At What Stage Are the Developing Babys Organs Most Susceptible

Prenatal Development

Figure 1. The stages of pregnancy

How did you come up to be who you are? From beginning as a one-cell construction to your nativity, your prenatal evolution occurred in an orderly and delicate sequence. There are three stages of prenatal development: germinal, embryonic, and fetal. Keep in listen that this is dissimilar than the three trimesters of pregnancy.

Prenatal Development

Let's take a look at some of the changes that take place during each of the 3 periods of prenatal development: the germinal period, the embryonic catamenia, and the fetal menstruation.

The Germinal Period (Weeks 1-ii)

Figure 2. Sperm and Ovum at Conception

Conception occurs when a sperm fertilizes an egg and forms azygote, which begins equally a one-cell structure. The mother and father's Dna is passed on to the child at the moment of conception. The genetic makeup and sex of the baby are set at this point. The germinal period (nearly xiv days in length) lasts from formulation to implantation of the zygote (fertilized egg) in the lining of the uterus.

During the first calendar week later on formulation, the zygote divides and multiplies, going from a one-cell construction to two cells, then 4 cells, so eight cells, and so on. The procedure of prison cell division is called mitosis. Subsequently the fourth division, differentiation of the cells begins to occur likewise. Differentiated cells become more specialized, forming different organs and body parts.  After 5 days of mitosis, there are 100 cells, and after ix months there are billions of cells. Mitosis is a frail procedure, and fewer than i-half of all zygotes survive across the first two weeks.^[1]

After the zygote divides for about 7–ten days and has 150 cells, it travels down the fallopian tubes and implants itself in the lining of the uterus. It'southward estimated that about 60 percent of natural conceptions fail to implant in the uterus. The rate is higher for in vitro conceptions. Once the zygote attaches to the uterus, the next stage begins.

The Embryonic Menstruation (Weeks 3-8)

Figure 3. Human Embryo

The embryonic menstruation begins once the zygote is implanted in the uterine wall. It lasts from the third through the eighth calendar week after formulation. Upon implantation, this multi-cellular organism is called anembryo. Now blood vessels abound, forming the placenta. Theplacenta is a construction connected to the uterus that provides nourishment and oxygen from the mother to the developing embryo via the umbilical cord.

During this period, cells continue to differentiate. Basic structures of the embryo start to develop into areas that will get the head, chest, and abdomen. During the embryonic stage, the heart begins to vanquish and organs form and begin to role. At 22 days afterwards conception, the neural tube forms along the back of the embryo, developing into the spinal cord and brain.

Growth during prenatal development occurs in ii major directions: from head to tail (cephalocaudal development) and from the midline outward (proximodistal evolution). This means that those structures nearest the head develop before those nearest the anxiety and those structures nearest the torso develop earlier those away from the center of the body (such every bit easily and fingers).

The head develops in the fourth week and the precursor to the heart begins to pulse. In the early stages of the embryonic period, gills and a tail are apparent. Just past the end of this stage, they disappear and the organism takes on a more human appearance. The embryo is approximately 1 inch in length and weighs almost iv grams at the end of this flow. The embryo can move and reply to touch at this time.

About twenty pct of organisms fail during the embryonic period, usually due to gross chromosomal abnormalities. As in the case of the germinal period, ofttimes the female parent does not all the same know that she is meaning. It is during this stage that the major structures of the body are taking form making the embryonic flow the time when the organism is most vulnerable to the greatest amount of impairment if exposed to harmful substances. Potential mothers are non oftentimes aware of the risks they introduce to the developing kid during this time.

The Fetal Flow (Weeks ix-forty)

Figure 4. A fetus at 10 weeks of evolution.

When the organism is about nine weeks old, the embryo is called a fetus. At this stage, the fetus is virtually the size of a kidney bean and begins to take on the recognizable form of a man as the "tail" begins to disappear.

From 9–12 weeks, the sex organs brainstorm to differentiate. By the 12th week, the fetus has all its torso parts including external genitalia. In the following weeks, the fetus will develop hair, nails, teeth and the excretory and digestive systems will continue to develop. At the terminate of the 12th week, the fetus is about iii inches long and weighs about 28 grams.

At near 16 weeks, the fetus is approximately 4.v inches long. Fingers and toes are fully developed, and fingerprints are visible. During the 4-sixth months, the optics become more sensitive to light and hearing develops. The respiratory system continues to develop. Reflexes such as sucking, swallowing, and hiccupping develop during the 5th month. Cycles of sleep and wakefulness are present at that fourth dimension likewise. Throughout the fetal stage, the brain continues to grow and develop, nearly doubling in size from weeks 16 to 28. The majority of the neurons in the brain have developed by 24 weeks although they are yet rudimentary and the glial or nurse cells that support neurons proceed to grow. At 24 weeks the fetus can feel hurting. ^[2]

The showtime gamble of survival outside the womb, known as the historic period of viabilityis reached at about 22 to 26 weeks. ^[3] Past the time the fetus reaches the sixth month of development (24 weeks), information technology weighs up to ane.4 pounds. The hearing has adult, so the fetus can respond to sounds. The internal organs, such equally the lungs, heart, tum, and intestines, have formed enough that a fetus born prematurely at this point has a adventure to survive outside of the mother's womb.

