Teratology : Science that studies fetal malformations caused by exposure to chemical substances, biological, environmental factors, physical agents, deficiencies and socioeconomic factors during pregnancy. From the Greek teras monster, and logos study, the word was coined by the Frenchman Geoffroy St Hilaire in 1832 in his treatise on human and animal malformations.

Teratogen : any substance, organism, physical agent or deficiency state that being present during pregnancy leads to structural or functional alterations in the offspring.

Teratogenesis : refers to the origin and manifestation of embryo-fetal structural damage, is a process that depends on the dose of the harmful agent. Every substance is potentially teratogenic in the appropriate dose, in small doses usually does not cause any damage.

Malformation : structural defect caused by a major defect of development.

Major malformation (up to 3% of births): lethal, life-threatening or severely disabled the bearer.

Minor malformation (up to 14% of births): generates mild disability or only has cosmetic effects.

Deformation : alteration of the shape or structure of a previously normal organ. Example, deformation of a fetal foot by position in the uterus.

Disruption : stop the normal development of an organ, depends on time, not on external agents.

Syndrome : pattern of multiple recognized malformations with a known etiology.

The Teratology Society is the world authority in research, education and prevention of newborn defects.

Mother to Baby: follow this link to get detailed information about medications, chemicals and other conditions that could affect your baby. Never make decisions based on this information without the concurrence of a qualified specialist.

Teratogenesis: degrees of fetal damage

The degree of injury depends on the period during which the exposure occurs, the dose and time of use of the harmful agent and the genetic susceptibility of the mother and her embryo. Not all exposure to a teratogenic agent leads inexorably to severe embryo-fetal damage and one must be very careful in evaluating each particular case. We have received many inquiries from fatigued parents who consider the termination of pregnancy due to inadequate information regarding exposure to potential teratogens of viral origin, chemicals, drugs and ionizing radiation.

The spectrum of the consequences of exposure, in order from highest to lowest frequency , is as follows:

Newborn normal

Fetal growth compromised

Malformation

Embryo-fetal death

As you can see, the usual thing is that nothing happens. A healthy baby is the most frequent option after exposure to a known teratogen.

I Aneuploidies

The human cell nucleus contains 46 chromosomes, 44 somatic chromosomes and 2 sex chromosomes that determine the sex of the individual. This conformation is called Euploidy. The chromosomal study is called Karyotype and there are only two: Female 46, XX and Male 46, XY

Aneuploidies are numerical chromosomal disorders, that is, excess or defects in the number of chromosomes in the human cell and the syndromes they produce. They constitute 95% of the chromosomal problems of the progeny, they are widely known and occur randomly without hereditary trait and scarce risk of recurrence in future pregnancies. These syndromes can be detected by genetic ultrasound and diagnosed by chorionic villus biopsy or amniocentesis. There are non-invasive tests that are based on the detection and study of fetal DNA in maternal blood (cffDNA), they are expensive but they give a lot of peace of mind.

Down Syndrome (47, XX [XY], + 21):

Popularly known as Mongolism (this term is considered pejorative and should be abandoned) for its distinctive Asian features, it is due to the presence of three somatic chromosomes 21, Trisomy 21, due to an error in the cell division of the maternal ovule or gamete. It is the most frequent aneuploidy because the survival rate is relatively high. The manifestations include mental retardation in variable degree, congenital defects in multiple organs and susceptibility to certain types of cancer. They can be trained to a variable degree to integrate them into the social and economic environment, allowing them a certain degree of independence. Survive around 50 years. An extra portion of chromosome 21 can give rise to the syndrome, only accounts for 5% of cases

Edwards syndrome (47, XX [XY], + 18):

It is due to the transmission of 3 chromosomes 18 to the progeny, Trisomy 18, due to a defect in the female cell division of the gamete similar to that which occurs in Down Syndrome. The structural and functional defects are very severe and usually prevent an independent life and without continuous monitoring by parents or guardians. Survival is very limited due to the large malformations they suffer, the average life is 15 days after birth and the maximum age reported is 10 years. Cardiac malformations are the main cause of morbidity and mortality. Mental retardation is severe. 1 in 6000 births

Patau syndrome (47, XX [XY], + 13):

It is due to the transmission of 3 chromosomes 13 to the progeny by mistake in the cell division of the female gamete. It is extremely severe and includes obvious and severe physical malformations in multiple organs and systems. It is the worst of the trisomies diagnosable. Survival is similar to Edwards Syndrome, less than 10% of newborns reach one year of age. Frequency: 1 in 15,000 births, which indicates a small frequency of births with the syndrome and high mortality in utero. The most severe craniofacial malformation of the syndrome was the origin of the mythological being known as Cyclops, a single frontal eye with a kind of frontal protuberance known as proboscide.

Turner syndrome (45, X0):

This syndrome is due to the lack of a sexual chromosome in a girl, therefore instead of having two X chromosomes has only one, denoting 45, X0. In this case the problem of the transmission or functionality of the chromosome can be derived from both the mother and the father. The main characteristics are short stature due to skeletal development disorders, infertility due to early ovarian failure, cervical fins and some congenital cardiovascular problems. There is no mental retardation and survival is basically normal. Although the Turner is relatively benign, in postnatal life, it is estimated that in utero mortality is 99%. Frequency 1: 2000 live births.

Triploidy:

It is due to the presence of 69 chromosomes due to the lack of meiotic disjunction (meiosis is the process by which sex cells generate cells with half the chromosome charge) of some of the gametes. This means that one of the gametes had complete chromosomal charge of 46 chromosomal instead of the normal 23. Another option is that an egg has been fertilized by 2 sperm. Both the man (sperm) and the woman (ovum) can give rise to the disorder although it is more frequent in men than in women. Fetal development is fraught with problems and the fetus manifests large malformations from very early stages of pregnancy: growth retardation, malformacines cardiac and CNS, craniofacial anomalies, motor dysfunction, limb disorders and high intrauterine and postnatal mortality if a birth occurs I live under these conditions 1: 57,000. Triploidy is the cause of Molar Pregnancy

II Genetic syndromes

This is a heterogeneous group of hundreds of diseases of genetic origin, with the potential to be transmitted from generation to generation in a hereditary way or of recent appearance by mutations in the genetic sequence contained in some portion of any chromosome, not the complete chromosome, as happens in aneuploidies. The spectrum of problems ranges from the simple alteration in the perception of color (color blindness) to severe disability or pre or postnatal death. Many of these diseases do not have antenatal manifestations and it is not possible to detect them through routine studies. Amniocentesis could provide the diagnostic element of the disease if one can search for the specific genetic component (DNA sequence of the gene / genes) that gives rise to it. This is not routine and the studies that are practiced are aimed at families with backgrounds.

With the development of methods for the detection of free fetal DNA (cell free fetal DNA, cffDNA) in maternal blood (weeks 10-12), an infinity of chromosomal disorders and frequent genetic syndromes can be ruled out. If you need information you can contact me, the costs vary depending on the amount of diseases discarded but they vary between USD $ 600 to $ 1200.

The most frequent genetic syndromes are:

Cystic fibrosis of the pancreas

Huntington’s Korea

Hemoglobinopathies: Sickle Cells and Thalassemias

Hemophilia and coagulation disorders

Muscular dystrophies