Dana Is Seven Weeks Pregnant. In Which Stage of Prenatal Development Is Her Baby?

What y'all'll larn to do: explain the main stages of prenatal evolution

How did you come up to be who y'all are? From kickoff as a one-cell construction to your birth, your prenatal development occurred in an orderly and delicate sequence. There are three stages of prenatal development: germinal, embryonic, and fetal. Continue in listen that this is different than the 3 trimesters of pregnancy. Let's have a expect at what happens to the developing infant 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
• Explicate potential complications of pregnancy and commitment

Prenatal Evolution

"The body of the unborn baby is more than circuitous than ours. The preborn baby has several extra parts to his body which he needs just so long every bit he lives inside his mother. He has his own space sheathing, the amniotic sac. He has his own lifeline, the umbilical string, and he has his own root system, the placenta. These all belong to the baby himself, not to his mother. They are all developed from his original prison cell."^[1]

Periods of Prenatal Development

Permit's take a await at some of the changes that take place during each of the 3 periods of prenatal evolution: the germinal period, the embryonic period, and the fetal period.

The Germinal Menses (Weeks one-2)

Figure i. Sperm and Ovum at Conception

Formulation occurs when a sperm fertilizes an egg and forms azygote, which begins equally a one-prison cell structure. The mother and father's DNA is passed on to the kid at the moment of conception. The genetic makeup and sexual practice of the baby are set at this bespeak. The germinal period (nigh 14 days in length) lasts from conception to implantation of the zygote (fertilized egg) in the lining of the uterus.

During the start week later on conception, the zygote divides and multiplies, going from a one-cell structure to ii cells, and then four cells, then 8 cells, and so on. The process of cell division is chosen mitosis. Later on the quaternary division, differentiation of the cells begins to occur as well. Differentiated cells get more specialized, forming different organs and body parts.  After 5 days of mitosis, in that location are 100 cells, and later nine months there are billions of cells. Mitosis is a frail process, and fewer than one-half of all zygotes survive across the commencement two weeks (Hall, 2004).

Afterwards the zygote divides for about 7–ten days and has 150 cells, it travels downward the fallopian tubes and implants itself in the lining of the uterus. It's estimated that well-nigh 60 percent of natural conceptions fail to implant in the uterus. The rate is higher for in vitro conceptions. In one case the zygote attaches to the uterus, the adjacent stage begins.

The Embryonic Catamenia (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 later on formulation. Upon implantation, this multi-cellular organism is chosen anembryo. Now blood vessels grow, forming the placenta. Theplacenta is a structure connected to the uterus that provides nourishment and oxygen from the mother to the developing embryo via the umbilical cord.

During this period, cells go along to differentiate. Bones structures of the embryo outset to develop into areas that will become the head, chest, and abdomen. During the embryonic phase, the heart begins to beat and organs course and begin to part. At 22 days after formulation, the neural tube forms along the back of the embryo, developing into the spinal cord and brain.

Growth during prenatal evolution occurs in two major directions: from head to tail (cephalocaudal development) and from the midline outward (proximodistal development). This ways that those structures nearest the head develop earlier those nearest the feet and those structures nearest the torso develop earlier those away from the heart of the body (such as hands 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. Only past 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 iv grams at the end of this period. The embryo can move and reply 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 menstruation, often the mother does not even so know that she is pregnant. It is during this stage that the major structures of the torso are taking grade making the embryonic period the time when the organism is most vulnerable to the greatest corporeality of impairment if exposed to harmful substances. Potential mothers are not often aware of the risks they innovate to the developing child during this fourth dimension.

The Fetal Period (Weeks ix-twoscore)

Figure three. A fetus at 10 weeks of development.

When the organism is near 9 weeks one-time, the embryo is chosen a fetus. At this stage, the fetus is about the size of a kidney bean and begins to take on the recognizable form of a homo being as the "tail" begins to disappear.

From 9–12 weeks, the sexual practice organs begin to differentiate. By the 12th week, the fetus has all its body parts including external genitalia. In the following weeks, the fetus volition develop hair, nails, teeth and the excretory and digestive systems will continue to develop. At the end of the 12th week, the fetus is about three inches long and weighs nigh 28 grams.

At about 16 weeks, the fetus is approximately iv.5 inches long. Fingers and toes are fully adult, and fingerprints are visible. During the iv-sixth months, the optics become more sensitive to light and hearing develops. The respiratory organization continues to develop. Reflexes such equally sucking, swallowing and hiccuping develop during the fifth month. Cycles of sleep and wakefulness are present at that time as well. Throughout the fetal stage, the encephalon continues to grow and develop, nearly doubling in size from weeks 16 to 28. The bulk of the neurons in the brain have adult by 24 weeks although they are still rudimentary and the glial or nurse cells that support neurons continue to grow. At 24 weeks the fetus can feel pain (Royal College of Obstetricians and Gynecologists, 1997).

