Growth patterns of monochorionic twin pregnancy complicated by Type-III selective fetal growth restriction.

OBJECTIVES: Little is known regarding fetal growth patterns in monochorionic twin pregnancy complicated by Type-III selective fetal growth restriction (sFGR). We aimed to assess fetal growth and umbilical artery Doppler pattern in Type-III sFGR across gestation and evaluate the effect of changing Doppler flow pattern on growth and intertwin growth discordance. METHODS: This was a retrospective cohort study of all Type-III sFGR pregnancies managed at nine fetal centers over a 12-year time period. Higher-order multiple pregnancy and cases with major fetal anomaly or other monochorionicity-related complications at presentation were excluded. Estimated fetal weight (EFW) was assessed on ultrasound for each twin pair at five timepoints (16-20, 21-24, 25-28, 29-32 and > 32 weeks' gestation) and compared with singleton and uncomplicated monochorionic twin EFW. EFW and intertwin EFW discordance were compared between pregnancies with normalization of umbilical artery Doppler of the smaller twin later in pregnancy and those with persistently abnormal Doppler. RESULTS: Overall, 328 pregnancies (656 fetuses) met the study criteria. In Type-III sFGR, the smaller twin had a lower EFW than an average singleton fetus (EFW Z-score ranging from -1.52 at 16 weeks to -2.69 at 36 weeks) and an average monochorionic twin in uncomplicated pregnancy (Z-score ranging from -1.73 at 16 weeks to -1.49 at 36 weeks) throughout the entire gestation, while the larger twin had a higher EFW than an average singleton fetus until 22 weeks' gestation and was similar in EFW to an average uncomplicated monochorionic twin throughout gestation. As pregnancy advanced, growth velocity of both twins decreased, with the larger twin remaining appropriately grown and the smaller twin becoming more growth restricted. Intertwin EFW discordance remained stable throughout gestation. On multivariable longitudinal modeling, normalization of fetal umbilical artery Doppler was associated with better growth of the smaller twin (P = 0.002) but not the larger twin (P = 0.1), without affecting the intertwin growth discordance (P = 0.09). CONCLUSIONS: Abnormal fetal growth of the smaller twin in Type-III sFGR was evident early in pregnancy, while EFW of the larger twin remained normal throughout gestation. Normalization of umbilical artery Doppler was associated with improved fetal growth of the smaller twin. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of fetal death in monochorionic twin pregnancies complicated by Type-III selective fetal growth restriction.

OBJECTIVE: Monochorionic diamniotic twin pregnancies complicated by Type-III selective fetal growth restriction (sFGR) are at high risk of fetal death. The aim of this study was to identify predictors of fetal death in these pregnancies. METHODS: This was an international multicenter retrospective cohort study. Type-III sFGR was defined as fetal estimated fetal weight (EFW) of one twin below the 10th percentile and intertwin EFW discordance of ≥ 25% in combination with intermittent absent or reversed end-diastolic flow in the umbilical artery of the smaller fetus. Predictors of fetal death were recorded longitudinally throughout gestation and assessed in univariable and multivariable logistic regression models. The classification and regression trees (CART) method was used to construct a prediction model of fetal death using significant predictors derived from the univariable analysis. RESULTS: A total of 308 twin pregnancies (616 fetuses) were included in the analysis. In 273 (88.6%) pregnancies, both twins were liveborn, whereas 35 pregnancies had single (n = 19 (6.2%)) or double (n = 16 (5.2%)) fetal death. On univariable analysis, earlier gestational age at diagnosis of Type-III sFGR, oligohydramnios in the smaller twin and deterioration in umbilical artery Doppler flow were associated with an increased risk of fetal death, as was larger fetal EFW discordance, particularly between 24 and 32 weeks' gestation. None of the parameters identified on univariable analysis maintained statistical significance on multivariable analysis. The CART model allowed us to identify three risk groups: a low-risk group (6.8% risk of fetal death), in which umbilical artery Doppler did not deteriorate; an intermediate-risk group (16.3% risk of fetal death), in which umbilical artery Doppler deteriorated but the diagnosis of sFGR was made at or after 16 + 5 weeks' gestation; and a high-risk group (58.3% risk of fetal death), in which umbilical artery Doppler deteriorated and gestational age at diagnosis was < 16 + 5 weeks' gestation. CONCLUSIONS: Type-III sFGR is associated with a high risk of fetal death. A prediction algorithm can help to identify the highest-risk group, which is characterized by Doppler deterioration and early referral. Further studies should investigate the potential benefit of fetal surveillance and intervention in this cohort. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Placental gas exchange during amniotic carbon dioxide insufflation in sheep.

