Temporal ultrasound findings in the first trimester of a dual fetal demise occurring in a monochorionic diamniotic twin gestation

Single fetal demise in monochorionic gestations in the 2nd and 3rd trimester is associated with adverse outcomes for the co-twin. We present a case of single demise in a monochorionic gestation in the 1st trimester with evidence of subsequent hemodynamic aberrations in the co-twin, supportive of feto-fetal hemorrhage occurring early in gestation.

Third-trimester fetoscopic ablation therapy for types II and III vasa previa

BACKGROUND

Vasa previa is an obstetrical condition in which fetal vessels located near the cervix traverse the fetal membranes unprotected by underlying placenta. Type I vasa previa arises directly from a velamentous cord root, whereas types II and III arise from an accessory lobe or a distal lobe of the same placenta, respectively. Fetoscopic laser ablation for types II and III vasa previa is a novel therapeutic option with benefits that include surgical resolution of the vasa previa, avoidance of prolonged hospitalization, and opportunity for a term vaginal delivery. The potential risks of fetoscopy can be mitigated by delaying laser surgery until a gestational age of 31 to 33 weeks, immediately before anticipated hospitalized surveillance.

OBJECTIVE

This study aimed to assess feasibility and outcomes of types II and III vasa previa patients treated via fetoscopic laser ablation in the third trimester.

STUDY DESIGN

This is a retrospective study of singleton pregnancies with types II and III vasa previa treated with fetoscopic laser ablation at a gestational age ≥31 weeks at a single center between 2006 and 2022. Pregnancy and newborn outcomes were assessed. Continuous variables are expressed as mean±standard deviation.

RESULTS

Of 84 patients referred for vasa previa, 57 did not undergo laser ablation: 19 either had no or resolved vasa previa, 25 had type I vasa previa (laser-contraindicated), and 13 had type II or III vasa previa but declined laser treatment. Of the remaining 27 patients who underwent laser ablation, 7 were excluded (laser performed at <31 weeks and/or twins), leaving 20 study patients. The mean gestational age at fetoscopic laser ablation was 32.0±0.6 weeks, and total operative time was 62.1±19.6 minutes. There were no perioperative complications. All patients had successful occlusion of the vasa previa vessels (1 required a second procedure). All patients were subsequently managed as outpatients. The mean gestational age at delivery was 37.2±1.8 weeks, the mean birthweight was 2795±465 g, and 70% delivered vaginally. Neonatal intensive care unit admission occurred in 3 cases: 1 for respiratory distress syndrome and 2 for hyperbilirubinemia requiring phototherapy. There were no cases of neonatal transfusion, intraventricular hemorrhage, sepsis, patent ductus arteriosus, or death.

CONCLUSION

Laser ablation for types II and III vasa previa at 31 to 33 gestational weeks was technically achievable and resulted in favorable outcomes.

Diagnosis and Management of 2 Cases of Spontaneous Septostomy: Monochorionic/Dichorionic Hybrid Twin Gestation and Dichorionic Triamniotic Triplet Gestation

INTRODUCTION

Spontaneous septostomy is a rare complication of multiple gestations. Related complications include cord entanglement and preterm delivery. Limited data exist to guide the management of these high-risk patients. The majority of spontaneous septostomy cases have been reported in monochorionic diamniotic twins. We present 2 cases of spontaneous septostomy occurring in a monochorionic/dichorionic hybrid twin gestation (chorionicity transitions from dichorionicity to monochorionicity within the placenta) and in a dichorionic triamniotic triplet gestation.

CASE PRESENTATION

Case 1 was a monochorionic/dichorionic hybrid twin gestation with a septostomy complicated by fetal parts of one twin protruding into the co-twin's sac as well as symptomatic polyhydramnios. Fetal magnetic resonance imaging confirmed the septostomy. Case 2 was a dichorionic triamniotic triplet gestation with septostomy and cord entanglement. Both patients were managed akin to a pseudo-monoamniotic gestation with serial ultrasound surveillance and eventual inpatient admission for heightened fetal monitoring. Case 1 underwent elective scheduled cesarean delivery at 33 weeks, and case 2 underwent emergent cesarean delivery for fetal heart rate decelerations at 28 weeks.

CONCLUSION

With a high degree of clinical suspicion, spontaneous septostomy can be diagnosed in uncommon settings such as hybrid twin gestations and higher order multiples. Management of such patients is individualized and may include a combination of heightened outpatient and inpatient surveillance.

Subclassification of fetal growth restriction type IIa vs type IIb applied to twin-twin transfusion syndrome

BACKGROUND

Subclassification of monochorionic twins with selective fetal growth restriction type II into IIa vs IIb has been proposed because of differing neonatal survival outcomes of the fetus with growth restriction after laser surgery based on preoperative Doppler findings in the middle cerebral artery and ductus venosus. There is substantial clinical overlap between selective fetal growth restriction and twin-twin transfusion syndrome.

OBJECTIVE

This study aimed to compare donor twin neonatal survival after laser surgery in cases of twin-twin transfusion syndrome with concomitant donor fetal growth restriction type IIa vs IIb.

STUDY DESIGN

This was a retrospective study of monochorionic multifetal pregnancies treated with laser surgery for stage III twin-twin transfusion syndrome and concomitant donor twin fetal growth restriction type II at a referral center from 2006 to 2021. Donor fetal growth restriction type II was defined as having an estimated fetal weight <10th percentile with persistent absent and/or reversed end-diastolic velocity in the umbilical artery. Moreover, patients were subclassified as type IIa (having normal middle cerebral artery peak systolic velocities and ductus venosus Doppler waveforms) vs type IIb (having middle cerebral artery peak systolic velocities ≥1.5 multiples of the median and/or ductus venosus with persistent absent or reversed atrial systolic flow). This study compared 30-day neonatal survival of the donor twin by fetal growth restriction type IIa vs IIb using logistic regression to adjust for relevant preoperative covariates (P<.10 in bivariate analysis).

