Teratogenic Birth Defects

Congenital malformations or teratogenic birth defects are developmental disorders that arise before birth during the embryonic or fetal period. The rate of incidence for children born alive is approximately 3%. The cause may be genetic or contingent on external influences or teratogens. Teratogens are environmental factors that result in permanent structural or functional malformations, or the death of the embryo or fetus. Teratogens include infections, certain medications, drugs, and radiation.

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Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Table of Contents

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Epidemiology

  • Incidence rate of malformations: 4%–6%
    • 2%–3% of all newborns
    • 2%–3% of children < 5 years of age
  • Malformations are the most common cause of child mortality (approximately 21%) and the primary cause of disabilities.
  • A direct cause is only known in 40%–60% of cases:
    • 15%: genetic factors (e.g., chromosomal anomalies and mutations)
    • 10%: teratogens
    • 20%–25%: a combination of genetic and external factors
    • 0.5%–1%: development of twins

Classification

Primary malformations:

  • Occur during organogenesis (3rd to 8th week of gestation)
  • Complete or partial organ failure
  • Structural defects (e.g., agenesis)

Secondary malformations:

  • Occur via destruction or alteration of already developing organs
  • E.g., intestinal atresia, defects in the amniotic bands

Double malformations or “Siamese twins:”

Two fetuses that have grown together due to incomplete intertwining of the embryoblast in the blastocyst stage (13th day):

  • Symmetrical double malformation: Both fetuses have a complete set of organs.
  • Asymmetrical malformation: Uneven allocation leads to the uneven development of both fetuses.

Terminology

  • Agenesis: an organ that has not developed
  • Aplasia: organ develops with defective differentiation → regression or loss of function
  • Hypoplasia: organ grows insufficiently → functional disabilities
  • Hyperplasia: organ grown too large → functional disabilities
  • Dysplasia: abnormal cell differentiation
  • Dystopia: An organ is not located in its normal physiological location.
  • Heterotopia: Typically differentiated tissue is found dispersed in ≥ 1 nontypical location in the body.
  • Choristia: embryonic tissue in a nontypical location
  • Deformations: mechanical forces affecting the locomotor system (e.g., clubfoot)
  • Dysraphism: defective closure of the neural tube (e.g., spina bifida)
  • Stenosis: constriction within a hollow organ
  • Atresia: absence or occlusion of the lumen of a hollow organ
  • Syndromes include multiple malformations with the same cause and in a characteristic combination (e.g., Down syndrome Down syndrome Down syndrome, or trisomy 21, is the most common chromosomal aberration and the most frequent genetic cause of developmental delay. Both boys and girls are affected and have characteristic craniofacial and musculoskeletal features, as well as multiple medical anomalies involving the cardiac, gastrointestinal, ocular, and auditory systems. Down Syndrome).
  • Persistence: continued existence of an organ or part of an organ which, physiologically, only exists for a limited period during embryonic development
  • Association: frequent appearance of ≥ 2 malformations with an unknown shared cause

Pathophysiology

The development of malformations varies throughout different stages of embryological/fetal development and is referred to as phase-dependent vulnerability.

