Anthropometry Anthropometry () refers to the measurement of the human individual. An early tool of physical anthropology, it has been used for identification, for the purposes of understanding human physical variation, in paleoanthropology and in various atte ...

is defined as the

scientific study Scientific study is a kind of study that involves scientific theory, scientific models, experiments and physical situations. It may refer to: *Scientific method, a body of techniques for investigating phenomena, based on empirical or measurabl ...

of the

human body The human body is the structure of a Human, human being. It is composed of many different types of Cell (biology), cells that together create Tissue (biology), tissues and subsequently organ systems. They ensure homeostasis and the life, viabi ...

measurements and proportions. These studies are generally used by

clinicians A clinician is a health care professional typically employed at a skilled nursing facility or clinic. Clinicians work directly with patients rather than in a laboratory or as a researcher. A clinician may diagnose, treat, and otherwise care for pat ...

and

pathologists A list of people notable in the field of pathology. A * John Abercrombie, Scottish physician, neuropathologist and philosopher. * Maude Abbott (1869–1940), Canadian pathologist, one of the earliest women graduated in medicine, expert in co ...

for adequate assessments of the growth and development of the

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal deve ...

at any specific point of gestational maturity. Fetal height, fetal weight, head circumference (HC), crown to rump length (CR), dermatological observations like skin thickness etc. are measured individually to assess the growth and development of the

organs In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a fu ...

and the fetus as a whole and can be a parameter for normal or abnormal

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped *Photographi ...

also including adaptation of the fetus to its newer environment. Another important factor that contributes towards the anthropometric measurement of the human fetal growth is the

maternal nutrition Nutrition and pregnancy refers to the nutrient intake, and dietary planning that is undertaken before, during and after pregnancy. Nutrition of the fetus begins at conception. For this reason, the nutrition of the mother is important from before co ...

and maternal well-being.

Malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is "a deficiency, excess, or imbalance of energy, protein and other nutrients" which adversely affects the body's tissues a ...

, as already established by

WHO Who or WHO may refer to: * Who (pronoun), an interrogative or relative pronoun * Who?, one of the Five Ws in journalism * World Health Organization Arts and entertainment Fictional characters * Who, a creature in the Dr. Seuss book ''Horton Hear ...

, is a global serious health problem not only in adults but in

pregnant Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

and

lactating Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...

mothers too and is a serious problem in

third world countries The term "Third World" arose during the Cold War to define countries that remained non-aligned with either NATO or the Warsaw Pact. The United States, Canada, Japan, South Korea, Western European nations and their allies represented the "First W ...

. In

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

and

South Asia South Asia is the southern subregion of Asia, which is defined in both geographical and ethno-cultural terms. The region consists of the countries of Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.;;;;;;;; ...

, 27%-50% of women in the reproductive age are

underweight An underweight person is a person whose body weight is considered too low to be healthy. A person who is underweight is malnourished. Assessment The body mass index, a ratio of a person's weight to their height, has traditionally been used t ...

resulting in 30 million

low birth weight Low birth weight (LBW) is defined by the World Health Organization as a birth weight of an infant of or less, regardless of gestational age. Infants born with LBW have added health risks which require close management, often in a neonatal intensi ...

babies. For decades, the topic of question pertaining to crown-rump length (CR), crown-heel length (CH), head circumference (HC) with respect to the body weight of human fetus at different time periods of

gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...

has baffled many developmental researchers and

biostatisticians Biostatistics (also known as biometry) are the development and application of statistical methods to a wide range of topics in biology. It encompasses the design of biological experiments, the collection and analysis of data from those experimen ...

. These biological variations are all based on linear curves based on human fetuses between 9 and 28 weeks of gestation.

Co-relation of fetal weight and fetal growth

Body weight Human body weight is a person's mass or weight. Strictly speaking, body weight is the measurement of weight without items located on the person. Practically though, body weight may be measured with clothes on, but without shoes or heavy accessor ...