OBJECTIVE: Insufflation of the amniotic cavity with carbon dioxide (CO2 ) is used clinically to improve visibility during complex fetoscopic surgery. Insufflation with heated, humidified CO2 has recently been shown to reduce fetal hypercapnia and acidosis in sheep, compared with use of cold and dry CO2 , but the underlying mechanisms are unclear. The aim of this study was to investigate whether differences in placental CO2 and oxygen (O2 ) exchange during insufflation with heated and humidified vs cold and dry CO2 could explain these findings. METHODS: Thirteen fetal lambs at 105 days of gestation (term, 146 days) were exteriorized partially, via a midline laparotomy and hysterotomy, and instrumented with an umbilical artery catheter, an umbilical vein catheter and a common umbilical vein flow probe. Arterial and venous catheters and flow probes were also inserted into the maternal uterine circulation. Six ewes were insufflated with cold, dry CO2 (22°C; 0-5% humidity) and seven with heated, humidified CO2 (40°C; 95-100% humidity) at 15 mmHg for 180 min. Blood-flow recordings and paired arterial and venous blood gases were sampled from uterine and umbilical vessels. Rates of placental CO2 and O2 exchange were calculated. RESULTS: After 180 min of insufflation, fetal survival was 33% (2/6) using cold, dry CO2 and 71% (5/7) using heated, humidified CO2 . By 120 min, fetuses insufflated with heated, humidified CO2 had lower arterial CO2 levels and higher arterial pH compared to those insufflated with cold, dry gas. Insufflation decreased significantly placental gas exchange in both groups, as measured by rates of both (i) fetal CO2 clearance and O2 uptake and (ii) maternal O2 delivery and CO2 uptake from the fetal compartment. CONCLUSIONS: Lower arterial CO2 and higher pH levels in fetuses insufflated with heated and humidified, compared to cold and dry, CO2 could not be explained by differences in placental gas exchange. Instead, heated and humidified insufflation appeared to reduce fetal CO2 absorption from the uterus, supporting its use in preference to cold, dry CO2 . © 2019 International Society of Ultrasound in Obstetrics and Gynecology.

Outcome of monochorionic twin pregnancy complicated by Type-III selective intrauterine growth restriction.

OBJECTIVE: Type-III selective intrauterine growth restriction (sIUGR) is associated with a high and unpredictable risk of fetal death and fetal brain injury. The objective of this study was to describe the prospective risk of fetal death and the risk of adverse neonatal outcome in a cohort of twin pregnancies complicated by Type-III sIUGR and treated according to up-to-date guidelines. METHODS: We reviewed retrospectively all monochorionic diamniotic twin pregnancies complicated by Type-III sIUGR managed at nine fetal centers over a 12-year period. Higher-order multiple gestations and pregnancies with major fetal anomalies or other monochorionicity-related complications at initial presentation were excluded. Data on fetal and neonatal outcomes were collected and management strategies reviewed. Composite adverse neonatal outcome was defined as neonatal death, invasive ventilation beyond the resuscitation period, culture-proven sepsis, necrotizing enterocolitis requiring treatment, intraventricular hemorrhage Grade > I, retinopathy of prematurity Stage > II or cystic periventricular leukomalacia. The prospective risk of intrauterine death (IUD) and the risk of neonatal complications according to gestational age were evaluated. RESULTS: We collected data on 328 pregnancies (656 fetuses). After exclusion of pregnancies that underwent selective reduction (n = 18 (5.5%)), there were 51/620 (8.2%) non-iatrogenic IUDs in 35/310 (11.3%) pregnancies. Single IUD occurred in 19/328 (5.8%) pregnancies and double IUD in 16/328 (4.9%). The prospective risk of non-iatrogenic IUD per fetus declined from 8.1% (95% CI, 5.95-10.26%) at 16 weeks, to less than 2% (95% CI, 0.59-2.79%) after 28.4 weeks and to less than 1% (95% CI, -0.30 to 1.89%) beyond 32.6 weeks. In otherwise uncomplicated pregnancies with Type-III sIUGR, delivery was generally planned at 32 weeks, at which time the risk of composite adverse neonatal outcome was 29.0% (31/107 neonates). In twin pregnancies that continued to 34 weeks, there was a very low risk of IUD (0.7%) and a low risk of composite adverse neonatal outcome (11%). CONCLUSIONS: In this cohort of twin pregnancies complicated by Type-III sIUGR and treated at several tertiary fetal centers, the risk of fetal death was lower than that reported previously. Further efforts should be directed at identifying predictors of fetal death and optimal antenatal surveillance strategies to select a cohort of pregnancies that can continue safely beyond 33 weeks' gestation. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Physiological effects of partial amniotic carbon dioxide insufflation with cold, dry vs heated, humidified gas in a sheep model.