The first run a risk of survival outside the womb, known equally the age of viability is reached at nearly 22 to 26 weeks (Moore & Persaud, 1998). Past the time the fetus reaches the 6th month of development (24 weeks), it weighs up to ane.4 pounds. The hearing has developed, and so the fetus tin answer to sounds. The internal organs, such equally the lungs, eye, stomach, and intestines, have formed enough that a fetus born prematurely at this betoken has a take a chance to survive outside of the mother's womb.

Between the 7th and ninth months, the fetus is primarily preparing for nascency. It is exercising its muscles, its lungs begin to expand and contract. It is developing fat layers under the skin. The fetus gains about 5 pounds and 7 inches during this last 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 trunk temperature afterward birth.

Around 36 weeks, the fetus is near ready for birth. Information technology weighs about 6 pounds and is well-nigh 18.5 inches long, and by week 37 all of the fetus's organ systems are developed plenty that it could survive exterior the mother'south uterus without many of the risks associated with premature birth. The fetus continues to gain weight and grow in length until approximately forty weeks. By then, the fetus has very little room to move around and nativity becomes imminent.

Figure 4. During the fetal stage, the baby's brain develops and the trunk adds size and weight until the fetus reaches total-term development.

Watch It

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

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Ecology Risks

Teratology

Good prenatal care is essential. The developing kid is most at risk for some of the near severe problems during the commencement three months of development. Unfortunately, this is a time at which most mothers are unaware that they are pregnant. Information technology is estimated that x% of all nativity 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 as well include ecology and occupational exposures. Today, we know many of the factors that can jeopardize the health of the developing kid. Teratogen-caused birth defects are potentially preventable.

The study of factors that contribute to birth defects is chosen teratology. Teratogens are usually discovered after an increased prevalence of a particular nascency defect. For example, in the early 1960'south, a drug known as thalidomide was used to treat morn sickness. Exposure of the fetus during this early on phase of evolution resulted in cases of phocomelia, a built malformation in which the easily and anxiety are fastened to abbreviated artillery and legs.

A Look at Some Teratogens

Booze

Figure v. Some distinguishing characteristics of fetal alcohol spectrum disorders include more narrow centre openings, A smoothen philtrum, pregnant a smoothen area between the upper lip and the nose, and a sparse upper lip.

One of the almost commonly used teratogens is alcohol. Because half of all pregnancies in the United States are unplanned, it is recommended that women of child-bearing historic period take great caution against drinking alcohol when not using birth control and when pregnant (Surgeon General's Advisory on Booze Use During Pregnancy, 2005). Alcohol consumption, particularly during the 2d month of prenatal evolution, but at any point during pregnancy, may lead to neurocognitive and behavioral difficulties that can last a lifetime.

There is no adequate safe limit for alcohol use during pregnancy, just binge drinking (5 or more drinks on a single occasion) or having 7 or more drinks during a single week places a child at particularly high adventure. In extreme cases, alcohol consumption tin pb to fetal expiry, but more frequently it can result infetal alcohol spectrum disorders (FASD). This terminology is now used when looking at the furnishings of exposure and replaces the term fetal alcohol syndrome. It is preferred because it recognizes that symptoms occur on a spectrum and that all individuals do non accept the same characteristics. Children with FASD share certain physical features such as flattened noses, small eye openings, small heads, intellectual developmental delays, and behavioral problems. Those with FASD are more at chance for lifelong problems such as criminal behavior, psychiatric bug, and unemployment (CDC, 2006).

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

watch information technology

Several medical experts debunk common myths about the condom of drinking booze during pregnancy.

