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.

Prenatal diagnosis and in utero treatment of congenital adrenal hyperplasia: An up-to-date comprehensive review.

Congenital adrenal hyperplasia (CAH) is a term that encompasses a wide range of conditions that affect the adrenals. Diagnosis and treatment before birth are important as irreparable birth defects can be avoided, decreasing the need for surgical intervention later in life, especially regarding genitalia anomalies. Although early implementation of dexamethasone in the prenatal treatment of CAH has been controversial, there is recent evidence that this treatment can reduce long-term complications.

Prenatal Diagnosis of Fetal Aqueductal Stenosis: A Multicenter Prospective Observational Study through the North American Fetal Therapy Network.

INTRODUCTION: A critical component of an evidence-based reassessment of in-utero intervention for fetal aqueductal stenosis (fetal AS) is determining if the prenatal diagnosis can be accurately made at a gestational age amenable to in-utero intervention. METHODS: A multicenter, prospective, observational study was conducted through the North American Fetal Therapy Network (NAFTNet). Pregnancies complicated by severe central nervous system (CNS) ventriculomegaly (lateral ventricle diameter >15 mm) not secondary to a primary diagnosis (myelomeningocele, encephalocele, etc.) were recruited at diagnosis. Imaging and laboratory findings were recorded in an online REDCap database. After evaluation, investigators were asked to render their degree of confidence in the diagnosis of fetal AS. The prenatal diagnosis was compared to the postnatal diagnosis obtained through neonatal neuroimaging. Performance characteristics of ultrasound and magnetic resonance imaging (MRI) were calculated, as was the mean gestational age at diagnosis. RESULTS: Between April 2015 and October 2022, eleven NAFTNet centers contributed 64 subjects with severe fetal CNS ventriculomegaly. Of these, 56 had both prenatal and postnatal diagnoses recorded. Ultrasound revealed 32 fetal AS true positives, 4 false positives, 7 false negatives, and 13 true negatives, rendering a sensitivity of 0.82, a specificity of 0.76, a positive predictive value of 0.89, and a negative predictive value of 0.65. The mean gestational age at diagnosis by ultrasound was 25.5 weeks (std +/- 4.7 weeks). The proportion of agreement (true positive + true negative/n) was highest at 24 weeks gestation. For fetal MRI (n = 35), the sensitivity for fetal AS was 0.95, specificity was 0.69, positive predictive value was 0.84, and negative predictive value was 0.90. MRI was performed at 25 weeks on average. CONCLUSION: The prenatal diagnosis of fetal AS can be made with accuracy at a gestational age potentially amenable to in-utero intervention. Only 7% of subjects were incorrectly diagnosed prenatally with fetal AS by ultrasound and 11% by MRI. Diagnostic accuracy of fetal AS will likely improve with increased experience.

Neonatal Survival After Serial Amnioinfusions for Bilateral Renal Agenesis: The Renal Anhydramnios Fetal Therapy Trial.

Importance: Early anhydramnios during pregnancy, resulting from fetal bilateral renal agenesis, causes lethal pulmonary hypoplasia in neonates. Restoring amniotic fluid via serial amnioinfusions may promote lung development, enabling survival. Objective: To assess neonatal outcomes of serial amnioinfusions initiated before 26 weeks' gestation to mitigate lethal pulmonary hypoplasia. Design, Setting, and Participants: Prospective, nonrandomized clinical trial conducted at 9 US fetal therapy centers between December 2018 and July 2022. Outcomes are reported for 21 maternal-fetal pairs with confirmed anhydramnios due to isolated fetal bilateral renal agenesis without other identified congenital anomalies. Exposure: Enrolled participants initiated ultrasound-guided percutaneous amnioinfusions of isotonic fluid before 26 weeks' gestation, with frequency of infusions individualized to maintain normal amniotic fluid levels for gestational age. Main Outcomes and Measures: The primary end point was postnatal infant survival to 14 days of life or longer with dialysis access placement. Results: The trial was stopped early based on an interim analysis of 18 maternal-fetal pairs given concern about neonatal morbidity and mortality beyond the primary end point despite demonstration of the efficacy of the intervention. There were 17 live births (94%), with a median gestational age at delivery of 32 weeks, 4 days (IQR, 32-34 weeks). All participants delivered prior to 37 weeks' gestation. The primary outcome was achieved in 14 (82%) of 17 live-born infants (95% CI, 44%-99%). Factors associated with survival to the primary outcome included a higher number of amnioinfusions (P = .01), gestational age greater than 32 weeks (P = .005), and higher birth weight (P = .03). Only 6 (35%) of the 17 neonates born alive survived to hospital discharge while receiving peritoneal dialysis at a median age of 24 weeks of life (range, 12-32 weeks). Conclusions and Relevance: Serial amnioinfusions mitigated lethal pulmonary hypoplasia but were associated with preterm delivery. The lower rate of survival to discharge highlights the additional mortality burden independent of lung function. Additional long-term data are needed to fully characterize the outcomes in surviving neonates and assess the morbidity and mortality burden. Trial Registration: ClinicalTrials.gov Identifier: NCT03101891.