, for example, is an important function and parameter for growth with respect to

gestational age In obstetrics, gestational age is a measure of the age of a pregnancy which is taken from the beginning of the woman's last menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method if available. Suc ...

of the fetus. There will be great variations in the body

weight In science and engineering, the weight of an object is the force acting on the object due to gravity. Some standard textbooks define weight as a Euclidean vector, vector quantity, the gravitational force acting on the object. Others define weigh ...

of a 16 weeks old fetus. The weight will not be constant for every fetus and will vary from individual to individual. Therefore, rather than an appropriate or standard value, a range can be specified like 90 to 100 grams. This number of variations applies to all other anthropometric measurements. Often, the scientific world cover up their ignorance by stating that the rate of growth of particular human fetus depends on its intrinsic growth potential and environment provided by the normal mother. It is a visible function of the genetic potential. The fetal growth is not an individual growth and is dependent on the composite growth of the organs. Growth of the individual organs is controlled by the genetic potential, the environment provided by the mother and by the fetus itself. Scientists have or are trying to determine such relationships through series of investigations. Streetr, Schults et al., all studied the fetal dimensions obtained from

spontaneous abortions Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is fetal viability, able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE a ...

and pathological

pregnancies Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but can ...

on mainly formed and fixed specimens. The growth of an organ from inception to a definitive functional stage is dependent on the integrated function of the whole organism which depends on a number of parameters such as the

nucleic acid Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main cl ...

content of the cells which is one of the most important factors. Functioning of an organ is important for development of the organism. A Nigerian study showed that the birth weight of the human fetus also depends upon the

size Size in general is the Magnitude (mathematics), magnitude or dimensions of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to linear dimensions (length, width, height, diameter, perimeter), area, or volume ...

and weight of the mother including her height and weight. Further a Polish study reported a similar report that some measurements like the ear height, muscular strength of the shoulders, skin fold thickness, mandibular breadth including the height of the upper and the lower limbs can be co-related to the mother also. Similar observations were also reported by Gueri et al. One of the first original and unique works to be conducted on the anthropometric measurement of the human fetus in the Indian context was conducted by a group of scientists in

Calcutta Kolkata (, or , ; also known as Calcutta , List of renamed places in India#West Bengal, the official name until 2001) is the Capital city, capital of the Indian States and union territories of India, state of West Bengal, on the eastern ba ...

between 1977 and 1987 under the supervision of K.L.Mukherjee, a stalwart in the field of medical

biochemistry Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and ...

in Institute of Post Graduate Medical Education and Research. The researchers divided the fetuses into 6 groups consisting of A, B, C, D, E and F with a difference of 4 weeks of gestation period among the 6 groups. Group A had 90 fetuses of 9–12 weeks of gestation and the weight varied between 1-14 grams. Group B had 337 fetuses, age 13–16 weeks of gestation with weight variation between 15 and 105 grams whereas the third group had 435 fetuses of 17–20 weeks of gestation with a weight range between 106 and 310 grams. Group D consisted of 531 fetuses of 21–24 weeks and weight between 331 and 640 grams and Group E had fetuses of the age range 25–28 weeks of gestation and weight 640-1070

gram The gram (originally gramme; SI unit symbol g) is a Physical unit, unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram. Originally defined as of 1795 as "the absolute weight of a volume of pure wate ...

s. The last two groups F and G had fetuses with gestation period between 29-32 and 33–36 weeks. All aborted fetuses were collected after permission from the institute

ethics committee An ethics committee is a body responsible for ensuring that medical experimentation and human subject research are carried out in an ethical manner in accordance with national and international law. Specific regions An ethics committee in the E ...

followed with donor consent form with primary objective being the aborted mother's health and safety.

Liver growth

Researchers observed that the

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

weight is directly proportional to the body weight. At 8–12 weeks of gestation, liver is a relatively bigger organ which forms 4-5-5.5% of the total body weight and protrudes through the abdominal wall. By 13 to 32 weeks of gestation, it forms 3.4% to 4.0% of the total body weight. The liver weight hence forms a more or less constant proportion of the total body weight of the fetus.

Growth of the lung

Although in adult life, the

lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...

is the only major respiratory organ, in case of fetal life such is not the case though the fetal lung is known to expand and contract in the last phase of development. Both the weight of the right and left lungs are normally assessed at different periods of gestation and is expressed as a function of the total body weight. An irregular graph was observed by K.L.Mukherjee and his group instead of the standard normal linear graphs which should be normally observed after plotting a graph of weight of the lungs expressed as gm/kg of body weight against the body weight. This relationship was observed from fetuses weighing 350 grams to 850 grams after which the rate of the growth became uniformly proportional again.

Brain and Central nervous System

Brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

and the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...

are the two most important components of the fetus. Further analysis by this same group involved the CNS up to the

medulla Medulla or Medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ovary * Medulla of th ...

at 2nd cervical vertebral level. The process of analyzing the fetal brain and the CNS involved dissecting out the whole brain tissue followed by decantation of an 8.5 weeks old fetal brain weighing 15 grams. The brain at this time had already assumed the appearance of primary divisions and flexures, and the prosen, messen and rhombocephalon already gave rise to the different brain-derived constituents like rhinocephalon, corporastriata,

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...

