Question

What is a major versus minor anomaly? Which is worse? Which is easier for us to gather information on and why?

What are the causes of congenital anomalies? How much do we really know about the causes?

What is the major cause of infant mortality and morbidity?

Answer 1

Major anomaly: An unusual anatomic feature that is of serious medical or cosmetic consequence to the patient. For example, a major anomaly might be a cleft lip and palate. By contrast, a minor anomaly is an unusual anatomic feature not of serious medical or cosmetic consequence to the patient.

Major anomaly is worse.

Major congenital anomalies are defects that are present at birth and that have surgical, medical, or serious cosmetic significance. Major anomalies occur in about 3% of infants, according to data from the Metropolitan Atlanta Congenital Defects Program, a birth defects surveillance system administered by the Centers for Disease Control and Prevention (CDC) . A few examples of major congenital defects are cleft lip, gastroschisis, spina bifida, and congenital heart defects, such as atrial and ventricular septal defects. Minor congenital anomalies are also present at birth but are without medical, surgical, or serious cosmetic significance. Some examples include epicanthal folds, single transverse palmar crease, and fifth finger clinodactyly. Minor anomalies are useful in the study of birth defects for several reasons . Minor anomalies are often associated with and helpful for making a diagnosis of syndromes of known etiology, such as chromosome abnormalities or single gene disorders . For example, bilateral single transverse palmar creases are seen in >30% of persons with Down syndrome but in only 2% of persons without Down syndrome. In addition, minor anomalies have also been shown to be critical for the identification of the teratogenicity of certain exposures, such as alcohol, hydantoin, and carbamazepine.

  

Examples of minor congenital anomalies: Left: Epicanthal folds (defined as presence of folds of skin that cover the medial corners of the eyes) . Middle: fifth finger clinodactyly (defined as incurving of the fifth finger toward the radius). Right: ...
Although minor congenital anomalies are of significance when considering exposures during pregnancy, they are common and not consistently ascertained: in four studies, the rates of minor anomalies identified among newborns ranged from 14.7% to 40.7% . In addition, ascertainment of specific min

Causes and risk factors

Although approximately 50% of all congenital anomalies cannot be linked to a specific cause, there are some known genetic, environmental and other causes or risk factors.

Genetic factors

Genes play an important role in many congenital anomalies. This might be through inherited genes that code for an anomaly, or resulting from sudden changes in genes known as mutations.

Consanguinity (when parents are related by blood) also increases the prevalence of rare genetic congenital anomalies and nearly doubles the risk for neonatal and childhood death, intellectual disability and other anomalies.

Some ethnic communities (such as Ashkenazi Jews or Finns) have a comparatively high prevalence of rare genetic mutations such as Cystic Fibrosis and Haemophilia C.

Socioeconomic and demographic factors

Low-income may be an indirect determinant of congenital anomalies, with a higher frequency among resource-constrained families and countries. It is estimated that about 94% of severe congenital anomalies occur in low- and middle-income countries. An indirect determinant, this higher risk relates to a possible lack of access to sufficient, nutritious foods by pregnant women, an increased exposure to agents or factors such as infection and alcohol, or poorer access to healthcare and screening. Factors often associated with lower-income may induce or increase the incidence of abnormal prenatal development.

Maternal age is also a risk factor for abnormal intrauterine fetal development. Advanced maternal age increases the risk of chromosomal abnormalities, including Down syndrome.

Environmental factors

Maternal exposure to certain pesticides and other chemicals, as well as certain medications, alcohol, tobacco and radiation during pregnancy, may increase the risk of having a fetus or neonate affected by congenital anomalies. Working or living near, or in, waste sites, smelters or mines may also be a risk factor, particularly if the mother is exposed to other environmental risk factors or nutritional deficiencies.

Infections

Maternal infections such as syphilis and rubella are a significant cause of congenital anomalies in low- and middle-income countries.

More recently, the effect of in utero exposure to Zika virus on the developing fetus has been reported. In 2015, Brazil detected cases of Zika virus and a spatio-temporally associated increase in microcephaly. By 2016, Brazil reported that of 4180 suspected cases of microcephaly, 270 were confirmed, 462 were discarded and 3448 are still under investigation. This is compared to an average of 163 microcephaly cases recorded nationwide per year. With 6 of the 270 confirmed cases of microcephaly showing evidence of Zika infection, health authorities and agencies are investigating and conducting comprehensive research to confirm a causal link. Following the Zika outbreak in French Polynesia, health authorities reported an unusual increase in the number of congenital malformations in babies born between March 2014 and May 2015.

Maternal nutritional status

Maternal folate insufficiency increases the risk of having a baby with a neural tube defect while excessive vitamin A intake may affect the normal development of an embryo or fetus.

or anomalies among different examiners has been shown to have poor reproducibility, emphasizing the need for efforts to improve the inter-examiner reliability of their ascertainment.

Major causes of mortality and morbidity are Neonatal encephalopathy or problems with brain function after birth. Neonatal encephalopathy usually results from birth trauma or a lack of oxygen to the baby during birth.
Infections, especially blood infections
Complications of preterm birth
Lower respiratory infections (such as flu and pneumonia)
Diarrheal diseases