Human fetus at eight weeks. A small part of the placenta is shown at the bottom, while the fluid-filled amnion surrounds it. For the alien race in Stephen Donaldson 's The Gap Cycle, see Amnion (Gap Cycle.

A fetus (or foetus or fœtus) is a developing mammal or other viviparous vertebrate, after the embryonic stage and before birth. Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands A viviparous Animal is an animal employing vivipary: the embryo develops inside the body of the mother as opposed to outside in an egg ( Ovipary Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular Childbirth (also called labour, birth, partus or parturition) is the culmination of a Human Pregnancy or The plural is fetuses, or sometimes feti. The fetal stage of prenatal development starts when the major structures have formed, and lasts until birth. Prenatal development is the process in which an embryo or fetus (or foetus) gestates during Pregnancy, from fertilization ^[1]

In humans, the fetal stage of prenatal development starts at approximately the beginning of the 9th week after fertilization, which is equivalent to the start of the eleventh week in "gestational age. Prenatal development is the process in which an embryo or fetus (or foetus) gestates during Pregnancy, from fertilization For soil improvement see Fertilization (soil. Gestational age is usually considered to be the age of an Embryo or Fetus (or newborn infant from the first day of the woman's last menstrual period (LMP "^[2][3]

Etymology and spelling variations

The word fetus is from the Latin fetus, meaning offspring, bringing forth, hatching of young. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. ^[4] It has Indo-European roots related to sucking or suckling. Breastfeeding is the feeding of an Infant or young Child with Breast milk directly from human Breasts, not from a Baby bottle or other ^[5]

Fœtus is an English variation on the Latin spelling, and has been in use since at least 1594, according to the Oxford English Dictionary, which describes "fœtus" as "incorrectly written". The Oxford English Dictionary ( OED) published by the Oxford University Press (OUP is a comprehensive Dictionary of the English The variant fœtus may have originated with an error by Saint Isidore of Seville, in AD 620. Saint Isidore of Seville ( Spanish: es ''San Isidro'' or es ''San Isidoro de Sevilla'' Latin: latin ''Isidorus Hispalensis'' (c ^[6] The preferred spelling in the United States is fetus, but the variants foetus and fœtus persist in other English-speaking countries and in some medical contexts, as well as in some other languages (e. g. , French).

Human fetus

Selection from "Views of a Fetus in the Womb", a drawing by Leonardo da Vinci. Leonardo di ser Piero da Vinci ( April 15 1452 – May 2 1519 was an Italian Polymath, having been a scientist Mathematician, Engineer

The fetal stage starts at the beginning of the 9th week following fertilization, after the zygote, blastocyst, and embryonic stages. For soil improvement see Fertilization (soil. For other meanings see Zygote (disambiguation. A zygote (from Greek ζυγωτός zugōtos "joined" or "yoked" The blastocyst is the structure formed in early Embryogenesis, after the formation of the Blastocoel, but before Implantation. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular The risk of miscarriage decreases sharply at the beginning of the fetal stage. ^[7] The fetus is not as sensitive to damage from environmental exposures as the embryo was, though toxic exposures can often cause physiological abnormalities or minor congenital malformation. Fetal growth can be terminated by various factors, including miscarriage, feticide committed by a third party, or induced abortion. Miscarriage or spontaneous abortion is the natural or spontaneous end of a Pregnancy at a stage where the embryo or fetus is incapable of surviving generally defined Feticide or foeticide is an act that causes the death of a fetus An

Development

The following describes some of the specific changes in fetal anatomy and physiology by fertilization age (i. Anatomy (from the Greek anatomia, from ana separate apart from and temnein, to cut up cut open is a branch of Biology that is the consideration Physiology (from Greek grc φύσις physis, "nature origin" and grc -λογία -logia) is the study of the mechanical physical e. the time elapsed since fertilization). Obstetricians often use "gestational age" which, by convention, is measured from 2 weeks earlier than fertilization. Gestational age is usually considered to be the age of an Embryo or Fetus (or newborn infant from the first day of the woman's last menstrual period (LMP For purposes of this article, age is measured from fertilization rather than from two weeks earlier, except as noted.

