Rate of Baby Weight Gain During 8th and 9th Month

What you'll learn to do: explain the main stages of prenatal development

How did you come to be who y'all are? From beginning equally a one-jail cell construction to your nativity, your prenatal development occurred in an orderly and fragile sequence. There are three stages of prenatal evolution: germinal, embryonic, and fetal. Keep in mind that this is unlike than the iii trimesters of pregnancy. Allow's take a look at what happens to the developing baby in each of these stages.

Learning outcomes

• Differentiate between development during the germinal, embryonic, and fetal periods
• Examine risks to prenatal development posed by exposure to teratogens
• Explain potential complications of pregnancy and delivery

Prenatal Development

"The body of the unborn babe is more circuitous than ours. The preborn baby has several extra parts to his torso which he needs only so long as he lives inside his mother. He has his own space sheathing, the amniotic sac. He has his ain lifeline, the umbilical cord, and he has his own root system, the placenta. These all vest to the baby himself, not to his mother. They are all adult from his original cell."^[one]

Periods of Prenatal Development

Let's have a wait at some of the changes that take place during each of the three periods of prenatal development: the germinal period, the embryonic period, and the fetal period.

The Germinal Menstruum (Weeks 1-two)

Figure 1. Sperm and Ovum at Formulation

Conception occurs when a sperm fertilizes an egg and forms azygote, which begins equally a i-cell structure. The mother and father'south DNA is passed on to the child at the moment of conception. The genetic makeup and sex of the babe are set at this betoken. The germinal period (about 14 days in length) lasts from formulation to implantation of the zygote (fertilized egg) in the lining of the uterus.

During the first calendar week after conception, the zygote divides and multiplies, going from a 1-cell structure to two cells, then four cells, then eight cells, and and so on. The process of cell division is chosen mitosis. After the fourth sectionalisation, differentiation of the cells begins to occur also. Differentiated cells become more specialized, forming different organs and torso parts.  Afterward v days of mitosis, there are 100 cells, and later ix months at that place are billions of cells. Mitosis is a frail process, and fewer than one-one-half of all zygotes survive across the starting time two weeks (Hall, 2004).

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

The Embryonic Period (Weeks 3-8)

Effigy 2. Human Embryo

The embryonic period begins once the zygote is implanted in the uterine wall. It lasts from the 3rd through the eighth week after conception. Upon implantation, this multi-cellular organism is called anembryo. Now blood vessels grow, forming the placenta. Theplacenta is a construction connected to the uterus that provides nourishment and oxygen from the female parent to the developing embryo via the umbilical cord.

During this period, cells continue to differentiate. Bones structures of the embryo starting time to develop into areas that will become the head, chest, and abdomen. During the embryonic stage, the eye begins to beat and organs class and begin to office. At 22 days subsequently conception, the neural tube forms along the dorsum of the embryo, developing into the spinal cord and brain.

Growth during prenatal development occurs in 2 major directions: from caput to tail (cephalocaudal development) and from the midline outward (proximodistal development). This ways that those structures nearest the caput develop before those nearest the feet and those structures nearest the trunk develop before those away from the heart of the body (such as easily and fingers).

The caput develops in the fourth week and the forerunner to the eye begins to pulse. In the early stages of the embryonic period, gills and a tail are credible. But by the end of this stage, they disappear and the organism takes on a more human appearance. The embryo is approximately one inch in length and weighs about 4 grams at the end of this period. The embryo can motion and answer to touch at this time.

About 20 pct of organisms fail during the embryonic period, usually due to gross chromosomal abnormalities. As in the case of the germinal period, oft the mother does non all the same know that she is pregnant. It is during this stage that the major structures of the torso are taking form making the embryonic menstruum the time when the organism is most vulnerable to the greatest amount of damage if exposed to harmful substances. Potential mothers are not often aware of the risks they introduce to the developing child during this time.

The Fetal Period (Weeks 9-40)

Figure 3. A fetus at 10 weeks of development.

When the organism is about nine weeks old, the embryo is called a fetus. At this stage, the fetus is about the size of a kidney edible bean and begins to accept on the recognizable grade of a human being as the "tail" begins to disappear.