  • Gametopathy: preconception impairment of the maternal or paternal gamete → structural or numerical chromosome defects → abortion
  • Blastopathy: impairments of the fertilized blastocyst (days 1–14 of gestation) → failure to implant, double malformations, or identical twins
  • Embryopathy: all impairments of the organs during organogenesis (weeks 2–8):
    • High vulnerability to teratogens
    • CNS, neural tube (weeks 3 to 32–40) → neural tube defects Neural tube defects Neural tube defects (NTDs) are the 2nd-most common type of congenital birth defects. Neural tube defects can range from asymptomatic (closed NTD) to very severe malformations of the spine or brain (open NTD). Neural tube defects are caused by the failure of the neural tube to close properly during the 3rd and 4th week of embryological development. Neural Tube Defects such as spina bifida and mental disability
    • Heart (weeks 3 to 7–9) → truncus arteriosus Truncus arteriosus Truncus arteriosus (TA) is a congenital heart defect characterized by the persistence of a common cardiac arterial trunk tract that fails to divide into the pulmonary artery and aorta during embryonic development. Truncus arteriosus is a rare congenital malformation with a high mortality rate within the 1st 5 weeks of life if not managed promptly. Truncus Arteriosus communis, atrial septal defect Atrial Septal Defect Atrial septal defects (ASDs) are benign acyanotic congenital heart defects characterized by an opening in the interatrial septum that causes blood to flow from the left atrium (LA) to the right atrium (RA) (left-to-right shunt). Atrial Septal Defect, and ventricular septal defect
    • Extremities (weeks 4 to 6–9) → partial absence (meromelia) or complete absence (amelia) of ≥ 1 extremity
    • Ears (weeks 4 to 10–32) → deafness, auricular dysplasia, or a deep base of the ear
    • Respiratory tract (weeks 4 to 16–40) → fistulas, stenoses, and atresia
    • Urogenital system (weeks 4 to 16–40) → urachal fistula, horseshoe kidney
    • GI tract (weeks 5 to 32–40) → stenoses, atresia, rotational disabilities, hernias, or omphalocele Omphalocele Omphalocele is a congenital anterior abdominal wall defect in which the intestines are covered by peritoneum and amniotic membranes. The condition results from the failure of the midgut to return to the abdominal cavity by 10 weeks' gestation. Omphalocele
    • Face, lips Lips The lips are the soft and movable most external parts of the oral cavity. The blood supply of the lips originates from the external carotid artery, and the innervation is through cranial nerves. Oral Cavity: Lips and Tongue, palate Palate The palate is the structure that forms the roof of the mouth and floor of the nasal cavity. This structure is divided into soft and hard palates. Oral Cavity: Palate (weeks 5–8 to 16) → cleft lip Cleft lip The embryological development of craniofacial structures is an intricate sequential process involving tissue growth and directed cell apoptosis. Disruption of any step in this process may result in the formation of a cleft lip alone or in combination with a cleft palate. As the most common craniofacial malformation of the newborn, the diagnosis of a cleft is clinical and usually apparent at birth. Cleft Lip and Cleft Palate and palate Palate The palate is the structure that forms the roof of the mouth and floor of the nasal cavity. This structure is divided into soft and hard palates. Oral Cavity: Palate
  • Fetopathy: impairments in the maturation/differentiation of organs (weeks 9–38) → functional disabilities
Periods of time within gestation in which organ systems are most susceptible to teratogens

Periods of time within gestation in which organ systems are most susceptible to teratogens:
Gray: less sensitive period (functional and/or minor structural anomalies)
Green: highly sensitive period (major structural anomalies)

Image by Lecturio.

Maternal Systemic Illnesses

  • Diabetes mellitus Diabetes mellitus Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus:
    • Maternal hyperglycemia → fetal hyperglycemia → fetal hyperinsulinemia + islet-cell hyperplasia → macrosomia → higher risks of injuries during birth and neonatal hypoglycemia Hypoglycemia Hypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia
    • Increased risk of:
      • Congenital malformations (especially cardiac and neural defects)
      • Pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care loss
      • Growth restriction
      • Diabetic ketoacidosis Diabetic ketoacidosis Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) are serious, acute complications of diabetes mellitus. Diabetic ketoacidosis is characterized by hyperglycemia and ketoacidosis due to an absolute insulin deficiency. Hyperglycemic Crises
      • Maternal and perinatal mortality
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension → ↓ flow of nutrients to the fetus + ↓ placental blood flow → fetal growth restriction Fetal growth restriction Fetal growth restriction (FGR), also known as intrauterine fetal growth restriction (IUGR), is an estimated fetal weight (EFW) or abdominal circumference < 10th percentile for gestational age. The term small for gestational age (SGA) is sometimes erroneously used interchangeably with FGR. Fetal Growth Restriction, preeclampsia, preterm delivery, placental abruption, and need for cesarean section
  • Obesity: BMI ≥ 30
    • ↑ Maternal risk of gestational diabetes, preeclampsia, and sleep Sleep Sleep is a reversible phase of diminished responsiveness, motor activity, and metabolism. This process is a complex and dynamic phenomenon, occurring in 4-5 cycles a night, and generally divided into non-rapid eye movement (NREM) sleep and REM sleep stages. Physiology of Sleep apnea
    • ↑ Fetal risk of macrosomia, preterm birth Preterm birth Preterm labor refers to regular uterine contractions leading to cervical change prior to 37 weeks of gestation; preterm birth refers to birth prior to 37 weeks of gestation. Preterm birth may be spontaneous due to preterm labor, preterm prelabor rupture of membranes (PPROM), or cervical insufficiency. Preterm Labor and Birth, and stillbirth
    • Neural tube defects, heart defects, omphalocele Omphalocele Omphalocele is a congenital anterior abdominal wall defect in which the intestines are covered by peritoneum and amniotic membranes. The condition results from the failure of the midgut to return to the abdominal cavity by 10 weeks' gestation. Omphalocele
  • Graves disease → neonatal thyrotoxicosis Thyrotoxicosis Thyrotoxicosis refers to the classic physiologic manifestations of excess thyroid hormones and is not synonymous with hyperthyroidism, which is caused by sustained overproduction and release of T3 and/or T4. Graves' disease is the most common cause of primary hyperthyroidism, followed by toxic multinodular goiter and toxic adenoma. Thyrotoxicosis and Hyperthyroidism
  • Hypothyroidism Hypothyroidism Hypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto's disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism → congenital hypothyroidism

