Pregnancy and Delivery

First Trimester

Fertilization: the sperm and egg join in the fallopian tube to form a unique human being. Forty-six chromosomes combine, which pre-determine all of a person's physical characteristics.

First Trimester

The picture is a fertilized egg, only thirty hours after conception. Magnified here, it is no larger than the head of a pin. Still rapidly dividing, the developing embryo, called a zygote at this stage, floats down from the fallopian tube and towards the uterus.

First Trimester

3 weeks - Once in the uterus, the developing embryo, called a blastocyst, searches for a nice place to implant, where it actually burrows beneath the surface of the uterus. The yolk sac, shown on the left, produces blood cells during the early weeks of life. The unborn child is only one-sixth of an inch long, but is rapidly developing. The backbone, spinal column, and nervous system are forming. The kidneys, liver, and intestines are taking shape.

First Trimester• 4 weeks - The embryo produces hormones

which stop the mother's menstrual cycle. • 5 weeks - Embryo is the size of a raisin. By day

twenty-one, the embryo's tiny heart has begun beating. The neural tube enlarges into three parts, soon to become a very complex brain. The placenta begins functioning. The spine and spinal cord grows faster than the rest of the body at this stage and give the appearance of a tail. This disappears as the child continues to grow.

First Trimester

7 weeks - Facial features are visible, including a mouth and tongue. The eyes have a retina and lens. The major muscle system is developed, and the unborn child practices moving. The child has its own blood type, distinct from the mother's. These blood cells are produced by the liver now instead of the yolk sac.

First Trimester 8 weeks - The unborn

child, called a fetus at this stage, is about half an inch long. The tiny person is protected by the amnionic sac, filled with fluid. Inside, the child swims and moves gracefully. The arms and legs have lengthened, and fingers can be seen. The toes will develop in the next few days. Brain waves can be measured.

First Trimester

10 weeks - The heart is almost completely developed and very much resembles that of a newborn baby. An opening the atrium of the heart and the presence of a bypass valve divert much of the blood away from the lungs, as the child's blood is oxygenated through the placenta. Twenty tiny baby teeth are forming in the gums.

First Trimester

12 weeks - Vocal chords are complete, and the child can and does sometimes cry (silently). The brain is fully formed, and the child can feel pain. The fetus may even suck his thumb. The eyelids now cover the eyes, and will remain shut until the seventh month to protect the delicate optical nerve fibers.

Second Trimester• 14 weeks - Muscles lengthen and become

organized. The mother will soon start feeling the first flutters of the unborn child kicking and moving within.

• 15 weeks - The fetus has an adult's taste buds and may be able to savor the mother's meals.

• 16 weeks - Five and a half inches tall and only six ounces in weight, eyebrows, eyelashes and fine hair appear. The child can grasp with his hands, kick, or even somersault.

Second Trimester

20 weeks - The child can hear and recognize her mother's voice. Though still small and fragile, the baby is growing rapidly and could possibly survive if born at this stage. Fingernails and fingerprints appear. Sex organs are visible. Using an ultrasound device, the doctor can tell if the child is a girl or a boy. The one on the right is a baby girl.

Second Trimester

20 weeks - The child can hear and recognize her mother's voice. Though still small and fragile, the baby is growing rapidly and could possibly survive if born at this stage. Fingernails and fingerprints appear. Sex organs are visible. Using an ultrasound device, the doctor can tell if the child is a girl or a boy. The one on the left is a baby girl.

Second Trimester

Third Trimester

24 weeks - Seen here at six months, the unborn child is covered with a fine, downy hair called lanugo. Its tender skin is protected by a waxy substance called vernix. Some of this substance may still be on the child's skin at birth at which time it will be quickly absorbed. The child practices breathing by inhaling amnionic fluid into developing lungs.

Third Trimester

30 weeks - For several months, the umbilical cord has been the baby's lifeline to the mother. Nourishment is transferred from the mother's blood, through the placenta, and into the umbilical cord to the fetus. If the mother ingests any toxic substances, such as drugs or alcohol, the baby receives these as well.

Third Trimester

32 weeks - The fetus sleeps 90-95% of the day, and sometimes experiences REM sleep, an indication of dreaming.

Third Trimester

40 weeks - The baby, now approximately seven and a half pounds, is ready for life outside its mother's womb. At birth the placenta will detach from the side of the uterus and the umbilical cord will cease working as the child takes his first breaths of air. The child's breathing will trigger changes in the structure of the heart and bypass arteries which will force all blood to now travel through the lungs.

Labor and Delivery• For 9 months, the unborn child has been developing

within the womb. Now the fetus is prepared to make an exit. Birth in human beings typically occurs 270 days after conception, near the end of a full 9 months. Shortly before birth (typically a few weeks for first births but sometimes only a few hours for later pregnancies), the fetus usually rotates into a head-downward position. This movement is referred to as lightening because it releases pressure on the mother's abdomen.

• For women giving birth for the first time, labor will usually last between 12 and 24 hours, with an average of 14 hours. However, for women who have given birth before, labor usually averages only 6 hours.

Labor and Delivery~ 1st Labor is commonly divided into three stages that

typically overlap each other. During the first stage, which lasts, on the average, about 13 hours for a woman having her first child, uterine contractions begin. It was discovered that the levels of a certain enzyme increase dramatically as labor starts. This enzyme chews up the collagen that holds together the fetal membrane, which in turn causes the amniotic sac to rupture (commonly referred to as the time when a woman's "water breaks.") The ensuing contractions associated with the rupture are usually spaced from 10 to 20 minutes apart. Initially the contractions are gentle, but they tend to become more powerful and sometimes uncomfortable.