Development and in-vitro characterization of a novel fetal vesicoamniotic shunt - The Vortex shunt.

OBJECTIVES: To develop and test a novel vesicoamniotic shunt (VAS) to treat fetal lower urinary tract obstruction (LUTO), decrease dislodgement and optimize shunt deployment in-vitro. METHODS: Vesicoamniotic shunt design objectives included: (1) robust and atraumatic fixation elements, (2) kink resistant conduit to adjust to fetal movement and growth, (3) one-way pressure valve to facilitate bladder cycling, and (4) echogenic deployment visualization aids. The force to dislodge the novel Vortex shunt was compared with existing commercially available shunts in a bench-top porcine bladder model. Sonographic echogenicity was evaluated with ultrasound-guided deployment, and the shunt valve pressure measured. RESULTS: A prototype novel Vortex shunt was developed using braided nitinol "umbrella-type" ends with a kink-resistant stem incorporating an internal one-way valve. The peak force required to dislodge the Vortex shunt was significantly higher than commercially available shunts (p < 0.01). Shunt deployment in the bench-top model was easily confirmed with ultrasound guidance and the brisk decompression of the inflated porcine bladder thereafter. In-vitro valve gauge pressure testing mirrored bladder pressures in human LUTO cases. CONCLUSION: In-vitro testing shows that the Vortex shunt may improve deployment, sonographic visualization, kink resistance, and dynamic size adjustment. Validation in preclinical animal models are warranted and currently underway.

Outcomes of laser surgery for stage I twin-twin transfusion syndrome.

OBJECTIVE: A recent randomized controlled trial (RCT) demonstrated no difference in 6 month survival in expectantly managed stage I twin-twin transfusion syndrome (TTTS) patients and those undergoing immediate laser surgery. We aimed to describe outcomes following immediate laser surgery at a single fetal surgery center. METHODS: A retrospective study of monochorionic diamniotic twins diagnosed with stage I TTTS who underwent laser surgery between 16 and 26 gestational weeks from 2006 to 2019. The primary outcome was 6 month survivorship. Intact survival was also assessed. Secondarily, outcomes were compared to the RCT expectant management group. RESULTS: Of 126 consecutive stage I TTTS patients, 114 (90.5%) met inclusion criteria. Median (range) gestational age at delivery was 34.1 (20.6-39.4) weeks. At 6 months, the proportion of patients with at-least-one survivor in the single-center-laser cohort was 97.4%, with 88.6% dual survivorship. Neurological morbidity outcomes were available in 110 pregnancies (220 fetuses). Severe neurological morbidity occurred in 2.7% (6/220), and 6 month survival without severe neurological morbidity was 90.0%. Outcomes compared favorably with the RCT expectant management group. CONCLUSIONS: Given favorable survival and neurological outcomes, laser surgery is a reasonable treatment option for stage I TTTS at experienced fetal surgery centers. Further study is warranted to optimize treatment strategies.

Open surgery for in utero repair of spina bifida: Microneurosurgery versus standard technique - A systematic review.