RESULTS

Of 919 patients who underwent laser surgery for twin-twin transfusion syndrome, 262 had sstage III donor or donor and recipient twin-twin transfusion syndrome; of these patients, 189 (20.6%) had concomitant donor fetal growth restriction type II. Moreover, 12 patients met the exclusion criteria, yielding 177 patients (19.3%) who composed the study cohort. Patients were subclassified as donor fetal growth restriction type IIa (146 [82%]) vs type IIb (31 [18%]). Donor neonatal survival for fetal growth restriction type IIa vs IIb was 71.2% vs 41.9% (P=.003). Recipient neonatal survival did not differ between the 2 types (P=1.000). Patients classified with twin-twin transfusion syndrome and concomitant donor fetal growth restriction type IIb were 66% less likely to have neonatal survival of the donor after laser surgery (adjusted odds ratio, 0.34; 95% confidence interval, 0.15-0.80; P=.0127). The logistic regression model was adjusted for gestational age at the procedure, estimated fetal weight percent discordance, and nulliparity. The c-statistic was 0.702.

CONCLUSION

For patients with stage III twin-twin transfusion syndrome and concurrent donor fetal growth restriction with persistent absent or reversed end-diastolic velocity in the umbilical artery (ie, fetal growth restriction type II), subclassification into fetal growth restriction type IIb based on elevated middle cerebral artery peak systolic velocity and/or abnormal ductus venosus flow in the donor conveyed poorer prognosis. Although donor neonatal survival after laser surgery was lower for patients with stage III twin-twin transfusion syndrome with donor fetal growth restriction type IIb than patients with stage III twin-twin transfusion syndrome with donor fetal growth restriction with type IIa, laser surgery for fetal growth restriction type IIb in the setting of twin-twin transfusion syndrome (as opposed to pure selective fetal growth restriction type IIb) still allows for the possibility of dual survivorship and should be offered with shared decision-making when counseling patients on management options.

Selective Fetal Growth Restriction Type III: Application of a Recent Expert Consensus Definition

OBJECTIVES

Per a recent expert definition, diagnosis of selective fetal growth restriction (sFGR) in monochorionic diamniotic twins is based on an estimated fetal weight (EFW) <3% as sole criterion and/or combinations of 4 contributory criteria (1 twin EFW <10%; 1 twin abdominal circumference <10%; EFW discordance ≥25%; and smaller twin umbilical artery [UA] pulsatility index >95th percentile). We assessed these criteria in sFGR Type III (intermittent absent or reversed end-diastolic flow of the UA [iAREDF]) patients to test whether meeting the more stringent parameters of the consensus definition had worse outcomes, that is, progression to sFGR Type II (persistent AREDF) or twin-twin transfusion syndrome; or secondarily, decreased dual survivorship.

METHODS

This was a retrospective study of referred sFGR Type III patients (2006-2017). Patients were retrospectively categorized using consensus criteria for 2 comparisons: 1) EFW <3% versus remaining cohort; 2) EFW <3% or met all 4 contributory criteria versus remaining cohort.

RESULTS

Forty-eight patients were studied. Comparison 1: EFW <3% patients (58.3%) were not more likely to demonstrate disease progression (46.4% versus 65.0%, P = .2489) or worse dual survivorship (78.6% versus 85.0%, P = .7161). Comparison 2: EFW <3% or met all 4 contributory criteria (75.0%) patients were not more likely than the others to demonstrate progression (44.4% versus 83.3%, P = .0235) or worse dual survivorship (80.6% versus 83.3%, P = 1.0000).

CONCLUSIONS

In a referred cohort of sFGR Type III patients, there was no evidence that meeting more stringent parameters of the consensus definition was associated with disease progression or dual survivorship.

Percutaneous/mini-laparotomy fetoscopic repair of open spina bifida: a novel surgical technique

Open spina bifida (OSB) is the most common congenital anomaly of the central nervous system compatible with life. Prenatal repair of open spina bifida via open maternal-fetal surgery has been shown to improve postnatal neurological outcomes, including reducing the need for ventriculoperitoneal shunting and improving lower neuromotor function. Fetoscopic repair of OSB minimizes the maternal risks while providing similar neurosurgical outcomes to the fetus. Two fetoscopic techniques are currently in use: (1) the laparotomy-assisted approach, and (2) the percutaneous approach. The laparotomy-assisted fetoscopic technique appears to be associated with less risk of preterm birth compared to the percutaneous approach. However, the percutaneous approach avoids laparotomy and uterine exteriorization, and is associated with less anesthesia risk and improved maternal post-surgical recovery. The purpose of this paper is to describe our experience with a novel surgical approach, which we call percutaneous/mini-laparotomy fetoscopy (PML), in which access to the uterus for one of the ports is done via a mini-laparotomy, while the other ports are inserted percutaneously. This technique draws on the benefits of both the laparotomy-assisted and the percutaneous techniques, while minimizing their drawbacks. This surgical approach may prove invaluable in the prenatal repair of open spina bifida as well as other complex fetal surgical procedures.

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.

Twin-twin transfusion syndrome and the definition of recipient polyhydramnios

BACKGROUND

Controversy exists regarding the threshold of recipient twin polyhydramnios required to diagnose twin-twin transfusion syndrome at a gestational age of ≥20 weeks. One criterion set (Quintero staging) requires the amniotic fluid maximum vertical pocket for the recipient twin to measure ≥8 cm, whereas another (European) system uses a maximum vertical pocket for the recipient twin of ≥10 cm.

OBJECTIVE

This study aimed to characterize the patients with twin-twin transfusion syndrome who were treated with laser surgery and would be excluded from laser surgery according to the European criteria.

STUDY DESIGN

A total of 366 monochorionic diamniotic twins diagnosed with twin-twin transfusion syndrome from 20 to 26 weeks' gestation who underwent laser surgery at our center were studied. A maximum vertical pocket for the recipient twin of ≥8 cm was used to diagnose twin-twin transfusion syndrome. Patients were retrospectively divided into the following 2 groups: group A with a maximum vertical pocket for the recipient twin of ≥8 cm and <10 cm and group B with a maximum vertical pocket for the recipient twin of ≥10 cm. The association of each of the groups with the survivorship outcomes was tested. Bivariate associations between the patient characteristics and the 30-day donor twin and dual survivorship outcomes were evaluated. Tests used in the analysis were chi-square or Fisher exact tests as appropriate for categorical variables and Kruskal-Wallis tests for continuous variables. Multiple logistic regression models for each of the survivorship outcomes were then assessed. The results are reported as mean±standard deviation.

