Doctor Nguyen Phuong Thao, from the Fetal Medicine Unit at Tam Anh General Clinic, District 7, explains that genetic screening for couples before pregnancy can contribute to having healthy children, preventing and detecting genetic diseases early, reducing the burden of disease, and improving quality of life. The ideal time for genetic screening is before pregnancy, but screening for pregnant women is still important if they haven't been tested pre-conception. Therefore, couples planning to have children or who are currently pregnant, especially those in the high-risk groups below, should consider genetic screening.

History of miscarriage or stillbirth: Chromosomal abnormalities are the cause of miscarriage and natural stillbirth in about 50-60% of cases. According to Dr. Thao, about 2-8% of recurrent miscarriages are also due to chromosomal abnormalities. These abnormalities can be caused by the embryo having extra or missing chromosomes.

In cases of recurrent miscarriage, the father or mother may be a carrier of a balanced translocation (where different chromosomes exchange segments without loss or gain of genetic material) but are completely healthy and have no symptoms because they still have all the necessary genetic information. However, when a carrier's gamete combines with a normal gamete from the other parent, it can result in an embryo with an abnormal set of chromosomes. This can increase the risk of recurrent miscarriage, infertility, and severe birth defects in the child. Therefore, doctors recommend that parents undergo chromosomal testing to assess the genetic causes of recurrent miscarriage or stillbirth.

Previous child with birth defects or genetic disease: In many cases, parents have had a child with birth defects or a genetic disease, or have terminated a pregnancy due to severe fetal abnormalities. Genetic screening before the next pregnancy helps doctors analyze the parents' genes to look for genetic mutations or chromosomal abnormalities (translocations, inversions, extra or missing chromosomes) that may cause birth defects or genetic diseases. Based on the screening results, doctors can assess the risk of recurrence in subsequent pregnancies and advise the couple on the best options for a safe pregnancy and a healthy baby.

A woman undergoes reproductive health checks and genetic screening before pregnancy. Illustrative photo: Tam Anh General Clinic, District 7

Infertility: Genetic conditions such as Klinefelter syndrome (extra X chromosome in males), Turner syndrome (missing X chromosome in females), Fragile X syndrome, Kallmann syndrome (a condition causing delayed or absent puberty in males), and Y chromosome microdeletion can cause infertility. These abnormalities disrupt gamete formation, leading to azoospermia, premature ovarian failure, or recurrent miscarriage. Genetic screening helps doctors identify the cause and guide appropriate treatment for each infertile couple.

Older parents: Women are born with a fixed number of eggs in their ovaries. The quantity and quality of eggs decrease with age. Men continuously produce new sperm, but sperm quality also declines with age and other factors. This increases the risk of birth defects, chromosomal abnormalities, or genetic mutations in the fetus. In particular, when the father is over 40, the risk of the fetus having skeletal abnormalities such as achondroplasia or osteogenesis imperfecta increases to 0.5%. Therefore, older parents will have specific genetic screening procedures.

Dr. Thao notes that for women who become pregnant before the age of 25, the rate of Down syndrome in the fetus is about 0.1%, but this risk increases to nearly 0.3% in pregnant women 35 and older. Men over 35 also have an increased risk of new mutations forming in their sperm's DNA.

Family history of birth defects or developmental delays: Many genetic diseases such as Thalassemia, spinal muscular atrophy (SMA), and metabolic disorders are caused by recessive genes that can be passed down through generations. This means a person can carry a copy of the disease gene without showing any symptoms (a healthy carrier). A family history of birth defects or developmental delays is a warning sign of the possibility of a recessive disease-causing gene in the family.

Ngoc Chau