From 9–12 weeks, the sex activity organs begin to differentiate. By the 12th week, the fetus has all its torso parts including external ballocks. In the post-obit weeks, the fetus will develop hair, nails, teeth and the excretory and digestive systems volition continue to develop. At the finish of the 12th week, the fetus is about 3 inches long and weighs about 28 grams.

At about 16 weeks, the fetus is approximately 4.5 inches long. Fingers and toes are fully developed, and fingerprints are visible. During the 4-6th months, the eyes become more than sensitive to light and hearing develops. The respiratory system continues to develop. Reflexes such as sucking, swallowing and hiccuping develop during the fifth month. Cycles of slumber and wakefulness are present at that time as well. Throughout the fetal phase, the brain continues to abound and develop, about doubling in size from weeks 16 to 28. The bulk of the neurons in the brain have developed by 24 weeks although they are still rudimentary and the glial or nurse cells that support neurons proceed to grow. At 24 weeks the fetus tin can experience pain (Royal College of Obstetricians and Gynecologists, 1997).

The commencement risk of survival outside the womb, known as the historic period of viability is reached at almost 22 to 26 weeks (Moore & Persaud, 1998). Past the time the fetus reaches the sixth month of development (24 weeks), it weighs up to 1.4 pounds. The hearing has adult, so the fetus can answer to sounds. The internal organs, such equally the lungs, center, tum, and intestines, have formed plenty that a fetus built-in prematurely at this point has a hazard to survive outside of the mother'southward womb.

Between the 7th and ninth months, the fetus is primarily preparing for birth. It is exercising its muscles, its lungs begin to expand and contract. It is developing fatty layers nether the skin. The fetus gains about 5 pounds and 7 inches during this final trimester of pregnancy which includes a layer of fat gained during the eighth month. This layer of fat serves as insulation and helps the infant regulate body temperature after nativity.

Around 36 weeks, the fetus is nearly ready for birth. It weighs about six pounds and is nearly 18.v inches long, and by calendar week 37 all of the fetus's organ systems are developed enough that it could survive outside the mother's uterus without many of the risks associated with premature nascence. The fetus continues to gain weight and grow in length until approximately xl weeks. By then, the fetus has very little room to move around and birth becomes imminent.

Effigy 4. During the fetal stage, the baby's brain develops and the body adds size and weight until the fetus reaches full-term development.

Watch It

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

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Environmental Risks

Teratology

Good prenatal care is essential. The developing child is most at risk for some of the most severe issues during the offset three months of development. Unfortunately, this is a time at which most mothers are unaware that they are pregnant. It is estimated that 10% of all birth defects are acquired past a prenatal exposure or teratogen. Teratogens are factors that can contribute to nascency defects which include some maternal diseases, drugs, alcohol, and stress. These exposures can also include ecology and occupational exposures. Today, we know many of the factors that tin can jeopardize the health of the developing kid. Teratogen-caused birth defects are potentially preventable.

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

A Wait at Some Teratogens

Alcohol

Figure 5. Some distinguishing characteristics of fetal alcohol spectrum disorders include more narrow eye openings, A polish philtrum, meaning a shine area between the upper lip and the olfactory organ, and a thin upper lip.

Ane of the almost usually used teratogens is alcohol. Because one-half of all pregnancies in the Us are unplanned, information technology is recommended that women of child-begetting age take great caution confronting drinking alcohol when not using nativity control and when pregnant (Surgeon General's Advisory on Alcohol Use During Pregnancy, 2005). Alcohol consumption, particularly during the second calendar month of prenatal evolution, just at any indicate during pregnancy, may lead to neurocognitive and behavioral difficulties that tin can terminal a lifetime.