OBJECTIVE: Partial amniotic carbon dioxide (CO2 ) insufflation (PACI) is used to improve visualization and facilitate complex fetoscopic surgery. However, there are concerns about fetal hypercapnic acidosis and postoperative fetal membrane inflammation. We assessed whether using heated and humidified, rather than cold and dry, CO2 might reduce the impact of PACI on the fetus and fetal membranes in sheep. METHODS: Twelve fetal lambs of 105 days' gestational age (term = 145 days) were exteriorized partially, via a midline laparotomy and hysterotomy, and arterial catheters and flow probes were inserted surgically. The 10 surviving fetuses were returned to the uterus, which was then closed and insufflated with cold, dry (22 °C at 0-5% humidity, n = 5) or heated, humidified (40 °C at 100% humidity, n = 5) CO2 at 15 mmHg for 180 min. Fetal membranes were collected immediately after insufflation for histological analysis. Physiological data and membrane leukocyte counts, suggestive of membrane inflammation, were compared between the two groups. RESULTS: After 180 min of insufflation, fetal survival was 0% in the group which underwent PACI with cold, dry CO2 , and 60% (n = 3) in the group which received heated, humidified gas. While all insufflated fetuses became progressively hypercapnic (PaCO2  > 68 mmHg), this was considerably less pronounced in those in which heated, humidified gas was used: after 120 min of insufflation, compared with those receiving cold, dry gas (n = 3), fetuses undergoing heated, humidified PACI (n = 5) had lower arterial partial pressure of CO2 (mean ± standard error of the mean, 82.7 ± 9.1 mmHg for heated, humidified CO2 vs 170.5 ± 28.5 for cold, dry CO2 during PACI, P < 0.01), lower lactate levels (1.4 ± 0.4 vs 8.5 ± 0.9 mmol/L, P < 0.01) and higher pH (pH, 7.10 ± 0.04 vs 6.75 ± 0.04, P < 0.01). There was also a non-significant trend for fetal carotid artery pressure to be higher following PACI with heated, humidified compared with cold, dry CO2 (30.5 ± 1.3 vs 8.7 ± 5.5 mmHg, P = 0.22). Additionally, the median (interquartile range) number of leukocytes in the chorion was significantly lower in the group undergoing PACI with heated, humidified CO2 compared with the group receiving cold, dry CO2 (0.7 × 10-5 (0.5 × 10-5 ) vs 3.2 × 10-5 (1.8 × 10-5 ) cells per square micron, P = 0.02). CONCLUSIONS: PACI with cold, dry CO2 causes hypercapnia, acidosis, hypotension and fetal membrane inflammation in fetal sheep, raising potential concerns for its use in humans. It seems that using heated, humidified CO2 for insufflation partially mitigates these effects and this may be a suitable alternative for reducing the risk of fetal acid-base disturbances during, and fetal membrane inflammation following, complex fetoscopic surgery. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Antenatal sildenafil treatment improves neonatal pulmonary hemodynamics and gas exchange in lambs with diaphragmatic hernia.

