Society for Maternal-Fetal Medicine Consult Series #75: Evaluation and management of non-immune hydrops fetalis
SMFM, TN Sparks, ME Norton, SMFM Publications Committee2026
This Consult replaces Society for Maternal-Fetal Medicine Clinical Guideline #7: Non-immune hydrops fetalis.
Non-immune hydrops fetalis (NIHF) can result from a multitude of underlying causes, such as fetal genetic diseases, congenital anomalies, infections, fetal arrhythmias, placental tumors, monochorionic twin complications, and other disorders. Management is complex and rooted in the preferences of the pregnant individual and the known or suspected etiology of NIHF. In this Consult, we review general considerations and a contemporary approach to the diagnosis, evaluation, and management of NIHF, providing recommendations based on the available evidence. The following are the Society for Maternal-Fetal Medicine's recommendations: (1) we recommend fetal diagnostic testing for all pregnancies when one or more fetal effusions are detected; this testing should include chromosomal microarray analysis (CMA) with or without karyotype. When infectious etiologies are in the differential diagnosis, polymerase chain reaction studies should also be performed (grading of recommendations assessment, development, and evaluation [GRADE] 1C); (2) we recommend that exome or genome sequencing be offered in pregnancies with NIHF or NIHF spectrum following CMA or karyotype that does not yield a diagnosis and in the absence of another suspected etiology. If the risk of aneuploidy is low or a single-gene disorder is strongly suspected, offering exome or genome sequencing concurrently with CMA is reasonable (GRADE 1C); (3) we recommend that all patients who develop mirror syndrome in the setting of NIHF receive individualized counseling about delivery or abortion care; expectant management should be reserved only for rare circumstances, after counseling about the maternal risks and shared decision-making (GRADE 1C); (4) given the associated maternal risks, we recommend that all patients with pregnancies complicated by NIHF receive individualized counseling and be offered all management options, including abortion care (GRADE 1C); (5) we recommend that timing of delivery be individualized for each pregnancy with NIHF and that preterm delivery be reserved for obstetrical indications such as preeclampsia or mirror syndrome, preterm labor or premature rupture of membranes, new or worsening NIHF, or when the overall maternal or fetal risks of continued management are expected to outweigh those of delivery (GRADE 1C); (6) we recommend antenatal corticosteroids for continuing pregnancies with NIHF when preterm delivery is anticipated within 7 days, if neonatal resuscitation is desired and would be offered (GRADE 1C); (7) we recommend that cesarean delivery be performed for standard obstetrical indications in the setting of NIHF when postnatal resuscitation and life-supporting care are planned for the neonate (GRADE 1C). This Consult replaces Society for Maternal-Fetal Medicine Clinical Guideline #7: Non-immune hydrops fetalis.
Non-immune hydrops fetalis (NIHF) can result from a multitude of underlying causes, such as fetal genetic diseases, congenital anomalies, infections, fetal arrhythmias, placental tumors, monochorionic twin complications, and other disorders. Management is complex and rooted in the preferences of the pregnant individual and the known or suspected etiology of NIHF. In this Consult, we review general considerations and a contemporary approach to the diagnosis, evaluation, and management of NIHF, providing recommendations based on the available evidence. The following are the Society for Maternal-Fetal Medicine's recommendations: (1) we recommend fetal diagnostic testing for all pregnancies when one or more fetal effusions are detected; this testing should include chromosomal microarray analysis (CMA) with or without karyotype. When infectious etiologies are in the differential diagnosis, polymerase chain reaction studies should also be performed (grading of recommendations assessment, development, and evaluation [GRADE] 1C); (2) we recommend that exome or genome sequencing be offered in pregnancies with NIHF or NIHF spectrum following CMA or karyotype that does not yield a diagnosis and in the absence of another suspected etiology. If the risk of aneuploidy is low or a single-gene disorder is strongly suspected, offering exome or genome sequencing concurrently with CMA is reasonable (GRADE 1C); (3) we recommend that all patients who develop mirror syndrome in the setting of NIHF receive individualized counseling about delivery or abortion care; expectant management should be reserved only for rare circumstances, after counseling about the maternal risks and shared decision-making (GRADE 1C); (4) given the associated maternal risks, we recommend that all patients with pregnancies complicated by NIHF receive individualized counseling and be offered all management options, including abortion care (GRADE 1C); (5) we recommend that timing of delivery be individualized for each pregnancy with NIHF and that preterm delivery be reserved for obstetrical indications such as preeclampsia or mirror syndrome, preterm labor or premature rupture of membranes, new or worsening NIHF, or when the overall maternal or fetal risks of continued management are expected to outweigh those of delivery (GRADE 1C); (6) we recommend antenatal corticosteroids for continuing pregnancies with NIHF when preterm delivery is anticipated within 7 days, if neonatal resuscitation is desired and would be offered (GRADE 1C); (7) we recommend that cesarean delivery be performed for standard obstetrical indications in the setting of NIHF when postnatal resuscitation and life-supporting care are planned for the neonate (GRADE 1C). This Consult replaces Society for Maternal-Fetal Medicine Clinical Guideline #7: Non-immune hydrops fetalis.