Between the 7th and 9th months, the fetus is primarily preparing for birth. It is exercising its muscles, its lungs brainstorm to aggrandize and contract. It is developing fatty layers under the skin. The fetus gains about 5 pounds and vii inches during this concluding trimester of pregnancy which includes a layer of fat gained during the 8th month. This layer of fatty serves as insulation and helps the infant regulate body temperature afterwards nativity.

Effectually 36 weeks, the fetus is almost ready for birth. Information technology weighs about half dozen pounds and is about 18.v inches long, and by week 37 all of the fetus's organ systems are adult enough that it could survive outside the uterus without many of the risks associated with premature nativity. The fetus continues to gain weight and grow in length until approximately 40 weeks. Past so, the fetus has very little room to motion around and birth becomes imminent.

Figure 5. During the fetal stage, the brain develops and the torso adds size and weight until the fetus reaches total-term development.

This video on prenatal evolution explains many of the developmental milestones and changes that happen during each month of development for the embryo and fetus.

Environmental Risks

Teratology

Adept prenatal care is essential. The developing embryo is most at take a chance for some of the most astringent problems during the first three months of development. Unfortunately, this is a time at which most women are unaware that they are significant. It is estimated that x% of all birth defects are caused by a prenatal exposure or teratogen. Teratogens are factors that can contribute to birth defects which include some maternal diseases, drugs, alcohol, and stress. These exposures can also include environmental and occupational exposures. Today, we know many of the factors that can jeopardize the wellness of the developing embryo and fetus. Some teratogen-caused nascency defects are potentially preventable.

The report of factors that contribute to birth defects is called teratology. Teratogens are usually discovered after an increased prevalence of a particular birth defect. For example, in the early 1960's, a drug known as thalidomide was used to treat morning sickness. Exposure of the fetus during this early on phase of development resulted in cases of phocomelia, a congenital malformation in which the hands and feet are fastened to abbreviated artillery and legs.

A Wait at Some Teratogens

Alcohol

Figure 6. Some distinguishing characteristics of fetal booze spectrum disorders include more narrow eye openings, A polish philtrum, meaning a smooth surface area betwixt the upper lip and the nose, and a sparse upper lip.

One of the most commonly used teratogens is booze. Considering half of all pregnancies in the U.s. are unplanned, it is recommended that women of changeable age take great circumspection confronting drinking alcohol when not using nativity control and when pregnant.^[4] Alcohol consumption, particularly during the second month of prenatal development, but at whatever point during pregnancy, may pb to neurocognitive and behavioral difficulties that tin can last a lifetime.

There is no acceptable safe limit for alcohol use during pregnancy, simply binge drinking (five or more drinks on a single occasion) or having 7 or more than drinks during a single week places an embryo and fetus at particularly high take chances. In extreme cases, alcohol consumption can lead to fetal death, simply more than oftentimes information technology can result in fetal alcohol spectrum disorders (FASD). This terminology is now used when looking at the effects of exposure and replaces the term fetal booze syndrome. It is preferred considering it recognizes that symptoms occur on a spectrum and that all individuals do not have the same characteristics. Children with FASD share certain physical features such equally flattened noses, modest eye openings, small heads, intellectual developmental delays, and behavioral bug. Those with FASD are more at risk for lifelong problems such as criminal behavior, psychiatric issues, and unemployment. ^[5]

The terms alcohol-related neurological disorder (ARND) and alcohol-related birth defects (ARBD) accept replaced the term Fetal Alcohol Effects to refer to those with less extreme symptoms of FASD. ARBD include kidney, os and heart problems.

