Placental differences between uncomplicated and complicated monochorionic diamniotic pregnancies on diffusion and multicompartment Magnetic Resonance Imaging

INTRODUCTION

Twin-twin transfusion syndrome (TTTS) and selective fetal growth restriction (sFGR) are common complications in monochorionic diamniotic (MCDA) pregnancies. The Diffusion-rElaxation Combined Imaging for Detailed Placental Evaluation (DECIDE) model, a placental-specific model, separates the T2 values of the fetal and maternal blood from the background tissue and estimates the fetal blood oxygen saturation. This study investigates diffusion and relaxation differences in uncomplicated MCDA pregnancies and MCDA pregnancies complicated by TTTS and sFGR in mid-pregnancy.

METHODS

This prospective monocentric cohort study included uncomplicated MCDA pregnancies and pregnancies complicated by TTTS and sFGR. We performed MRI with conventional diffusion-weighted imaging (DWI) and combined relaxometry - DWI-intravoxel incoherent motion. DECIDE analysis was used to quantify different parameters within the placenta related to the fetal, placental, and maternal compartments.

RESULTS

We included 99 pregnancies, of which 46 were uncomplicated, 12 were complicated by sFGR and 41 by TTTS. Conventional DWI did not find differences between or within cohorts. On DECIDE imaging, fetoplacental oxygen saturation was significantly lower in the smaller member of sFGR (p = 0.07) and in both members of TTTS (p = 0.01 and p = 0.004) compared to the uncomplicated pairs. Additionally, average T2 relaxation time was significantly lower in the smaller twin of the sFGR (p = 0.004) compared to the uncomplicated twins (p = 0.03).

CONCLUSION

Multicompartment functional MRI showed significant differences in several MRI parameters between the placenta of uncomplicated MCDA pregnancies and those complicated by sFGR and TTTS in mid-pregnancy.

Umbilical venous diameter and flow in monochorionic diamniotic twin pregnancy: association with placental sharing and fetal demise

OBJECTIVE

To examine the association of umbilical venous diameter and flow in monochorionic diamniotic twin pregnancy with placental sharing and fetal demise.

METHODS

This was a prospective longitudinal cohort study of a consecutive series of monochorionic diamniotic twin pregnancies that underwent ultrasound assessments at 12, 16, 20 and 28 weeks' gestation. Fetal biometry (crown-rump length at 12 weeks or estimated fetal weight (EFW) thereafter) and cord insertion sites were recorded at each visit, as well as the diameter of the umbilical vein (UV) in both the intra-abdominal part and a free loop of the umbilical cord. Time-averaged maximum velocity in the intra-abdominal part of the UV was measured to calculate UV-flow. Univariate and multivariate linear regression analyses were performed to assess the relationship between intertwin ratios of these variables and placental sharing at 12, 16, 20 and 28 weeks' gestation. Placental sharing was calculated by dividing the larger by the smaller placental share, as measured on placental injection studies after birth. Additionally, the Mann-Whitney U-test and receiver-operating-characteristics-curve analysis were used to explore the relationship between the occurrence of fetal demise and intertwin differences in fetal biometry, cord insertion sites, UV diameters and flow at 12, 16, 20 and 28 weeks.

RESULTS

Of 200 consecutive monochorionic twin pregnancies enrolled, injection studies were performed in 165 (82.5%) placentas. On univariate analysis, intertwin differences in fetal biometry, cord insertions and UV variables were associated significantly with placental sharing at 12, 16, 20 and 28 weeks' gestation. On multivariate analysis, intertwin differences in fetal biometry, cord insertions and all three UV variables remained associated significantly with placental sharing at 12 and 16 weeks. However, at 20 and 28 weeks, only the intertwin EFW ratio was associated consistently with placental sharing. Fetal demise of one or both twins complicated 26 (13.0%) pregnancies. Differences in EFW and cord insertion sites were not associated significantly with fetal demise, while at 16 weeks, differences in intra-abdominal UV diameter and flow were associated with an increased risk of subsequent fetal demise.

CONCLUSIONS

At 12 and 16 weeks' gestation, intertwin differences in UV diameter and flow reflect placental sharing more accurately than do differences in fetal growth and cord insertion sites. At 16 weeks, discordance in intra-abdominal UV diameter and flow is also associated with an increased risk of fetal demise. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Skin grafting prevents recurrence in Dupuytren's disease and extension correlates with fibrosis diathesis score

Full thickness grafting can be considered after fasciectomy for Dupuytren contracture in severe cases with skin shortage or in radical dermofasciectomy. It is a common dogma that these skin grafts may prevent disease recurrence. We reviewed 47 patients after fasciectomy and full-thickness skin grafting for Dupuytren contracture at 3-16 years' follow-up. Recurrence beneath the skin graft and extension of the disease in the rest of the hand were recorded. Age at onset, gender and factors considered to influence the outcome due to fibrosis diathesis, such as bilateral disease, family history and ectopic lesions, were noted. The Tubiana classification was used to grade disease severity at surgery and at follow-up. None of the patients manifested recurrence underneath the skin graft, but the disease did show extension in 83% of cases. Disease extension was more likely in patients with higher fibrosis diathesis scores. We conclude that skin grafting may prevent disease recurrence underneath the grafts, but extension of the disease correlates with fibrosis diathesis. LEVEL OF EVIDENCE: IV, therapeutic cohort study.