Condition at start of fetal stage

Artist's depiction of fetus 8 weeks after fertilization. The crown-rump length is 1. Crown-rump length is usually abbreviated as CRL. It is the measurement of the length of human Embryos and Fetuses from the top of the head (crown to the 25 inches. ^[8]

The fetal stage commences at the beginning of the 9th week after fertilization (i. e. at the beginning of the 11th week of gestational age). Gestational age is usually considered to be the age of an Embryo or Fetus (or newborn infant from the first day of the woman's last menstrual period (LMP ^[3] At the start of the fetal stage, the fetus is typically about 30 mm (1. 2 inches) in length from crown to rump, and weighs about 8 grams. ^[3] The head makes up nearly half of the fetus' size. ^[9] Breathing-like movement of the fetus is necessary for stimulation of lung development, rather than for obtaining oxygen. ^[10] The heart is beating. ^[11]

The heart, hands, feet, brain and other organs are present, but are not developed sufficiently for the fetus to survive on its own. ^[12] The fetus is surrounded by amniotic fluid which offers protection and allows room for movement. Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the Amnion of a pregnant woman The pregnant woman's placenta and umbilical cord provide oxygen, nutrients, and allow waste elimination. The placenta is an Ephemeral organ present in placental Vertebrates, such as Eutherial Mammals and Sharks during Gestation In placental Mammals the umbilical cord (also called the birth cord or funiculus umbilicalis) is the connecting cord from the developing Embryo ^[12]

According to current data, fetuses are not capable of feeling pain at the beginning of the fetal stage. ^[13][14] At this point, complex and generalized movements occur. ^[15]

9th to 15th weeks

From weeks 9 to 12, the fetal eyelids close and remain closed for several months, and the appearance of the genitals in males and females becomes more apparent. ^[16] Tooth buds appear, the limbs are long and thin, and red blood cells are produced in the liver, however the majority of red blood cells will be made later in gestation (at 21 weeks) by bone marrow. A limb (from the Old English lim) is a jointed or Prehensile (as Octopus tentacles or new world Monkey tails Appendage of the Red blood cells are the most common type of Blood cell and the Vertebrate body's principal means of delivering Oxygen to the body tissues via the Blood The liver is a vital organ in the human body and is present in Vertebrates and some other animals ^[9] A fine hair called lanugo develops on the head. Lanugo is fine downy Hair; it is a type of Pelage. In humans Fetal development The gastrointestinal tract, still forming, starts to collect sloughed skin and lanugo, as well as hepatic products, forming meconium (stool). Meconium is the earliest ^[9] Fetal skin is almost transparent. The skin is the outer covering of living tissue of an animal (or plant The first measurable signs of EEG movement occur in the 12th week. ^[17] By the end of this stage, the fetus has reached about 15 cm (6 inches).

16th to 25th weeks

Artist's depiction of fetus at 18 weeks after fertilization, about 6. 5 inches crown to rump.

The lanugo covers the entire body. Lanugo is fine downy Hair; it is a type of Pelage. In humans Fetal development Eyebrows, eyelashes, fingernails, and toenails appear. The fetus has increased muscle development. Alveoli (air sacs) are forming in lungs. An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity The nervous system develops enough to control some body functions. The nervous system is a Network of specialized cells that communicate information about an animal's surroundings and itself The cochlea are now developed, though the myelin sheaths in the neural portion of the auditory system will continue to develop until 18 months after birth. The cochlea is the auditory portion of the Inner ear. Its core component is the Organ of Corti, the sensory organ of hearing, which is distributed along Myelin is an electrically-insulating Dielectric Phospholipid layer that surrounds only the Axons of many Neurons It is an outgrowth The respiratory system has developed to the point where gas exchange is possible. A woman pregnant for the first time (i. e. a primiparous woman) typically feels fetal movements at about 18-19 weeks, whereas a woman who has already given birth at least two times (i. e. a multiparous woman) will typically feel movements around 16 weeks. ^[18] By the end of the fifth month, the fetus is about 20 cm (8 inches).

26th to 38th weeks

Artist's depiction of fetus at 38 weeks after fertilization, about 20 inches head to toe.

The amount of body fat rapidly increases. Lungs are not fully mature. Thalamic brain connections, which mediate sensory input, form. The thalamus (from Greek θάλαμος = room chamber, IPA= /ˈθæləməs/ is a pair and symmetric part of the brain Bones are fully developed, but are still soft and pliable. Iron, calcium, and phosphorus become more abundant. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Fingernails reach the end of the fingertips. The lanugo begins to disappear, until it is gone except on the upper arms and shoulders. Small breast buds are present on both sexes. Thelarche is the first stage of secondary (postnatal Breast development usually occurring at the beginning of Puberty in girls Head hair becomes coarse and thicker. Birth is imminent and occurs around the 38th week. The fetus is considered full-term between weeks 35 and 40,^[19] which means that the fetus is considered sufficiently developed for life outside the uterus. ^[20] It may be 48 to 53 cm (19 to 21 inches) in length, when born.