RESULTS

Of the 366 studied patients, 53 (14.5%) had a maximum vertical pocket for the recipient twin of ≥8 and <10 cm (group A) and 313 (85.5%) had a maximum vertical pocket for the recipient twin of ≥10 cm (group B). Groups A and B did not differ in the Quintero stage. Notably, 60.4% (32 of 53) of group A patients were stage III or IV. When compared with group B, group A was diagnosed with twin-twin transfusion syndrome at an earlier gestational age (21.7±1.6 vs 22.3±1.6 weeks; P=.0037) and had a higher prevalence of donor growth restriction (81.1% [43 of 53] vs 65.5% [205 of 313]; P=.0260). Rates of at least 1 twin and dual twin survival between group A and B were similar (98.1% [52 of 53] vs 95.8% [300 of 313]; P=.7023, and 79.2% [42 of 53] vs 83.4% [261 of 313]; P=.4369, respectively). Logistic regression models adjusted for perioperative characteristics showed no difference in the outcomes between the groups (group B as reference) (donor twin survival odds ratio, 0.64; 95% confidence interval, 0.29-1.42; P=.2753; and dual survivor odds ratio, 0.90; 95% confidence interval, 0.42-1.91; P=.7757).

CONCLUSION

Restriction of the definition of twin-twin transfusion syndrome to a maximum vertical pocket for the recipient of ≥10 cm beyond 20 weeks gestational age would potentially exclude 14.5% of patients from laser surgery, the majority of whom had advanced stage twin-twin transfusion syndrome. A unifying criterion of a maximum vertical pocket for the recipient of ≥8 cm regardless of gestational age would allow inclusion of these patients and access to surgical management.

Dual demise following laser surgery for twin-twin transfusion syndrome: Analysis of 52 cases at a single fetal surgery center

OBJECTIVE

To evaluate all individual cases of dual twin demise following laser surgery for twin-twin transfusion syndrome (TTTS).

METHOD

This is an analysis of all monochorionic diamniotic twin gestations with TTTS complicated by dual demise following laser surgery from 2006 to 2019. Cases were reviewed by (1) a fetal surgeon researcher and (2) a panel of independent experienced maternal-fetal medicine specialists to code an etiology of demise for the donor and recipient, and to assess for possible preventability.

RESULTS

Of 753 twins that underwent laser surgery for TTTS, 52 (6.9%) had postoperative dual demise. In this subgroup, gestational age at surgery was 19.5 (16.1-24.9) weeks, and 36 (69.2%) patients were Quintero stage III and IV. The most common etiology was the spectrum of disorders leading to preterm delivery, which included cervical insufficiency, preterm premature rupture of membranes, and preterm labor (44.2% and 48.1%, donor and recipient, respectively). Some degree of preventability was estimated for 23.1% of dual demises.

CONCLUSIONS

The most common cause of dual demise post laser surgery for TTTS was preterm birth, reinforcing the need for studies regarding the etiology and prevention of post-fetoscopy prematurity. Nearly one-quarter of dual demise cases were deemed potentially preventable.

Fetal blood gases after in utero carbon dioxide insufflation for percutaneous fetoscopic spina bifida repair

BACKGROUND

Prenatal repair of open spina bifida via the percutaneous fetoscopic approach does not require maternal laparotomy, hysterotomy, or exteriorization of the uterus. This technique requires intrauterine partial CO₂ insufflation. Limited data exist on the physiological effects of CO₂ insufflation on human fetuses, with no data on open spina bifida repair performed using the entirely percutaneous fetoscopic surgical technique.

OBJECTIVE

Our aim was to examine the effects of intrauterine partial CO₂ insufflation on fetal blood gases after percutaneous fetoscopic open spina bifida repair.

STUDY DESIGN

This was a prospective study of patients who underwent percutaneous fetoscopic open spina bifida repair from February 2019 to July 2020. Fetal cordocentesis of the umbilical vein was performed in cases with favorable access to the umbilical cord. The umbilical vein cord blood samples were obtained under ultrasound guidance immediately at the conclusion of the open spina bifida repair. Simultaneous maternal arterial blood gas samples were also obtained. The results are reported as median (range).

RESULTS

Of the 20 patients who underwent percutaneous fetoscopic open spina bifida repair during the study period, 7 patients (35%) underwent fetal blood sampling. The gestational age at the time of surgery was 27.4 (24.0-27.9) weeks and the operative time was 183 (156-251) minutes. The CO₂ exposure time was 122 (57-146) minutes with maximum pressure of 13.5 (12.0-15.0) mm Hg. Fetal umbilical vein results were as follows: pH 7.35 (7.30-7.39), partial pressure of O₂ 56.2 (47.1-99.9) mm Hg, partial pressure of CO₂ 43.8 (36.2-53.0) mm Hg, HCO₃ 23.9 (20.1-25.6) mmol/L, and base excess -2.2 (-4.5 to -0.4) mmol/L. Simultaneous maternal arterial blood gas results were as follows: pH 7.37 (7.28-7.42), partial pressure of O₂ 187.5 (124.4-405.2) mm Hg, partial pressure of CO₂ 36.6 (30.7-46.0) mm Hg, HCO₃ 21.3 (18.0-22.8) mmol/L and base excess -3.2 (-5.9 to -1.8) mmol/L.

CONCLUSION

Despite prolonged CO₂insufflation of the uterus, fetal umbilical vein pH and base excess values did not approach those associated with potentially pathologic fetal acidemia.

Fetal neurodevelopmental recovery in donors after laser surgery for twin-twin transfusion syndrome

BACKGROUND

Fetal magnetic resonance imaging (MRI) and spectroscopy (MRS) provide a unique opportunity to non-invasively measure markers of neurodevelopment in survivors of twin-twin transfusion syndrome (TTTS).

OBJECTIVE

To characterize fetal brain maturation after laser surgery for TTTS by measuring brain volumes and cerebral metabolite concentrations using fetal MRI + MRS.

STUDY DESIGN

Prospective study of dual surviving fetuses treated with laser surgery for TTTS. At 4-5 postoperative weeks, fetal MRI was used together with novel image analysis to automatically extract major brain tissue volumes. Fetal MRS was used to measure major metabolite concentrations in the fetal brain.