Tobacco

Smoking is also considered a teratogen because nicotine travels through the placenta to the fetus. When the mother smokes, the developing baby experiences a reduction in claret oxygen levels. Tobacco use 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 month before getting pregnant and throughout pregnancy increases the chances of these risks. Quitting smokingbefore getting pregnant is best. All the same, for women who are already pregnant, quitting as early on every bit possible can even so help protect against some wellness problems 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 lowest dose possible should be used. Combination drug therapies and offset trimester exposures should be avoided. Almost 3 percentage of pregnant women use illicit drugs such as marijuana, cocaine, Ecstasy and other amphetamines, and heroin. These drugs can cause low birth-weight, withdrawal symptoms, nascency defects, or learning or behavioral problems. Babies born with a heroin habit need 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

Ecology chemicals tin 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 organisation include lead poisoning, which is connected with low birth weight and slowed neurological development. Children who alive in older housing in which lead-based paints take been used accept been known to consume peeling paint chips thus being exposed to lead. The chemicals in sure herbicides are as well potentially damaging. Radiations is another environmental hazard that a pregnant woman must be enlightened of. If a mother is exposed to radiation, especially during the first three months of pregnancy, the child may suffer some congenital deformities. There is as well an increased risk of miscarriage and stillbirth. Mercury leads to concrete deformities and intellectual disabilities (Dietrich, 1999).

Sexually Transmitted Infections

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

Maternal Diseases

Maternal illnesses increase the chance that a baby will be born with a birth defect or have a chronic health trouble. Some of the diseases that are known to potentially have an agin effect on the fetus include: diabetes, cytomegalovirus, toxoplasmosis, Rubella, varicella, hypothyroidism, and Strep B. If the mother contracts Rubella during the get-go three months of pregnancy, damage can occur in the eyes, ears, heart, or brain of the unborn child. On a positive note, Rubella has been virtually eliminated in the industrial world due to the vaccine created in 1969. Diagnosing these diseases early and receiving appropriate medical care can help improve the outcomes. Routine prenatal care now includes screening for gestational diabetes and Strep B.^[4]

Maternal Stress

Stress represents the effects of any cistron able to threaten the homeostasis of an organism; these either real or perceived threats are referred to as the "stressors" and comprise a long list of potentially adverse factors, which can exist emotional or physical. Considering of a link in blood supply between a mother and fetus, information technology has been establish that stress can leave lasting effects on a developing fetus, fifty-fifty earlier a child is born. The best-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 multifariousness of changes of the kid's brain, and a chance factor for conditions such as behavioral problems, learning disorders, loftier levels of anxiety, attention deficit hyperactivity disorder, autism, and schizophrenia. Furthermore, maternal prenatal stress has been associated with a college take a chance for a variety of immune and metabolic changes in the child such every bit asthma, allergic disorders, cardiovascular diseases, hypertension, hyperlipidemia, diabetes, and obesity.^[five]

Factors influencing prenatal risks

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

• The timing of the exposure: Structures in the trunk are vulnerable to the near astringent damage when they are forming. If a substance is introduced during a particular structure's critical menses (time of development), the damage to that construction may be greater. For example, the ears and arms reach their critical periods at well-nigh 6 weeks after conception. If a mother exposes the embryo to certain substances during this menstruum, the artillery and ears may exist malformed.
• The amount of exposure:Some substances are not harmful unless the amounts reach a certain level. The disquisitional level depends in function on the size and metabolism of the female parent.
• Genetics:Genetic make-up also plays a role on the impact a particular teratogen might have on the child. This is suggested by fraternal twin studies who are exposed to the same prenatal surround, withal do not experience the same teratogenic effects. The genetic make-up of the mother tin also have an effect; some mothers may exist more resistant to teratogenic furnishings than others.
• Being male or female person: Males are more probable to feel damage due to teratogens than are females. Information technology is believed that the Y chromosome, which contains fewer genes than the X, may have an impact.

Figure 6. Critical Periods of Prenatal Development.This epitome summarizes the 3 developmental periods in prenatal evolution. The blue images bespeak where major development is happening and the aqua signal where refinement is happening. Equally shown, the bulk of organs are especially susceptible during the embryonic catamenia. The central nervous organisation withal continues to develop in major ways through the fetal period as well.

Interactive: reducing the risk

Did you know that pregnant women tin can amend outcomes for themselves and their babies through a balanced diet and adequate do? Click through this interactive to learn more about the importance of maternal wellness.

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Complications of Pregnancy and Commitment

Complications of Pregnancy and Delivery

Effigy seven. Pregnancy affects  women in unlike ways; some notice few agin side effects, while others experience loftier levels of discomfort, or develop more serious complications.

There are a number of common side furnishings of pregnancy. Not everyone experiences all of these nor practice women experience them to the aforementioned caste. And although they are considered "minor" these problems are potentially very uncomfortable. These side furnishings include nausea (especially during the first 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 belly). What is the cure? Commitment!

Major Complications

The following are some serious complications of pregnancy which tin pose wellness risks to mother and child and that often crave special care.