Variation in growth

See also: Birth weight

There is much variation in the growth of the fetus. Birth weight is the weight of a baby at its birth. It has direct links with the Gestational age at which the child was born and can be estimated When fetal size is less than expected, that condition is known as intrauterine growth restriction (IUGR) also called fetal growth restriction (FGR); factors affecting fetal growth can be maternal, placental, or fetal. The placenta is an Ephemeral organ present in placental Vertebrates, such as Eutherial Mammals and Sharks during Gestation ^[21]

Maternal factors include maternal weight, body mass index, nutritional state, emotional stress, toxin exposure (including tobacco, alcohol, heroin, and other drugs which can also harm the fetus in other ways), and uterine blood flow. In the Physical sciences weight is a Measurement of the gravitational Force acting on an object The body mass index ( BMI) or Quetelet index, is a statistical measurement which compares a person's weight and height Tobacco is an Agricultural product recognized as an addictive drug processed from the fresh Leaves of plants in the genus Nicotiana. In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon Heroin ( INN: diacetylmorphine, BAN: diamorphine) is a semi-synthetic opioid synthesized from Morphine, a derivative

Placental factors include size, microstructure (densities and architecture), umbilical blood flow, transporters and binding proteins, nutrient utilization and nutrient production.

Fetal factors include the fetus genome, nutrient production, and hormone output. Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body Also, female fetuses tend to weigh less than males, at full term. ^[21]

Fetal growth is often classified as follows: small for gestational age (SGA), appropriate for gestational age (AGA), and large for gestational age (LGA). ^[22] SGA can result in low birth weight, although premature birth can also result in low birth weight. Low birth weight increases risk for perinatal mortality (death shortly after birth), asphyxia, hypothermia, polycythemia, hypocalcemia, immune dysfunction, neurologic abnormalities, and other long-term health problems. Death is the termination of the biological functions that define living Organisms It refers both to a specific Hypothermia is a condition in which an organism's temperature drops below that required for normal Metabolism and bodily functions Polycythemia (or polycythaemia or erythrocytosis) is a condition in which there is a net increase in the total number of Blood cells, primarily Red In Medicine, hypocalcaemia is the presence of low serum Calcium levels in the Blood, usually taken as less than 2 Autoimmunity is the failure of an organism to recognize its own constituent parts as self, which results in an immune response against its own cells and tissues SGA may be associated with growth delay, or it may instead be associated with absolute stunting of growth.

3D ultrasound of 3-inch fetus (about 12 weeks after fertilization)

3D ultrasound at 17 weeks

3D ultrasound at 20 weeks

Viability

The lower limit of viability is approximately five months gestational age, and usually later. 3D ultrasound is a Medical ultrasound technique used during Pregnancy, providing three dimensional images of the Fetus. Gestational age is usually considered to be the age of an Embryo or Fetus (or newborn infant from the first day of the woman's last menstrual period (LMP ^[23] According to The Developing Human:

Viability is defined as the ability of fetuses to survive in the extrauterine environment. . . There is no sharp limit of development, age, or weight at which a fetus automatically becomes viable or beyond which survival is assured, but experience has shown that it is rare for a baby to survive whose weight is less than 500 gm or whose fertilization age is less than 22 weeks. Even fetuses born between 26 and 28 weeks have difficulty surviving, mainly because the respiratory system and the central nervous system are not completely differentiated. . . If given expert postnatal care, some fetuses weighing less than 500 gm may survive; they are referred to as extremely low birth weight or immature infants. . . . Prematurity is one of the most common causes of morbidity and prenatal death. ^[24]

During the past several decades, neonatal care has improved with advances in medical science, and therefore the point of viability may have moved earlier. ^[25] As of 2006, the two youngest children to survive premature birth are thought to be James Elgin Gill (born on 20 May 1987 in Ottawa, Canada, at 21 weeks and 5 days gestational age),^[26][27] and Amillia Taylor (born on 24 October 2006 in Miami, Florida, at 21 weeks and 6 days gestational age). Premature birth (also known as preterm birth) is the Birth of a Baby before the standard period of Pregnancy is completed Events 325 - The First Council of Nicaea &ndash the first Ecumenical Council of the Christian Church is held Year 1987 ( MCMLXXXVII) was a Common year starting on Thursday (link displays 1987 Gregorian calendar) Ottawa (ˈɒtəwə or sometimes /ˈɒtəwɑː/ is the Capital of Canada and the country's fourth largest municipality. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Events 69 - Second Battle of Bedriacum, forces under Antonius Primus the commander of the Danube armies loyal to Vespasian, defeat Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the ^[28][29][30] Both children were born just under 20 weeks from fertilization, or a few days past the midpoint of an average full-term pregnancy. Despite their premature births, both developed into healthy children.