RESULTS

Twenty-one twin pairs were studied. The average (±SD) gestational age at MRI was 25.89 (±2.37) weeks. Total brain volume (TBV) was lower in the donors, although cerebral volumes were not different between twin pairs. Recipients showed lower proportions of cortical and cerebellar volumes, normalized to TBV and cerebral volumes. MRS data showed that biochemical differences between twin brains were related to discrepancy in their brain volumes.

CONCLUSION

Although donors have a smaller TBV compared to recipients, proportionality of brain tissue volumes are preserved in donors. MRS maturational markers of fetal brain development show that recovery in donors persists 4 weeks after surgery.

Risk Factors for Co-Twin Fetal Demise following Radiofrequency Ablation in Multifetal Monochorionic Gestations

BACKGROUND

Umbilical cord occlusion via radiofrequency ablation (RFA) is utilized to maximize outcomes of the co-twin in complicated multifetal monochorionic (MC) gestations. However, post-procedure co-twin fetal demise is of concern.

OBJECTIVE

The aim of this study was to determine risk factors for co-twin fetal demise following RFA.

METHODS

This is a retrospective study of MC multiples that underwent RFA. Indications for RFA included twin reversed arterial perfusion (TRAP) sequence, selective fetal growth restriction (sFGR) type II, discordant lethal anomalies, and twin-twin transfusion syndrome (TTTS) with proximate placental cord insertion sites. The primary outcome was co-twin fetal demise. Bivariate analyses and multiple logistic regression modeling of identified risk factors were conducted.

RESULTS

Of 36 patients studied, surgical indications were: TRAP (n = 15, 41.7%), sFGR (n = 10, 27.8%), discordant anomalies (n = 9, 25.0%), and TTTS (n = 2, 5.6%). Nine patients (25.0%) experienced a co-twin fetal demise. In multiple logistic regression analysis, fetal growth restriction (FGR) of one co-twin was associated with increased risk of co-twin fetal demise (OR = 10.85, 95% CI 1.03-114.48, p = 0.0474) and a preoperative diagnosis of TRAP was protective against fetal demise (OR = 0.06, 95% CI 0.00-0.84, p = 0.0368).

CONCLUSION

Co-twin FGR was associated with an increased risk of post-RFA demise. When compared to other indications, patients with TRAP sequence were less likely to have a co-twin demise.

Twin-Twin Transfusion Syndrome Complicated by Proximate Placental Cord Insertion Sites: Endoscopic Clip-Assisted Laser Occlusion

INTRODUCTION

Severe twin-twin transfusion syndrome (TTTS) with a large vascular communication between proximate placental cord insertion sites is a therapeutic dilemma because laser ablation may cause thermal injury to the cord roots and subsequent fetal demise.

CASE PRESENTATION

Stage IV TTTS with placental cord insertion sites 1.3 cm apart and with an intervening large arterio-arterial (AA) anastomosis presented for treatment. The application of endoclips onto the large AA anastomosis between the cord roots allowed for successful laser occlusion using minimal energy. Both the donor and recipient twins were alive and well at 6 months of age.

CONCLUSION

Endoscopic clip-assisted laser occlusion of a placental vessel is technically feasible and may be a useful therapeutic option in select cases.

Survival Outcomes by Fetal Weight Discordance after Laser Surgery for Twin-Twin Transfusion Syndrome Complicated by Donor Fetal Growth Restriction

INTRODUCTION

Management options for treatment of twin-twin transfusion syndrome (TTTS) with severe donor intrauterine growth restriction (IUGR) include fetoscopic laser surgery and umbilical cord occlusion (UCO). We studied perinatal survival outcomes in this select group after laser surgery, stratifying patients by preoperative estimated fetal weight (EFW) discordance.

METHODS

In this retrospective study of monochorionic diamniotic twin gestations with TTTS and selective donor IUGR who underwent laser surgery (2006-2017), preoperative EFW discordance was calculated ([(larger twin - smaller twin)/(larger twin)] × 100) and cases were divided into discordance strata. Severe EFW discordance was defined as >35%. The primary outcome was 30-day donor twin neonatal survival.

RESULTS

The 371 cases were distributed by discordance strata: ≤20% (74 [19.9%]), 21-25% (49 [13.2%]), 26-30% (68 [18.3%]), 31-35% (53 [14.3%]), 36-40% (51 [13.7%]), 41-45% (38 [10.2%]), >45% (38 [10.2%]). Donor 30-day survival declined as the discordance strata increased: 86.5, 85.7, 83.8, 75.5, 64.7, 63.2, and 65.8% (p = 0.0046); 30-day survival was inversely associated with severe discordance (>35%) (64.6 vs. 83.2%, p < 0.0001).

DISCUSSION

In TTTS cases complicated by donor IUGR with severe growth discordance, laser surgery was associated with donor survivorship greater than 60% suggesting that, in this setting, laser surgery remains a reasonable alternative treatment to UCO.

Fetoscopic Laser Ablation Therapy for Type II Vasa Previa

BACKGROUND

In type II vasa previa, fetoscopic laser ablation has the potential to avoid prolonged hospitalization, elective prematurity, and cesarean delivery associated with traditional conservative management.

OBJECTIVE

To assess the feasibility and to report perinatal outcomes of type II vasa previa patients treated via fetoscopic laser ablation.

STUDY DESIGN

This is a retrospective descriptive study of all women with vasa previa treated with laser at our center between 2006 and 2019. After 2010, laser ablation of vasa previa was only offered after 31 gestational weeks. Continuous variables are expressed as means ± SD.

RESULTS

33 patients were evaluated for laser ablation of suspected vasa previa. Fifteen were not candidates (7 had type I vasa previa and 8 had no vasa previa), and the 18 remaining had type II vasa previa. Ten (56%) elected to undergo in utero laser ablation of the vasa previa vessel(s), which was successful in all patients. The mean gestational age (GA) at the time of the procedure was 28.8 ± 5.4 weeks, and the total operative time was 48.1 ± 21.3 min; there were no perioperative complications. The number of vessels lasered were distributed as follows: 1 (2 cases), 2 (5 cases), and 3 (3 cases). All patients except for 1 were subsequently managed as outpatients. The mean GA at delivery was 35.5 ± 3.2 weeks, and vaginal delivery occurred in 5 cases. The 5 patients with singletons who underwent laser ablation for primary diagnosis of type II vasa previa after the protocol change in 2010 had the following outcomes: mean GA of surgery was 32.5 ± 0.8 weeks, mean GA at delivery was 38.1 ± 1.4 weeks, vaginal delivery occurred in all cases, mean birth weight was 2,965 ± 596 g, and none were admitted to the neonatal intensive care unit.

