After 6 years of infertility, Doan and her husband conceived twins through in vitro fertilization. At 12 weeks, an ultrasound at the Fetal Medicine Center of Tam Anh General Hospital in Ho Chi Minh City revealed one fetus with a nuchal translucency thickness of 3.5 mm and subchorionic hematoma.

Doctor Le Quang Hung from the Fetal Medicine Center explained that a nuchal translucency of 3.5 mm is a high-risk marker, indicating a potential chromosomal abnormality (Down syndrome, Patau syndrome, Edwards syndrome), genetic mutation, or congenital heart defect. Subchorionic hematoma, a condition where blood collects between the placenta and the uterus, can threaten miscarriage. Invasive testing (chorionic villus sampling or amniocentesis) was recommended for both fetuses to check for genetic abnormalities, but Doan and her husband declined. The pregnancy was then closely monitored, with particular attention to fetal morphology, especially for congenital heart defects.

Doan was considered high-risk for preeclampsia and was prescribed aspirin as a preventative measure. Doctor Hung advised her on a healthy diet, limiting sweets and starches while increasing protein, green vegetables, and unsweetened milk. He also recommended small, frequent meals and light exercise, along with home monitoring of blood sugar and blood pressure.

At 29 weeks, a Doppler ultrasound revealed intrauterine growth restriction in both fetuses, posing risks of fetal heart failure, stillbirth, premature birth, and respiratory distress after birth. Weekly monitoring assessed the fetuses' health. At 32 weeks, the smaller twin showed increased umbilical artery pulsatility index (reduced oxygen and nutrient supply through the placenta) and decreased cerebroplacental ratio (reduced blood flow to other organs to prioritize blood and oxygen to the brain). Doppler ultrasounds were then performed every three days. By 37 weeks, the smaller twin's amniotic fluid index had decreased to 1.8 cm (the normal range is 2-8 cm for twins).

"At this point, the risks of keeping the growth-restricted twin with low amniotic fluid in the womb outweighed the risks of premature delivery," Doctor Hung explained. A cesarean section was scheduled at 37 weeks to ensure the safety of both babies. The twins were safely delivered, weighing 2.5 kg and 2.3 kg, respectively, and were in stable condition.

The medical team performs a C-section. Illustration: Tam Anh General Hospital. *Patient's name has been changed.*

Causes of intrauterine growth restriction can stem from the mother (high blood pressure, chronic diseases), the fetus (chromosomal abnormalities, birth defects, fetal infections), or the placenta (placental insufficiency).

Accurate gestational age assessment is crucial to determine if fetal size corresponds to the pregnancy's stage. According to the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG), measuring crown-rump length in the thu nhat trimester (11-13 weeks and 6 days) is the optimal method. Doppler ultrasound assesses blood flow in the umbilical artery, which supplies oxygen and nutrients to the fetus, helping to determine if intrauterine growth restriction is present.

Currently, there's no way to prevent this condition. Doctors recommend regular prenatal checkups. Early diagnosis, fetal health monitoring, and choosing the right time for delivery can reduce mortality and the risk of future health problems for the baby.

Ngoc Chau