Congenital rubella syndrome (CRS) occurs when an unborn baby is infected with the rubella virus via maternal-fetal transmission and develops birth defects. The most common congenital defects affect the ophthalmologic, cardiac, auditory, and neurologic systems.
Spina bifida /ˌspaɪnə ˈbɪfɪdə/ is a birth defect in which there is incomplete closing of the spine and the membranes around the spinal cord during early development in pregnancy. There are three main types: spina bifida occulta, meningocele and myelomeningocele. Meningocele and myelomeningocele may be grouped as spina bifida cystica. The most common location is the lower back, but in rare cases it may be in the middle back or neck.
Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology caused by teratogens. Teratogens are substances that may cause non-heritable birth defects via a toxic effect on an embryo or fetus. Defects include malformations, disruptions, deformations, and dysplasia that may cause stunted growth, delayed mental development, or other congenital disorders that lack structural malformations. The related term developmental toxicity includes all manifestations of abnormal development that are caused by environmental insult. The extent to which teratogens will impact an embryo is dependent on several factors, such as how long the embryo has been exposed, the stage of development the embryo was in when exposed, the genetic makeup of the embryo, and the transfer rate of the teratogen.
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders.
Gestational diabetes is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and of needing a Caesarean section. Babies born to mothers with poorly treated gestational diabetes are at increased risk of macrosomia, of having hypoglycemia after birth, and of jaundice. If untreated, diabetes can also result in stillbirth. Long term, children are at higher risk of being overweight and of developing type 2 diabetes.
Environmental toxicants and fetal development is the impact of different toxic substances from the environment on the development of the fetus. This article deals with potential adverse effects of environmental toxicants on the prenatal development of both the embryo or fetus, as well as pregnancy complications. The human embryo or fetus is relatively susceptible to impact from adverse conditions within the mother's environment. Substandard fetal conditions often cause various degrees of developmental delays, both physical and mental, for the growing baby. Although some variables do occur as a result of genetic conditions pertaining to the father, a great many are directly brought about from environmental toxins that the mother is exposed to.
Large for gestational age (LGA) is a term used to describe infants that are born with an abnormally high weight, specifically in the 90th percentile or above, compared to other babies of the same developmental age. Macrosomia is a similar term that describes excessive birth weight, but refers to an absolute measurement, regardless of gestational age. Typically the threshold for diagnosing macrosomia is a body weight between 4,000 and 4,500 grams, or more, measured at birth, but there are difficulties reaching a universal agreement of this definition.
Complications of pregnancy are health problems that are related to, or arise during pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal disorders. While some complications improve or are fully resolved after pregnancy, some may lead to lasting effects, morbidity, or in the most severe cases, maternal or fetal mortality.
A vertically transmitted infection is an infection caused by pathogenic bacteria or viruses that use mother-to-child transmission, that is, transmission directly from the mother to an embryo, fetus, or baby during pregnancy or childbirth. It can occur when the mother has a pre-existing disease or becomes infected during pregnancy. Nutritional deficiencies may exacerbate the risks of perinatal infections. Vertical transmission is important for the mathematical modelling of infectious diseases, especially for diseases of animals with large litter sizes, as it causes a wave of new infectious individuals.
Maternal use of androgens or high doses of certain weakly androgenic synthetic progestogens (progestins) structurally related to testosterone can masculinize (virilize) the vulva of a female fetus during susceptible times in pregnancy.
For pregnant women with diabetes, some particular challenges exist for both mother and fetus. If the pregnant woman has diabetes as a pre-existing disorder, it can cause early labor, birth defects, and larger than average infants. Therefore, experts advise diabetics to maintain blood sugar level close to normal range about 3 months before planning for pregnancy.
Neural tube defects (NTDs) are a group of birth defects in which an opening in the spine or cranium remains from early in human development. In the third week of pregnancy called gastrulation, specialized cells on the dorsal side of the embryo begin to change shape and form the neural tube. When the neural tube does not close completely, an NTD develops.
Fetal surgery also known as antenatal surgery, prenatal surgery, is a growing branch of maternal-fetal medicine that covers any of a broad range of surgical techniques that are used to treat congenital abnormalities in fetuses who are still in the pregnant uterus. There are three main types: open fetal surgery, which involves completely opening the uterus to operate on the fetus; minimally invasive fetoscopic surgery, which uses small incisions and is guided by fetoscopy and sonography; and percutaneous fetal therapy, which involves placing a catheter under continuous ultrasound guidance.
Metabolic imprinting refers to the long-term physiological and metabolic effects that an offspring's prenatal and postnatal environments have on them. Perinatal nutrition has been identified as a significant factor in determining an offspring's likelihood of it being predisposed to developing cardiovascular disease, obesity, and type 2 diabetes amongst other conditions.
