the approximate size of shoes and body that this person will have one day.
From the beginning, the unborn therefore is a unique and irreproducible human being.
The insemination is the defining event in the child’s development which then flows on from there. There is no other moment which can define the beginning of life.
1st and 2nd week (3th + 4th week of pregnancy)
This new cell which was created by the insemination (the so called zygote) now begins to devide and grow and at the same time travels towards the uterus that it will reach within four to five days. The attachment to the lining of the uterus (implantation) is completed after 14 days (i.e. four weeks after the last period). From now on the child is directly connected to the mother’s metabolism. The blood circulation of mother and child will remain separated, though.
3rd Woche (5th week of pregnancy)
The embryo is now 1.25 mm in size. Its tiny body is transparent and very soft. Even now, the development of the spinal cord and the brain start: slowly, liver, kidneys, muscles and bones develop, too. Eyes and ears are already forming on the little head. Inside the embryo’s body organs and circulation systems are evolving as well as the central nervous system. Around the 15th day of its life the first blood vessels appear; two of these vessels unite to form the heart which will start working on the 21st day.
4th week (6th week of pregnancy)
The unborn now has the size of a lentil. The intestinal system, lungs, liver and thyroid are developing. The face is distinguishable, tiny vocal chords are taking form. The inner ear is already developed. Around the 28th day, the arm and a little later also the leg buds are becoming visible. The development of our complicated grip system only takes 14 days.
The unborn is now growing about 1mm per day.
5th week (7th week of pregnancy)
The facial features are starting to develop. Little depressions which will become eyes and the beginning of mouth and tongue are forming. The pigment is already being formed in the eyes.
Around the little body a delicate, thin layer of skin is forming. At the ends of the arms rudiments of the palms are developing.
The brain cells are separating into three sections: the forebrain, the midbrain and the rear brain. All three parts work together and form the brain of every human being.
6th week (8th week of pregnancy)
Loosely connected cranial bones are starting to cover the brain. The embryo’s facial features are developing more and more, the eye lids are developed, in place of the mouth there is a little hole and even the nostrils are forming as two tiny holes.
Fingers and toes are also growing and the esophagus is being formed this week.
7th week (9th week of pregnancy)
In the 9th week all organic systems of the embryo are not only complete but also already partially working. The brain is the fastest growing organ with 100 000 new nerve cells per minute. During this week small testicles or ovaries are developing. The faces continues to become more and more detailed with eyes and eye lids, lips and the beginning of what will one day be teeth. The nose has reached its form and the eye lids are covering the eyes.
8th week (10th week of pregnancy)
The unborn is able to move arms and legs, the sense of smell and taste develop and the baby is able to react to touch. Different kinds of glands are developed in the skin and tiny hair starts to grow. Until the 10th week of the pregnancy all organic systems are fully in place. From this point on they only have to mature.
9th week (11th week of pregnancy)
This week is the start of the fetal stage.
The yolk sack has become obsolete. Liver and spleen have taken over its tasks. The face is fully developed. 32 permanent teeth buds also already exist.
10th week (12th week of pregnancy)
The cerebral gland produces hormones, the voice chords develop and the bones are gradually hardening. Within the spleen, liver and bone marrow a blood circuit develops. The baby moves in the uterus like an acrobat, well-protected and floating weightlessly in the fluid of the amniotic sac. The baby can change its position up to 20 times per minute. Through this the baby practices the interplay between nerves and muscles.
11th week (13th week of pregnancy)
This is now the last week of the first third of the pregnancy (first trimester). At the end of this week your child will be about 7,5cm long. The diameter of the fetus’ head is between 21 and 29mm. The baby will weigh about 20 grams.
The main work regarding the development of the organs, limbs and other party parts is completed.
12th week (14th week of pregnancy)
The eyelids are completed and are now closed. From now on the baby will keep its eyes closed until about the 7th month. It is drinking amniotic fluid regularly and is also excreting it.
