Outcome of monochorionic twin pregnancy with selective intrauterine growth restriction according to umbilical artery Doppler flow pattern of smaller twin: systematic review and meta-analysis

What is the role of intrauterine transfusion after single intrauterine death in monochorionic twin pregnancies? Evidence from a systematic review and meta-analysis

OBJECTIVE

To investigate the role of intrauterine transfusion (IUT) in affecting the outcome of the surviving twin showing sign of fetal anemia after a single intrauterine fetal death (IUFD) in monochorionic (MC) twin pregnancies.

METHODS

PubMed, Medline and Embase databases were searched (2010-2024). The inclusion criteria were studies reporting the outcome of fetuses showing signs of fetal anemia, defined as the presence of the peak systolic velocity (PSV) of the middle cerebral artery (MCA) >1.5 MoM, after single IUFD receiving compared to those not receiving IUT. The outcomes observed were preterm birth (PTB) <34 and 28 weeks of gestation, either iatrogenic or spontaneous, co-twin intra-IUFD, co-twin neonatal death (NND), anomalies at pre- or post-natal brain imaging, abnormal neurodevelopmental outcome. Risk of bias of the included studies was assessed using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool. The GRADE methodology was used to assess the quality of the body of retrieved evidence. Random effect meta-analyses of proportions were used to analyze the data.

RESULTS

Six studies (78 twin pregnancies complicated by single IUFD showing signs of fetal anemia) were included in the systematic review. Assessment of risk of bias of observational studies according to the ROBINS-I tool is presented. Only one study reported a non-matched comparison between anemic fetuses undergoing compared to those not undergoing IUT, so we could not calculate the summary odd ratios, and we reported the results as pooled proportions. PTB occurred in 51.25% (95% CI 35.76-66.62) of cases < 34 weeks and in 17.99% (95% CI 5.84-34.91) < 28 weeks of gestation. Co-twin IUFD and NND were reported in 8.02% (95% CI 2.30-16.78) and 15.49% (95% CI 7.89-25.05), while abnormal findings at pre-or post-natal brain imaging in 20.30% (95% CI 11.61-30.69). Abnormal neurodevelopmental outcome was reported in 5.93% (95% CI 2.50-18.30).

CONCLUSION

There is a very low grade of evidence that IUT can affect the outcome of anemic fetuses after single IUFD in MC pregnancies. The findings how this systematic review, in view of the limitations of the included studies, highlighted the need for large multicenter studies sharing objective protocols of prenatal management and post-natal assessment of pregnancies complicated by single IUFD are needed to report whether IUT in the anemic fetus after single IUFD can prevent mortality and neuromorbidity.

Prenatal care for twin pregnancies: analysis of maternal and neonatal morbidity and mortality

OBJECTIVES

To analyze maternal and neonatal morbidity and mortality in twin pregnancies, associated with the quality of prenatal and labor care, through the level of adherence to recommended protocols.

METHODS

This was a retrospective cohort study carried out between 2019 and 2022 involving twin pregnancies. The socioeconomic and demographic characteristics of the pregnant women were assessed, as well as maternal and perinatal outcomes. The association between variables was measured by the odds ratio (OR) obtained from the logistic regression.

RESULTS

The sample was constituted by 118 twin pregnancies, being 72 monochorionic (MC) and 46 dichorionic (DC). The majority of mothers (44.9 %) were between 16 and 25 years old. The majority of pregnant women developed some disorder during pregnancy (69.5 %). The most common neonatal complication was respiratory distress, which mainly affected the 2nd twins in both MC and DC twin pregnancies (65.8 and 52.2 %, respectively). Regarding the outcome "complications after delivery of the 1st twin", some predictors showed statistical significance such as "professionals responsible for prenatal care" (OR=3.37) and "breastfeeding in the first hour of life" (OR=1.07). With regard to the outcome "death of the 2nd twin", only variables related to prenatal care showed statistical significance such as "mode of delivery" (OR=0.25), "calcium supplementation" (OR=5.81), and "unit of prenatal care visits" (OR=9.96).