There is no acceptable safe limit for alcohol use during pregnancy, but binge drinking (v or more than drinks on a unmarried occasion) or having 7 or more drinks during a single week places a child at peculiarly high take a chance. In extreme cases, booze consumption can lead to fetal death, but more ofttimes it can event infetal alcohol spectrum disorders (FASD). This terminology is now used when looking at the effects of exposure and replaces the term fetal alcohol syndrome. It is preferred because information technology recognizes that symptoms occur on a spectrum and that all individuals practise not accept the same characteristics. Children with FASD share certain physical features such equally flattened noses, small middle openings, pocket-size heads, intellectual developmental delays, and behavioral bug. Those with FASD are more at adventure for lifelong problems such as criminal behavior, psychiatric bug, and unemployment (CDC, 2006).

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, bone and eye problems.

watch it

Several medical experts deflate mutual myths virtually the safety of drinking alcohol during pregnancy.

Tobacco

Smoking is also considered a teratogen because nicotine travels through the placenta to the fetus. When the mother smokes, the developing babe experiences a reduction in blood oxygen levels. Tobacco apply during pregnancy has been associated with low birth weight, placenta previa, birth defects, preterm delivery, fetal growth brake, and sudden infant death syndrome. Smoking in the calendar month before getting meaning and throughout pregnancy increases the chances of these risks. Quitting smokingearlier getting significant is best. Withal, for women who are already meaning, quitting as early on as possible can still help protect against some wellness issues for the mother and baby.^[2]

Drugs

Prescription, over-the-counter, or recreational drugs can have serious teratogenic effects. In general, if medication is required, the everyman dose possible should be used. Combination drug therapies and outset trimester exposures should exist avoided. Almost three percent of significant women use illicit drugs such equally marijuana, cocaine, Ecstasy and other amphetamines, and heroin. These drugs can cause low birth-weight, withdrawal symptoms, nascence defects, or learning or behavioral problems. Babies born with a heroin habit demand heroin merely similar an adult addict. The child will need to be gradually weaned from the heroin under medical supervision; otherwise, the child could have seizures and die.

Environmental Chemicals

Environmental chemicals can include an exposure to a wide array of agents including pollution, organic mercury compounds, herbicides, and industrial solvents. Some environmental pollutants of major business include lead poisoning, which is connected with low nativity weight and slowed neurological development. Children who alive in older housing in which lead-based paints have been used accept been known to swallow peeling pigment fries thus being exposed to lead. The chemicals in sure herbicides are also potentially damaging. Radiations is some other environmental hazard that a pregnant woman must exist aware of. If a mother is exposed to radiation, particularly during the first 3 months of pregnancy, the child may suffer some congenital deformities. At that place is also an increased risk of miscarriage and stillbirth. Mercury leads to physical deformities and intellectual disabilities (Dietrich, 1999).

Sexually Transmitted Infections

Sexually transmitted infections (STIs) can complicate pregnancy and may have serious effects on both the mother and the developing babe. Most prenatal care today includes testing for STIs, and early on detection is of import. STIs, such equally chlamydia, gonorrhea, syphilis, trichomoniasis and bacterial vaginosis can all be treated and cured with antibiotics that are safe to have during pregnancy. STIs that are caused past viruses, like genital herpes, hepatitis B, or HIV cannot exist cured. However, in some cases these infections tin can be treated with antiviral medications or other preventive measures can be taken to reduce the hazard of passing the infection to the baby.^[three]

Maternal Diseases

Maternal illnesses increase the adventure that a baby will exist born with a birth defect or accept a chronic health problem. Some of the diseases that are known to potentially have an adverse effect on the fetus include: diabetes, cytomegalovirus, toxoplasmosis, Rubella, varicella, hypothyroidism, and Strep B. If the mother contracts Rubella during the first 3 months of pregnancy, damage can occur in the eyes, ears, heart, or brain of the unborn child. On a positive note, Rubella has been near eliminated in the industrial earth due to the vaccine created in 1969. Diagnosing these diseases early and receiving advisable medical care can help ameliorate the outcomes. Routine prenatal care now includes screening for gestational diabetes and Strep B.^[iv]