All organic systems are fully developed and functional – although only in the mother’s womb! The oxygen supply is still being secured through the placenta. Besides the hand grip reflex, the sucking reflex is also functioning. Thumb-sucking is one of its favorite activities.
13th week (15th week of pregnancy)
The fetus is now about 10cm in size and weighs about 70g.
The fetus’ facial features are becoming more refined. The eye’s cornea, lens and iris are fully developed but still covered by the eyelid.
The baby is able to perceive noises like its mother’s voice or her heart beat which are carried to its ear through sound waves.
14th week (16th week of pregnancy)
Blood circuit and urinary passages are functioning. Between the 16th and 20th week, many mothers feel little kicks and pushes of the child for the first time. The movement feels like short fluttering and quivering.
15th week (17th week of pregnancy)
The baby has bowel movement. This is a mix of dead cells and intestinal secretion as well as everything that is contained in the amniotic liquid. The baby’s skin looks wrinkly as it doesn’t have any fatty tissue yet. This fatty tissue now starts to slowly accumulate underneath the skin (hypodermic fat tissue).
16th week (18. SSW 5th week of pregnancy)
The head is now 38-48mm in diameter. The baby is about 14cm long and weighs about 200g. Now the baby’s most active phase begins.
17th week (19th week of pregnancy)
Between the 19th and 22nd week the growth of the head hair begins. Also, the roots for the milk teeth are being set up. The skin loses its transparency.
18th week (20th week of pregnancy)
The child is growing quickly now. It is about 20cm long now (measured from top to toe) and weighs about 400g. The head’s diameter is about 46-55mm now. The movements are becoming more coordinated.
The current phase is very important for the development of his or her senses. Special focus is now on the senses of taste, smell, vision, touch and hearing. The correspondent areas of the senses are being set up in the brain. By now the fetus is able to differentiate between light and dark.
19th week (21st week of pregnancy)
The senses are being developed continually, the baby is able to perceive touch. From now on, the sleep-wake cycle is visible.
20th week (22nd week of pregnancy)
Rapid increase in weight: every week the baby is now gaining 100g in weight. The skin of the baby gets thicker and thicker and therefore loses its transparency, but the blood vessels are still clearly visible.
21st week (23rd week of pregnancy)
The baby now has the shape of a full term baby but its bones and organs can be seen as being directly underneath a thin layer of pink skin. The sense of hearing is becoming more sophisticated: the baby can distinguish between different voices now.
22nd week (24th week of pregnancy)
The fetus is now about 30cm long and weighs about 600g. Even though the baby is still very thin and delicate, if born now it would have a chance of survival of 20 to 25 percent.
23rd week (25th week of pregnancy)
The teeth are developing deep in the gums in the roof of the mouth. Around the mouth and the lips nerves are developing for a more sensitive perception. By now the baby is so strong that its mother can clearly sense its movements.
24th week (26th week of pregnancy)
The fetus now weighs about 750g while being about 35-37cm long.
The baby is slowly developing a sleeping rhythm.
7th & 8th month
25th week (27th week of pregnancy)
The fetus opens its eyes now and is able to blink. Your baby is also now developing eyelashes. As the hypodermic fat tissue increases the skin tightens and appears less wrinkly every week.
26th week (28th week of pregnancy)
At the beginning of the last trimester the child weighs about 1,000g, is about 30.5 to 40.5cm and if born now, it would have a chance of survival of 79%. Its organs and nerves are already developed well and only have to mature. The head, clearly covered by hair, has a diameter of about 7.5cm.
27th week (29th week of pregnancy)
In this week your baby is about 26cm big from top to toe and weighs about 1,250g.
During the next 2 weeks the face of your child will be developed so well that its individuality is formed so that there will almost be no difference to its face after the birth. It will have the whole range of facial expressions (yawning, sucking, swallowing, smiling, grimacing, moving the lips, blinking).
28th week (30th week of pregnancy)
During this week many babies move into a suitable position for the birth. They turn upside down inside the uterus with their head facing down.