CONCLUSIONS

MC twin pregnancies had more adverse perinatal outcomes than DC twin pregnancies. In addition, adherence to prenatal care and labor protocols for twin pregnancies was associated with the outcomes studied, such as complications after delivery and death.

Survival rates in pregnancies complicated by twin-to-twin transfusion syndrome undergoing laser therapy: a systematic review and meta-analysis

OBJECTIVE

Twin-to-twin transfusion syndrome (TTTS) is associated with excess perinatal mortality and morbidity. Even though Quintero staging is commonly used to assess its severity, the limitations of its prognostic value have been highlighted by researchers over the years. Recent literature indicates that fetal survival, whether for both twins or at least one, following fetoscopic laser photocoagulation of the placental anastomoses is similar in TTTS Quintero stages I and II (combined) and III and IV (combined). In this context we perform a systematic review and meta-analysis of the published literature to elucidate the survival rate of twins according to the stage of TTTS and to compare the survival rates in pregnancies complicated by stage I and II (combined) vs those with stages III and IV (combined).

DATA SOURCES

Medline, Embase, and Cochrane databases were searched.

STUDY ELIGIBILITY CRITERIA

The inclusion criteria were studies reporting the outcome of monochorionic diamniotic (MCDA) twin pregnancies with TTTS undergoing laser therapy according to the Quintero stage of the disease. The primary outcome was double survival at birth. The secondary outcomes were no survival and survival of at least one twin. All the explored outcomes were reported according to the Quintero staging system. Furthermore, we aimed to compare all the observed outcomes in pregnancies complicated by TTTS affected by stage I and II vs those with stages III and IV.

STUDY APPRAISAL AND SYNTHESIS METHODS

Random-effect meta-analyses were used to combine data, and the results reported as pooled proportions or odd ratios (OR) with their 95% confidence intervals (CI).

RESULTS

A total of 26 studies were included. Survival of both fetuses was observed in 72.9% (95% CI 68.2-77.3) of pregnancies complicated by stage I, 67.9% (95% CI 62.3-73.3) with stage II, 48.1% (95% CI 42.5-53.8) with stage III, and 53.4% (95% CI 42.5-64.3) with stage IV TTTS. At least one survivor was reported in 89.4% (95% CI 86.9-91.9) of cases with stage I, 87.1% (95% CI 82.9-90.7) with stage II, 77.3% (95% CI 71.7-82.5) with stage III, and 80.1% (95% CI 69.4-89.0) with stage 4. The corresponding figures for no survivors were 10.7% (95% CI 7.7-14.0), 11.4% (95% CI 7.8-15.6), 20.4% (95% CI 15.6-25.8), and 16.7% (95% CI 8.3-27.2), respectively. When comparing the different outcomes according to the different TTTS stages, there was no significant difference in the incidence of double survival (P=.933), at least one survivor (P=.688), and no survivors (P=.866) between stages I and II TTTS. There was also no significant difference in the incidence of double survival (P=.201), at least one survivor (P=.380), and no survivors (P=.947) between stages III and IV. Conversely, when comparing the outcome of pregnancies with stage I/II (combined) vs stages III/IV (combined), the incidence of double survival was significantly higher in pregnancies with stages I/II (OR 2.19; 95% CI 1.9-2.6, P<.001). Likewise, the incidence of at least one survivor was significantly higher (OR 1.85, 95% CI 1.5-2.6, P<.001) while that of no survivor (OR 0.56, 95% CI 0.4-0.7, P<.001) significantly lower in pregnancies with stages I/II compared to III/IV.

CONCLUSION

Perinatal survival of MCDA twin pregnancies complicated by TTTS and treated with fetoscopic laser coagulation of placental anastomoses is not significantly different between stages I and II, or between stages III and IV, apart from a higher chance of one survivor in stage III compared to stage IV. The findings from this systematic review will be useful in individualized risk assessment of twin pregnancies complicated by TTTS and tailored counseling of the parents. It also highlights the need for studies aimed at better characterizing the prenatal risk factors for mortality in pregnancies complicated by TTTS.