CONCLUSION

This cohort represents the largest number of vasa previa cases treated via in utero laser reported to date. Laser occlusion of type II vasa previa was technically achievable in all cases and resulted in favorable outcomes.

Selective intrauterine growth restriction (SIUGR) type II: proposed subclassification to guide surgical management

Background: Optimal surgical management of monochorionic diamniotic twins complicated by selective intrauterine growth restriction (SIUGR) type II is unknown. Surgical management may involve selective laser photocoagulation of communicating vessels (SLPCV), which offers the possibility of dual twin survivors versus umbilical cord occlusion (UCO) of the SIUGR twin.Objective: To identify patient characteristics associated with SIUGR twin survival for those undergoing SLPCV.Study design: All patients studied were those who underwent fetal treatment for SIUGR type II at our center from 2006-2018. SIUGR type II was defined as an estimated fetal weight <10th percentile with persistent absent and/or reversed end diastolic flow in the umbilical artery of the SIUGR twin, in the absence of twin-twin transfusion syndrome. Patients were offered SLPCV versus UCO, and those undergoing SLPCV, patient characteristics associated with 30-day survival of the SIUGR twin were examined using bivariate analysis and multiple logistic regression models.Results: Fifty-four consecutive SIUGR type II patients were treated, 45 via SLPCV and nine via UCO. Of the 45 SLPCV cases, there were 16 (35.6%) with SIUGR twin (and dual) survival. SIUGR twin survival appeared associated with middle cerebral artery (MCA) peak systolic velocity (psv) <1.5 multiples of the median, and forward atrial systolic flow in the ductus venosus (DV). In a post hoc analysis, we subsequently categorized patients as: SIUGR type IIa (N = 32 (71.1%)): normal MCA psv, and normal DV waveform, versus SIUGR type IIb (N = 13 (28.9%)): MCA psv ≥1.5 multiples of the median, and/or DV with absent or reversed atrial systolic flow. Thirty-day survival of the SIUGR twin was 50% for type IIa and 0% for type IIb.Conclusion: Over one-third of SIUGR type II patients experienced dual survival after treatment with laser surgery. Normal MCA psv and normal DV waveforms were associated with SIUGR type II survival of the SIUGR twin. Post hoc exploration and subclassification of SIUGR type II patients by preoperative Doppler indices created two groups, one (type IIa) with 50% survival and one (type IIb) with 0% survival of the SIUGR twin after laser surgery. Upon further confirmation, these findings may provide guidance for counseling patients and conducting fetal therapy.

Percent Absent End-Diastolic Velocity in the Umbilical Artery and Donor Twin Demise after Laser Surgery for Twin-Twin Transfusion Syndrome

INTRODUCTION

To examine the association of preoperative absent end-diastolic velocity (AEDV) and percent AEDV (%AEDV) in the umbilical artery (UA) with donor twin intrauterine fetal demise (IUFD) after laser surgery for twin-twin transfusion syndrome (TTTS).

METHODS

We performed a retrospective study of stage III/IV TTTS patients who underwent laser surgery from 2006 to 2016. Donors were classified as having preoperative persistent AEDV (yes/no). %AEDV was calculated for those with AEDV as 100× the proportion of the total cardiac cycle in AEDV. Using multiple logistic regression, we tested for an association between the outcome donor IUFD and AEDV risk factors (part 1) and %AEDV (part 2). We stratified these analyses by estimated fetal weight (EFW) discordance ≥20 versus <20%.

RESULTS

Of 344 cases, 153 (44.5%) donors had AEDV. Part 1 did not confirm an independent association between AEDV and donor IUFD. In the part 2 analysis of the 153 patients with AEDV, %AEDV was a positive risk factor for donor IUFD only in those with discordance (n = 129) (OR 1.04, 95% CI 1.01-1.08, p = 0.0278) when adjusting for %EFW discordance, presence of arterioarterial anastomoses, and multiparity.

DISCUSSION

Among stage III/IV TTTS patients with AEDV, %AEDV was a risk factor for donor IUFD only in the presence of EFW discordance.

Antenatal course of referred monochorionic diamniotic twins complicated by selective intrauterine growth restriction (SIUGR) type III

Objective: To describe the antenatal course of selective intrauterine growth restriction (SIUGR) type III patients.Study design: Retrospective study of monochorionic diamniotic twins with SIUGR type III. Patients were divided into those who did and did not progress to SIUGR type II or twin-twin transfusion syndrome (TTTS) (Groups A and B, respectively). Patient characteristics and perinatal survival were compared by Group, and continuous data are reported as median (range).Results: Forty-eight patients were studied; Group A [26 (54.2%)] and Group B [22 (45.8%)]. The difference in 30-day survivorship for the appropriate for gestational age twin (88.5 vs. 100%, p = .2394) and for the SIUGR twin (73.1 vs. 95.5%, p = .0551) was not statistically significant. However, dual survivorship was lower in Group A compared to Group B (69.2 vs. 95.4%, p = .0276).Conclusions: Approximately half of the SIUGR type III patients had antenatal progression. Lack of antenatal progression was associated with 95% dual survivorship.Rationale: The antenatal course of monochorionic diamniotic twins complicated by SIUGR type III is not well-understood and antenatal management remains a clinical dilemma. We provide pregnancy outcomes in a referred group of SIUGR type III patients, including the rate of progression to SIUGR type II and TTTS.

Membrane Separation and Perinatal Outcomes after Laser Treatment for Twin-Twin Transfusion Syndrome

INTRODUCTION

Postoperative membrane separation is a complication of selective laser photocoagulation of communicating vessels (SLPCV) for the treatment of twin-twin transfusion syndrome (TTTS).

OBJECTIVE

The aim of this work was to determine whether a quantitative grading system of membrane separation following SLPCV was associated with preterm premature rupture of membranes (PPROM) and preterm delivery (PTD).