Related videos

Substance Abuse

Smoking

  • Nicotine is a strong vasoconstrictor → ↓ uterine and placental blood flow → ↓ fetal blood supply
  • Significantly increases the risk of:
    • Spontaneous abortion Spontaneous abortion Spontaneous abortion, also known as miscarriage, is the loss of a pregnancy before 20 weeks' gestation. However, the layperson use of the term "abortion" is often intended to refer to induced termination of a pregnancy, whereas "miscarriage" is preferred for spontaneous loss. Spontaneous Abortion
    • Premature birth
    • Placental abruption
    • SIDS
    • Asthma Asthma Asthma is a chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. The disease is believed to result from the complex interaction of host and environmental factors that increase disease predisposition, with inflammation causing symptoms and structural changes. Patients typically present with wheezing, cough, and dyspnea. Asthma
    • Upper respiratory infections
    • Orofacial clefts
    • Low birth weight
  • Moderately increases the risk for:
    • Transposition of the great arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries
    • Atrial septal defect
    • Pulmonary stenosis Pulmonary stenosis Valvular disorders can arise from the pulmonary valve, located between the right ventricle (RV) and the pulmonary artery (PA). Valvular disorders are diagnosed by echocardiography. Pulmonary stenosis (PS) is valvular narrowing causing RV outflow tract obstruction. Pulmonary Stenosis
    • Common truncus arteriosus Truncus arteriosus Truncus arteriosus (TA) is a congenital heart defect characterized by the persistence of a common cardiac arterial trunk tract that fails to divide into the pulmonary artery and aorta during embryonic development. Truncus arteriosus is a rare congenital malformation with a high mortality rate within the 1st 5 weeks of life if not managed promptly. Truncus Arteriosus

Alcohol abuse

Alcohol abuse → fetal alcohol spectrum disorder Fetal alcohol spectrum disorder Fetal alcohol spectrum disorder (FASD) is a group of neonatal pediatric disorders caused by maternal alcohol consumption during pregnancy. The term entails a range of physical and neurodevelopmental effects. Classification is based on severity and clinical presentation. Fetal Alcohol Spectrum Disorder (FASD)/fetal alcohol syndrome (severe end of the spectrum for alcohol-related defects)

  • Approximately 1 in 100 children have FASD.
  • Leading cause of intellectual disability
  • Alcohol dehydrogenase activity is lower in fetal liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver → amniotic fluid acts as a reservoir for alcohol → ethanol and acetaldehyde alter fetal development
  • The most severe is fetal alcohol syndrome characterized by congenital abnormalities, growth retardation, intellectual disability, and characteristic craniofacial features:
    • Short palpebral fissures
    • Flat and small midface
    • Long and flat philtrum
    • Thin vermilion border of the upper lip
    • Small head circumference
    • Small eye opening
Characteristic facial features of an individual with fetal alcohol spectrum disorder

