During her first pregnancy, Ms. Tham received prenatal care in Japan. At 33 weeks, the fetus developed severe anemia and acute fetal distress, necessitating an emergency C-section. However, the baby died shortly after birth due to prematurity and severe anemia, with a suspected underlying genetic blood disorder.

For her second pregnancy, she had prenatal check-ups in Japan until week 27 before returning to Vietnam. Dr. Le Quang Hung, from the Fetal Medicine Center at Tam Anh General Hospital, Ho Chi Minh City, reported that the fetus continued to show signs of cardiomegaly, anemia, and hydrops fetalis. Genetic test results confirmed the fetus carried a homozygous alpha thalassemia gene with Hb Bart's hydrops fetalis. This is the most severe form of congenital alpha thalassemia.

This condition occurs when the body fails to produce the alpha globin chains necessary for normal hemoglobin (an iron-rich protein in red blood cells) production, instead creating an abnormal hemoglobin called Hb Bart that cannot effectively transport oxygen to cells. Fetuses with this condition often experience severe anemia, enlarged liver and spleen, hydrops, heart failure, and effusions in the pericardium and pleura. Most fetuses with Hb Bart's hydrops fetalis die in utero or immediately after birth. Pregnant women carrying such fetuses face risks of mirror syndrome (maternal edema mirroring fetal hydrops), pre-eclampsia, eclampsia, and postpartum hemorrhage.

Dr. Hung explained that congenital alpha thalassemia is typically inherited in an autosomal recessive pattern. If both parents are carriers (asymptomatic carriers of the disease gene), their fetus has a 25% risk of developing Hb Bart's hydrops fetalis, a 50% chance of being a thalassemia carrier like the parents, and a 25% chance of not carrying the disease gene.

Ms. Tham and her husband underwent specialized genetic testing, which confirmed both were carriers of the alpha thalassemia gene. Doctors counseled them on the genetic risks in subsequent pregnancies. For natural pregnancies, Ms. Tham would require early prenatal diagnosis through chorionic villus sampling or amniocentesis to determine if the fetus had severe disease. If they chose in vitro fertilization (IVF), she was advised to undergo preimplantation genetic testing (PGT) to screen out embryos carrying the Hb Bart mutation before embryo transfer.

After a period of physical and psychological recovery, the couple conceived naturally for the third time. Upon learning of her pregnancy, Ms. Tham remotely consulted with Dr. Hung and made arrangements in Japan to visit Tam Anh General Hospital for an early check-up.

First-trimester screening ultrasound results at the Fetal Medicine Center showed no abnormalities. Three weeks later, doctors collected an amniotic fluid sample for testing, which confirmed the fetus carried only one alpha thalassemia gene, similar to the parents, and would not develop severe disease.

She received regular prenatal monitoring and gave birth to a healthy baby boy at 40 weeks, weighing 3,5 kg.

The Obstetrics and Gynecology Center team performs a C-section for the patient. Photo: Tam Anh General Hospital

According to the Ministry of Health, Vietnam currently has nearly 14 million healthy individuals who are thalassemia gene carriers, accounting for 13% of the population. Each year, approximately 8,000 children are born with thalassemia, with about 2,000 of these cases being severe.

Dr. Hung stated that thalassemia is a genetic disease requiring lifelong monitoring, imposing mental, marital, reproductive, and quality of life burdens. Thalassemia is a group of genetic disorders that necessitates screening through pre-marital examinations or before pregnancy to reduce the incidence of severe cases. Couples should undergo comprehensive to specialized blood tests, family history assessment, genetic counseling, and personalized pregnancy monitoring plans to mitigate disease risks for their children.

Ngoc Chau

*Patient's name has been changed.