METHODS

Patients with membrane separation after SLPCV on postoperative day 1 were stratified into greatest width of separation <1 cm (Group A) or ≥1 cm (Group B) and compared to patients without separation by the following outcomes: PPROM ≤21 postoperative days, PTD <28 gestational weeks, and PTD <32 gestational weeks.

RESULTS

Of 654 patients, 123 (18.8%) had membrane separation. Of these, 120 patients were eligible for study and divided into Groups A (n = 91) and B (n = 29). Multiple logistic regression analysis yielded associations with PPROM ≤21 days for Groups B (OR 8.60, 95% CI 3.38-21.90, p < 0.0001) and A (OR 2.39, 95% CI 1.05-5.40, p = 0.0369) compared to those without membrane separation. In similar models, Group B was associated with PTD <32 weeks (OR 2.41, 95% CI 1.10-5.28, p = 0.0274).

CONCLUSION

Postoperative membrane separation was associated with an increased risk of PPROM ≤21 days. Membrane separation ≥1 cm had a higher risk of PTD <32 weeks.

Iodine-Induced Fetal Hypothyroidism: Diagnosis and Treatment with Intra-Amniotic Levothyroxine

BACKGROUND

Iodine is necessary for fetal thyroid development. Excess maternal intake of iodine can cause fetal hypothyroidism due to the inability to escape from the Wolff-Chaikoff effect in utero.

CASE REPORT

We report a case of fetal hypothyroid goiter secondary to inadvertent excess maternal iodine ingestion from infertility supplements. The fetus was successfully treated with intra-amniotic levothyroxine injections. Serial fetal blood sampling confirmed fetal escape from the Wolff-Chaikoff effect in the mid third trimester. Early hearing test and neurodevelopmental milestones were normal.

CONCLUSION

Intra-amniotic treatment of fetal hypothyroidism may decrease the rate of impaired neurodevelopment and sensorineural hearing loss.

Quantitative fetal fibronectin to predict spontaneous preterm delivery after laser surgery for twin-twin transfusion syndrome

Our goal was to assess whether quantitative fetal fibronectin (qfFN) is associated with spontaneous preterm birth (sPTB) after laser surgery for twin-twin transfusion syndrome (TTTS). qfFN was collected within 24 hours before and after laser surgery. Aims were: (1) To determine if qfFN changed with operative fetoscopy; and (2) To estimate the number of patients needed to study the predictive value of qfFN for sPTB <28 and <32 weeks. Results are reported as median (range). Among 49 patients, there was no net difference in qfFN levels after laser surgery [0.0 ng/mL (-37 to +400), p = 0.6041]. However, patients with a qfFN increase >10 ng/mL were 19 times more likely to undergo sPTB at <28 weeks (OR = 19.5). We determined that 383 and 160 patients would be needed to achieve adequate statistical power for qfFN to be predictive of sPTB at a GA <28 weeks and <32 weeks, respectively. In conclusion, laser surgery did not alter the qfFN level within the entire cohort, but qfFN may be useful in identifying a subset of patients at increased risk of preterm delivery.

Long-Term Outcomes After Thoracoamniotic Shunt for Pleural Effusions With Secondary Hydrops

BACKGROUND

Congenital pleural effusion is a rare condition with an incidence of approximately one per 15,000 pregnancies. The development of secondary hydrops is a poor prognostic indicator and such cases can be managed with a thoracoamniotic shunt (TAS). Our objective is to describe postnatal outcomes in survivors after TAS placement for congenital pleural effusions.

MATERIALS AND METHODS

A retrospective study of all cases with fetal pleural effusions treated between 2006 and 2016. Patients with dominant unilateral or bilateral pleural effusions complicated by secondary hydrops fetalis received TAS placement. The results are reported as median (range).

RESULTS

A total of 29 patients with pleural effusion with secondary hydrops underwent TAS placement. The gestational age at the initial TAS placement was 27.6 (20.3-36.9) wk. Before delivery, hydrops resolved in 17 (58.6%) patients. The delivery gestational age was 35.7 (25.4-41.0) wk and the overall survival rate was 72.4%. Among the 21 survivors, 19 (90.5%) required admission to the neonatal intensive care unit for 15 (5-64) d. All 21 survivors had postnatal resolution of the pleural effusions. All 21 children were long-term survivors, with a median age of survivorship of 3 y 3 mo (9 mo-7 y 6 mo) at the time of last reported follow-up.

CONCLUSIONS

Thoracoamniotic shunting in fetuses with a dominant pleural effusion(s) and secondary hydrops resulted in a 72% survival rate. Nearly all survivors required admission to the neonatal intensive care unit. However, a majority did not have significant long-term morbidity.

The Use of Fetal Bronchoscopy in the Diagnosis and Management of a Suspected Obstructive Lung Mass

Etiologies of fetal lung anomalies include congenital pulmonary airway malformation (CPAM), intra- or extralobar pulmonary sequestration, congenital high airway obstruction syndrome (CHAOS), bronchogenic cyst, and bronchial atresia. Fetal tracheobronchoscopy has been reported both as a diagnostic and therapeutic procedure in the setting of severe congenital lung lesions. In this case report, prenatal imaging of a fetus with a large chest mass was suspicious for an obstructive bronchial lesion. The absence of visible normal lung tissue on the right side and mass effect on the left side raised the concern for pulmonary hypoplasia. After antenatal betamethasone and a period observation, hydropic changes developed. Fetal tracheobronchoscopy was then performed in an effort to identify and decompress the suspected obstructive bronchial lesion. Other than release of bronchial debris, no anatomical abnormalities were visualized. However, the right lung lesion and mediastinal shift both decreased after the fetal bronchoscopy. The newborn underwent postnatal resection of a CPAM Type II and is doing well. We hypothesize that fetal tracheobronchoscopy provided the following potential diagnostic and therapeutic benefits: (1) exclusion of an obstructive bronchial lesion; (2) disimpaction of bronchial debris from the saline lavage that we posit may have contributed to the rapid reduction in CPAM size.