CONDENSATION

Perinatal survival of MCDA twin pregnancies complicated by TTTS and treated with fetoscopic laser coagulation of placental anastomoses is not significantly different between stages I and II, or between stages III and IV. El resumen está disponible en Español al final del artículo.

Update on Management and Outcomes of Monochorionic Twin Pregnancies

The management of multiple pregnancies complicated by monochorionicity continues to evolve as new investigations support a change in clinical practice to optimize outcomes. Monochorionic twins are at risk of unique conditions such as monoamnionicity, conjoined twinning, twin reversed arterial perfusion sequence, twin-twin transfusion syndrome, twin anemia-polycythemia sequence, unequal placental sharing with discordant twin growth or selective fetal growth restriction, and single-twin death that puts co-twins at risk of death or neurologic injury attributable to the shared placenta. Contemporary practice guidelines recommend serial ultrasonographic surveillance of monochorionic pregnancies to increase the early detection of problems and timely management decisions that may include increased surveillance, selective reduction or pregnancy termination, referral for in utero treatment, or earlier delivery than initially planned. Improvements in prenatal diagnosis and antenatal testing and advances in fetal therapy have contributed to more favorable outcomes in these complicated monochorionic gestations.

Selective termination: a life-saving procedure for complicated monochorionic gestations

Monochorionic twin pregnancies are a subset of twin pregnancies that face potential complications related to a shared circulation between the fetuses. These complications are related to anastomotic placental vessels connecting the cardiovascular systems of the two fetuses, which can result in significant sequela if one twin experiences intrauterine death. The sudden cardiovascular collapse in this scenario leads to a massive blood shift away from the healthy co-twin, significantly jeopardizing its life and long-term neurodevelopmental outcome. Such conditions include selective fetal growth restriction with abnormal Doppler findings, twin-twin transfusion with impending death in one twin and discordant fetal anomalies, for which fetal interventions are ineffective in improving outcomes or preventing the imminent death of the abnormal twin. Obstetricians have a professional obligation to respect the autonomy of pregnant patients and to maximize beneficence-based obligations to both pregnant and fetal patients. The goal of a selective termination is to maximize the health and life of the surviving fetal patient. It is recommended that policymakers consider including selective termination as an exemption to abortion ban laws.

Cardiac function and neurological development in complicated monochorionic pregnancies: Current evidence and clinical implications

Monochorionic twin pregnancies, characterized by a shared placenta and unique vascular architecture, face significantly elevated risks of perinatal complications compared to dichorionic and singleton pregnancies. This review examines the pathophysiology, cardiovascular, and neurological adaptations in three primary complications of monochorionic pregnancies: Twin-to-Twin Transfusion Syndrome (TTTS), Selective Fetal Growth Restriction (sFGR), and Twin Anemia Polycythemia Sequence (TAPS). TTTS disrupts hemodynamic balance, leading to distinct cardiac dysfunctions and increased neurodevelopmental injury (NDI). In sFGR, unequal placental sharing induces cardiovascular and neurological disparities between twins, while TAPS causes chronic anaemia and polycythemia with associated risks of brain injury. Advances in fetal therapy, such as fetoscopic laser surgery, have significantly improved survival, yet long-term sequelae remain concerning. This review emphasizes the importance of specialised prenatal care, multidisciplinary management, and comprehensive postnatal follow-up to mitigate adverse outcomes. The findings call for further research into the mechanisms of fetal adaptation and injury, aiming to refine diagnostic tools and therapeutic strategies.

Management of monochorionic diamniotic twin gestation affected by Type-II selective fetal growth restriction: cost-effectiveness analysis

OBJECTIVE

Monochorionic twin gestations affected by Type-II selective fetal growth restriction (sFGR) are at increased risk of intrauterine fetal demise, extreme preterm birth, severe neurodevelopmental impairment (NDI) and neonatal death of one or both twins. In the absence of a consensus on the optimal management strategy, we chose to evaluate which strategy was cost-effective in the setting of Type-II sFGR.