Fetal pain

Main article: Fetal pain

Fetal pain, its existence, and its implications are debated politically and academically. Fetal pain, its existence and its implications are part of a larger debate about Abortion. According to the conclusions of a review published in 2005, "Evidence regarding the capacity for fetal pain is limited but indicates that fetal perception of pain is unlikely before the third trimester. "^[13][14] However, there may be an emerging consensus among developmental neurobiologists that the establishment of thalamocortical connections" (at about 26 weeks) is a critical event with regard to fetal perception of pain. Neurobiology is the study of cells of the Nervous system and the organization of these cells into functional circuits that process information and mediate behavior The thalamus (from Greek θάλαμος = room chamber, IPA= /ˈθæləməs/ is a pair and symmetric part of the brain ^[31] Nevertheless, because pain can involve sensory, emotional and cognitive factors, it is "impossible to know" when painful experiences may become possible, even if it is known when thalamocortical connections are established. ^[31]

Whether a fetus has the ability to feel pain and to suffer is part of the abortion debate. Pain, in the sense of physical pain, is a typical sensory experience that may be described as the unpleasant awareness of a noxious stimulus or bodily harm Suffering, or pain, is an individual's basic Affective experience of unpleasantness and aversion associated with harm or threat of harm An ^{[32] [33]} For example, in the USA legislation has been proposed by pro-life advocates requiring abortion providers to tell a woman that the fetus may feel pain during the abortion procedure, and that require her to accept or decline anesthesia for the fetus. Overview See also Ethical aspects of abortion Pro-life individuals generally believe that human life should be valued either from conception or Implantation ^[34]

Fetal movement

Main article: Fetal movement

The parts of the fetal brain that control movement will not fully form until late in the second trimester, and the first part of the third trimester. Fetal movement refers to motion of a Fetus caused by its own Muscle activity ^[35] Control of movement is limited at birth, and purposeful voluntary movements develop in the first year after birth. ^[36][37]

Locomotor activity begins during the late embryonic stage, and changes in nature throughout development. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular Prenatal development is the process in which an embryo or fetus (or foetus) gestates during Pregnancy, from fertilization Muscles begin to move as soon as they are innervated. A nerve is an enclosed cable-like bundle of peripheral Axons (the long slender projections of Neurons. These first movements are not reflexive, but arise from nerve impulses originating in the spinal cord. The spinal cord is a long thin tubular bundle of Nerves that is an extension of the Central nervous system from the brain and is enclosed in and protected As the nervous system matures, muscles can move in response to stimuli, though this is not a voluntary movement. The nervous system is a Network of specialized cells that communicate information about an animal's surroundings and itself ^[38]

Quickening is the first maternally discernible fetal movement, which is often felt around the middle of pregnancy. In Pregnancy terms the moment of quickening refers to the initial motion of the Fetus in the Uterus as it is perceived or felt by the pregnant woman Women who have already given birth have more relaxed uterine muscles that are consequently more sensitive to fetal motion, and for them fetal motion can sometimes be felt as early as 14 weeks. ^[39]

Complex and generalized movements occur at the beginning of the fetal stage, with movements and startles that involve the whole body. These movements occur as muscles and neural pathways begin to develop^[15] Movement of hands, hips and knees have been observed at nine weeks,^[40] stretches and yawns at ten weeks,^[41] and isolated limb movements beginning shortly thereafter. ^[15]

Circulatory system

Diagram of the human fetal circulatory system. This is an article about the rock music band "Circulatory System"

The circulatory system of a human fetus works differently from that of born humans, mainly because the lungs are not in use: the fetus obtains oxygen and nutrients from the mother through the placenta and the umbilical cord. This is an article about the rock music band "Circulatory System" Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the The placenta is an Ephemeral organ present in placental Vertebrates, such as Eutherial Mammals and Sharks during Gestation In placental Mammals the umbilical cord (also called the birth cord or funiculus umbilicalis) is the connecting cord from the developing Embryo ^[42]