29th week (31st week of pregnancy)
The baby now opens and closes its eyes according to its sleep-wake cycle. The eye color is becoming visible now in the iris.
The baby will soon turn 29 weeks old. It is about 28cm long from top to toe. Compared to the previous week it has gained about 200g in weight and now weighs 1,590g on average.
30th week (32nd week of pregnancy)
If your baby was to see the light of day at this point in the pregnancy, it would have a chance of survival of 96% with its average weight of 1,700g and a length of about 42cm.
31st week (33rd week of pregnancy)
The baby will turn towards the pelvis so that when the birth starts it will be lying with the head in the birth canal. The movements are becoming stronger but also fewer. This is because the fetus doesn’t have as much room any more weighing about 1,900g and being about 44cm long.
32nd week (34th week of pregnancy)
The fetus, now being between 43 and 44cm big and weighing 2,100g, is continuing to build up hypodermic fat tissue. Around this time your baby is no longer swimming around freely in the amniotic fluid.
33rd week (35th week of pregnancy)
The fetus, now between 40 and 45cm big and weighing 2,200 – 2,500g is stretching more and more often. Although your baby is not yet ready to be born, his respiratory and digestive systems are ready and your baby starts to develop its own immune system now. Also, the “little things” are completed now: toe nails and finger nails are covering the tips of the hands and feet.
34th week (36th week of pregnancy)
With a size of about 45cm and a weight of about 2,300 – 2,600g, ca. 15% of the baby’s weight consists of fat which is located in the hypodermic fat tissue for protection and regulation of temperature. Many babies now slide deeper into the pelvis – a sign that it probably won’t take long until the birth.
35th week (37th week of pregnancy)
Until now the baby has gained between 200 and 250g in weight per week to build up the hypodermic fat tissue. It is about 47cm big now and weighs 2,600 to 2,900g. In the last weeks before the birth this growth decreases. The immune system that the baby develops during the last weeks will be further positively influenced after the birth through the breast feeding. For mother milk is extremely nutritious and full of antibodies that will protect your child from harmful influences in its first months outside the womb.
36th week (38th week of pregnancy)
This week your baby is about 35cm long from crown to rump and about 48 to 49cm altogether. It weighs about 3,100 grams. From now on your baby will not gain a lot in length any more but therefore gain a lot in weight: about 20 to 30 grams every day.
The placenta provided your baby with oxygen and nutrition during the last months but soon it will not be needed any more. It starts to age and also reduces the supply of nutrients. The head and the tummy of your baby have the same circumference now.
37th week (39th week of pregnancy)
The birth of the baby could start any moment now. Hormones in your body will induce the contractions. Only 5% of all babies see the light of day on the calculated due day. By the way, at the time of the birth a baby has 300 bones. Many of them will grow together as it becomes older. Adults only have 206 bones. With their legs and arms bent tightly 95% of the babies are lying headfirst in their mother’s womb.
The baby weighs about 3,250g now and is about 49 to 51cm long from top to toe so that the child and the umbilical cord have the same length now.
38th week (40th week of pregnancy)
The baby is now definitely ready for the outside world. It has a total length of 48 to 52cm. It weighs 3,300 to 3,500g. The amniotic fluid appears cloudy and milky at the time of birth due to the excrements as well as the body grease (vernix caseosa) that has started to peel away.
During birth, the placenta will also detach itself from the uterus. The umbilical cord stops the supply as soon as the baby has taken its first breath. Then the baby’s blood circulation will also be redirected as it will use its own from now on.
3. Woche (5. SSW)
der Embryo misst ungefähr 1,25 Millimeter. Sein winziger Körper ist durchsichtig und sehr weich.
Bereits jetzt fängt die Entwicklung des Rückenmarks und des Gehirns an. Langsam bilden sich auch Leber, Nieren, Muskeln und Knochen. Augen und Ohren sind sogar schon an dem kleinen Kopf angedeutet.