METHODS

A decision-analytic model was used to compare expectant management (EM), bipolar cord occlusion (BCO), radiofrequency ablation (RFA) and fetoscopic laser photocoagulation (FLP) for a hypothetical cohort of 10 000 people with a monochorionic diamniotic twin pregnancy affected by Type-II sFGR. Probabilities and utilities were derived from the literature. Costs were derived from the Healthcare Cost and Utilization Project and adjusted to 2023 USD. The analytic horizon, taken from the perspective of the pregnant patient, extended throughout the life of the child or children. An incremental cost-effectiveness ratio of 50 000 USD per quality-adjusted life year defined the willingness-to-pay threshold. One-way and probabilistic sensitivity analysis was also performed.

RESULTS

For base-case estimates, RFA was the most cost-effective strategy compared with all of the other interventions included, with an incremental cost-effectiveness ratio of 14 243 USD per quality-adjusted life year. One-way sensitivity analysis demonstrated that the utilities assigned to fetal demise and severe NDI, as well as the costs of preterm birth before 32 weeks, most strongly impacted the model outcomes. On probabilistic sensitivity analysis, RFA was the most cost-effective strategy in 78% of runs, followed by BCO at 20%, EM at 2% and FLP in 0% of runs. When compared with EM, RFA led to 58 fewer births before 28 weeks' gestation, 273 fewer cases of severe NDI and 22 more deliveries after 32 weeks. When compared with FLP, RFA resulted in 259 fewer cases of severe NDI and 3177 more births after 32 weeks. When compared with BCO, RFA resulted in 1786 more neurologically intact neonates and 34 fewer cases of severe NDI.

CONCLUSIONS

On base-case analysis, RFA was found to be the most cost-effective strategy in the management of monochorionic diamniotic twin pregnancies affected by Type-II sFGR. However, these findings were not robust on sensitivity analysis, indicating the potential benefit of BCO and EM. In the absence of large clinical trials, these data should not be taken to guide management. Future studies should evaluate management strategies for Type-II sFGR related to long-term neonatal outcomes, inclusive of quality-of-life indicators, in a prospective multicenter cohort. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Counselling in Fetal Medicine: Complications of Monochorionic Diamniotic Twin Pregnancies

Twin pregnancies are at increased risk of morbidity and mortality compared to singletons. Among all twins, monochorionic pregnancies are at higher risk of specific and non-specific complications compared to dichorionic pregnancies. Therefore, it is of great importance to properly counsel future parents with monochorionic pregnancies regarding the risks of adverse outcomes and the modalities of monitoring and intervention of the potential complications. Conditions related to the monochorionicity include twin-to-twin transfusion syndrome (TTTS), twin reversed arterial perfusion sequence (TRAP), and twin anemia polycythemia syndrome (TAPS); other complications include selective fetal growth restriction (sFGR) and congenital anomalies. This review aims to summarize the information available in the current literature regarding the complications in monochorionic diamniotic twin pregnancies, including outcomes and guideline recommendations about the clinical surveillance, management, and timing of interventions of these conditions that should be included in counselling in routine clinical practice.

Development and validation of an ultrasound-based estimated fetal weight reference for Chinese twin pregnancy: a retrospective cohort study

BACKGROUND

Fetal growth monitoring is important for twin pregnancies. However, there has been no clinically validated tool for monitoring fetal growth of twin pregnancies in China. This study aims to develop and validate a chorionicity-specific growth chart of ultrasound estimated fetal weight (EFW) for Chinese twin pregnancies.