BACKGROUND/OBJECTIVES: Prenatal myelomeningocele (MMC) repair has been shown to improve neurological outcomes. It has been suggested that decreases in the hysterotomy diameter during surgery can improve perinatal outcomes without altering neurologic outcomes. The objective of this study is to describe and compare the main maternal and fetal outcomes of fetuses undergoing open surgery for MMC repair, through the different modifications (standard-classical, mini-hysterotomy, and microneurosurgery). DATA SOURCE: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Ovid, SciELO, LILACS, PROSPERO. RESULTS: From a total of 112 studies, seven case series were selected including 399 fetuses with open fetal surgery, five studies using the classical technique (n = 181), one with mini-hysterotomy (n = 176), and one with the microneurosurgery technique (n = 42). The mini-hysterotomy and microneurosurgery techniques presented a lower risk of preterm delivery (21.4% and 30%, respectively) compared to the classic technique (47.3%), premature rupture of membranes (78%, 62%, and 72.5 %, respectively), oligohydramnios (0% and 72.5%, respectively), dehiscence of hysterotomy, maintaining the same frequency of Chiari reversion (78%, 62%, and 72.5%, respectively), postnatal correction requirement (0%, 4.8%, and 5.8%, respectively), and lower frequency of requirement for a ventriculoperitoneal shunt placement (13.0%, 7.5%, and 29.1%, respectively). CONCLUSION: The least invasive techniques (minihysterotomy-microneurosurgery) are possible and reproduceable, as they are associated with better maternal and perinatal outcomes.

Fetal open spinal dysraphism repair through a mini-hysterotomy: Influence of gestational age at surgery on children's ability to walk.

OBJECTIVE: To analyze the impact of gestational age (GA) at the time of fetal open spinal dysraphism (OSD) repair through a mini-hysterotomy on the ability of children to walk. METHODS: Children who underwent in utero repair of OSD and had formal neurological assessment after 2.5 years of age were compared regarding their ability to walk in relation to pre-surgical predictors. RESULTS: Sixty-nine children fulfilled the inclusion criteria. Among them, 63.7% (44/69) were able to walk with or without orthesis. Fetal OSD correction performed earlier in gestation (from 19.7 to 26.9 weeks) was associated with a higher probability of walking with or without orthesis (p = 0.033). The median GA at delivery was 35.3 weeks. Multivariate binary logistic regression showed that the upper anatomical level of the OSD ( L5) (p < 0.004; OR: 10.31 [95% CI: 2.07-51.28]) and GA at the time of fetal surgery (p = 0.026; OR = 0.68 [95% CI: 0.48-0.95]) were independent predictors of the postnatal ability to walk with or without orthesis. CONCLUSION: Fetuses with OSD who were operated on earlier in pregnancy (range: 19.7-26.9 weeks), were more likely to walk with or without orthesis.

Serial neurosonography in fetuses with congenital heart defects shows mild delays in cortical development.

INTRODUCTION: Neurodevelopmental delay is more common in children born with congenital heart defects (CHD), even with optimal perinatal and peri-operative care. It is hypothesized that fetuses with CHD are prone to neurological impairment in utero due to their cardiac defect, possibly leading to delayed cortical development. METHODS: Cerebral cortical maturation was assessed with advanced neurosonographic examinations every 4 weeks in fetuses with CHD and compared to control fetuses. Five different primary fissures and four areas were scored (ranging 0-5) by blinded examiners using a cortical maturation scheme. RESULTS: Cortical staging was assessed in 574 ultrasound examinations in 85 CHD fetuses and 61 controls. Small differences in grading were seen in Sylvian and cingulate fissures. (Sylvian fissure: -0.12 grade, 95% CI (-0.23; -0.01) p = 0.05, cingulate fissure: -0.24 grade, 95% CI (-0.38; -0.10) p = <0.001. Other cortical areas showed normal maturation as compared to control fetuses. CONCLUSION: Small differences were seen in three of the nine analyzed cortical areas in CHD fetuses, in contrast to previous reports on progressive third-trimester delay. The clinical implications of the small differences however, remain unknown.