Im inneren des Körpers des Embryos bilden sich Organe und Kreislaufsystem, sowie das zentrale Nervensystem. Um den 15. Lebenstag zeigen sich die ersten Blutgefäße, zwei solcher Gefäße verbinden sich zu einem Herz, das schon am 21. Tag seine Arbeit aufnimmt.
4.Woche (6. SSW)
Darmsystem, Lunge, Leber, Bauchspeicheldrüse und Schilddrüse entstehen.
Das Gesicht ist zu erkennen, winzige Stimmbänder nehmen Form an, das Innenohr ist schon ausgebildet.
Vom 33. Tag an wird eine unterschiedliche Entwicklung von Rückenmark und Gehirn festgestellt.
Um den 28. Tag werden Arm – und ein wenig später Beinknospen sichtbar. Die Entwicklung unseres so komplizierten Greifsystems dauert nur 14 Tage.
Das Ungeborene wächst jetzt etwa 1 Millimeter pro Tag.
Voraussetzungen bei der Frau
Eine Frau hat in jedem Eierstock 500.000 bis 1.000.000 fast reife Eizellen. Einmal im Monat findet der Eisprung statt, das passiert im Leben der Frau etwa 400mal, beginnend ca. zwei Wochen vor der ersten Regelblutung.
Dabei reifen viele Eizellen gleichzeitig mit heran, aber nur eine wird aus dem Eierstock ausgeschüttet. Das Ei wird vom Eileiter aufgefangen, bleibt dort einige Tage liegen, es ist aber nur etwa 12 bis 24 Stunden lang befruchtungsfähig. Dann wandert es weiter in die Gebärmutter, wo es, wenn es nicht befruchtet wird, allmählich abstirbt.
Die fruchtbaren Tage sind zwei Tage bevor und der Tag an dem der Eisprung stattfindet.Voraussetzungen beim Mann
Der Mann bildet ständig neue befruchtungsfähige Spermien, von der Geschlechtsreife bis ins hohe Alter.
Jeder Samenausstoß enthält an die 350 - 500 Millionen Spermien. Für den Weg zu den Eileitern benötigen die Spermien durchschnittlich ca. 10 - 12 Stunden, wobei nur ca. 1 % überhaupt diese Strecke zurücklegen. Die Spermien können zwei bis fünf Tage im Körper der Frau am Leben bleiben.
Wenn kein Ei im Eileiter vorhanden ist, verbleiben die Spermien dort manchmal für mehrere Tage, bevor sie absterben.
Befruchtung der Eizelle
Ein einzelnes Spermium dringt in die Eizelle ein, die Zellkerne des Spermiums und der Eizelle verschmelzen.
Die daraus entstandene Zelle trägt die Information für die ganze folgende Entwicklung in sich, wie z.B. Geschlecht, Augenfarbe Begabungen, die ungefähre Schuh- und Körpergröße, die der Mensch in zwanzig Jahren haben wird.
Von Anfang an ist das Ungeborene also eine einzigartige und unwiederholbare menschliche Person.
Die Befruchtung ist das einzige gravierende Ereignis in der Entwicklung des Kindes, die dann fließend verläuft. Es gibt keinen anderen Zeitpunkt, der sonst als der Beginn des Lebens bewiesen bezeichnet werden könnte.
Diese Zelle, die bei der Verschmelzung entstanden ist (die so genannte Zygote) beginnt nun, sich immer wieder zu teilen und dabei in Richtung Gebärmutter zu wandern, die nach ca. vier, fünf Tagen erreicht wird.
Die Einnistung in die Gebärmutterschleimhaut ist nach etwa 14 Tagen (d.h. vier Wochen nach der letzten Periode) abgeschlossen.
Von nun an ist das Kind direkt an den mütterlichen Stoffwechsel angeschlossen, mütterlicher und kindlicher Blutkreislauf bleiben jedoch stets voneinander getrennt.