The 29-year-old mother received first-trimester prenatal care at a local private clinic, where no abnormalities were noted. She screened high risk for pre-eclampsia and was prescribed Aspirin for prevention. At 20 weeks of pregnancy, she visited Tam Anh General Clinic District 7. Doctor Nguyen Thi Lien Phuong, a specialist in fetal medicine, performed an ultrasound that revealed the fetal heart and stomach were on the right side of the body, instead of the usual left, indicating situs inversus. This condition means the body's organs are positioned opposite to their normal anatomical locations.

Ultrasound image showing the fetal heart and stomach on the right side. *Photo: Tam Anh General Clinic District 7*

Situs inversus can occur as an isolated condition without other abnormalities, or it may appear alongside other congenital defects. Approximately 5% to 10% of children with situs inversus also have congenital heart defects. Depending on the specific presentation, some children born with the condition may not exhibit any symptoms. However, if situs inversus is accompanied by other malformations, children face risks including respiratory failure, pneumonia, bronchitis, infections, intestinal dysfunction, and intestinal malrotation.

To determine the cause of the situs inversus, the pregnant woman underwent amniocentesis. Specialized gene sequencing revealed the fetus carried a heterozygous MMP21 gene mutation, an autosomal dominant inheritance pattern, linked to Heterotaxy syndrome. Situs inversus associated with Heterotaxy syndrome often results in abnormal organ arrangement in the chest and abdomen, leading to complex heart defects and other serious complications. However, in this specific case, the ultrasound showed the fetal organs were reversed in a "mirror image" fashion, with no accompanying malformations. Doctor Phuong noted, "This condition currently lacks comprehensive statistics in world medical literature," while offering a positive prognosis that it was unlikely to cause severe health problems for the child.

Doctors advised the pregnant woman to maintain a balanced diet, increase her intake of green vegetables and fruits, reduce sugar and salt, drink sufficient water, exercise as able, and avoid stress to manage the risk of pre-eclampsia. At 39 weeks of pregnancy, the baby girl was born healthy, weighing 3,5 kg. Doctors advised the family to monitor the child's health and seek immediate medical attention if any abnormalities arose.

The surgical team performing a C-section for the pregnant woman. *Photo: Tam Anh General Hospital*

Situs inversus primarily results from gene mutations in one or more genes. Over 100 genes are linked to this condition, including ANKS3, NME7, NODAL, CCDC11, WDR16, MMP21, PKD1L1, and DNAH9. Gene mutations can be inherited in various ways, such as autosomal dominant, autosomal recessive, X-linked, or through de novo mutations, depending on the specific gene involved.

When situs inversus in a fetus is not accompanied by other defects, the child will typically have no symptoms and live a healthy life. However, in cases associated with other congenital defects or syndromes, doctors can provide appropriate management plans, depending on the extent of impact on vital functions.

Doctors recommend that all pregnant women undergo screening for fetal malformations and genetic diseases at specialized medical centers. Pregnant women should attend scheduled prenatal appointments, especially at important milestones: the first trimester (11-13 weeks and 6 days), second trimester (20-24 weeks), and third trimester (28 weeks). Depending on the specific case, doctors will develop a suitable pregnancy management plan to ensure the safety of both mother and baby.

Ngoc Chau