Induction of Tertiary Phase Epileptiform Discharges after Postasphyxial Infusion of a Toll-Like Receptor 7 Agonist in Preterm Fetal Sheep.

BACKGROUND: Toll-like receptor (TLR) agonists are key immunomodulatory factors that can markedly ameliorate or exacerbate hypoxic-ischemic brain injury. We recently demonstrated that central infusion of the TLR7 agonist Gardiquimod (GDQ) following asphyxia was highly neuroprotective after 3 days but not 7 days of recovery. We hypothesize that this apparent transient neuroprotection is associated with modulation of seizure-genic processes and hemodynamic control. METHODS: Fetuses received sham asphyxia or asphyxia induced by umbilical cord occlusion (20.9 ± 0.5 min) and were monitored continuously for 7 days. GDQ 3.34 mg or vehicle were infused intracerebroventricularly from 1 to 4 h after asphyxia. RESULTS: GDQ infusion was associated with sustained moderate hypertension that resolved after 72 h recovery. Electrophysiologically, GDQ infusion was associated with reduced number and burden of postasphyxial seizures in the first 18 h of recovery (p < 0.05). Subsequently, GDQ was associated with induction of slow rhythmic epileptiform discharges (EDs) from 72 to 96 h of recovery (p < 0.05 vs asphyxia + vehicle). The total burden of EDs was associated with reduced numbers of neurons in the caudate nucleus (r2 = 0.61, p < 0.05) and CA1/2 hippocampal region (r2 = 0.66, p < 0.05). CONCLUSION: These data demonstrate that TLR7 activation by GDQ modulated blood pressure and suppressed seizures in the early phase of postasphyxial recovery, with subsequent prolonged induction of epileptiform activity. Speculatively, this may reflect delayed loss of early protection or contribute to differential neuronal survival in subcortical regions.

From non-invasive to invasive fetal therapy: A comprehensive review and current update.

"Fetus as patient" indicates fundamental concept of fetal therapy. With advance in maternal serum analysis and fetal imaging, prenatal screening has become standard of care. Accurate diagnosis in early gestation allows intervention to reverse pathophysiology and delay progression immediately. Non-invasive, minimally invasive and invasive therapies demonstrate their therapeutic potential in certain diseases. Recently, stem cell and gene therapies have been developed to avoid irreversible impairment. To elevate efficacy of treatment modality, extensive studies should be conducted according to regulatory authority. Striking a balance between scientific and ethical integrity is essential, so long-term follow up should be arranged for protecting mother and fetus.

Laser therapy for twin-twin transfusion syndrome in a dizygotic monochorionic twin pregnancy: A case report.

OBJECTIVE: A monochorionic dizygotic (MCDZ) twin is rare, especially when complicated with twin-twin transfusion syndrome (TTTS) and treated by laser therapy. CASE REPORT: A pregnancy achieved from oocyte donation and intracytoplasmic sperm injection resulted in two embryos transferred. A monochorionic diamniotic twin pregnancy was diagnosed by an early ultrasound; however, at 16 weeks of gestation, instead of the same sex, the ultrasound suspected there was sex discrepancy between the twins. TTTS with severe polyhydramnios occurred at 22 weeks, leading to a laser therapy, which was followed with a smooth post-operation course. Then the Cesarean section was performed at the gestational age of 29 weeks due to severe preeclampsia, giving birth to two live newborns: one female and one male baby both without neurological sequelae at the time of discharge. Blood chromosomes obtained at delivery and 65 days after delivery all revealed an XX and XY chimera from both babies. CONCLUSION: Laser therapy is also effective in MCDZ twin complicated with TTTS. Determination of chorionicity in early pregnancy could timely prompt us to watch out for complications unique to monochorionic twin pregnancy.

Toward Eliminating Perinatal Comfort Care for Prenatally Diagnosed Severe Congenital Heart Defects: A Vision.