• Gestational diabetesis when a adult female without diabetes develops loftier claret sugar levels during pregnancy.
• Hyperemesis gravidarum is the presence of astringent and persistent vomiting, causing aridity and weight loss. It is more astringent than the more common morn sickness.
• Preeclampsia is gestational hypertension. Astringent preeclampsia involves blood pressure over 160/110 with additional signs.Eclampsia is seizures in a pre-eclamptic patient.
• Deep vein thrombosis is the formation of a blood clot in a deep vein, nearly unremarkably in the legs.
• A pregnant woman is more susceptible to infections. This increased chance is caused past an increased immune tolerance in pregnancy to prevent an immune reaction confronting the fetus.
• Peripartum cardiomyopathy is a decrease in middle function which occurs in the last month of pregnancy, or upwardly to vi months post-pregnancy.

Maternal Bloodshed

Maternal mortality is unacceptably high. Nearly 830 women die from pregnancy or childbirth-related complications effectually the world every day. It was estimated that in 2015, roughly 303,000 women died during and post-obit pregnancy and childbirth. Nearly 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. Near 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 tin can exist prevented, every bit evidenced by the huge disparities institute betwixt the richest and poorest countries. The lifetime take a chance of maternal death in loftier-income countries is i in 3,300, compared to 1 in 41 in low-income.^[6]

Figure viii. This graph shows failing maternal mortality rates, equally measured as the number of deaths per 100,000 live births. in 1990, 903 out of 100,000 live births resulted in death in the least developed countries, but that number has improved to 436 out of 100,000 births in 2015. Globally, there were 216 deaths for every 100,000 live births in 2015. Source: UNICEF, https://information.unicef.org/topic/maternal-wellness/maternal-mortality/.

Even though maternal mortality in the The states is relatively rare today considering of advanced in medical care, information technology is still an effect that needs to be addressed. The number of reported pregnancy-related deaths in the United States steadily increased from 7.2 deaths per 100,000 alive births in 1987 to 18.0 deaths per 100,000 live births in 2014. The Centers for Disease Control and Prevention define a pregnancy-related decease as the death of a woman while pregnant or within 1 year of the end of a pregnancy–regardless of the outcome, elapsing, or site of the pregnancy–from whatever cause related to or aggravated by the pregnancy or its management, but non from accidental or incidental causes. The reasons for the overall increase in pregnancy-related mortality are unclear. What practice yous think are some reasons for this surprising increase in the The states? What can be done to modify this statistic?

Lookout Information technology: Maternal Mortality in the united States

In the United States, black women are disproportionately more than likely to die from complications related to pregnancy or childbirth than whatever other race; they are iii or 4 times more likely than white women to die due to pregnancy-related decease and are more than probable to receive worse maternal care.^[seven] Black women from higher income groups and with advanced educational activity levels likewise have heightened risks—even lawn tennis superstar Serena Williams had near-deadly complications during the birth of her daughter, Olympia. Why is this the case in our modern earth? Watch this video to learn more:

The information below shows percentages of the causes of pregnancy-related deaths in the United States during 2011–2014:

• Cardiovascular diseases, 15.2%.
• Non-cardiovascular diseases, fourteen.seven%.
• Infection or sepsis, 12.8%.
• Hemorrhage, 11.v%.
• Cardiomyopathy, x.3%.
• Thrombotic pulmonary embolism, nine.1%.
• Cerebrovascular accidents, seven.4%.
• Hypertensive disorders of pregnancy, 6.eight%.
• Amniotic fluid embolism, 5.5%.
• Anesthesia complications, 0.three%.

The cause of death is unknown for 6.five% of all 2011–2014 pregnancy-related deaths.^[8]

Miscarriage

Spontaneous abortion is experienced in an estimated 20-xl percentage of undiagnosed pregnancies and in another 10 pct of diagnosed pregnancies. Usually, the body aborts due to chromosomal abnormalities and this typically happens before the twelfth week of pregnancy. Cramping and bleeding result and normal periods return subsequently several months. Some women are more likely to have repeated miscarriages due to chromosomal, amniotic, or hormonal problems; but miscarriage can too be a issue of defective sperm (Carroll et al., 2003).

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Glossary

embryo:

a multi-celled organism between ii and eight weeks after fertilization

fetal booze spectrum disorders:

a group of abnormalities in babies born to mothers who consume alcohol during pregnancy

fetus:

an unborn human baby from ix weeks subsequently conception until birth

mitosis:

the process of cell division

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 pregnant or within ane year of the stop of a pregnancy from any cause related to or aggravated by the pregnancy

teratogen:

any amanuensis which tin can cause a birth defect

zygote:

a 1-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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