Causes of congenital malformations
Release time : 03/18/2025 09:30:02
Congenital malformations generally refer to fetal malformations, occurring due to structural or chromosome abnormalities within the womb during embryonic development. The majority of congenital malformations are formed in the early stages of embryonic development. The causes of congenital malformations are numerous, and many can be avoided. It is important for expectant mothers to avoid potential risk factors during their prenatal period or pregnancy. Here, we have compiled common causes of these conditions for reference.
1. Maternal or environmental factors (1) Radiation.
The risk of congenital malformations increases significantly when the fetus absorbs a radiation dose of more than 5 rad during the early gestation period.
(2) Chemical agent.
Certain medications can cause congenital malformations, especially during the early stages of pregnancy. Therefore, medication use during pregnancy should be managed in a manner that is reasonable under the guidance of a physician.
Furthermore, long-term and excessive alcohol consumption can lead to fetal alcohol syndrome, characterized by microcephaly, intellectual disability, and distinctive facial features.
Heavy metals (such as mercury and lead) increase the risk of congenital malformations.
Infection?
Infections in pregnant women can lead to fetal infection and congenital malformations, such as rubella, giant cell, herpes simplex, toxoplasmosis, syphilis, etc.
High fever during early pregnancy.
(5) In pregnant women with gestational hyperglycemia, inadequate glycemic control during the early pregnancy can increase the risk of congenital anomalies, primarily including congenital heart disease, neural tube defects, and cleft lip or palate.
(6) Dietary Factors: Inadequate folate intake increases the risk of neural tube defects and cleft lip and palate in fetuses.
2. Genetic factors refer to abnormalities caused by genetic material from parents, such as: parental chromosome abnormalities and parental carrying mutated genes.
Sometimes, it is due to abnormal segregation of chromosomes or mutations in genes during fertilization.
In close-knit marriages, the risk of carrying the same abnormal genes is increased, leading to a significant increase in the incidence of certain recessive genetic diseases. Therefore, it is advisable not to marry or have children with close relatives.
The symptoms of congenital malformations mainly include the following five aspects: 1. Body surface characteristics: Some congenital malformations can be observed at birth, such as facial structure abnormalities and abnormal hand and foot shapes. These characteristics may be immediately recognizable to parents or medical staff. 2. Function abnormalities: Some congenital malformations affect the physiological functions of babies, such as heart defects, digestive system problems, and vision impairments. These issues may only be discovered with professional medical assessment. 3. Developmental delay: Some congenital malformations may cause the physical development of a baby to be slower than that of peers of the same age, which may be due to incomplete organ development or dysfunction. 4. Growth and developmental obstruction: Some congenital malformations may affect the growth rate and height of babies, leading to slow growth or stunted growth. 5. Neurological problems: Some congenital malformations may affect the nervous system of babies, causing abnormal muscle tone, poor motor coordination, and other issues.
I. The main types of limb deformities include: polydactyly, syndactyly, abnormal foot, joint abnormalities, dislocation of the epiphysis, shortening of limbs, etc.
Syndactyly, characterized by extra fingers or toes, can be either dominant or recessive, with a family history.
Syndactyly, sometimes accompanied by other limb deformities, sometimes affecting only one limb, and sometimes affecting both limbs.
II. Congenital Heart Disease: Congenital heart disease is a congenital malformation formed during fetal development due to abnormalities in the development of the heart vessels.
The exact etiology of congenital heart disease has not yet been fully elucidated. The incidence rate of congenital heart disease, accounting for 0.3% to 1% of live births, can be divided into three categories from a genetic perspective: the first category involves chromosomal abnormalities.
The second group consists of monogenic inheritance.
The third category includes isolated congenital heart diseases.
3. Cleft lip and palate, simple cleft lip and palate are mainly inherited polygenic.
Generally, the probability of a fetal cleft lip is 1‰ for healthy pregnant women. The risk of having a child with a cleft lip in subsequent pregnancies is higher for couples who have had a child with a cleft lip.
Persistent vomiting during pregnancy for more than three months or longer is associated with an increased incidence of cleft lip and palate.
Viral infections during pregnancy, such as TORCH infection, and maternal diseases, such as diabetes and epilepsy, also increase the risk of cleft lip and palate.
Additionally, consuming anti-epileptic drugs during the early stages of pregnancy, or taking barbiturates, benzodiazepines, and salicylates can increase the risk by 2 to 10 times.