Over the past 40 years, the medical and surgical management of congenital heart disease has advanced considerably. However, substantial room for improvement remains for certain lesions that have high rates of morbidity and mortality. Although most congenital cardiac conditions are well tolerated during fetal development, certain abnormalities progress in severity over the course of gestation and impair the development of other organs, such as the lungs or airways. It follows that intervention during gestation could potentially slow or reverse elements of disease progression and improve prognosis for certain congenital heart defects. In this review, we detail specific congenital cardiac lesions that may benefit from fetal intervention, some of which already have documented improved outcomes with fetal interventions, and the state-of-the-science in each of these areas. This review includes the most relevant studies from a PubMed database search from 1970 to the present using key words such as fetal cardiac, fetal intervention, fetal surgery, and EXIT procedure. Fetal intervention in congenital cardiac surgery is an exciting frontier that promises further improvement in congenital heart disease outcomes. When fetuses who can benefit from fetal intervention are identified and appropriately referred to centers of excellence in this area, patient care will improve.

Cardiac rhabdomyoma with hydrops fetalis: Prenatal management by abdominal drainage.

OBJECTIVE: We described a case of fetal cardiac rhabdomyoma complicated by hydrops. And we discussed our approach during pregnancy. CASE REPORT: A 23-year-old woman primigravida was referred at 29 weeks of gestation (WG) to prenatal unit for a large hyperechogenic intracardiac mass associated with fetal hydrops. An intrauterine peritoneo-amniotic shunt was placed. Complete regression of ascites and pericardial effusions were observed after 34 WG with drain in good position. CONCLUSION: Cardiac rhabdomyoma is the most common prenatal cardiac tumor. These tumors are benign, asymptomatic and spontaneously regress after birth. However, in some cases, these tumors may cause severe obstructions on the fetal heart and need specific treatment.

Effect of different cardioprotective methods on extracorporeal circulation in fetal sheep: a randomized controlled trial.

BACKGROUND: Congenital heart disease is a leading cause of death in newborns and infants. The feasibility of fetal cardiac surgery is linked to extracorporeal circulation (ECC); therefore, cardioplegic solutions need to be effective and long-lasting. METHODS: Eighteen pregnant sheep were divided into an ECC-only group, St. Thomas' Hospital cardioplegic solution (STH1) group (STH group), and HTK preservation solution (Custodiol®) group (HTK group). Markers of myocardial injury including troponin I (cTnI), troponin T (cTnT) and creatine kinase myocardial band (CKMB) were measured at specific time points (T1: pre-ECC, T2: 30 min of ECC, T3: 60 min of ECC, T4: 60 min post-ECC, T5: 120 min post-ECC). Myocardial tissue was removed from the fetal sheep at T5, and apoptosis was detected by TUNEL staining. RESULTS: Changes in the serum cTnI, cTnT and CKMB concentrations were not significantly different among the three groups before and during the ECC(T1,T2,T3). At 60 min after ECC shutdown(T4), cTnI and cTnT concentrations were significantly higher in the STH group than before the start of ECC. The concentration of cTnI was higher in the STH group than in the HTK and ECC-only groups. The concentration of cTnT was higher in the STH group than in the ECC-only group. At 120 min after ECC shutdown(T5), cTnI and cTnT concentrations were significantly higher in the ECC and HTK groups than before the start of ECC, and CKMB concentration was significantly higher in STH and HTK groups. The concentrations of cTnT, cTnI and CKMB was higher in the STH group than in the HTK and ECC-only groups. The number of TUNEL-positive cells in the HTK and STH groups was higher than in the ECC-only group. The number of TUNEL-positive cells in the STH group was higher than in the HTK group. There was no statistically significant difference among the groups in the heart rate and mean arterial pressure after ECC. CONCLUSION: The HTK preservation solution was significantly better than STH1 in reducing the release of cardiomyocyte injury markers and the number of apoptotic cells in fetal sheep ECC. Fetal sheep receiving ECC-only had an advantage in all indicators, which suggests ECC-only fetal heart surgery is feasible.

[Maternal-fetal therapy: from saving the fetus towards a better life for the future child]. / Ontwikkelingen in maternale-foetale therapie.