Characteristic facial features of an individual with fetal alcohol spectrum disorder Fetal alcohol spectrum disorder Fetal alcohol spectrum disorder (FASD) is a group of neonatal pediatric disorders caused by maternal alcohol consumption during pregnancy. The term entails a range of physical and neurodevelopmental effects. Classification is based on severity and clinical presentation. Fetal Alcohol Spectrum Disorder

Image: “FASkid” by NIH/National Institute on Alcohol Abuse and Alcoholism. License: Public Domain

Opioids Opioids Opiates are drugs that are derived from the sap of the opium poppy. Opiates have been used since antiquity for the relief of acute severe pain. Opioids are synthetic opiates with properties that are substantially similar to those of opiates. Opioid Analgesics

  • Opioid use increases the risk of:
    • Intrauterine growth restriction (IUGR)
    • Placental abruption
    • Preterm labor Preterm labor Preterm labor refers to regular uterine contractions leading to cervical change prior to 37 weeks of gestation; preterm birth refers to birth prior to 37 weeks of gestation. Preterm birth may be spontaneous due to preterm labor, preterm prelabor rupture of membranes (PPROM), or cervical insufficiency. Preterm Labor and Birth
    • Fetal death
    • Neural tube defects
    • Heart defects
    • Gastroschisis Gastroschisis Gastroschisis is a congenital abdominal wall defect characterized by the complete lack of closure of the abdominal musculature. A portion of intestine does not return to the abdominal cavity, thereby remaining in its early embryonic herniated state but with no coverings. Gastroschisis
  • Once born, babies present with neonatal abstinence syndrome Neonatal Abstinence Syndrome Neonatal abstinence syndrome (NAS), or neonatal withdrawal syndrome (NWS), occurs when in-utero addictive substances are suddenly discontinued due to birth. The most common substances include alcohol, nicotine, and rapidly increasing opioids. Neonatal Abstinence Syndrome and withdrawal.

Marijuana

  • Linked to a number of adverse pregnancy outcomes irrespective of whether it is smoked or ingested
  • Associated with an increased risk of anencephaly (drug use during the 1st 4 weeks)
  • Increases the risk of neurodevelopmental deficiencies:
    • ADHD
    • Learning disabilities
    • Memory impairment

Medications

Medications that are contraindicated during pregnancy and the potential complications they are associated with are as follows:

  • Antibiotics:
    • Aminoglycosides Aminoglycosides Aminoglycosides are a class of antibiotics including gentamicin, tobramycin, amikacin, neomycin, plazomicin, and streptomycin. The class binds the 30S ribosomal subunit to inhibit bacterial protein synthesis. Unlike other medications with a similar mechanism of action, aminoglycosides are bactericidal. Aminoglycosides (ototoxicity)
    • Tetracyclines Tetracyclines Tetracyclines are a class of broad-spectrum antibiotics indicated for a wide variety of bacterial infections. These medications bind the 30S ribosomal subunit to inhibit protein synthesis of bacteria. Tetracyclines cover gram-positive and gram-negative organisms, as well as atypical bacteria such as chlamydia, mycoplasma, spirochetes, and even protozoa. Tetracyclines (dental diseases or deafness)
  • Antihypertensives:
    • ACE inhibitors ( oligohydramnios Oligohydramnios Oligohydramnios refers to amniotic fluid volume less than expected for the current gestational age. Oligohydramnios is diagnosed by ultrasound and defined as an amniotic fluid index (AFI) of ‰¤ 5 cm or a single deep pocket (SDP) of < 2 cm in the 2nd or 3rd trimester. Oligohydramnios, renal failure)
    • ARBs (renal dysplasia)
  • Anticonvulsants: phenytoin or valproic acid (facial dysmorphia, neural tube defects Neural tube defects Neural tube defects (NTDs) are the 2nd-most common type of congenital birth defects. Neural tube defects can range from asymptomatic (closed NTD) to very severe malformations of the spine or brain (open NTD). Neural tube defects are caused by the failure of the neural tube to close properly during the 3rd and 4th week of embryological development. Neural Tube Defects, congenital heart disease)
  • Psychiatric medications: lithium (cardiac abnormalities, including Ebstein anomaly)
  • Isotretinoin (facial abnormalities, congenital heart disease, neural tube defects Neural tube defects Neural tube defects (NTDs) are the 2nd-most common type of congenital birth defects. Neural tube defects can range from asymptomatic (closed NTD) to very severe malformations of the spine or brain (open NTD). Neural tube defects are caused by the failure of the neural tube to close properly during the 3rd and 4th week of embryological development. Neural Tube Defects)
  • Warfarin (skeletal abnormalities)
  • Thalidomide (amelia/meromelia and cardiac disorders)
  • Diethylstilbestrol (vaginal clear cell adenocarcinoma)

