First-trimester biomarkers and ultrasound biometries in relation to growth discordance in monochorionic diamniotic twins.

Objective: The aim of this study was to investigate the association and predictive value between intertwin discordance in first trimester biometries crown-rump length (CRL) and nuchal translucency (NT), and the first trimester biochemical markers PAPP-A and free ß-hCG in relation to birth weight discordance (BWD) ≥25% in monochorionic diamniotic (MCDA) twin pregnancies.Methods: First trimester screening information and pregnancy outcome data on MCDA twin pregnancies with delivery from July 2008 to July 2017 were retrieved from the Danish Fetal Medicine Database. CRL discordance was divided into: <10% (reference group) and ≥10%. NT discordance was divided into: <20% (reference group) and ≥20%. The twin pregnancies were classified according to BWD into the following groups: <10% (reference group), 10-24.9%, and ≥25% including cases undergoing umbilical cord occlusion due to selective fetal growth restriction (sFGR). The twin pregnancies with the most severe BWD (BWD ≥25%) were subdivided into three groups including cases with only one growth-restricted (<10th centile) infant defined as sFGR, and cases where both twins were <10th centile. Median multiples of the median (MoM) values of PAPP-A and free ß-hCG were compared with the group with BWD <10% using the Wilcoxon two-sample test. The ability of CRL discordance and NT discordance to predict BWD ≥25% was examined by the area under the receiver operator characteristic (ROC) curve.Results: A total of 762 MCDA pregnancies were included. The proportion of pregnancies with CRL discordance ≥10% and NT discordance ≥20% was significantly higher in the group with severe BWD discordance (27.0% vs. 4.7% (p < 0.001) and 40.9% vs. 23.9% (p = 0.001), respectively). When examining the three subgroups of severe BWD, we found a significantly higher percentage of pregnancies with CRL discordance ≥10% in the group where umbilical cord occlusion was performed (52.6% vs. 4.7% in the group with BWD <10% (p < 0.001)) and in the group of BWD ≥25% with sFGR (21.7% vs. 4.7% (p < 0.001)). Additionally, a significantly higher percentage of pregnancies with NT discordance ≥20% was found in the group where umbilical cord occlusion was performed (52.6% vs. 23.9% (p = 0.005)) and in the group with both twins <10th centile (66.7% vs. 23.9% (p = 0.003)). No statistically significant differences were found when comparing levels of PAPP-A and free ß-hCG MoMs with the group with BWD <10%. In ROC curves, CRL discordance yielded an AUC for prediction of BWD ≥25% of 0.70 (95% CI 0.63-0.76), and for NT discordance AUC was 0.59 (95% CI 0.52-0.66)). OR for any BWD ≥ 25% was 6.7 (95% CI 3.8-12.0) for pregnancies with a CRL discordance ≥10% compared to pregnancies with a CRL discordance <10%.Conclusions: This study shows that a discordance in CRL and NT in MCDA twins are both significantly associated with development of BWD. The most important predictor remains CRL discordance ≥10%, thereby suggesting the unequal growth pattern in many cases with BWD is evident already in the first trimester of the pregnancy. No association was found between first trimester biochemical markers and severe BWD.

Short-Term Flow Changes in Monochorionic Survivor Twins after Ultrasound-Guided Umbilical Cord Occlusion.