METHODS

This retrospective cohort study included all twin pregnancies who delivered two live fetuses with gestational age ≥ 34 weeks without severe obstetric complications at a tertiary hospital from January 2007 to March 2021. The participants were divided into a development set (delivered in or before December 2017) and a validation set (delivered in or after January 2018). Chorionicity-specific growth charts were created using the generalized additive models for location, scale, and shape (GAMLSS) based on the development set. The fetuses from the validation set were classified into three groups based on the last EFW: small-for-gestational-age (SGA) indicated by both the newly established twin charts and the Hadlock singleton chart currently used for twin pregnancies in China, suspected SGA indicated by only the singleton chart, and no SGA indicated by either chart. The incidence of neonatal outcomes among the three groups was then compared accordingly, including intensive care unit (NICU) stay length, respiratory diseases, and neurological disorders.

RESULTS

The development set included 883 twin pregnancies and a total of 6374 EFW measurements between 16 and 38 weeks of gestation, and the validation set included 801 twin pregnancies and 7630 EFW measurements. In the development set, monochorionic diamniotic (MCDA) twins had a significantly lower EFW compared to dichorionic diamniotic (DCDA) twins beginning at 26 weeks, with the difference gradually increasing thereafter, supporting the establishment of chorionicity-specific growth charts. Of the 1,602 twin neonates in the validation set, 103 (6.4%) were classified into the SGA group, 164 (10.2%) into the suspected SGA group, and 1335 (83.3%) into the no SGA group. The incidence of respiratory diseases and neurological disorders was comparable between the suspected SGA group and the no SGA group, but apparently higher in the SGA group. Meanwhile, NICU stay lengths were consistently longer for twins in the SGA group compared to the no SGA group (difference: 0.57, 95% CI: 0.31-0.83), with no significant differences observed between the suspected SGA and no SGA groups.

CONCLUSIONS

The fetal growth trajectories differed by chorionicity, with a lower EFW for MCDA twins beginning at 26 weeks. The establishment of chorionicity-specific growth chart could reduce overdiagnosis of SGA and improve fetal growth monitoring of twin pregnancies.

Diagnosis and management of selective fetal growth restriction in monochorionic twin pregnancies: A cross-sectional international survey

OBJECTIVE

To identify current practices in the management of selective fetal growth restriction (sFGR) in monochorionic diamniotic (MCDA) twin pregnancies.

DESIGN

Cross-sectional survey.

SETTING

International.

POPULATION

Clinicians involved in the management of MCDA twin pregnancies with sFGR.

METHODS

A structured, self-administered survey.

MAIN OUTCOME MEASURES

Clinical practices and attitudes to diagnostic criteria and management strategies.

RESULTS

Overall, 62.8% (113/180) of clinicians completed the survey; of which, 66.4% (75/113) of the respondents reported that they would use an estimated fetal weight (EFW) of <10th centile for the smaller twin and an inter-twin EFW discordance of >25% for the diagnosis of sFGR. For early-onset type I sFGR, 79.8% (75/94) of respondents expressed that expectant management would be their routine practice. On the other hand, for early-onset type II and type III sFGR, 19.3% (17/88) and 35.7% (30/84) of respondents would manage these pregnancies expectantly, whereas 71.6% (63/88) and 57.1% (48/84) would refer these pregnancies to a fetal intervention centre or would offer fetal intervention for type II and type III cases, respectively. Moreover, 39.0% (16/41) of the respondents would consider fetoscopic laser surgery (FLS) for early-onset type I sFGR, whereas 41.5% (17/41) would offer either FLS or selective feticide, and 12.2% (5/41) would exclusively offer selective feticide. For early-onset type II and type III sFGR cases, 25.9% (21/81) and 31.4% (22/70) would exclusively offer FLS, respectively, whereas 33.3% (27/81) and 32.9% (23/70) would exclusively offer selective feticide.

CONCLUSIONS

There is significant variation in clinician practices and attitudes towards the management of early-onset sFGR in MCDA twin pregnancies, especially for type II and type III cases, highlighting the need for high-level evidence to guide management.

Ductus Venosus Agenesis in Monochorionic Twin Pregnancies Complicated by Fetal Growth Restriction: When to Deliver?