Maternal Stress

Stress represents the effects of any factor able to threaten the homeostasis of an organism; these either existent or perceived threats are referred to as the "stressors" and comprise a long list of potentially adverse factors, which can be emotional or physical. Because of a link in blood supply between a mother and fetus, it has been plant that stress tin can leave lasting effects on a developing fetus, even before a child is born. The all-time-studied outcomes of fetal exposure to maternal prenatal stress are preterm birth and low birth weight. Maternal prenatal stress is also considered responsible for a variety of changes of the child's brain, and a risk factor for weather condition such every bit 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 take a chance for a variety of immune and metabolic changes in the child such as asthma, allergic disorders, cardiovascular diseases, hypertension, hyperlipidemia, diabetes, and obesity.^[5]

Factors influencing prenatal risks

There are several considerations in determining the type and amount of harm that might consequence from exposure to a detail teratogen (Berger, 2004). These include:

• The timing of the exposure: Structures in the body are vulnerable to the nigh severe damage when they are forming. If a substance is introduced during a particular structure's disquisitional period (time of evolution), the damage to that structure may be greater. For example, the ears and arms attain their critical periods at about 6 weeks after formulation. If a mother 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 reach a certain level. The critical level depends in office on the size and metabolism of the mother.
• Genetics:Genetic make-upwards also plays a part on the touch a particular teratogen might take on the child. This is suggested by fraternal twin studies who are exposed to the same prenatal environment, all the same do non experience the aforementioned teratogenic effects. The genetic brand-up of the mother can besides have an effect; some mothers may be more resistant to teratogenic furnishings than others.
• Existence male or female: Males are more likely to experience damage due to teratogens than are females. It is believed that the Y chromosome, which contains fewer genes than the X, may have an bear upon.

Figure 6. Critical Periods of Prenatal Development.This image summarizes the three developmental periods in prenatal evolution. The blue images betoken where major development is happening and the aqua point where refinement is happening. Equally shown, the majority of organs are particularly susceptible during the embryonic period. The central nervous arrangement however continues to develop in major ways through the fetal catamenia also.

Interactive: reducing the gamble

Did you know that meaning women can meliorate outcomes for themselves and their babies through a counterbalanced diet and adequate exercise? Click through this interactive to learn more about the importance of maternal health.

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Complications of Pregnancy and Delivery

Complications of Pregnancy and Delivery

Figure seven. Pregnancy affects  women in different means; some notice few agin side effects, while others feel loftier levels of discomfort, or develop more than serious complications.

There are a number of common side effects of pregnancy. Non everyone experiences all of these nor do women experience them to the same degree. And although they are considered "minor" these problems are potentially very uncomfortable. These side furnishings include nausea (particularly during the first 3-4 months of pregnancy as a result of college levels of estrogen in the system), heartburn, gas, hemorrhoids, backache, leg cramps, insomnia, constipation, shortness of breath or varicose veins (as a issue of carrying a heavy load on the abdomen). What is the cure? Delivery!

Major Complications

The following are some serious complications of pregnancy which can pose health risks to female parent and kid and that often require special care.

• Gestational diabetesis when a woman without diabetes develops high blood sugar levels during pregnancy.
• Hyperemesis gravidarum is the presence of severe and persistent vomiting, causing aridity and weight loss. Information technology is more severe than the more common morning time sickness.
• Preeclampsia is gestational hypertension. Severe preeclampsia involves claret pressure over 160/110 with additional signs.Eclampsia is seizures in a pre-eclamptic patient.
• Deep vein thrombosis is the germination of a claret clot in a deep vein, virtually commonly in the legs.
• A meaning adult female is more susceptible to infections. This increased risk is caused past an increased immune tolerance in pregnancy to prevent an immune reaction against the fetus.
• Peripartum cardiomyopathy is a decrease in eye function which occurs in the last month of pregnancy, or upwards to half-dozen months post-pregnancy.

Maternal Mortality

Maternal mortality is unacceptably loftier. About 830 women dice from pregnancy or childbirth-related complications around the world every twenty-four hour period. It was estimated that in 2015, roughly 303,000 women died during and post-obit pregnancy and childbirth. Almost all of these deaths occurred in low-resource settings, and most could have been prevented. The high number of maternal deaths in some areas of the world reflects inequities in access to health services and highlights the gap between rich and poor. Well-nigh all maternal deaths (99%) occur in developing countries. More than half of these deaths occur in sub-Saharan Africa and almost one third occur in South asia.