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.

Outcome of monochorionic twin pregnancy with selective fetal growth restriction at 16, 20 or 30 weeks according to new Delphi consensus definition

OBJECTIVES

To report the outcome of selective fetal growth restriction (sFGR) diagnosed according to the new Delphi consensus definition, and determine potential predictors of survival, in a cohort of unselected monochorionic diamniotic twin pregnancies.

METHODS

This was a retrospective study of monochorionic diamniotic twin pregnancies followed from the first trimester onward, which were diagnosed with sFGR at 16, 20 or 30 weeks' gestation. sFGR was defined according to the new Delphi consensus criteria as presence of either an estimated fetal weight (EFW) < 3^rd centile in one twin or at least two of the following: EFW of one twin < 10^th centile, abdominal circumference of one twin < 10^th centile, EFW discordance ≥ 25% or umbilical artery pulsatility index of the smaller twin > 95^th centile. The primary outcomes were the overall survival rate (up to day 28 after birth) and risk of loss of one or both twins. We further determined possible predictors of survival using uni- and multivariate generalized estimated equation modeling.

RESULTS

We analyzed 675 pregnancies, of which 177 (26%) were diagnosed with sFGR at 16, 20 or 30 weeks. The overall survival rate was 313/354 (88%) with 146/177 (82%) pregnancies resulting in survival of both twins, 21/177 (12%) in survival of one twin and 10/177 (6%) in loss of both twins. Subsequent twin anemia-polycythemia sequence (TAPS) developed in 6/177 (3%) and twin-twin transfusion syndrome (TTTS) in 17/177 (10%) pregnancies. All TAPS fetuses survived. The survival rate in sFGR pregnancies that subsequently developed TTTS was 65% (22/34), compared with 91% (279/308) in those with isolated sFGR (no subsequent TAPS or TTTS) (P < 0.001). The majority of sFGR cases were Type I (110/177 (62%)) and had a survival rate of 96% (212/220), as compared with a survival of 55% (12/22) in those with Type-II (P < 0.001) and 83% (55/66) in those with Type-III (P = 0.006) sFGR. The majority of sFGR pregnancies (130/177 (73%)) were first diagnosed at 16 or 20 weeks (early onset), with a survival rate of 85% (221/260), as compared with a survival of 98% (92/94) in sFGR first diagnosed at 30 weeks (late onset) (P = 0.04). A major anomaly in at least one twin was present in 28/177 (16%) sFGR cases. In these pregnancies, survival was 39/56 (70%), compared with 274/298 (92%) in those without an anomaly (P < 0.001). Subsequent development of TTTS (odds ratio (OR), 0.18 (95% CI, 0.06-0.52)), Type-II sFGR (OR, 0.06 (95% CI, 0.02-0.24)) and Type-III sFGR (OR, 0.21 (95% CI, 0.07-0.60)) and presence of a major anomaly in at least one twin (OR, 0.12 (95% CI, 0.04-0.34)), but not gestational age at first diagnosis, were independently associated with decreased survival.

CONCLUSIONS

Isolated sFGR is associated with a 90% survival rate in monochorionic diamniotic twin pregnancies. The subsequent development of TTTS, absent or reversed end-diastolic flow in the umbilical artery of the smaller twin and the presence of a major anomaly adversely affect survival in sFGR. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Monochorionic twins after in-vitro fertilization: do they have poorer outcomes?

OBJECTIVE

To compare the outcome of monochorionic diamniotic (MCDA) twin pregnancies conceived by in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) with that of spontaneously conceived MCDA twins.

METHODS

This was a retrospective cohort study of MCDA twin pregnancies conceived after IVF/ICSI or spontaneously, followed from the first trimester onwards at a single center between January 2002 and September 2018. The primary outcome was survival per fetus from the first trimester until 28 days after birth. Secondary outcome measures were number of survivors, miscarriage, termination of pregnancy, intrauterine and neonatal death, major congenital anomalies, twin-twin transfusion syndrome, selective fetal growth restriction, gestational age at birth, delivery before 32 weeks' gestation, mode of delivery, admission to the neonatal intensive care unit, birth weight and birth-weight discordance.

RESULTS

Of the 654 MCDA pregnancies included in the analysis, 80 were conceived by IVF/ICSI and 574 spontaneously. Overall fetal and neonatal survival was significantly lower in the IVF/ICSI group than in the spontaneous-conception group (79% vs 90%; P = 0.001). In the IVF/ICSI group, compared with the spontaneous-conception group, loss of one or both twins occurred twice as often (29% vs 14%; P = 0.001) and there was a higher risk of second-trimester miscarriage (8% vs 1%; P = 0.002).