Maternal-fetal therapy (MFT) is special because treatment of the fetus is exclusively possible through the body of another person, the pregnant woman. MFT is a broad specialty with diverse interventions. In this manuscript several examples of innovations in MFT are discussed to illustrate the shift of lifesaving interventions to interventions aiming to improve morbidity of the future child. The broadening of the scope and shift towards prenatal treatments improving morbidity result in new ethical challenges. Particularly attention is needed for counseling and (the risk of) therapeutic misconception.

Strategies for intra-amniotic administration of fetal therapy in a rabbit model of intrauterine growth restriction.

Intrauterine growth restriction affects up to 10% of all pregnancies, leading to fetal programming with detrimental consequences for lifelong health. However, no therapeutic strategies have so far been effective to ameliorate these consequences. Our previous study has demonstrated that a single dose of nutrients administered into the amniotic cavity, bypassing the often dysfunctional placenta via intra-amniotic administration, improved survival at birth but not birthweight in an intrauterine growth restriction rabbit model. The aim of this study was to further develop an effective strategy for intra-amniotic fetal therapy in an animal model. Intrauterine growth restriction was induced by selective ligation of uteroplacental vessels on one uterine horn of pregnant rabbits at gestational day 25, and fetuses were delivered by cesarean section on GD30. During the five days of intrauterine growth restriction development, three different methods of intra-amniotic administration were used: continuous intra-amniotic infusion by osmotic pump, multiple intra-amniotic injections, and single fetal intraperitoneal injection. Technical feasibility, capability to systematically reach the fetus, and survival and birthweight of the derived offspring were evaluated for each technique. Continuous intra-amniotic infusion by osmotic pump was not feasible owing to the high occurrence of catheter displacement and amnion rupture, while methods using two intra-amniotic injections and one fetal intraperitoneal injection were technically feasible but compromised fetal survival. Taking into account all the numerous factors affecting intra-amniotic fetal therapy in the intrauterine growth restriction rabbit model, we conclude that an optimal therapeutic strategy with low technical failure and positive fetal impact on both survival and birthweight still needs to be found.

Intrafetal laser therapy in a monochorionic diamniotic triplet pregnancy with two acardiac fetuses: a case report and literature review.

BACKGROUND: Monochorionic diamniotic triplet pregnancies are rare. Twin reversed arterial perfusion sequence in monochorionic triplet pregnancies is extremely rare, and it is associated with high perinatal morbidity and mortality rates in the "pump fetus." CASE PRESENTATION: We reported a case of monochorionic diamniotic triplet pregnancy with twin reversed arterial perfusion sequence, including two acardiac fetuses sharing a single amniotic sac and a normal fetus in another amniotic sac. Due to rapid growth of the acardiac fetuses, intrafetal laser therapy was performed in both of them under ultrasound guidance at 15 weeks +5 days. Subsequently, regular and careful antenatal care including fetal ultrasonography and doppler and fetal echocardiography was conducted. At 37 weeks +4 days, a healthy female baby weighing 2510 g was delivered. The baby was followed up and now at 11 months old is in good health. CONCLUSIONS: Twin reversed arterial perfusion sequence in monochorionic triplet pregnancy should be diagnosed early by ultrasound imaging during pregnancy. Individualized management should be based on clinical conditions to improve the perinatal outcome of the pump twin. Intrafetal laser therapy could be an alternative procedure when intrauterine intervention is required.

Fetal therapy using rapamycin for a rapidly enlarging, obstructive, cervical lymphatic malformation: a case report.

WHAT'S ALREADY KNOWN ABOUT THIS TOPIC?: Fetal lymphatic malformations (LMs) can be detected on prenatal ultrasound and until recently, therapeutic options were limited. Recently the mammalian target of rapamycin inhibitor rapamycin has emerged as a safe, effective therapy for children with LMs and multiple studies have demonstrated improved efficacy if started early. WHAT DOES THIS STUDY ADD?: We report the first in-utero therapy with rapamycin for a rapidly enlarging, obstructive, fetal cervical LM. Fetal therapy with rapamycin was safe and effective in managing this severe malformation, despite rapamycin being started only in the last 6.5 weeks of pregnancy. We speculate that had rapamycin been commenced earlier, the reduction in mass size might have been even greater.