Blood from the placenta is carried to the fetus by the umbilical vein. The umbilical vein is a Blood vessel present during fetal development that carries Oxygenated Blood from the Placenta to the growing Fetus About half of this enters the fetal ductus venosus and is carried to the inferior vena cava, while the other half enters the liver proper from the inferior border of the liver. In the Fetus, the ductus venosus shunts a significant majority (80% of the blood flow of the Umbilical vein directly to the Inferior vena cava. The inferior vena cava (or IVC is the large Vein that carries de-oxygenated Blood from the lower half of the body into the Heart. The liver is a vital organ in the human body and is present in Vertebrates and some other animals The branch of the umbilical vein that supplies the right lobe of the liver first joins with the portal vein. The blood then moves to the right atrium of the heart. The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic In the fetus, there is an opening between the right and left atrium (the foramen ovale), and most of the blood flows through this hole directly into the left atrium from the right atrium, thus bypassing pulmonary circulation. In the fetal Heart, the foramen ovale (or ostium secundum of Born allows blood to enter the left atrium from the right atrium Pulmonary circulation is the portion of the Cardiovascular system which carries Oxygen -depleted Blood away from the heart to the Lungs, and The continuation of this blood flow is into the left ventricle, and from there it is pumped through the aorta into the body. Some of the blood moves from the aorta through the internal iliac arteries to the umbilical arteries, and re-enters the placenta, where carbon dioxide and other waste products from the fetus are taken up and enter the woman's circulation. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single ^[42]

Some of the blood entering the right atrium does not pass directly to the left atrium through the foramen ovale, but enters the right ventricle and is pumped into the pulmonary artery. In the fetal Heart, the foramen ovale (or ostium secundum of Born allows blood to enter the left atrium from the right atrium The pulmonary arteries carry Blood from the Heart to the Lungs. In the fetus, there is a special connection between the pulmonary artery and the aorta, called the ductus arteriosus, which directs most of this blood away from the lungs (which aren't being used for respiration at this point as the fetus is suspended in amniotic fluid). In the developing Fetus, the ductus arteriosus ( DA) is a shunt connecting the Pulmonary artery to the aortic arch that allows most Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the Amnion of a pregnant woman ^[42]

Postnatal development

Main article: Adaptation to extrauterine life

With the first breath after birth, the system changes suddenly. At the end of Pregnancy, the Fetus must take the journey of Childbirth to leave the Reproductive Female mother The pulmonary resistance is dramatically reduced ("pulmo" is from the Latin for "lung"). lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive More blood moves from the right atrium to the right ventricle and into the pulmonary arteries, and less flows through the foramen ovale to the left atrium. In the fetal Heart, the foramen ovale (or ostium secundum of Born allows blood to enter the left atrium from the right atrium The blood from the lungs travels through the pulmonary veins to the left atrium, increasing the pressure there. The decreased right atrial pressure and the increased left atrial pressure pushes the septum primum against the septum secundum, closing the foramen ovale, which now becomes the fossa ovalis. This completes the separation of the circulatory system into two halves, the left and the right.

The ductus arteriosus normally closes off within one or two days of birth, leaving behind the ligamentum arteriosum. The umbilical vein and the ductus venosus closes off within two to five days after birth, leaving behind the ligamentum teres and the ligamentum venosus of the liver respectively. The ligamentum venosum is the fibrous remnant of the Ductus venosus of the Fetal circulation.

Differences from the adult circulatory system

Remnants of the fetal circulation can be found in adults:^[43][44]

In addition to differences in circulation, the developing fetus also employs a different type of oxygen transport molecule than adults (adults use adult hemoglobin). In the Fetus, the ductus venosus shunts a significant majority (80% of the blood flow of the Umbilical vein directly to the Inferior vena cava. The ligamentum venosum is the fibrous remnant of the Ductus venosus of the Fetal circulation. In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species The umbilical artery is a paired artery (with one for each half of the body that is found in the abdominal and pelvic regions The umbilical artery is a paired artery (with one for each half of the body that is found in the abdominal and pelvic regions The internal iliac artery (formerly known as the hypogastric artery) is the main Artery of the Pelvis. In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species The medial umbilical ligament is a paired structure found in human Anatomy. The urachus is an embryological canal connecting the Urinary bladder of the fetus with the Allantois, a structure that contributes to the formation of the umbilical Hemoglobin ( also spelled haemoglobin and abbreviated Hb or Hgb) is the Iron -containing Oxygen -transport Metalloprotein Fetal hemoglobin enhances the fetus' ability to draw oxygen from the placenta. Its association curve to oxygen is shifted to the left, meaning that it will take up oxygen at a lower concentration than adult hemoglobin will. This enables fetal hemoglobin to absorb oxygen from adult hemoglobin in the placenta, which has a lower pressure of oxygen than at the lungs.