CONCLUSIONS

MCDA twins conceived after IVF/ICSI have lower overall survival rates and higher rates of second-trimester miscarriage than do spontaneously conceived MCDA twins. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

The vascular equator in monochorionic twin placentas

INTRODUCTION

We aim to examine the location of the vascular equator according to the umbilical cord insertions in monochorionic twin placentas.

METHODS

We combined two prospective series of monochorionic diamniotic twin placentas of patients included in the first trimester between 2004 and 2008, and between 2016 and 2019. We injected the placentas after birth and divided them into three groups, with respectively concordant (eccentric-eccentric, marginal-marginal, and velamentous-velamentous), intermediate (eccentric-marginal and marginal-velamentous) and discordant (eccentric-velamentous) cord insertions. For each unidirectional anastomosis, we determined the cord-anastomosis ratio and then calculated the mean ratio per placenta in each group. We also calculated the deviation from the midline in all groups.

RESULTS

195 placentas were included. In concordant placentas, the mean cord-anastomosis ratio was 0.957 (95% CI [0.908-1.009]). In placentas with intermediate discordance, the mean ratio was 0.886 (95% CI [0.828-0.948]) and in discordant placentas it was 0.797 (95% CI [0,708-0.897]) (p < 0.001). In concordant placentas, the equator was in the middle of the cord insertions with an average deviation of 0.2 cm (95% CI [-0.1 - 0.3]). In the intermediate placentas, the equator deviated on average 0.5 cm (95% CI [0.2-0.8]) and was displaced from the middle towards the most central cord insertion. In discordant placentas, there was an average displacement of 1.0 cm (95% CI [0.50-1.6]).

DISCUSSION

In concordant placentas, the vascular equator lies in the middle between both cord insertions. In intermediate and discordant placentas, the equator is closer to the more central cord insertion.

Laser for twin-to-twin transfusion syndrome: a guide for endoscopic surgeons

Twin-to-twin-transfusion syndrome (TTTS) is the most important cause of handicap and death in monochorionic twin pregnancies. It is caused by a certain pattern of anastomoses between the two fetal circulations leading to an unbalanced blood and fluid transfer. This leads to severe amniotic fluid discordance and variable degrees of cardiac dysfunction. Untreated, this condition has a very poor survival rate. Fetoscopic laser has been shown to be the best first line treatment, which aims to dichorionise the placenta therefore arresting the inter-twin transfusion. Fetoscopic laser is a causative therapy, which aims to functionally create a dichorionized placenta hence arresting inter-twin transfusion. This is achieved by percutaneous sono-endoscopic coagulation of placental anastomoses. In addition, redundant amniotic fluid is drained. Fetoscopic laser coagulation of chorionic plate anastomoses is safe and effective. There is level I evidence that it is the best treatment modality, in particular when the placental surface is lined along the vascular equator. A recent meta-analysis confirmed an increased fetal survival and decreased risk for neonatal and pediatric neurologic morbidity. Laser therapy is the first line therapy for TTTS. The technique is quite standardized and safe and effective in experienced hands. Herein we describe the technique and current instrumentation used for this procedure.

Does site of cord insertion increase risk of adverse outcome, twin-to-twin transfusion syndrome and discordant growth in monochorionic twin pregnancy?

OBJECTIVES

It is not currently well known to what extent the sites of cord insertion influence the risk of complicated outcome in monochorionic twin pregnancy. The objectives of this study were to examine whether the sites of cord insertion, as determined on prenatal ultrasound examination, affect the risks of adverse outcome, twin-to-twin transfusion syndrome (TTTS) and discordant growth, and whether discordance in insertion sites or velamentous insertion in one or both twins best predicts risk.

METHODS

This was a retrospective cohort study of monochorionic diamniotic twin pregnancies followed from the first trimester. The cohort was divided into three groups of increasing discordance in cord insertion sites: concordant (normal-normal; marginal-marginal; velamentous-velamentous), intermediate (normal-marginal; marginal-velamentous) and discordant (normal-velamentous). Adverse outcome was defined as fetal or neonatal loss or birth prior to 32 weeks. The associations of adverse outcome, TTTS and discordant growth were assessed using logistic regression analysis with the following predictors: the three groups of insertion sites and velamentous insertion in one or both twins.

RESULTS

Included in the analysis were 518 pregnancies. On univariate analysis, both discordant and velamentous insertions in one twin increased the risk of adverse outcome, TTTS and discordant growth. Intermediate insertion only increased the risk of discordant growth. Velamentous insertion in both twins increased the risk of adverse outcome and TTTS, but not of discordant growth. Multivariate logistic regression analysis showed velamentous insertion in one or both twins to independently predict adverse outcome and TTTS. For discordant growth, both intermediate/discordant and velamentous cord insertion in one twin were independent predictors.

CONCLUSIONS

Velamentous cord insertion in one or both twins increases the risk of adverse outcome and TTTS, irrespective of discordance in the insertion sites, whereas the risk of discordant growth is determined by both discordance in insertion sites and velamentous cord insertion in one twin. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.