Introduction: The prevalence of ductus venosus agenesis (ADV) in singleton pregnancies ranges from 0.04% to 0.15%, while its prevalence in twins remains largely unknown. To our knowledge, in the literature, there is only a single case report of a monochorionic diamniotic (MCDA) pregnancy complicated by ADV. Fetuses with ADV are at increased risk for congenital cardiac disease, heart failure, and fetal growth restriction (FGR). Consequently, these pregnancies have a heightened risk of experiencing an adverse outcome, like stillbirth and neonatal or infant death. Closer antenatal monitoring is warranted when ADV is suspected. Currently, there are no guidelines regarding the standard of care in cases of ADV and no recommendations for the timing of delivery in either singleton or twin pregnancies. Cases: This study aims to provide a comprehensive overview of the management of twin pregnancies complicated by ADV, featuring two cases of MC twins with concurrent sFGR and ADV in one twin. Discussion: These pregnancies experienced completely different outcomes, underscoring the necessity for personalized management tailored to the specific risk factors present in each pregnancy. Typically, in MCDA pregnancies with severe sFGR (type II and III), delivery represents the most reasonable option when venous Doppler abnormalities are identified. However, the absence of the DV complicates the management and the process of decision-making regarding the timing of delivery in cases of sFGR and ADV. We emphasize that effective decision-making should be guided by the presence of additional risk factors, including velamentous insertion, significant estimated fetal weight discordance, and progressive deterioration of the Doppler over time. Conclusions: Our experience suggests that these factors are strongly correlated with poorer outcomes. Given this context, could it be acceptable, in the case of MC pregnancy complicated by severe sFGR and ADV, with worsening findings and additional risk factors (e.g., velamentous insertion, severe birth weight discrepancy), to anticipate the time of delivery starting from 30 weeks of gestational age?

FERN: is it possible to conduct a randomised controlled trial of intervention or expectant management for early-onset selective fetal growth restriction in monochorionic twin pregnancy - protocol for a prospective multicentre mixed-methods feasibility study

INTRODUCTION

Selective fetal growth restriction (sFGR) in monochorionic twin pregnancy, defined as an estimated fetal weight (EFW) of one twin <10th centile and EFW discordance ≥25%, is associated with stillbirth and neurodisability for both twins. The condition poses unique management difficulties: on the one hand, continuation of the pregnancy carries a risk of death of the smaller twin, with a high risk of co-twin demise (40%) or co-twin neurological sequelae (30%). On the other, early delivery to prevent the death of the smaller twin may expose the larger twin to prematurity, with the associated risks of long-term physical, emotional and financial costs from neurodisability, such as cerebral palsy.When there is severe and early sFGR, before viability, delivery is not an option. In this scenario, there are currently three main management options: (1) expectant management, (2) selective termination of the smaller twin and (3) placental laser photocoagulation of interconnecting vessels. These management options have never been investigated in a randomised controlled trial (RCT). The best management option is unknown, and there are many challenges for a potential RCT. These include the rarity of the condition resulting in a small number of eligible pregnancies, uncertainty about whether pregnant women will agree to participate in such a trial and whether they will agree to be randomised to expectant management or active fetal intervention, and the challenges of robust and long-term outcome measures. Therefore, the main objective of the FERN study is to assess the feasibility of conducting an RCT of active intervention vs expectant management in monochorionic twin pregnancies with early-onset (prior to 24 weeks) sFGR.