OBJECTIVES: Infants with congenital diaphragmatic hernia (CDH) are predisposed to pulmonary hypertension after birth, owing to lung hypoplasia that impairs fetal pulmonary vascular development. Antenatal sildenafil treatment attenuates abnormal pulmonary vascular and alveolar development in rabbit and rodent CDH models, but whether this translates to functional improvements after birth remains unknown. We aimed to evaluate the effect of antenatal sildenafil on neonatal pulmonary hemodynamics and lung function in lambs with diaphragmatic hernia (DH). METHODS: DH was surgically induced at approximately 80 days' gestation in 16 lamb fetuses (term in lambs is approximately 147 days). From 105 days' gestation, ewes received either sildenafil (0.21 mg/kg/h intravenously) or saline infusion until delivery (n = 8 fetuses in each group). At approximately 138 days' gestation, all lambs were instrumented and then delivered via Cesarean section. The lambs were ventilated for 120 min with continuous recording of physiological (pulmonary and carotid artery blood flow and pressure; cerebral oxygenation) and ventilatory parameters, and regular assessment of arterial blood gas tensions. Only lambs that survived until delivery and with a confirmed diaphragmatic defect at postmortem examination were included in the analysis; these comprised six DH-sildenafil lambs and six DH-saline control lambs. RESULTS: Lung-to-body-weight ratio (0.016 ± 0.001 vs 0.013 ± 0.001; P = 0.06) and dynamic lung compliance (0.8 ± 0.2 vs 0.7 ± 0.2 mL/cmH2 O; P = 0.72) were similar in DH-sildenafil lambs and controls. Pulmonary vascular resistance decreased following lung aeration to a greater degree in DH-sildenafil lambs, and was 4-fold lower by 120 min after cord clamping than in controls (0.6 ± 0.1 vs 2.2 ± 0.6 mmHg/(mL/min); P = 0.002). Pulmonary arterial pressure was also lower (46 ± 2 vs 59 ± 2 mmHg; P = 0.048) and pulmonary blood flow higher (25 ± 3 vs 8 ± 2 mL/min/kg; P = 0.02) in DH-sildenafil than in DH-saline lambs at 120 min. Throughout the 120-min ventilation period, the partial pressure of arterial carbon dioxide tended to be lower in DH-sildenafil lambs than in controls (63 ± 8 vs 87 ± 8 mmHg; P = 0.057), and there was no significant difference in partial pressure of arterial oxygen between the two groups. CONCLUSIONS: Sustained maternal antenatal sildenafil infusion reduced pulmonary arterial pressure and increased pulmonary blood flow in DH lambs for the first 120 min after birth. These findings of improved pulmonary vascular function are consistent with improved pulmonary vascular structure seen in two previous animal models. The data support the rationale for a clinical trial investigating the effect of antenatal sildenafil in reducing the risk of neonatal pulmonary hypertension in infants with CDH. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Fertility, pregnancy and gynecological outcomes after fetoscopic surgery for congenital diaphragmatic hernia.

STUDY QUESTION: What is the impact of fetoscopic surgery for isolated Congenital Diaphragmatic Hernia (CDH) on future reproductive and gynecological outcomes? SUMMARY ANSWER: We did not observe an increase of obstetric or gynecological problems after fetoscopic surgery nor was there an increased risk for subsequent infertility. WHAT IS KNOWN ALREADY: The reproductive and gynecological outcomes of patients undergoing open maternal-fetal surgery are known. The most relevant counseling items are the elevated risk for uterine dehiscence and rupture (up to 14%). STUDY DESIGN, SIZE, DURATION: Bi-centric study over a 10-year period including 371 women carrying a fetus with isolated CDH either managed expectantly (n = 167) or operated in utero (n = 204). PARTICIPANTS/MATERIALS, SETTING, METHODS: Consenting patients filled out a survey with 23 questions (2 open and 21 multiple choice). Questionnaires were custom designed to obtain information on subsequent reproductive or gynecological problems as well as psychological impact. MAIN RESULTS AND THE ROLE OF CHANCE: The response rate was 40% (147/371). More women in the FETO group attempted a subsequent pregnancy: 70% (62/89) when compared with 47% (27/58) in controls (P = 0.009). This coincided with a longer follow-up in the FETO group (76 versus 59 months; P < 0.001) and a lower survival rate in the index pregnancy (53 versus 72%; P = 0.028). There was no difference in the number of nulliparous or parous women, neither in the conception rate. In total, there were 129 subsequent pregnancies. Nobody reported secondary fertility problems. Four women in the FETO group and one in the control reported a congenital anomaly in a subsequent pregnancy. Twenty-one pregnancies were reported with at least one complication (FETO: 23% (14/60), controls 27% (7/26)). During delivery or in the post-partum period 11 patients reported at least 1 complication (FETO 17% (10/59), controls 4% (1/24)). New onset gynecological problems occurred in 14 participants (10%). None of these events were more likely in one or the other group. Psychological and emotional impacts were frequent in both the FETO (41%) and the control groups (46%) (P = 0.691). LIMITATIONS, REASONS FOR CAUTION: The response rate was 40% (147/371), less than desired. The use of unvalidated self-reported outcomes may skew exact determination of the nature and severity of medical complications. The number of observations for uncommon events was low. The mean follow-up period to detect gynecological complications may be too short. WIDER IMPLICATIONS OF THE FINDINGS: This is the first evidence that fetoscopic surgery for CDH does not compromise future reproductive potential or obstetrical outcome when compared with expectant management. A pregnancy complicated by a serious congenital birth defect, such as CDH, frequently has a measurable psychological impact. STUDY FUNDING/COMPETING INTEREST: The authors have no conflicts to declare. J.D. receives a fundamental clinical research grant of the Fonds Wetenschappelijk Onderzoek - Vlaanderen (FWO; 18.01207). A.C.E. is supported by the Erasmus+Program of the European Union (Framework agreement number 2013-0040; contract 1011990). This was presented at the 61st meeting of the Society of Gynaecologic Investigation, in Florence, March 2014 (F-111).