OBJECTIVE: To determine hemodynamic changes by Doppler ultrasound of the living fetus during 24 h after umbilical cord occlusion (UCO) in monochorionic diamniotic (MCDA) twin pregnancies. METHOD: We conducted a prospective observational study on fetuses undergoing UCO from 2015 to 2017. Doppler parameters peak systolic velocity (PSV) and umbilical pulsatility index (PI) were obtained in the middle cerebral artery (MCA), umbilical artery (UA) and ductus venosus (DV) before and right after UCO, and at 1, 3, 6, 12, and 24 h after. We used multiple of the median (MoM) to adjust for gestational age. Spaghetti plots visualized flow changes over time. Mixed model adjusting for paired longitudinal data compared the values at different time points. RESULTS: A total of 16 women were included. MCA-PSV dropped within the first hour after surgery from 0.91 to 0.82 MoM (p = 0.08). MCA-PI and UA-PI increased in the first hour from 0.75 to 0.91 MoM (p = 0.02) and 0.94 to 0.98 MoM (p = 0.22), respectively. The DV-PIV increased to 1.14 MoM 3 h after surgery (p = 0.07). The spaghetti plots illustrated the small changes within the first hours and showed a stabilization of flow measurements near initial values 24 h after UCO. CONCLUSION: Within the first hours after UCO the circulation of the survivor twin undergoes small hemodynamic changes.

Long-Term Neurodevelopmental Outcome of Monochorionic Twins after Laser Therapy or Umbilical Cord Occlusion for Twin-Twin Transfusion Syndrome.

INTRODUCTION: We sought to assess the incidence of severe neurodevelopmental impairment (NDI) in monochorionic twins treated for twin-twin transfusion syndrome (TTTS) and compare it to the incidence in uncomplicated monochorionic twins. MATERIAL AND METHODS: We included TTTS pregnancies treated by fetoscopic selective laser coagulation (FSLC) or umbilical cord occlusion (UCO) in 2004-2015. Primary outcome was severe NDI defined as cerebral palsy, bilateral blindness or bilateral deafness (ICD-10 diagnoses), and severe cognitive and/or motor delay (assessed by the Ages and Stages Questionnaires [ASQ]). RESULTS: A total of 124 children after TTTS and 98 controls were followed up at 25 months of age (SD 11.4). Severe NDI was found in 8.9% of the TTTS children (10.5% [9/86] after FSLC; 5.3% [2/38] after UCO) compared to 3.1% in the control group (p = 0.10). The odds ratio for severe NDI was 1.8 in cases versus controls (p = 0.37). The total ASQ score was significantly lower in the TTTS group than in controls (p = 0.03) after FSLC (p = 0.03) and after UCO (p = 0.14). DISCUSSION: Children after TTTS appear to have a higher risk of severe NDI and score significantly lower on the ASQ compared to monochorionic twins from uncomplicated pregnancies.

Invasive treatment in complicated monochorionic twin pregnancies: indications and outcome of 120 consecutively treated pregnancies.

OBJECTIVE: Monochorionic twin pregnancies are associated with increased risk of severe complications. Umbilical cord occlusion (UCO) and fetoscopic selective laser coagulation (FSLC) are used as invasive treatment. The study aim was to document treatment indications and pregnancy outcome where UCO and FSLC were used for treating fetal discrepancies and twin-to-twin transfusion syndrome (TTTS). DESIGN: Cohort study of all consecutively treated monochorionic twin pregnancies 2004-2010. SETTING: Tertiary care center. POPULATION: One hundred and twenty pregnancies treated by FSLC (55) or UCO (65). Umbilical cord occlusion was undertaken in 49 TTTS cases, in four cases with fetal abnormality and TTTS and in 12 cases because of fetal anomaly only. MAIN OUTCOME MEASURES: Overall survival per fetus, survival per pregnancy of at least one fetus and further survival according to the Quintero stages. Infant survival until at least one week after birth. RESULTS: Of the pregnancies studied, 84% had TTTS, 13% had a fetal malformation and 3% had both. Of TTTS cases, 69% were Quintero stage 3 and 4. In the UCO group with TTTS, 87% were in stage 3 and 4. Survival in the UCO group was 82%. In the laser group, the survival of at least one fetus was 85%. Overall survival per fetus was 60%. CONCLUSIONS: By far the most common indication for invasive treatment was TTTS in Quintero stage 3. Outcome by means of survival after FSLC and UCO were similar to what has been reported elsewhere. Cord occlusion was an acceptable treatment alternative to fetoscopic selective laser coagulation in severe TTTS cases.