Labor and Delivery 2nd The second stage of labor usually lasts about 90 minutes.

During this stage, the cervix opens sufficiently and the baby begins to move down the birth canal. At this point, if the mother has been well prepared, she may use her abdominal muscles to help push the baby along. This second stage of labor may often be shortened considerably by having the mother give birth in a vertical position, for example, by using a bed or room especially designed to include a birthing bar. When the mother is upright, gravity helps the baby move down the birth canal. Although the second stage of labor usually takes about 90 minutes, the average time in an upright position is only 30 minutes. At the end of the second stage of labor, the baby is born.

Labor and Delivery 2nd During birth, the human fetus is forced through the

birth canal under extreme pressure and is intermittently deprived of oxygen. During this time, the baby secretes the hormones adrenaline and noradrenaline at levels that are higher than they are likely to be at any other time throughout his or her life. Adrenaline helps open up the lungs, dry out the bronchi, and thus achieve the switch from a liquid to an air environment. Noradrenaline, which is especially prevalent, slows the heartbeat, enabling the fetus to withstand fairly lengthy oxygen deprivation.

Labor and Delivery ~ 3rd

Following the exit of the infant, the third stage of labor occurs, during which the placenta is expelled. The placenta and other expelled materials are called the afterbirth.

Cesarean section

Babies delivered by Cesarean section, are brought out of the mother surgically and do not pass through the birth canal. Interestingly these infants often have respiratory problems. One reason for such problems might be that the infant has not benefited from the usual stress of birth!

Question: Are all babies born in the head-first position?

About 97 percent of babies are born in the head-first position. The fetus's skull is soft and pliable, which helps the head to pass through the birth canal. However, 2.4 percent of babies are born rump first; this is called a breech birth. During a breech birth, great care must be taken to avoid damage to the baby's head, which is the most difficult part of the infant's body to pass through the birth canal. An even rarer occurrence is the shoulder presentation. This occurs in only 1 birth out of 200. The shoulder presentation is extremely dangerous because the baby must be forced by the attendants into a breech position. This forcing can rupture the uterus, which may cause the death of the infant and severe hemorrhaging in the mother.

AnoxiaAnother dangerous problem that can occur during birth is anoxia. Anoxia can occur if the placenta detaches prematurely if the umbilical cord is pinched or tangled, if the infant's head is injured to the point of hemorrhaging, or if the mother has been too heavily sedated during labor. If there is a problem during birth, the child may be removed from the uterus by Cesarean section. Approximately 23% of all births in the United States are Cesarean sections. In this procedure, the mother's abdomen is opened surgically and the baby is removed without passing through the vaginal canal. The surgical incision is then closed as it would be after any other surgical procedure.

1 Cesarean, 2 cesarean… Whenever possible, obstetricians use special

surgical incisions in the uterus so that a woman who has had one Cesarean section may later deliver babies vaginally. In addition, some obstetricians have recommended that Cesarean sections not be used routinely if breech birth or labor problems begin. They argue that breech births for low-weight babies, especially if the obstetrician is skilled, may present no difficulty and that abnormal labor of and by itself is not sufficient cause for a Cesarean section. When it is necessary, however, Cesarean section can be a lifesaver for both infant and mother.

                                                   

                             

Carnegie Stages

Carnegie stages are a system used by embryologists to describe the apparent maturity of embryos. An embryo is assigned a Carnegie stage (numbered from 1 to 23) based on its external features. This staging system is not dependent on the chronological age nor the size of the embryo. The stages, are in a sense, arbitrary levels of maturity based on multiple physical features. Embryos that might have different ages or sizes can be assigned the same Carnegie stage based on their external appearance because of the natural variation which occurs between individuals.

versus Postovulatory age Postovulatory age is frequently used by clinicians to

describe the maturity of an embryo. It refers to the length of time since the last ovulation before pregnancy. Postovulatory age is a good indication of embryonic age because the time of ovulation can be determined and fertilization must occur close to the time of ovulation. The terms "gestation", "pregnancy", and "conception" are usually avoided in describing embryonic age because fertilization is not universally accepted as the commencement of development (some consider implantation as the beginning of development)

Fetal Images – Early Pregnancy

• Twin gestation sacs at 4 ½ weeks gestation

Brain vesicles

• 8 week fetus showing the brain vesicles

heart

Four-chamber view of the fetal heart showing left ventricle (LV), right ventricle (RV), mitral valve (MV), tricuspid valve (TV), left atrium (LA), right atrium (RA), descending aorta (Ao), pulmonary vein (PV), the fetal spine(Sp) & rib.

Image of a 7 week twin pregnancy with two live embryos (arrowheads).

                      

References

• The Multi-Dimensional Human Embryohttp://embryo.soad.umich.edu/index.html

• Fetal Development http://www.w-cpc.org/fetal1.html

• The photograph is that of a 21-week-old unborn baby named Samuel Alexander Armas, who was being operated on by a surgeon named Joseph Bruner. The baby was diagnosed with spina bifida and would not survive if removed from his mother's womb. During the procedure, the doctor removes the uterus via C-section and makes a small incision to operate on the baby, then returns the uterus to the mother's womb after he completes the procedure.  As the doctor was completing the surgery, the little guy reached his tiny, but fully developed, hand through the incision and firmly grasped the surgeon's finger.

Dr. Bruner was reported as saying that when his finger was grasped, it was the most emotional moment of his life, and that for an instant during the procedure, he was just frozen, totally immobile.  The photograph captures this amazing event with perfect clarity. The editors titled the photograph, "Hand of Hope." Samuel was born in perfect health, the operation 100 per cent successful. Now see the actual photo; it is awesome... incredible.