Risks of Preterm Premature Rupture of Membranes and Preterm Birth Post Fetoscopy Based on Location of Trocar Insertion Site

OBJECTIVE

The objective of this study was to assess whether the location of the trocar insertion site for laser treatment of twin-twin transfusion syndrome was associated with preterm-premature rupture of membranes (PPROM) and preterm birth (PTB).

STUDY DESIGN

In this study trocar location was documented in the operating room. Lower uterine segment (LUS) location was defined as any insertion <10 cm vertically from the pubic symphysis. Lateral location was defined as ≥5 cm horizontally from the midline. Patient characteristics were tested against three outcomes: PPROM ≤ 21 days postoperative, PTB < 28 weeks, and PTB < 32 weeks. For each outcome, multiple logistic models were fitted to examine the effect of trocar location, controlling for potential risk factors.

RESULTS

A total of 743 patients were studied. Patients with LUS location were twice as likely as those with a more superior location to have PPROM ≤ 21 days (OR = 2.33, 1.12-4.83, p = 0.0236). Patients with both a LUS and Lateral location were over six times more likely to have PPROM ≤ 21 days (OR = 6.66, 2.36-18.78, p = 0.0003). Trocar insertion site was not associated with PTB.

CONCLUSION

We found that trocar insertion in the LUS, particularly the lateral LUS, was associated with an increased risk of PPROM.

Types II and III congenital pulmonary airway malformation with hydrops treated in utero with percutaneous sclerotherapy

OBJECTIVE

To present outcomes of fetuses with congenital pulmonary airway malformation (CPAM) treated with sclerotherapy.

METHODS

Retrospective study of 8 patients with a prenatal diagnosis of CPAM type II or III with secondary hydrops treated with percutaneous sclerotherapy using 5% ethanolamine oleate (EO). All patients underwent ultrasonic measurement of the CPAM volume ratio. Results are expressed as median (range).

RESULTS

Gestational age at initial sclerotherapy was 22.0 weeks (19.6-31.4); 3 patients underwent 2 procedures. Intrauterine fetal demise (IUFD) occurred in 4 cases; 2 died on postoperative day #1 (one from inadvertent intravascular EO injection); 2 died >6 weeks after the procedure. Preoperative CPAM volume ratio was 3.6 (1.6-7.8) in survivors and 2.7 (1.7-4.7) in those with IUFD. The volume of EO at the initial sclerotherapy procedure was 3 mL (2-5) in survivors and 7 mL (6-10) in IUFD cases. The gestational age at delivery of the 4 survivors was 38.4 weeks (37.4-39.3); all underwent postnatal resection.

CONCLUSION

The efficacy of percutaneous sclerotherapy for CPAM types II and III remains in question. Further studies are needed to determine the optimal dose of sclerotherapy agent and the safety and efficacy of this procedure.

Management of twin-twin transfusion syndrome with an extremely short cervix

The objective of this study was to describe the management and perinatal outcomes of patients with twin-twin transfusion syndrome (TTTS) and an extremely short cervical length (CL). This retrospective study examined 17 patients with TTTS and a preoperative CL ≤1.0 cm who had undergone laser surgery and perioperative cervical cerclage placement successfully. In this subset of patients, the median interval between surgery and delivery was 9.6 (range 2.1-13.9) weeks and only one patient had PPROM within 3 weeks of surgery. The median gestational age at delivery was 30.9 (range 23.1-37.6) weeks, 30-day survival of at-least-one twin was 88.2% and dual survivorship was 82.4%. Overall, patients with TTTS and a preoperative CL ≤1.0 cm who were able to undergo successful laser surgery and emergent cerclage placement had favourable outcomes. Impact statement The management of patients with twin-twin transfusion syndrome (TTTS) and extremely short cervical length (CL) varies between foetal surgery centres. This study demonstrates that laser surgery and cerclage placement in such patients are not only technically feasible, but also can result in favourable perinatal outcomes. Patients with an extremely short CL should not be uniformly excluded from laser surgery for TTTS.

The relationship between preoperative fetal head circumference and 2-year cognitive performance after laser surgery for twin-twin transfusion syndrome

OBJECTIVE

To determine the relationship between preoperative fetal head circumference (HC) and cognitive performance among children treated with laser surgery for twin-twin transfusion syndrome (TTTS).

METHODS

Donor and recipient twin HCs were measured preoperatively (16-26 weeks' gestation) and at 2 years corrected age. Multilevel multivariate regression models were used to test pregnancy and child-level risk factors for lower Battelle Developmental Inventory Second Edition (BDI-2) scores. A repeated-measures ANOVA was used to examine HC growth among recipients and donors between preoperative and 2 years.

RESULTS

Ninety-nine children were evaluated. The average BDI-2 score for the cohort was 101.4 (SD = 12.2). After controlling for covariates, larger preoperative HC percentiles were significantly associated with an increase in total BDI-2 scores (β = 0.29; P < 0.001), where a 12.5% increase in preoperative HC percentile was associated with 1-point increase in total BDI-2 score. The mean recipient and donor twin HC percentiles preoperatively and at age 2 years were 51^st percentile vs 20^th percentile (P = .050) and 60^th percentile vs 49^th percentile (P = .676), respectively.

CONCLUSION

Smaller preoperative HC percentiles identified children at risk of lower, but still within normal range, total BDI-2 scores. The discordance in HC percentiles between the donor and recipient twin decreased after laser surgery.

Risk factors for fetomaternal bleeding after laser therapy for twin-twin transfusion syndrome

OBJECTIVE

To quantify and assess potential risk factors for transplacental passage of fetal red blood cells (RBCs) into the maternal circulation (fetomaternal bleeding, FMB) after laser surgery for twin-twin transfusion syndrome (TTTS).

STUDY DESIGN

A retrospective study of Rhesus-D negative patients that underwent laser surgery for TTTS. Patients with and without postoperative detectable fetal RBCs on Kleihauer-Betke (KB) testing were compared to determine risk factors for FMB. Patients were further sub-classified into those with a FMB < 20% and ≥20% of estimated fetoplacental blood volume.

RESULTS

Of 60 studied patients, 26/60 (43%) had a positive postoperative KB test. The median fetal:adult RBC ratio was 0.00125, estimated to be a FMB volume of 6.25 mL. There were 17/26 (65%) of patients with FMB < 20% and 9/26 (35%) patients with ≥20% of the fetoplacental blood volume. Stage III-Recipient and III-Recipient/Donor patients were more likely to have a positive KB test (14/21 [66.7%] vs 12/39 [30.8%], OR = 4.50 [1.27-16.54], P = 0.0162). No other risk factors for FMB were apparent.