Developmental problems

See also: Congenital disorder

Congenital anomalies are anomalies that are acquired before birth. A congenital disorder is a disease or disorder that is present at birth Infants with certain congenital anomalies of the heart can survive only as long as the ductus remains open: in such cases the closure of the ductus can be delayed by the administration of prostaglandins to permit sufficient time for the surgical correction of the anomalies. A prostaglandin is any member of a group of Lipid compounds that are derived enzymatically from Fatty acids and have important functions in the Animal body Conversely, in cases of patent ductus arteriosus, where the ductus does not properly close, drugs that inhibit prostaglandin synthesis can be used to encourage its closure, so that surgery can be avoided. Patent ductus arteriosus ( PDA) is a Congenital Heart defect wherein a child's Ductus arteriosus fails to close after birth.

A developing fetus is highly susceptible to anomalies in its growth and metabolism, increasing the risk of birth defects. One area of concern is the pregnant woman's lifestyle choices made during pregnancy ^[45] Diet is especially important in the early stages of development. Studies show that supplementation of the woman's diet with folic acid reduces the risk of spina bifida and other neural tube defects. Folic acid (also known as Vitamin M and Folacin) and Folate (the Anionic form are forms of the water-soluble Vitamin B9 Spina bifida ( Latin: "split spine" is a developmental Birth defect involving the Neural tube: incomplete closure of the Embryonic neural In the developing vertebrate the neural tube is the Embryo 's precursor to the Central nervous system, which comprises the Brain and Spinal cord Another dietary concern is whether the woman eats breakfast. Skipping breakfast could lead to extended periods of lower than normal nutrients in the woman's blood, leading to a higher risk of prematurity, or other birth defects in the fetus. During this time alcohol consumption may increase the risk of the development of Fetal alcohol syndrome, a condition leading to mental retardation in some infants. History Historical references Anecdotal accounts of prohibitions against maternal alcohol use from biblical, ancient Greek, and ancient Roman Mental retardation is a generalized triarchic disorder characterized by subaverage cognitive functioning and deficits in two or more adaptive behaviors with onset before the age ^[46] Smoking during pregnancy may also lead to reduced birth weight. Low birth weight is defined as 2500 grams (5. 5 lb). Low birth weight is a concern for medical providers due to the tendency of these infants, described as premature by weight, to have a higher risk of secondary medical problems.

Legal issues

Main articles: Abortion Debate and Fetal rights

In the United States, some states have laws that impose strict punishments for those who inflict violence that results in damage to a fetus or the unwanted termination of a pregnancy. The abortion debate refers to discussion and controversy surrounding the moral and legal status of Abortion. The term fetal rights can refer either to legal rights accorded to Fetuses or to ethical rights of fetuses The severity of the punishment, and the stage of fetal development where laws start to apply vary from state to state. ^[47]

Abortion of a fetus is legal in many countries such as Australia, Canada, Mexico, UK and USA. Abortion law is legislation which pertains to the provision of Abortion. Many of those countries that allow abortion during the fetal stage have gestational time limits, so that late-term abortions are not normally allowed. Late-term abortions are Abortions which are performed during a later stage of Pregnancy. ^[48]

Non-human fetuses

Histological slice of a rat fetus at E17 from BrainMaps.org

The fetus of most mammals develops similarly to the Homo sapiens fetus. Histology (from the Greek = 'tissue' is the study of the microscopic anatomy of cells and tissues of Plants and Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus After the first stages of development, the human embryo reaches a stage very similar to all other vertebrates. ^[49] The anatomy of the area surrounding a fetus is different in litter-bearing animals compared to humans: each fetus is surrounded by placental tissue and is lodged along one of two long uteri instead of the single uterus found in a human female. Tissue is a cellular organizational level intermediate between cells and a complete organism Development at birth is similar, with animals also having a poorly developed sense of vision and other senses.

See also

• Prenate
• Embryo
• Pregnancy
• Child
• Superfetation
• Neural development
• Fetoscopy
• Fetal position
• Fetal rights
• Womens rights

References

External links

• High Resolution Nissl-stained Rat Fetus