Right-sided congenital diaphragmatic hernia in a decade of fetal surgery.

OBJECTIVE: To report a recent update on fetuses with right-sided congenital diaphragmatic hernia (RCDH) in the era of fetal surgery. DESIGN: Retrospective review of prospectively collected data. SETTING: Fetal treatment centres in Leuven and Barcelona. POPULATION: Consecutive cases of RCDH between 2002 and 2012. METHODS: Data on prenatal imaging, genetic testing, pregnancy and neonatal outcomes were extracted from our databases, including structural and genetic anomalies, candidate outcome predictors such as lung size, liver herniation ratio, polyhydramnios, cervical length, preterm prelabour rupture of membranes and gestational age at birth. MAIN OUTCOME MEASURES: Survival and oxygen dependency at discharge. RESULTS: Ten out of 86 fetuses with RCDH had associated abnormalities. Of 76 isolated pregnancies, eight women opted for termination of pregnancy, most with severe hypoplasia and one was lost to follow up. Nineteen pregnancies were expectantly managed and delivered at a mean gestational age of 36.0 ± 3.0 weeks. Survival at discharge was 53% (10/19), one being oxygen dependent. In the fetal surgery group (n = 48), mean gestational age at delivery was 34.5 ± 3.0 weeks. In our recent experience not previously published (n = 23) survival rate was 52 and 39% were oxygen dependent at discharge. Pooling these data with earlier reported observations by our group we observed a 42% survival rate in 57 fetuses. Lung size on magnetic resonance imaging and an interval of >24 hours between reversal of tracheal occlusion and delivery were predictors of outcome. CONCLUSIONS: Right-sided CDH seems to have a poorer outcome than that reported for fetuses with left-sided CDH with similar lung size before birth. Survival rates after expectant management with observed/expected lung-to-head ratio values ≤45 and ≤30% were 17 and 0%, respectively. In those undergoing fetal surgery (observed/expected lung-to-head ratio ≤45%) there was an apparent increase (42%).

Correlation of observed-to-expected total fetal lung volume with intrathoracic organ herniation on magnetic resonance imaging in fetuses with isolated left-sided congenital diaphragmatic hernia.

OBJECTIVES: To assess using fetal magnetic resonance imaging (MRI) the relationship between the position of the stomach as well as the volume of herniation of organs into the thorax, and the observed-to-expected total fetal lung volume (o/e-TFLV), as a measure of pulmonary hypoplasia, in fetuses with isolated left-sided congenital diaphragmatic hernia (LCDH). METHODS: This was a single-center retrospective study using archived MR images from fetuses > 20 weeks' gestation evaluated for isolated LCDH over an 11-year period between July 2002 and September 2013. We retrieved data on the gestational age at MRI, o/e-TFLV and liver position. Images were also reviewed by a single operator to determine retrospectively the position of the stomach as well as the proportion of the total thorax volume occupied by the herniated fetal liver, stomach and other viscera. Following confirmation of reproducibility, we assessed the correlation of intrathoracic organ volumes and stomach position with o/e-TFLV. RESULTS: The study included 205 fetuses which underwent a total of 259 MR examinations. The reproducibility of organ volume measurements was excellent (intraclass correlation coefficient range, 0.928-0.997). The average time spent to obtain intrathoracic organ volumes ranged from 2.28 to 5.13 min. Of all herniated organ-to-thoracic volume ratios, the liver-to-thoracic volume ratio had the strongest correlation with o/e-TFLV (ρ = -0.429, P<0.0001). Stomach volume did not correlate, although, when categorized by the position and extent of stomach herniation, there was an inverse relationship to o/e-TFLV. No intrathoracic organ-to-thoracic volume ratio was related to gestational age. CONCLUSIONS: We observed in fetuses with isolated LCDH an inverse relationship between lung volume and the amount of liver herniated as well as the position of the stomach in the chest.

Comparison of matching by body volume or gestational age for calculation of observed to expected total lung volume in fetuses with isolated congenital diaphragmatic hernia.

