Medically Reviewed By Experts Panel
When closely related individuals, such as cousins or other family members, marry, it is called intrafamilial or consanguineous marriage. These unions can increase the risk of pregnancy complications, such as birth defects, stillbirths, and higher child mortality, due to a greater chance of inherited genetic disorders. The impact varies based on the degree of relatedness and the community’s genetic diversity. Despite these health risks, consanguineous marriages are common in some communities in India, particularly in South India. The South region has the highest prevalence of consanguineous marriages at 23%, while the North-East region has the lowest at 3.1%. Globally, around 10% of marriages are consanguineous, with higher rates in rural areas. Genetic counseling and screening play a crucial role in reducing these risks and guiding reproductive decisions.
What is consanguineous marriage?
Consanguineous (kän-ˌsan-ˈgwin-ē-əs) marriage occurs when close relatives, such as cousins, marry, leading to a higher risk of genetic disorders in their offspring due to shared genes. Studies have consistently linked consanguinity to an increased likelihood of birth defects, genetic abnormalities, and other health issues. This is because inherited genetic conditions are more likely to manifest when both parents carry similar recessive (dormant) genes like hemophilia, cystic fibrosis, sickle cell anaemia. As a result, the chances of passing on harmful genetic traits to children are significantly higher. Multiple studies have established consanguinity as a high cause for birth defects and abnormalities. According to the latest National Family Health Survey, 11% of marriages in India are consanguineous.
Why cousins shouldn’t marry?
Marrying a cousin increases the risk of genetic disorders in offspring due to shared genetic material. This can lead to birth defects, developmental delays, and conditions like cystic fibrosis or sickle cell anaemia. While not always harmful, the likelihood of complications is higher in consanguineous marriages. Studies show that children from these unions are at greater risk for mental retardation, blindness, deafness, and other genetic issues. The American Medical Association’s Samuel Merrifield Bemiss warned that cousin inbreeding could result in both physical and intellectual disabilities to children. Therefore, genetic counseling and screening are crucial to assess and reduce these risks.
What pregnancy complications can mothers face in a consanguineous marriage?
Mothers in consanguineous marriages face higher risks of pregnancy complications, including increased rates of stillbirths, miscarriages, and preterm births. There is also a greater likelihood of birth defects and genetic disorders in newborns, leading to developmental issues and neonatal mortality. These risks stem from inheriting similar recessive genes from both parents.
What pregnancy risks can result from consanguineous marriages?
Pregnancy risks due to consanguineous marriages include:
- Increased Risk of Birth Defects: Genetic disorders such as heart defects, cleft lip, and neural tube defects are more common.
- Higher Risk of Miscarriage or Stillbirth: Consanguineous pregnancies may result in a higher likelihood of pregnancy loss.
- Neonatal Mortality: Increased chance of infants dying shortly after birth.
- Developmental Delays: Children born to consanguineous parents are more likely to face developmental and intellectual disabilities.
- Congenital Disabilities: Conditions like hearing loss, vision impairments, and physical disabilities are more prevalent.
These risks arise from inheriting the same genetic conditions from both parents due to their shared ancestry.
What genetic disorders are most frequently observed in children born from consanguineous marriages?
Genetic disorders commonly observed in children born from consanguineous marriages include autosomal recessive conditions such as cystic fibrosis, sickle cell anaemia, and thalassemia. These children may also face an increased risk of congenital malformations, intellectual disabilities, hearing loss, and visual impairments. The shared genetic material between closely related parents heightens the probability of inheriting the same defective genes.
What is the importance of preconception counselling in consanguineous marriages?
Preconception counseling is essential in consanguineous marriages, as it helps identify genetic risks and informs couples about potential inherited conditions. This counseling involves reviewing family medical history, offering genetic testing, and educating parents about reproductive options to reduce the chances of birth defects and complications. It empowers couples to make informed decisions, leading to healthier pregnancy outcomes. A study found that children of consanguineous couples face more than a fourfold higher risk of birth defects compared to those of non-consanguineous couples.
Doctor’s Voice
Can prenatal genetic counseling help reduce risks in consanguineous marriages?
Prenatal genetic counseling reduces risks in consanguineous marriages by assessing the likelihood of inherited disorders and guiding reproductive decisions. It involves reviewing family medical history, conducting genetic screening, and identifying health risks early. This proactive approach informs parents of preventive measures, enhancing pregnancy outcomes and reducing the chances of birth defects, developmental delays, and other complications linked to shared genetic material.
Why should consanguineous marriages be discouraged?
Marriage between close relatives, or consanguineous marriages, should be discouraged due to the increased risk of inherited genetic disorders, including birth defects, developmental delays, and conditions like cystic fibrosis or sickle cell anaemia. These unions heighten the chances of genetic complications due to shared genes, leading to higher rates of stillbirths and neonatal mortality. A notable example is the prevalence of hemophilia in European royal families. Community education through outreach programs, schools, and public health initiatives raises awareness of potential risks. Promoting genetic counseling before marriage supports informed decision-making, and some regions have introduced policies to reduce consanguinity.
My Experience:
The late Dr. Najoo Varkey’s book Stop Marrying Your Niece! (or Uncle or Cousin) is the result of three decades of meticulous, systematic research on the adverse health impacts of consanguineous marriages, particularly focusing on the prevalence of hearing loss in children across the southern states of Kerala, Karnataka, Tamil Nadu, and Andhra Pradesh.
Read More on
How To Calculate When You Conceived
Increased Sense of Smell
Pregnancy Abdominal Pain
Why Prenatal Vitamins Are Essential for a Healthy Pregnancy
Pregnancy Symptoms Month by Month