Infections

  • Urinary tract infections Urinary tract infections Urinary tract infections (UTIs) represent a wide spectrum of diseases, from self-limiting simple cystitis to severe pyelonephritis that can result in sepsis and death. Urinary tract infections are most commonly caused by Escherichia coli, but may also be caused by other bacteria and fungi. Urinary Tract Infections during pregnancy increase the risk of low birth weight, premature labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor, sepsis Sepsis Organ dysfunction resulting from a dysregulated systemic host response to infection separates sepsis from uncomplicated infection. The etiology is mainly bacterial and pneumonia is the most common known source. Patients commonly present with fever, tachycardia, tachypnea, hypotension, and/or altered mentation. Sepsis and Septic Shock, pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia, and miscarriage.
  • Rubella Rubella Rubella (also known as German measles or three-day measles) is caused by a single-stranded, positive-sense RNA virus of the Togaviridae family. Rubella only infects humans and spreads prenatally via vertical transmission or postnatally via droplet contact. Congenital rubella is associated with a classic triad of symptoms: cataracts, cardiac defects, and deafness. Infection in children and adults may be mild and present with constitutional symptoms along with a viral exanthem. Rubella Virus infection during pregnancy:
    • Can lead to a classic triad of cataracts, deafness, and patent ductus arteriosus Patent ductus arteriosus The ductus arteriosus (DA) allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent Ductus Arteriosus (PDA)
    • May also present with glaucoma Glaucoma Glaucoma is an optic neuropathy characterized by typical visual field defects and optic nerve atrophy seen as optic disc cupping on examination. The acute form of glaucoma is a medical emergency. Glaucoma is often, but not always, caused by increased intraocular pressure (IOP). Glaucoma, microphthalmia, pulmonary artery stenosis, intellectual disability, microcephaly, or hepatomegaly
  • Sexually transmitted infections can cause several problems in pregnancy:
    • Gonorrhea Gonorrhea Gonorrhea is a sexually transmitted infection (STI) caused by the gram-negative bacteria Neisseria gonorrhoeae (N. gonorrhoeae). Gonorrhea may be asymptomatic but commonly manifests as cervicitis or urethritis with less common presentations such as proctitis, conjunctivitis, or pharyngitis. Gonorrhea and/or chlamydia Chlamydia Chlamydiae are obligate intracellular gram-negative bacteria. They lack a peptidoglycan layer and are best visualized using Giemsa stain. The family of Chlamydiaceae comprises 3 pathogens that can infect humans: Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae. Chlamydia:
      • Increased risk of miscarriage and preterm birth Preterm birth Preterm labor refers to regular uterine contractions leading to cervical change prior to 37 weeks of gestation; preterm birth refers to birth prior to 37 weeks of gestation. Preterm birth may be spontaneous due to preterm labor, preterm prelabor rupture of membranes (PPROM), or cervical insufficiency. Preterm Labor and Birth
      • Congenital infection can cause conjunctivitis Conjunctivitis Conjunctivitis is a common inflammation of the bulbar and/or palpebral conjunctiva. It can be classified into infectious (mostly viral) and noninfectious conjunctivitis, which includes allergic causes. Patients commonly present with red eyes, increased tearing, burning, foreign body sensation, and photophobia. Conjunctivitis, pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia, and sepsis Sepsis Organ dysfunction resulting from a dysregulated systemic host response to infection separates sepsis from uncomplicated infection. The etiology is mainly bacterial and pneumonia is the most common known source. Patients commonly present with fever, tachycardia, tachypnea, hypotension, and/or altered mentation. Sepsis and Septic Shock.
    • Syphilis Syphilis Syphilis is a bacterial infection caused by the spirochete Treponema pallidum pallidum (T. p. pallidum), which is usually spread through sexual contact. Syphilis has 4 clinical stages: primary, secondary, latent, and tertiary. Syphilis:
      • Increases the risk of miscarriage and often results in stillbirth
      • Congenital syphilis can cause deafness, skeletal deformities, jaundice Jaundice Jaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice, and facial abnormalities.