OBJECTIVE: To determine the bias induced by matching fetuses according to gestational age (GA) or fetal body volume (FBV) when calculating the observed to expected total fetal lung volume (o/e TFLV) in cases of isolated congenital diaphragmatic hernia (CDH). METHODS: This was a single-center, retrospective study on archived magnetic resonance (MR) images of fetuses with isolated CDH over a 10-year period. We retrieved the TFLV, GA and o/e TFLVGA , and delineated FBV to obtain TFLVFBV in each case. We evaluated the relationship between o/e TFLVFBV and o/e TFLVGA by Bland-Altman analysis. All outliers were manually identified, and their specific clinical features were retrieved. RESULTS: Records of a total of 377 MR examinations of 225 fetuses were identified and included in the analysis. The mean ( ± SD) time spent on FBV measurement was 16.12 ± 4.95 min. On reproducibility analysis of FBV measurement (n = 10), the intraobserver intraclass correlation coefficient (ICC) was 0.998 and the interobserver ICC was 0.999. FBV was highly correlated with GA (R(2) = 0.899; P < 0.0001). There was good agreement between o/e TFLVGA and o/e TFLVFBV , with a mean difference of -1.10% and 95% limits of agreement of -8.58 to 6.39. There were no outliers in fetuses that had an o/e TFLV < 25%. Discrepancies induced by different methods were more likely in women with a body mass index ≥ 25 kg/m(2) (+16.5%), fetuses with an estimated fetal weight (EFW) ≤ 10(th) centile (+21.3%) or an EFW > 90(th) centile (+14.7%). CONCLUSIONS: Discrepancies in matching by FBV and GA when calculating o/e TFLV are more likely in fetuses with an abnormal EFW or in fetuses carried by overweight women. The clinical relevance of using FBV rather than GA for calculation of the o/e TFLV might be limited, as there was no discrepancy between the two methods in fetuses with small lungs ( < 25%), which is the group of most interest for lung volume assessment.

Cardiac assessment in fetuses with right-sided congenital diaphragmatic hernia: case-control study.

OBJECTIVE: To evaluate cardiac anatomy and function in fetuses with right-sided congenital diaphragmatic hernia (RCDH), and to compare these values with those of normal controls. METHODS: Fetal echocardiography was performed in 17 consecutive cases with isolated RCDH and 17 gestational age-matched controls. Two-dimensional measurements included ventricular and outflow tract diameters. Doppler ultrasound was used to measure the flow pattern in the ductus venosus and over the pulmonary and aortic valves, right and left ventricular myocardial performance index and the E/A wave ratio over the atrioventricular valves. Stroke volume, cardiac output and shortening fraction were calculated. RESULTS: Median gestational age at evaluation was 27.4 (interquartile range, 24.4-28.9) weeks. RCDH cases had a significantly smaller right ventricle and pulmonary valve diameter. Furthermore, stroke volume and cardiac output from the right ventricle were lower than in controls. Myocardial contractility, however, appeared normal. CONCLUSIONS: Despite significantly reduced right ventricular dimensions and cardiac output, cardiac contractility was normal in a cohort of fetuses with RCDH.

Collagen plug sealing of iatrogenic fetal membrane defects after fetoscopic surgery for congenital diaphragmatic hernia.

OBJECTIVES: To investigate the efficacy of collagen plugs at reducing the risk of preterm premature rupture of membranes (PPROM) after fetoscopic surgery for congenital diaphragmatic hernia (CDH). METHODS: This was a single-center cohort study on all consecutive cases undergoing fetoscopic endoluminal tracheal occlusion (FETO) for severe or moderate CDH, between April 2002 and May 2011 (n = 141). Cases either received a collagen plug for sealing the fetal membrane defect after FETO or did not, depending on the operating surgeon. The principal outcome measure was the time from fetal surgery to PPROM, further referred to as 'latency'. A multivariable Cox regression model was used to investigate the association between collagen plug and latency while adjusting for risk factors for PPROM. RESULTS: Of the 141 cases, 54 (38%) received a collagen plug and 87 (62%) did not. Sixty cases experienced PPROM, 26 among cases with and 34 among cases without a plug (48 vs 39%). The hazard ratio of plug use was 1.29 (95% CI, 0.76-2.19), which does not exclude a potentially increased risk for PPROM when a collagen plug is used. For cases with a plug, 24% had PPROM before balloon removal and 24% had PPROM after elective balloon removal. For cases without a plug, these rates were 30 and 9%, respectively. Perinatal outcomes were similar in both groups. CONCLUSIONS: No evidence was found that collagen plugs reduce the risk of PPROM after FETO for CDH.

Gestational age-specific reference ranges for amniotic fluid assessment in monochorionic diamniotic twin pregnancies.

