What do we know about the diagnosis and management of mirror syndrome?

The role of fetal therapy in the management of mirror syndrome: a narrative review

OBJECTIVES

Mirror syndrome (MS) is a condition characterized by the presence of maternal, fetal, and placental edema and is reversible through delivery or pregnancy termination. As fetal hydrops itself may be amenable to treatment, we sought to determine outcomes for MS primarily managed by fetal therapy through a narrative review of the literature and cases managed at our fetal center.

STUDY DESIGN

PubMed, Embase, Web of Science, Scopus, and Google Scholar databases were searched through January 2024 using key words: mirror syndrome, Ballantyne's syndrome, fetal hydrops, maternal hydrops, pseudotoxemia, triple edema, maternal recovery, fetal therapy, and resolution. Manuscripts describing primary management by fetal therapy that included maternal and fetal outcomes were identified. Clinical details of MS patients managed with fetal therapy at our center were also included for descriptive analysis.

RESULTS

16 of 517 manuscripts (3.1%) described fetal therapy as the primary intended treatment in 17 patients. 3 patients managed at our center were included in the analysis. Among 20 patients undergoing primary fetal therapy for management of mirror syndrome, median gestational age of presentation was 24 weeks and 5 days gestation; predominant clinical findings were maternal edema (15/20), proteinuria (10/20), pulmonary edema (8/20), and hypertension (8/20); the primary laboratory abnormalities were anemia (8/20) and elevated creatinine or transaminases (5/20). Condition-specific fetal therapies led to resolution of hydrops in 17 (85%) cases and MS in 19 (95%) cases. The median time to hydrops resolution was 7.5 days and to resolution of mirror syndrome was 10 days. Fetal therapy prolonged pregnancy by a median of 10 weeks with a median gestational age of 35 weeks and 5 days at delivery. All women delivered for indications other than mirror syndrome and 19/20 fetuses survived.

CONCLUSION

In appropriately selected cases, MS often resolves after fetal therapy of hydrops allowing for safe pregnancy prolongation with good maternal and infant outcomes.

Mirror syndrome associated with fetal cardiomyopathy

Mirror syndrome is a rare condition of generalized maternal oedema caused by fetal hydrops. A 37-year-old patient was admitted to our hospital because of suspected mirror syndrome caused by fetal cardiomyopathy. At 26th week of gestation patient developed bilateral pulmonary oedema as her condition rapidly deteriorated. Consequently, preterm labor was induced, percutaneous evacuation of fetal ascites was performed, and the patient finally vaginally delivered stillborn fetus. Although the initial postpartum period was severely complicated by hemorrhage, the condition of the patient significantly improved later, and she was discharged seven days after delivery. We believe this case is worth presenting due to its rarity and significant perinatal and obstetric challenges in treatment of those patients. Furthermore, preimplantation genetic testing could be performed to prevent at least some of the cases.

Clinical characteristics and risk factors of mirror syndrome: a retrospective case-control study

BACKGROUND

Mirror syndrome (MS) is a rare obstetric disorder complicated with high maternal morbidity and fetal mortality. MS is often misdiagnosed or underdiagnosed due to the low incidence and lack of awareness of its diverse features. This study aimed to summarise the etiology, clinical characteristics, and risk factors of MS among mothers with fetal hydrops.

METHODS

This retrospective case-control study included 37 pregnant women with fetal hydrops in the second and third trimesters from 58,428 deliveries performed at the Third Affiliated Hospital of Sun Yat-Sen University between January 2012 and December 2020. Cases were categorized as MS and non-MS according to the presence or absence of maternal mirroring symptoms. Binary logistic regression was performed for analysis.

RESULTS

Fourteen women developed MS with an overall incidence of 0.024% (14/58,428) and 37.8% (14/37) in the fetal hydrops cases. Among the 11 MS cases with known associated etiologies, seven had alpha thalassemia major. Onset of fetal hydrops was later (27.8 vs. 23.0 weeks) and the rate of placental thickening was higher (85.7% vs. 34.8%) in the MS group than in the non-MS group (P < 0.05). Regarding maternal characteristics, the MS group had higher maternal morbidity (85.7% vs. 8.7%), more weight gain (9.0 vs. 5.5 kg), higher rates of hypertension (35.7 vs. 0%) and proteinuria (64.3% vs. 4.3%), and lower levels of hemoglobin (88 vs. 105 g/L) and serum albumin (25.8 vs. 35.0 g/L) than the non-MS group (P < 0.05). Logistic regression analysis showed that onset of fetal hydrops at ≥24 weeks and placental thickening were associated with the risk of MS among fetal hydrops cases (OR 15.83, 95% CI 1.56-160.10 and OR 8.63, 95% CI 1.29-57.72, respectively).

CONCLUSIONS

MS is relatively common among fetal hydrops cases in the late second and third trimesters, and alpha thalassemia major is the main etiology for fetal hydrops and also MS in this population. Complicated with high maternal morbidity, the key maternal features of MS include more weight gain, hemodilution, and hypertension. Among those with fetal hydrops, the onset time of ≥24 weeks and placental thickening are risk factors for MS.