CONCLUSIONS

Fetomaternal bleed appears to be a common finding after laser surgery for TTTS. TTTS Stage, particularly stage III-Recipient and III-Recipient/Donor, appears to be a risk factor for FMB.

A Complication of Percutaneous Sclerotherapy for Congenital Pulmonary Airway Malformation: Intravascular Injection and Cardiac Necrosis

INTRODUCTION

A congenital pulmonary airway malformation (CPAM) type III may become large enough to cause hydrops fetalis. In such circumstances, the fetus can be treated with open fetal resection, maternal betamethasone administration, or percutaneous sclerotherapy.

CASE REPORT

A 24 week gestation fetus with a CPAM type III was treated by percutaneous sclerotherapy using ethanolamine oleate (EO). The EO inadvertently entered the left atrium and ventricle with subsequent fetal bradycardia and demise. Autopsy revealed myocardial necrosis.

CONCLUSION

Percutaneous sclerotherapy has been previously described in the literature for the treatment of microcystic CPAMs with secondary hydrops. This is the first reported case of an adverse event after fetal sclerotherapy.

Midtrimester isolated oligohydramnios in monochorionic diamniotic multiple gestations. J Matern Fetal Neonatal Med 2017;32:590-596. [PMID: 28965437 DOI: 10.1080/14767058.2017.1387530]

OBJECTIVE

To describe the natural history and perinatal outcomes of monochorionic diamniotic twins with midtrimester isolated oligohydramnios (iOligo).

MATERIALS AND METHODS

We performed a retrospective study of iOligo patients who were initially referred for the management of evolving twin-twin transfusion syndrome (TTTS) or selective intrauterine growth restriction (sIUGR). iOligo was defined as a maximum vertical pocket of amniotic fluid of ≤2 cm in the iOligo twin's sac and normal fluid level (>2 and <8 cm) in the co-twin's sac. "Group A" patients did not subsequently develop TTTS or sIUGR Type II (umbilical artery persistent absent or reversed end-diastolic flow), and "Group B" patients did develop TTTS or sIUGR Type II. Results are reported as median (range).

RESULTS

Of the 828 patients with complicated monochorionic twin gestations referred for possible TTTS or sIUGR, 36 (4.3%) were initially diagnosed with iOligo. After initial consultation, two patients terminated and one was lost to follow-up, resulting in a final study population of 33. Group A had 10 patients (30.3%) and Group B had 23 patients (69.7%). In Group A, nine of the 10 were expectantly managed, resulting in a median gestational age (GA) at delivery of 34.7 (18.0-36.4) weeks, a 30-day perinatal survival of at-least-one twin of 88.9% (8/9), and dual 30-day survivors in 8/9 (88.9%). In Group B, 12 (52.2%) developed TTTS and 11 (47.8%) developed sIUGR Type II. Fifteen Group B patients had laser surgery, resulting in a median GA at delivery of 33.7 (26.4-37.1) weeks, a 30-day perinatal survival of at-least-one twin of 100% (15/15), and dual survivorship of 46.7% (7/15).

CONCLUSIONS

Our findings show that the majority of patients with midtrimester iOligo have fetal growth restriction of the affected twin and subsequently progress to TTTS or sIUGR Type II.

Neonatal cerebral lesions predict 2-year neurodevelopmental impairment in children treated with laser surgery for twin-twin transfusion syndrome

OBJECTIVE

The objective of this study is to assess whether postnatally detected cerebral abnormalities are predictive of neurodevelopmental impairment (NDI) in survivors of twin-twin transfusion syndrome (TTTS) that underwent laser surgery.

MATERIALS AND METHODS

Ninety-nine children treated for TTTS had neurodevelopmental assessment at age 2-years (±6 weeks). 'High-risk survivors' had cerebral imaging in the neonatal period. 'High-risk survivors' were defined as (1) delivered at <32 weeks; or (2) cerebral imaging clinically indicated. NDI was a composite outcome of: Battelle Developmental Inventory 2nd edition (BDI-2) score <70, cerebral palsy, blindness, and/or deafness. Multilevel logistic regression with robust standard errors was used to evaluate associations between cerebral lesions and NDI.

RESULTS

Fifty-six children were 'high-risk survivors' and had neonatal cerebral imaging. Ten twins (18%) had at least one cerebral lesion, including grade 1-2 intraventricular hemorrhage (8), cystic periventricular leukomalacia (2), ventriculomegaly (1), and bilateral subependymal cyst (1). The risk of NDI in the 'high-risk survivors' was 7% (4/56) compared with 0% (0/43) in the remaining group. Among 'high-risk survivors', cerebral lesions were a significant risk factor for NDI (OR = 19.28, p < .001).

CONCLUSIONS

Among 'high-risk survivors' of TTTS treated with laser surgery, cerebral lesions identified on neonatal imaging were associated with NDI at 2-years.

Pseudoamniotic Band Syndrome Post Fetal Thoracoamniotic Shunting for Bilateral Hydrothorax

INTRODUCTION

Pseudoamniotic band syndrome (PABS) occurs iatrogenically after fetal surgery or amniocentesis due to chorioamniotic membrane separation. Separation of the amnion from the chorion can expand to form fibrous amniotic bands that can envelope fetal limbs or the umbilical cord, with consequences ranging from limb constriction to fetal demise.

CASE REPORT

We report a case of bilateral fetal pleural effusions at 27 weeks' gestation treated by bilateral thoracoamniotic shunts. Following shunt placement, the hydrothorax resolved. However, chorioamniotic membrane separation developed resulting in PABS with subsequent umbilical cord strangulation and fetal demise at 32 weeks' gestation.

CONCLUSION

PABS has been previously described in the literature following various fetal interventions. This is the first reported case of pseudoamniotic band syndrome after placement of fetal thoracoamniotic shunts. A high index of suspicion is required to diagnose PABS via postoperative ultrasound. Post intervention chorioamniotic membrane separation warrants close surveillance for sonographic evidence of PABS.