Tobacco

Smoking is also considered a teratogen because nicotine travels through the placenta to the fetus. When the pregnant adult female smokes, the developing fetus experiences a reduction in blood oxygen levels. Tobacco use during pregnancy has been associated with low nascence weight, placenta previa, birth defects, preterm delivery, fetal growth restriction, and sudden infant death syndrome. Smoking in the calendar month before getting pregnant and throughout pregnancy increases the chances of these risks. Quitting smoking before getting pregnant is best. However, for women who are already pregnant, quitting equally early equally possible can nonetheless help protect against some wellness problems for the female parent and babe.^{[half dozen]}

Drugs

Prescription, over-the-counter, or recreational drugs can have serious teratogenic furnishings. In general, if medication is required, the lowest dose possible should be used. Combination drug therapies and first trimester exposures should be avoided. Nearly iii percent of pregnant women utilise illicit drugs such equally marijuana, cocaine, Ecstasy and other amphetamines, and heroin. These drugs can cause depression nativity-weight, withdrawal symptoms, birth defects, or learning or behavioral problems. Babies built-in with a heroin addiction need heroin merely similar an adult aficionado. The child will need to be gradually weaned from the heroin nether medical supervision; otherwise, the child could have seizures and die. Visit this link for further information about opioid use during pregnancy.

Environmental Chemicals

Environmental chemicals tin can include exposure to a broad assortment of agents including pollution, organic mercury compounds, herbicides, and industrial solvents. Some ecology pollutants of major business include lead poisoning, which is connected with depression nascency weight and slowed neurological evolution. Children who live in older housing in which lead-based paints accept been used have been known to consume peeling pigment fries thus beingness exposed to atomic number 82. The chemicals in certain herbicides are besides potentially damaging. Radiations is another environmental hazard that a pregnant adult female must be enlightened of. If a adult female is exposed to radiation, specially during the first three months of pregnancy, the child may endure some congenital deformities. There is besides an increased risk of miscarriage and stillbirth. A meaning woman's exposure to mercury tin can also lead to concrete deformities and intellectual disabilities.^[7]

Sexually Transmitted Infections

Sexually transmitted infections (STIs) tin complicate pregnancy and may have serious effects on both the pregnant adult female and the developing fetus. Well-nigh prenatal intendance today includes testing for STIs, and early detection is of import. STIs, such as chlamydia, gonorrhea, syphilis, trichomoniasis, and bacterial vaginosis can all be treated and cured with antibiotics that are safe to take during pregnancy. STIs that are caused by viruses, like genital herpes, hepatitis B, or HIV cannot be cured. However, in some cases these infections can be treated with antiviral medications or other preventive measures that can be taken to reduce the risk of passing the infection to the baby.^[8]

Maternal Diseases

Maternal illnesses increment the chance that a baby volition be born with a birth defect or have a chronic health problem. Some of the diseases that are known to potentially have an adverse consequence on the fetus include diabetes, cytomegalovirus, toxoplasmosis, rubella, varicella, hypothyroidism, and Strep B. If the significant woman contracts Rubella during the first three months of pregnancy, damage can occur in the optics, ears, centre, or brain of the developing fetus. On a positive note, Rubella has been most eliminated in the industrial world due to the vaccine created in 1969. Diagnosing these diseases early and receiving appropriate medical care can assistance improve the outcomes. Routine prenatal care now includes screening for gestational diabetes and Strep B.^[9]

Maternal Stress

Stress represents the furnishings of whatever factor able to threaten the homeostasis of an organism; these either real or perceived threats are referred to every bit the "stressors" and comprise a long list of potentially agin factors, which tin can be emotional or physical. Because of a link in blood supply between a pregnant woman and her fetus, information technology has been found that stress tin can get out lasting furnishings on a developing fetus, fifty-fifty before nativity. The all-time-studied outcomes of fetal exposure to maternal prenatal stress are preterm nascence and low nascence weight. Maternal prenatal stress is besides considered responsible for a diverseness of changes in the child'southward brain, and a risk factor for conditions such as behavioral problems, learning disorders, high levels of anxiety, attention arrears hyperactivity disorder, autism, and schizophrenia. Furthermore, maternal prenatal stress has been associated with a higher risk for a diverseness of allowed and metabolic changes in the child such equally asthma, allergic disorders, cardiovascular diseases, hypertension, hyperlipidemia, diabetes, and obesity.^[10]

Factors influencing prenatal risks

In that location are several considerations in determining the blazon and corporeality of damage that might upshot from exposure to a particular teratogen.^[eleven] These include:

• The timing of the exposure: Structures in the trunk are vulnerable to the almost severe harm when they are forming. If a substance is introduced during a particular structure's critical period (fourth dimension of development), the harm to that structure may be greater. For example, the ears and arms attain their critical periods at about six weeks after conception. If a pregnant woman exposes the embryo to sure substances during this period, the arms and ears may be malformed.
• The amount of exposure:Some substances are not harmful unless the amounts attain a sure level. The critical level depends in part on the size and metabolism of the mother.
• Genetics:Genetic make-upward also plays a office in the impact a particular teratogen might have after the child is built-in. This is suggested by congenial twin studies who are exposed to the same prenatal environs, all the same do not experience the same teratogenic furnishings. The genetic make-upwards of the mother can likewise have an consequence; some mothers may be more than resistant to teratogenic effects than others.
• Biological sexual activity: Males are more likely to feel damage due to teratogens than are females. It is believed that the Y chromosome, which contains fewer genes than the 10, may have an impact.