, hypo and

epithalamus The epithalamus is a posterior (dorsal) segment of the diencephalon. The epithalamus includes the habenular nuclei and their interconnecting fibers, the habenular commissure, the stria medullaris and the pineal gland. Functions The function of ...

and pons medulla to a less differentiation extent. The growth of the fetal brain from this time onwards was proportional to the body weight although some brains from other groups showed variations at the same stage between 20% and even 12% or 13% of the body weight by and large. Scientists are still yet to find an explanation for this.

Kidney and the Adrenal Glands

In the early gestational period, the weight of the

adrenal gland The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which ...

s outweighs even the metanephric kidneys and is comparatively a larger organ. After the 10th week of gestation, the kidney grows at a much rapid rate than the adrenal glands. Hence with an increase in gestational time, i.e. by the 12th week of gestation, both the

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...

s and adrenal glands measure the same. Post 12 weeks the kidneys measure more than the adrenal glands. However, the Adrenal gland is a larger organ in the fetus than the adult. The same group of researchers further observed that with the increase of fetal age, the adrenal glands also weigh more as observed by the research group in 90 human fetuses. However, the rate of increase is not uniform and varies throughout the fetal growth like other organs.

Human fetal testes

The growth of the fetal

testes A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoster ...

is not uniform as revealed through various other studies. The weight of the right testes weighed more than the weight of the left testes. Exceptions were however noticed in some of the cases as reported by K.L.Mukherjee and his group. Normally like all other organs the growth of the testes including its weight also increases with increase in the gestational period. The research group through their graph plot studies further examined that the growth of testes was not uniform with proportional growth at the initial stages. It soon flattened to increase with different spikes consistently throughout the whole length of the gestational period. Further the weight of the human testes marked as mg/100 gram of body weight was investigated and was observed that there was a steep decline in the early gestation period from about 200 mg/100 gram of body weight to roughly about 60 mg/ 100 gram of body weight when the fetal weight was about 1.5 grams to 20 grams. In the case of a 1.6-kilogram fetus, the testes weighed only 20 mg/100 gram of body weight. This decline was however not maintained uniformly.

Growth of the Human fetal ovaries

A steep decline in the ovarian weight in the early gestational period was observed though it was not a uniformly maintained decline. With increase in the gestational time, progressive weight of the

ovaries The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...

was found and in most cases, the weight of the ovaries was identical to the weight of the fetuses although some exceptions were observed by the group.

Fetal Thymus growth

At 8 weeks of gestation when the fetus weighed 1 gram, the

thymus The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, thymus cell lymphocytes or ''T cells'' mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. ...

could not be detected. In many of the 39 fetuses weighing around 1.3-14.7 grams, the thymus tissues could not be dissected by the group especially in the smaller fetuses due to its non-detection. Fetuses weighing more than or equal to 5 grams could be detected. Plotting a graph it was observed that thymus organ formed 52 mg/100 gram of body weight in case of a 5 gram fetus. Further study on 28 fetuses weighing 15 to 100 grams revealed the thymic weight to be 77 mg per 100 grams of the body weight. The relative growth of the thymus was more in this group compared to all the earlier observations. A further group including 39 fetuses weighing between 100 and 300 grams showed a fetal thymic weight between 136 mg/100 gram to 77 mg/ 100 gram. In fetuses up to 28 weeks, it was observed by scientists that the fetal thymic weight was the highest and was in contrast to many other organs like brain, liver which constitute more or less constant proportion of the body weight with very few exceptions. Therefore, it was inferred that with an increase in the gestational period, the thymic weight also increase although exceptions were observed.

Conclusion

Growth and development throughout the fetal life are two most important factors which determine the growth rate of each individual and their specific organs. This process of maturation and development of the organs are observed in postnatal life also. With an increase in gestational time, the fetal organs also grow in progression to the body weight, the phenomenon which is still not understood clearly by many researchers. Some believe that genetic potentiality of the different

endocrine organs The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neu ...

related to the growth and various other unidentified processes mediate the whole phenomenon.

References

External links

* * * *{{cite web, url=https://www.cdc.gov/nchs/data/nhanes/nhanes3/cdrom/nchs/manuals/anthro.pdf , title=Body Measurements (Anthropometry) Manual , website=Cdc.gov , format=PDF , access-date=2016-11-23 Human biology