IV. Gastrointestinal Malformations: Gastrointestinal malformations can occur in any part of the gastrointestinal tract: esophagus, stomach, small intestine, large intestine, rectum, and anus. Most are due to incomplete development of organs, resulting in obstruction. Gastrointestinal malformations generally require surgical correction.
V. Neuro-Cerebral Anomalies In our country, the incidence of neural tube defects is the highest among congenital anomalies. The cerebral and spinal anomalies are mainly in the early stages of pregnancy, with a higher prevalence in female fetuses. The occurrence of anencephaly or spina bifida is primarily polygenic, with a recurrence risk of 5% if there has been a single episode of anencephaly or spina bifida delivery, and 10% if there has been two episodes. There is a tendency for familial cases to be recessive.
Prenatal examination methods generally involve regular prenatal check-ups. Prenatal anomalies can be detected during pregnancy, and pregnant women must adhere to routine prenatal care. If any abnormalities are discovered, timely treatment should be initiated. For more detailed information or counseling, please consult a doctor.
Anomaly screening is divided into three methods: 1. Blood screening, which includes testing maternal blood for human chorionic gonadotropin (hCG) and pregnancy-associated protein A (PAPP-A), to screen for fetal chromosomal aneuploidies, neural tube defects, etc.
2. Ultrasonographic screening includes the assessment of fetal chromosomal abnormalities through measurements of fetal nuchal translucency (NT) at 11-14 weeks gestation and examinations of the fetal nasal bone, as well as a major ultrasound examination conducted between 18-20 weeks of pregnancy.
3. Invasive procedures include chorionic villus sampling for fetal chromosomal examination, which is performed after 11 weeks of gestation for the purpose of diagnosing congenital genetic disorders, typically through abdominal puncture.
Amniotic Fluid Collection for Chromosomal Analysis: A 15-Week Postnatal Examination, with Fetal Chromosome Nuclear Type Analysis.
Fetal blood sampling involves puncturing the placenta at the site of attachment of the umbilical cord to diagnose chromosome abnormalities, monogenic diseases, anemia, thrombocytopenia, hypoxia and acidosis, infections, etc. It is necessary to be performed after 20 weeks of gestation.
The treatment of congenital malformations can be broadly categorized into two main approaches: treatment during pregnancy and treatment after birth.
1. Intrauterine treatment of fetal surgery is mainly used for the treatment of twin transfusion syndrome or reduction of twins, and for the treatment of fetal diaphragmatic hernia, meningocele, ureteral obstruction and so on.
2. Postpartum treatments include cerebrospinal fluid shunt surgery for hydrocephalus, repair of cleft lip and palate, surgical interventions for congenital heart disease, and medication therapy for phenylketonuria.
In fact, most non-lethal congenital anomalies do not require surgical intervention during pregnancy, such as congenital heart defects. They can be treated surgically after birth. However, some congenital anomalies may affect the fetal intrauterine safety and require intervention during pregnancy. Since the surgery carries high risks and demands high technical expertise, most fetal intrauterine treatments are still in the experimental phase at present.
How to Prevent Congenital Deformities: Not only are congenital deformities a source of pain for both parents and children, but they often persist throughout a child's life. For instance, congenital heart disease may require ongoing hospital visits from birth onward. Therefore, pregnant mothers must take preventive measures seriously. The "Mother's Net" has compiled the following summary for reference.
1. Premarital medical examinations, which reveal diseases such as hepatitis B and sexually transmitted infections, can affect the health of offspring and cause congenital malformations. Only after treatment is it possible to conceive.
2. Prepare for pregnancy by making necessary preparations and plans, undergoing necessary examinations such as rubella virus detection.
Rubella virus infection can cause congenital heart disease and congenital deafness, cataracts, etc., among fetuses. It is possible to prevent rubella virus infection by getting the rubella vaccine.
Folic acid supplementation before pregnancy: Taking folic acid starting from the first three months of pregnancy can effectively prevent neural tube defects in fetuses.
4. High-risk pregnant women should undergo prenatal consultation.
5. Postnatal check-ups after pregnancy: Avoid exposure to adverse environments and medications; abstain from alcohol and tobacco; undergo Down syndrome screening, B-mode ultrasound examination, etc. If necessary, perform prenatal diagnosis to timely identify congenital anomalies.
6. When medication is required, consult a doctor to avoid adverse effects on the fetus due to improper use of medications.
*The medical content involved in this text is for reference only.
In the event of discomfort, it is recommended to seek medical attention immediately. The diagnosis and treatment are based on a consultation with a professional in person.