OBJECTIVES: To establish gestational age-specific reference ranges for amniotic fluid measurements in monochorionic diamniotic twin pregnancies, to compare them with previously reported singleton and twin reference ranges and to examine the rationale for using a gestational age-dependent cut-off to define polyhydramnios in twin-twin transfusion syndrome, as is the practice in most European centers. METHODS: We retrospectively evaluated amniotic fluid volume in 32 monochorionic diamniotic twin pregnancies that were followed longitudinally at 2-week intervals from the first trimester until birth. Amniotic fluid volume was assessed by measuring the deepest vertical pocket in both amniotic sacs. We used multilevel modeling to estimate the gestational age-specific reference ranges for deepest vertical pocket measurements. RESULTS: Based on 429 observations in 64 fetuses, we constructed gestational age-specific reference ranges from 11 weeks until term. The deepest pocket increased from the first trimester to reach a maximum at 26 weeks, followed by a gradual decrease towards term. Measurements between 18 and 28 weeks were comparable to those in singleton pregnancies. However, before 18 weeks values were higher, whereas after 28 weeks they were lower, as compared to singleton references. CONCLUSION: In monochorionic twin pregnancies, the deepest vertical pocket is a gestational age-dependent measurement. Therefore, a gestational age-dependent definition of polyhydramnios in twin-twin transfusion syndrome, as used by most European centers, seems a logical approach.

Identification of dosage-sensitive genes in fetuses referred with severe isolated congenital diaphragmatic hernia.

OBJECTIVE: Congenital diaphragmatic hernia (CDH) is a fetal abnormality affecting diaphragm and lung development with a high mortality rate despite advances in fetal and neonatal therapy. CDH may occur either as an isolated defect or in syndromic form for which the prognosis is worse. Although conventional karyotyping and, more recently, chromosomal microarrays support a substantial role for genetic factors, causal genes responsible for isolated CDH remain elusive. We propose that chromosomal microarray analysis will identify copy number variations (CNVs) associated with isolated CDH. METHODS: We perform a prospective genome-wide screen for CNVs using chromosomal microarrays on 75 fetuses referred with apparently isolated CDH, six of which were later reclassified as non-isolated CDH. RESULTS: The results pinpoint haploinsufficiency of NR2F2 as a cause of CDH and cardiovascular malformations. In addition, the 15q25.2 and 16p11.2 recurrent microdeletions are associated with isolated CDH. By using gene prioritisation and network analysis, we provide strong evidence for several novel dosage-sensitive candidate genes associated with CDH. CONCLUSIONS: Chromosomal microarray analysis detects submicroscopic CNVs associated with isolated CDH or CDH with cardiovascular malformations.

In vitro sealing of iatrogenic fetal membrane defects by a collagen plug imbued with fibrinogen and plasma.

OBJECTIVES: We aimed to demonstrate local thrombin generation by fetal membranes, as well as its ability to generate fibrin from fibrinogen concentrate. Furthermore, we aimed to investigate the efficacy of collagen plugs, soaked with plasma and fibrinogen, to seal iatrogenic fetal membrane defects. METHODS: Thrombin generation by homogenized fetal membranes was measured by calibrated automated thrombography. To identify the coagulation caused by an iatrogenic membrane defect, we analyzed fibrin formation by optical densitometry, upon various concentrations of fibrinogen. The ability of a collagen plug soaked with fibrinogen and plasma was tested in an ex vivo model for its ability to seal an iatrogenic fetal membrane defect. RESULTS: Fetal membrane homogenates potently induced thrombin generation in amniotic fluid and diluted plasma. Upon the addition of fibrinogen concentrate, potent fibrin formation was triggered. Measured by densiometry, fibrin formation was optimal at 1250 µg/mL fibrinogen in combination with 4% plasma. A collagen plug soaked with fibrinogen and plasma sealed an iatrogenic membrane defect about 35% better than collagen plugs without these additives (P = 0.037). CONCLUSIONS: These in vitro experiments suggest that the addition of fibrinogen and plasma may enhance the sealing efficacy of collagen plugs in closing iatrogenic fetal membrane defects.

Outcome of fetuses with congenital diaphragmatic hernia and associated intrafetal fluid effusions managed in the era of fetal surgery.

OBJECTIVE: Fetuses with congenital diaphragmatic hernia (CDH) and for whom additional ultrasound findings are abnormal typically are considered to have a dismal prognosis. Our aim was to assess the outcome of fetuses with CDH and associated intrafetal fluid effusions. METHODS: This was a retrospective bicentric cohort study on the perinatal management of fetuses with CDH and intrafetal fluid effusions. RESULTS: The incidence of effusions was 5.2% (n = 14) in 269 consecutive cases of left-sided CDH and 29.2% (n = 14) in 48 cases of right-sided CDH. Hydrothorax (n = 19 (68%)) and ascites (n = 16 (57%)) were the most common effusions. A combination of both was present in 11 (39%) fetuses. Of 20 ongoing pregnancies with CDH and fluid effusions, without other anomalies, five with moderate or mild pulmonary hypoplasia were managed without fetoscopic endoluminal tracheal occlusion (FETO). The 15 other cases underwent FETO because of severe pulmonary hypoplasia. Neonatal survival rate was similar in both groups (n = 2/5 and n = 6/15, respectively (P = 1.0)). Survival among those who underwent FETO was similar to previously published results concerning isolated cases undergoing FETO. CONCLUSIONS: Our observations do not support the view that intrafetal effusions are an adverse prognostic factor in fetuses with CDH. In CDH fetuses with effusions and severe pulmonary hypoplasia treated with FETO, neonatal survival is similar to that in isolated cases undergoing the intervention. Whether pleural effusions should be addressed by thoracic drainage procedures remains unproven.