METHODS AND ANALYSIS

The FERN study is a prospective mixed-methods feasibility study. The primary objective is to recommend whether an RCT of intervention vs expectant management of sFGR in monochorionic twin pregnancy is feasible by exploring women's preference, clinician's preference, current practice and equipoise and numbers of cases. To achieve this, we propose three distinct work packages (WPs). WP1: A Prospective UK Multicentre Study, WP2A: a Qualitative Study Exploring Parents' and Clinicians' Views and WP3: a Consensus Development to Determine Feasibility of a Trial. Eligible pregnancies will be recruited to WP1 and WP2, which will run concurrently. The results of these two WPs will be used in WP3 to develop consensus on a future definitive study. The duration of the study will be 53 months, composed of 10 months of setup, 39 months of recruitment, 42 months of data collection, and 5 months of data analysis, report writing and recommendations. The pragmatic sample size for WP1 is 100 monochorionic twin pregnancies with sFGR. For WP2, interviews will be conducted until data saturation and sample variance are achieved, that is, when no new major themes are being discovered. Based on previous similar pilot studies, this is anticipated to be approximately 15-25 interviews in both the parent and clinician groups. Engagement of at least 50 UK clinicians is planned for WP3.

ETHICS AND DISSEMINATION

This study has received ethical approval from the Health Research Authority (HRA) South West-Cornwall and Plymouth Ethics Committee (REC reference 20/SW/0156, IRAS ID 286337). All participating sites will undergo site-specific approvals for assessment of capacity and capability by the HRA. The results of this study will be published in peer-reviewed journals and presented at national and international conferences. The results from the FERN project will be used to inform future studies.

TRIAL REGISTRATION NUMBER

This study is included in the ISRCTN Registry (ISRCTN16879394) and the NIHR Central Portfolio Management System (CPMS), CRN: Reproductive Health and Childbirth Specialty (UKCRN reference 47201).

The Role of MALAT1 in Regulating the Proangiogenic Functions, Invasion, and Migration of Trophoblasts in Selective Fetal Growth Restriction

Epigenetic regulation is an important entry point to study the pathogenesis of selective fetal growth restriction (sFGR), and an understanding of the role of long noncoding RNAs (lncRNAs) in sFGR is lacking. Our study aimed to investigate the potential role of a lncRNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), in sFGR using molecular biology experiments and gain- or loss-of-function assays. We found that the levels of MALAT1, ERRγ, and HSD17B1 were downregulated and that of miR-424 was upregulated in the placental shares of the smaller twins. Moreover, angiogenesis was impaired in the placental share of the smaller fetus and MALAT1 could regulate the paracrine effects of trophoblasts on endothelium angiogenesis and proliferation by regulating miR-424. In trophoblasts, MALAT1 could competitively bind to miR-424 to regulate the expression of ERRγ and HSD17B1, thus regulating trophoblast invasion and migration. MALAT1 overexpression could decrease apoptosis and promote proliferation, alleviating cell damage induced by hypoxia. Taken together, the downregulation of MALAT1 can reduce the expression of ERRγ and HSD17B1 by competitively binding to miR-424, impairing the proangiogenic effect of trophoblasts, trophoblast invasion and migration, and the ability of trophoblasts to compensate for hypoxia, which may be involved in the pathogenesis of sFGR through various aspects.

Balancing key stakeholder priorities and ethical principles to design a trial comparing intervention or expectant management for early-onset selective fetal growth restriction in monochorionic twin pregnancy: FERN qualitative study

OBJECTIVES

As part of the FERN feasibility study, this qualitative research aimed to explore parents' and clinicians' views on the acceptability, feasibility and design of a randomised controlled trial (RCT) of active intervention versus expectant management in monochorionic (MC) diamniotic twin pregnancies with early-onset (prior to 24 weeks) selective fetal growth restriction (sFGR). Interventions could include laser treatment or selective termination which could lead to the death or serious disability of one or both twins.

DESIGN

Qualitative semi-structured interviews with parents and clinicians. Data were analysed using reflexive thematic analysis and considered against the Principles of Biomedical Ethics.

PARTICIPANTS AND SETTING

We interviewed 19 UK parents experiencing (six mothers, two partners) or had recently experienced (eight mothers, three partners) early-onset sFGR in MC twin pregnancy and 14 specialist clinicians from the UK and Europe.