Figure 7. Critical Periods of Prenatal Development. This image summarizes the three developmental periods in prenatal development. The blueish images indicate where major evolution is happening and the aqua signal where refinement is happening. As shown, the bulk of organs are specially susceptible during the embryonic period. The central nervous system still continues to develop in major ways through the fetal period as well.

Did you lot know that pregnant women can better outcomes for themselves and their babies through a balanced diet and adequate exercise? Click through this interactive example to learn more about the importance of maternal health.

Visit this link for boosted information on how to assist foreclose birth defects.

Complications of Pregnancy and Delivery

Effigy eight. Pregnancy affects women in different means; some observe few adverse side furnishings, while others feel high levels of discomfort, or develop more than serious complications.

There are a number of common side effects of pregnancy. Not everyone experiences all of these nor do women experience them to the same caste. And although they are considered "minor" these problems are potentially very uncomfortable. These side effects include nausea (particularly during the start iii-4 months of pregnancy as a result of higher levels of estrogen in the system), heartburn, gas, hemorrhoids, backache, leg cramps, insomnia, constipation, shortness of breath or varicose veins (as a result of carrying a heavy load on the abdomen). What is the cure? Commitment!

Major Complications

The following are some serious complications of pregnancy which can pose health risks to mother and child and that oft require special care.

• Gestational diabetes is when a adult female without diabetes develops loftier blood saccharide levels during pregnancy.
• Hyperemesis gravidarum is the presence of astringent and persistent vomiting, causing aridity and weight loss. It is more than astringent than the more common morning sickness.
• Preeclampsia is gestational hypertension. Severe preeclampsia involves blood pressure over 160/110 with boosted signs.Eclampsia is seizures in a patient who is pre-eclamptic.
• Deep vein thrombosis is the formation of a blood clot in a deep vein, nigh commonly in the legs.
• A pregnant adult female is more susceptible toinfections. This increased run a risk is acquired by an increased immune tolerance in pregnancy to prevent an immune reaction against the fetus.
• Peripartum cardiomyopathyis a decrease in heart function which occurs in the last month of pregnancy, or up to six months post-pregnancy.

Maternal Mortality

Maternal mortality is unacceptably high. Near 830 women die from pregnancy or childbirth-related complications effectually the earth every day. It was estimated that in 2015, roughly 303,000 women died during and following pregnancy and childbirth. Almost all of these deaths occurred in low-resource settings, and nearly could take been prevented. The high number of maternal deaths in some areas of the earth reflects inequities in access to health services and highlights the gap between rich and poor. Near all maternal deaths (99%) occur in developing countries. More than half of these deaths occur in sub-Saharan Africa and most one third occur in Southern asia.

Almost all maternal deaths can be prevented, as evidenced by the huge disparities found between the richest and poorest countries. The lifetime adventure of maternal death in high-income countries is i in 3,300, compared to 1 in 41 in depression-income. ^[12]

Fifty-fifty though maternal mortality in the U.s.a. is relatively rare today considering of advanced in medical care, information technology is however an issue that needs to be addressed. The Centers for Affliction Command and Prevention ascertain a pregnancy-related death as the death of a woman while meaning or within one year of the end of a pregnancy–regardless of the outcome, duration, or site of the pregnancy–from whatever cause related to or aggravated past the pregnancy or its management, merely not from accidental or incidental causes. The reasons for the overall increase in pregnancy-related mortality are unclear. What practice y'all think are some reasons for this surprising increment in the United States? What tin can exist done to change this statistic?

In the United States, black women are disproportionately more likely to die from complications related to pregnancy or childbirth than any other race; they are three or four times more than likely than white women to dice due to pregnancy-related death and are more than likely to receive worse maternal intendance.^[13] Black women from higher income groups and with advanced instruction levels too accept heightened risks—even tennis superstar Serena Williams had near-deadly complications during the birth of her girl, Olympia. Why is this the example in our modern world? Watch this video to learn more:

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Miscarriage

Spontaneous ballgame, or miscarriage, is experienced in an estimated 20-40 percent of undiagnosed pregnancies and in some other 10 percent of diagnosed pregnancies. Usually, the body aborts due to chromosomal abnormalities and this typically happens before the 12th week of pregnancy. Cramping and bleeding upshot and normal periods return later several months. Some women are more than probable to take repeated miscarriages due to chromosomal, amniotic, or hormonal issues; just miscarriage tin too be a outcome of defective sperm.^[14]

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Source: https://iastate.pressbooks.pub/parentingfamilydiversity/chapter/prenatal-development/

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