Women should speak to their doctor or healthcare professional before starting or stopping any medications while pregnant. Non-essential drugs and medications should be avoided while pregnant. Tobacco, alcohol, marijuana, and illicit drug use while pregnant may be dangerous for the unborn baby and may lead to severe health problems and/or birth defects. Even small amounts of alcohol, tobacco, and marijuana have not been proven to be safe when taken while pregnant. In some cases, for example, if the mother has epilepsy or diabetes, the risk of stopping a medication may be worse than risks associated with taking the medication while pregnant. The mother's healthcare professional will help make these decisions about the safest way to protect the health of both the mother and unborn child. In addition to medications and substances, some dietary supplements are important for a healthy pregnancy, however, others may cause harm to the unborn child.
Maternal obesity refers to obesity of a woman during pregnancy. Parental obesity refers to obesity of either parent during pregnancy.
Prenatal nutrition addresses nutrient recommendations before and during pregnancy. Nutrition and weight management before and during pregnancy has a profound effect on the development of infants. This is a rather critical time for healthy development since infants rely heavily on maternal stores and nutrient for optimal growth and health outcome later in life.
Developmental toxicity is any developmental malformation that is caused by the toxicity of a chemical or pathogen. It is the structural or functional alteration, reversible or irreversible, which interferes with homeostasis, normal growth, differentiation, development or behavior. Developmental toxicity is caused by environmental insult, which includes drugs, alcohol, diet, toxic chemicals, and physical factors.
A high-risk pregnancy is one where the mother or the fetus has an increased risk of adverse outcomes compared to uncomplicated pregnancies. No concrete guidelines currently exist for distinguishing “high-risk” pregnancies from “low-risk” pregnancies; however, there are certain studied conditions that have been shown to put the mother or fetus at a higher risk of poor outcomes. These conditions can be classified into three main categories: health problems in the mother that occur before she becomes pregnant, health problems in the mother that occur during pregnancy, and certain health conditions with the fetus.
Wladimir Wertelecki is a Pediatrician and Medical Geneticist who in 1974 established one of the first free-standing Departments of Medical Genetics at the new South Alabama University College of Medicine in Mobile, Alabama, U.S.A. Since 1996 and following his retirement as Chairman and Emeritus Professor of Medical Genetics, Pediatrics, and Pathology, he has continued his investigations of developmental anomalies and their prevention as a Project Scientist at the Department of Pediatrics, University of California San Diego. Since 1996, his research has focused mainly on alcohol and ionizing radiation impacts on congenital anomalies. He is the author over 135 scientific reports. In 2000, he established the OMNI-Net Ukraine Programs to investigate reproductive risks posed by exposures to alcohol and Chornobyl ionizing radiation. OMNI-Net Ukraine established a population-based registry for the epidemiological surveillance of congenital anomalies. It qualified to become full member of EUROCAT, a network of over 38 such registries across Europe. OMNI-Net Ukraine is the sole full member of EUROCAT conducting such investigations in regions formerly ruled by the USSR. OMNI-Net Ukraine also implements a variety of collaborative investigations with experts from UCSD, Emory, and other Universities sponsored by the Collaborative Initiative on Fetal Alcohol Spectrum Disorders funded by then National Institute on Alcohol Abuse and Alcoholism (NIH). Many components of the OMNI-Net Ukraine programs introduced by Wertelecki were previously implemented in Alabama. He established a regional network of clinics across southern Alabama and West Florida and in 1978 organized the Southern Genetic Group, which expanded into the South-Eastern Regional Genetics Group, enhancing genetic services in six states. Wertelecki also contributed to the efforts by local Native-Americans to gain Federal Recognition as Native-Americans in Alabama. In 1992, he made a presentation to the US Senate regarding the reproductive risks posed by the Chornobyl radiation. Following an initial sponsorship by USAID, he established OMNI-Net programs in Ukraine, a not-for-profit network to provide training and to engage Ukrainian professionals to conduct monitoring of the frequency of birth defects. OMNI-Net teams promptly detected an epidemic of spina bifida and associated malformations collectively known as neural tube defects (NTD). The frequency of these malformations and the associated child mortality are persistently the highest in Europe. From the start, OMNI-Net advocates for Ukrainian authorities to introduce folic acid fortification programs, a measure that will significantly reduce the epidemic and related mortality. Flour fortification with folic acid is safe, effective and affordable as shown by implementations adopted by 80 countries. Currently, a legislative initiative to establish an NTD prevention program is under consideration by the Ukrainian National Parliament. OMNI-Net has also documented that thousands of pregnant women continue to accumulate in their bodies through eating, drinking, and inhaling radioactive elements (nuclides). Whole body counts of incorporated Cs-137 by pregnant women are much higher than in women residing away from Chornobyl radiation impacted regions. OMNI-Net teams seek national and international partners to elucidate the inherent risks of such facts. Although some reports state that Chornobyl radiation is not biologically harmful, OMNI-Net researchers note that such studies did not include pregnant women with known levels of incorporated nuclides. The association of incorporated levels of Cs-137 with prevalence of birth defects remains to be clarified. Another frequent known cause of birth defects in Ukraine is alcohol consumption by pregnant women. Since 2006, OMNI-Net has implemented an international initiative focused on fetal alcohol spectrum disorders. In summary, OMNI-Net is effectively a catalist for joint scientific collaborations of Ukrainian and International investigations.