Clinical Relevance

  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension: systolic blood pressure > 130 mm Hg and diastolic blood pressure > 80 mm Hg. Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension during pregnancy decreases blood flow through the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity and can lead to IUGR, preterm delivery, and a need for cesarean section.
  • Graves disease: caused by an excess of thyroid hormones Thyroid hormones The 2 primary thyroid hormones are triiodothyronine (T3) and thyroxine (T4). These hormones are synthesized and secreted by the thyroid, and they are responsible for stimulating metabolism in most cells of the body. Their secretion is regulated primarily by thyroid-stimulating hormone (TSH), which is produced by the pituitary gland. Thyroid Hormones, T3 and T4. Graves disease is the most common cause of hyperthyroidism Hyperthyroidism Thyrotoxicosis refers to the classic physiologic manifestations of excess thyroid hormones and is not synonymous with hyperthyroidism, which is caused by sustained overproduction and release of T3 and/or T4. Graves' disease is the most common cause of primary hyperthyroidism, followed by toxic multinodular goiter and toxic adenoma. Thyrotoxicosis and Hyperthyroidism and is an autoimmune disorder characterized by type II hypersensitivity. During pregnancy, Graves disease can lead to congenital thyrotoxicosis Thyrotoxicosis Thyrotoxicosis refers to the classic physiologic manifestations of excess thyroid hormones and is not synonymous with hyperthyroidism, which is caused by sustained overproduction and release of T3 and/or T4. Graves' disease is the most common cause of primary hyperthyroidism, followed by toxic multinodular goiter and toxic adenoma. Thyrotoxicosis and Hyperthyroidism.
  • Hypothyroidism Hypothyroidism Hypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto's disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism: a condition caused by a deficiency of T3 and T4 hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview. Hashimoto disease (autoimmune thyroiditis Thyroiditis Thyroiditis is a catchall term used to describe a variety of conditions that have inflammation of the thyroid gland in common. It includes pathologies that cause an acute illness with severe thyroid pain (e.g., subacute thyroiditis and infectious thyroiditis) as well as conditions in which there is no clinically evident inflammation and the manifestations primarily reflect thyroid dysfunction or a goiter (e.g., painless thyroiditis and fibrous Riedel's thyroiditis). Thyroiditis) is the leading cause of hypothyroidism in regions that are not iodine deficient. During pregnancy, iodine deficiency increases the risk of congenital hypothyroidism, which can lead to growth failure and permanent intellectual disability.
  • FASD: a group of neonatal pediatric disorders caused by maternal alcohol consumption during pregnancy. The term FASD entails a range of physical and neurodevelopmental effects. Classification is based on severity and clinical presentation. Diagnosis is based on a history of prenatal alcohol exposure and the presence of characteristic physical and developmental abnormalities.

References

  1. Hegde, S., Aedulla, N.R. (2021). Secondary Hypertension. StatPearls (Internet). Retrieved November 14, 2021. Secondary Hypertension – StatPearls – NCBI Bookshelf (nih.gov)
  2. Tsamantioti, E.S., Hashmi, M.F. (2021). Teratogenic Medications. StatPearls (Internet). Retrieved November 14, 2021. Teratogenic Medications – StatPearls – NCBI Bookshelf (nih.gov)
  3. Vorgias, D., Bernstein, B. (2021). Fetal Alcohol syndrome. StatPearls (Internet). Retrieved November 14, 2021. Fetal Alcohol Syndrome – StatPearls – NCBI Bookshelf (nih.gov)

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