Almost all maternal deaths can exist prevented, as evidenced by the huge disparities establish betwixt the richest and poorest countries. The lifetime risk of maternal death in high-income countries is one in 3,300, compared to 1 in 41 in low-income.^[6]

Figure 8. This graph shows failing maternal mortality rates, equally measured every bit the number of deaths per 100,000 alive births. in 1990, 903 out of 100,000 live births resulted in expiry in the least developed countries, but that number has improved to 436 out of 100,000 births in 2015. Globally, at that place were 216 deaths for every 100,000 alive births in 2015. Source: UNICEF, https://data.unicef.org/topic/maternal-health/maternal-mortality/.

Fifty-fifty though maternal mortality in the United States is relatively rare today considering of advanced in medical care, it is still an issue that needs to be addressed. The number of reported pregnancy-related deaths in the U.s. steadily increased from 7.2 deaths per 100,000 live births in 1987 to 18.0 deaths per 100,000 live births in 2014. The Centers for Disease Control and Prevention ascertain a pregnancy-related death as the death of a woman while pregnant or within 1 year of the end of a pregnancy–regardless of the consequence, duration, or site of the pregnancy–from whatsoever cause related to or aggravated by the pregnancy or its management, just not from accidental or incidental causes. The reasons for the overall increment in pregnancy-related bloodshed are unclear. What practice y'all think are some reasons for this surprising increase in the Us? What tin can be done to change this statistic?

Sentry It: Maternal Mortality in the united states

In the U.s., blackness women are disproportionately more than likely to die from complications related to pregnancy or childbirth than any other race; they are three or iv times more than likely than white women to dice due to pregnancy-related death and are more likely to receive worse maternal intendance.^[7] Black women from college income groups and with avant-garde education levels also take heightened risks—even tennis superstar Serena Williams had near-deadly complications during the nativity of her daughter, Olympia. Why is this the case in our modern world? Lookout this video to learn more than:

The data below shows percentages of the causes of pregnancy-related deaths in the Us during 2011–2014:

• Cardiovascular diseases, fifteen.2%.
• Non-cardiovascular diseases, 14.seven%.
• Infection or sepsis, 12.viii%.
• Hemorrhage, eleven.v%.
• Cardiomyopathy, ten.iii%.
• Thrombotic pulmonary embolism, ix.1%.
• Cerebrovascular accidents, 7.iv%.
• Hypertensive disorders of pregnancy, 6.viii%.
• Amniotic fluid embolism, 5.5%.
• Anesthesia complications, 0.iii%.

The cause of death is unknown for vi.5% of all 2011–2014 pregnancy-related deaths.^[8]

Miscarriage

Spontaneous abortion is experienced in an estimated 20-40 percent of undiagnosed pregnancies and in another 10 percent of diagnosed pregnancies. Usually, the torso aborts due to chromosomal abnormalities and this typically happens before the 12th week of pregnancy. Cramping and bleeding result and normal periods return after several months. Some women are more likely to have repeated miscarriages due to chromosomal, amniotic, or hormonal bug; but miscarriage can also be a upshot of defective sperm (Carroll et al., 2003).

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Glossary

embryo:

a multi-celled organism betwixt two and eight weeks after fertilization

fetal alcohol spectrum disorders:

a grouping of abnormalities in babies built-in to mothers who consume alcohol during pregnancy

fetus:

an unborn human baby from nine weeks after conception until nativity

mitosis:

the process of cell segmentation

placenta:

a structure connected to the uterus that provides nourishment and oxygen from the mother to the developing embryo via the umbilical cord

pregnancy-related death:

the death of a woman while significant or inside ane yr of the stop of a pregnancy from whatever cause related to or aggravated by the pregnancy

teratogen:

any agent which tin cause a birth defect

zygote:

a ane-cell structure that is created when a sperm and egg merge

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Source: https://courses.lumenlearning.com/wmopen-lifespandevelopment/chapter/prenatal-development/

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