Fetal cerebral blood flow velocities in congenital diaphragmatic hernia.

OBJECTIVES: Left ventricular cardiac output is decreased in fetuses with congenital diaphragmatic hernia (CDH). Our aim was to assess whether this alters cerebral perfusion or growth in utero. METHODS: Fetal head circumference, biparietal diameter, lung-to-head ratio and middle cerebral artery (MCA) Doppler flow patterns were assessed by ultrasonography in 103 fetuses with prenatally diagnosed CDH. Total fetal lung volume and cerebral volume were measured using magnetic resonance imaging. Values were transformed to gestational age-independent scores (multiples of the median (MoM)) and compared with controls. Subanalyses were made according to whether the CDH was left- (n = 86) or right-sided (n = 17) and to whether it was isolated (n = 86) or associated with other anomalies (n = 17). RESULTS: MCA flow velocity was significantly lower in fetuses with CDH than in healthy fetuses (0.79 ± 0.19 MoM; P < 0.0001) but MCA pulsatility index was unchanged (0.99 ± 0.25 MoM; P = 0.79). Cranial biometry and cerebral volume in CDH fetuses fell in the normal range. Gestational age-adjusted lung area was correlated with MCA peak systolic velocity, which was in turn correlated with brain volume. CONCLUSIONS: Fetal cerebral blood flow velocities are decreased in CDH yet cranial and cerebral growth are conserved. Further work will be needed to address whether part of the neurologic impairment observed in long-term survivors of CDH finds its origin in the prenatal period.

Spontaneous hepatic rupture in a normotensive monoamniotic twin pregnancy: case report and review of the literature.

BACKGROUND: Spontaneous liver rupture during pregnancy is extremely rare, and often associated with hypertensive disorders. Maternal outcomes are poor and morbidity is high. CASE: A 27-year-old women (G1P0), pregnant with monochorionic-monoamniotic twins, developed extensive abdominal pain while she was electively admitted at 32 weeks for fetal pulmonary maturation. Diagnosed with preterm labor, a caesarean section was performed. Postoperatively, our patient deteriorated and a second laparotomy revealed an extensive liver rupture. There was no evidence of hypertensive disorders or hepatic tumors. After perihepatic packing and embolization, our patient required long-term treatment in our intensive care unit. She survived, and both mother and children are healthy after 6 months. CONCLUSION: Despite being rare, spontaneous liver rupture in absence of hypertensive disorders during pregnancy is associated with high maternal morbidity and mortality. Adequate treatment requires a multidisciplinary approach.

Vascular distribution patterns in monochorionic twin placentas.

Several recent publications have focused on the association between the occurrence of twin-to-twin transfusion syndrome (TTTS) in diamniotic-monochorionic twins and the presence of a number of selected anatomic placental characteristics (distribution of vascular territory, cord insertion, type and number of inter-twin anastomoses). In contrast, the potential importance of the vascular distribution patterns of the individual twins remains to be elucidated. Based on its gross architectural distribution pattern, chorionic vasculature is traditionally described as disperse, magistral or mixed. The aim of this study was (1) to determine the relative prevalence of these vascular distribution patterns in monochorionic twin placentas, and (2) to correlate these patterns with the presence of TTTS and known anatomic placental features linked to TTTS. The placentas of 89 consecutive diamniotic-monochorionic twins (15 with TTTS, 74 without TTTS), examined at Women and Infants Hospital, were studied. Disperse vascular patterns were seen in 53% of twins, and magistral or mixed patterns in 47%. The prevalence of magistral/mixed vascular patterns was significantly higher in TTTS gestations than in non-TTTS gestations (60% versus 44%, P<0.05) and, in TTTS gestations, much higher in donor twins than in recipient twins (87% versus 33%, P<0.005). A strong association was found between the presence of magistral/mixed patterns and marginal/velamentous cord insertion, low number of inter-twin anastomoses, and uneven distribution of the vascular territories. These findings suggest that the magistral/mixed vascular distribution pattern may represent an important placental architectural feature contributing to the complex pathophysiology of TTTS.