The Prenatal Environment and Birth Complications
Gail S. Anderson in Biological Influences on Criminal Behavior, 2019
FASD is caused by prenatal exposure to alcohol. This does not mean that the baby is born addicted to alcohol, as is seen in drug-addicted babies born to drug users. Instead, prenatal alcohol results in classic teratogenic effects. A teratogen is something that causes birth defects. German measles (rubella) is a well-known example of a teratogen, and pregnant women are now tested for the antibodies to rubella. The disease of rubella itself is not generally severe, so it does not normally have much effect on a person. However, if a woman contracts it when she is pregnant, the fetus may be miscarried, or if it survives, it has a very high chance of being disabled physically and mentally. This has been recognized for decades, and in the past, if a child contracted the disease, all their friends would be invited to a German measles party to expose all the children to the mild virus and therefore give them immunity for life. In this way, the chances of a young woman developing the disease during pregnancy were greatly reduced, as she would be protected by the antibodies she had developed when she harmlessly contracted it as a child. Boys were also deliberately exposed, so they could not infect their sisters and lovers. Now, most of us are vaccinated against rubella as children and the days of German measles parties are long gone. However, protection against other, more insidious teratogens is not so simple.
Human Development and Its Theories
Mohamed Ahmed Abd El-Hay in Understanding Psychology for Medicine and Nursing, 2019
The embryo forms a protective sac (the amniotic sac) in which the embryo floats, and the umbilical cord through which nourishment, oxygen, and water flow to the embryo, and it carries away carbon dioxide and other wastes. The placenta is a vascular organ, disk-shaped, that prevents the mother’s blood from directly mixing with that of the developing embryo. It acts as a filter that prevents many, but not all harmful substances that might be present in the mother’s blood from reaching the embryo. Harmful substances that can cause birth defects or abnormal development are called teratogens. The vulnerability to teratogens is greatest during the embryonic stage, when the major body systems are forming. Known teratogens include exposure to radiation or toxic substances (e.g., mercury and lead), infection by viruses and bacteria (e.g., German measles, genital herpes, and human immunodeficiency virus), use of addictive drugs (e.g., heroin and cocaine), and some prescription drugs. Alcohol drinking during pregnancy can cause several disorders that are collectively referred to as fetal alcohol spectrum disorders (FASD), which include mental retardation, heart problems, and a number of distinctive facial features (Sokol et al., 2003). It is interesting to know that the mother’s psychological state can affect the fetus. Chronic stress, depression, and anxiety are associated with low birth weight and premature birth (Dunkel Schetter, 2011), while poor maternal nutrition, lack of sleep, and other unhealthy behaviors can affect the fetal growth and development.
Embryology of malformations
Prem Puri in Newborn Surgery, 2017
These figures probably do not reflect a real increase in the actual incidence of congenital malformations. The observed mortality shift might rather be due to improved intensive care medicine in today’s Western world countries where neonates (even those with birth defects) have a better chance of survival. On the other hand, this statistical shift indicates that knowledge about congenital malformations lags behind the progress clinical research has made in the surrounding fields. Efforts are needed to close the gap and learn more about baby killer no. 1. Identification of teratogens will help to reduce the incidence of malformations when exposure can be avoided, and pathogenetic studies might aid in designing therapeutic measures. Both treatment and prevention critically depend on basic embryological research.
Genotoxic and mutagenic studies of teratogens in developing rat and mouse
Published in Drug and Chemical Toxicology, 2019
Eyyüp Rencüzoğulları, Muhsin Aydın
Teratogens are defined as agents that cause congenital defects. The effects of these agents depend on the time of exposure of the pregnant women, the dose of the medicine, the duration of the drug exposure, and the genetic susceptibility of the person. In Environment and Birth Defects book, which was published by James G. Wilson in 1973, it was stated that chemicals kill the embryo when taken in the early embryonic period and causes structural abnormalities in the embryogenesis period (Wilson, 1973). In the same book, Wilson stated that all mutagens could not be teratogenic, but the mechanisms of teratogenesis was listed as follows: (a) mutation, (b) chromosomal breaks or nondisjunction, (c) miotic interference, (d) altered nucleic acid integrity or function, (e) lack of precursors, (f) altered energy sources, (g) enzyme inhibition, (h) fluid-osmolyte imbalance, and (i) changed membrane characteristics. This suggests that genotoxic and mutagenic agents may also be teratogenic (el-Ashmawy et al. 2011, Shreder et al. 2011, Murkunde et al. 2012, El-Shershaby et al. 2014, Carvalho et al. 2016). Similarly, Wedebye et al. (2015) reported that the germline mutations were reproductive toxic.
Review of Ilana Löwy, Imperfect Pregnancies: A History of Birth Defects & Prenatal Diagnosis
Published in The American Journal of Bioethics, 2019
Chapter 3 examines the identification of and concerns over environmental teratogens in the 1960s. This includes the rubella and thalidomide crises, which generated much concern in women who feared they would give birth to a malformed child, and ultimately led to greater sympathy and public acceptance of abortion. Löwy places her discussion in the broader context of the efforts by scientists interested in fetal malformation to rename the field of teratology as dysmorphology, with the hope it would destigmatize birth defects previously labeled as “monstrosities.” At this time, visibility of birth defects was increasing through national and international registries, created to identify unusual anomalies potentially caused by environmental teratogens. As a consequence, eliminating birth defects became a public health concern. This chapter also discusses the increase in obstetric ultrasound to identify structural fetal malformations in the 1970s and 1980s as ultrasound resolution increased and it became a routine component of prenatal care.
Oculo-auriculo-vertebral spectrum and maternal drug ingestion: cause or coincidence?
Published in Hearing, Balance and Communication, 2023
Joana Raquel Costa, Miguel Bebiano Coutinho, Teresa Soares, Luís Meireles
The present study has some limitations. First of all, this study is a retrospective one and the data used are collected from the parents’ memories which can be subjective. However, data were collected most of the time at the first consultation and, as such, shortly after birth, reducing the risk of memory bias. On the other hand, the results may reflect the teratogenic effect of the drugs used during pregnancy, but the association observed in some cases may only reflect the effects of the underlying disease. Excessive fear of drug use during pregnancy may also be detrimental, which may lead to untreated illness, non-compliance by pregnant women, use of suboptimal doses and/or failure of treatment. It is also important to bear in mind that the children evaluated were children referred to our Infant Deafness Consultation. Thus, some cases were not evaluated, such as: (1) cases that resulted in abortions during pregnancy; (2) cases of severe OAVS, who were never discharged from hospital and died in the first days or months of life; (3) cases that due to the multiple comorbidities they present are not candidates to be sent to the Infant Deafness Consultation; (4) some children with OAVS without hearing loss are not referred to an ENT consultation.
Related Knowledge Centers
- Birth Defect
- Developmental Toxicity
- Dysmorphic Feature
- Fetus
- Toxicity
- Embryo
- Development of The Human Body
- Medical Genetics
- Insult
- Fetal Alcohol Spectrum Disorder