RESULTS

Participants viewed the proposed RCT as 'ethically murky' because they believed that the management of sFGR in MC twin pregnancy should be individualised according to the type and severity of sFGR. Clinicians prioritised the gestational age, size, decrease in growth velocity, access to the placental vessels and acceptability of intervention for parents. Discussions and decision-making about selective termination appeared to cause long-term harm (maleficence). The most important outcome for parents and clinicians was 'live birth'. For clinicians, this was the live birth of at least one twin. For parents, this meant the live birth of both twins, even if this meant that their babies had neurodevelopmental impairment or disabilities.

CONCLUSIONS

All three pregnancy management approaches for sFGR in MC twin pregnancy carry risks and benefits, and the ultimate goal for parents is to receive individualised care to achieve the best possible outcome for both twins. An RCT was not acceptable to parents or clinicians or seen as ethically appropriate. Alternative study designs should be considered to answer this important research question.

Infant outcome at 3 years of age of monochorionic twins with Type-II or -III selective fetal growth restriction and isolated oligohydramnios that underwent fetoscopic laser photocoagulation

OBJECTIVE

To examine infant outcomes at 3 years of age in monochorionic twin pregnancies with Type-II or -III selective fetal growth restriction (sFGR) and isolated oligohydramnios who underwent fetoscopic laser photocoagulation (FLP).

METHODS

This multicenter prospective cohort study included monochorionic diamniotic twins that underwent FLP for sFGR between 16 and 25 weeks' gestation. The indication for performing FLP was Type-II or -III sFGR with oligohydramnios of the growth-restricted (FGR) twin in which the maximum vertical pocket of amniotic fluid was ≤ 2 cm. This was done in the absence of a typical diagnosis of twin-twin transfusion syndrome. The primary outcome was intact survival rate of both infants at the corrected gestational age of 40 weeks and at 3 years of age. Intact survival at the corrected age of 40 weeks was defined as survival without Grade-III or -IV intraventricular hemorrhage or cystic periventricular leukomalacia. Intact survival at 3 years of age was defined as survival without neurodevelopmental morbidity, which included cerebral palsy, neurodevelopmental impairment with a total developmental quotient of < 70, bilateral deafness or bilateral blindness.

RESULTS

Among 45 patients with sFGR, 30 (66.7%) were classified as having Type-II and 15 (33.3%) as Type-III sFGR. The prevalence of intact survival at the corrected age of 40 weeks was 51.1% (n = 23) in FGR twins and 95.5% (n = 42) in larger twins. The prevalence of intact survival at 3 years of age was 46.7% (n = 21) in FGR twins and 86.4% (n = 38) in larger twins. There was one case of miscarriage. Among the 24 FGR twins who were not classified as having intact survival at 3 years of age, 22 (91.7%) cases suffered fetal or infant demise (other than miscarriage), and there was one case of neurodevelopmental impairment. All larger twins who were not diagnosed with intact survival at 3 years of age (n = 6 (13.6%)) had neurological morbidity.

CONCLUSIONS

FGR twins and their larger cotwins, when subjected to FLP owing to sFGR coupled with umbilical artery Doppler abnormalities and isolated oligohydramnios, exhibit low rates of neurological morbidity and low mortality, respectively. Therefore, FLP for Type-II or -III sFGR with oligohydramnios may be a feasible management option and one that is preferable to expectant management. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Outcome of monochorionic diamniotic twin pregnancy with selective intrauterine growth restriction, a single center study in China

INTRODUCTION

This retrospective study aimed to evaluate clinical outcomes of monochorionic diamniotic (MCDA) twins with selective intrauterine growth restriction (sIUGR).

MATERIALS AND METHODS

MCDA twins, either sIUGR and non-sIUGR, underwent expectant management from 2016 to 2019 in our hospital were included. sIUGR fetuses were classified into three types according to umbilical artery Doppler assessment. Non-sIUGR were considered as the control group. Outcomes were pregnancy outcomes and maternal complications.

RESULTS

Forty-three sIUGR (type I: 23; type II: 14, and type III: 6) and 282 non-sIUGR fetuses were included. The sIUGR group had a significantly earlier birth, lower birth weight of the twins, larger inter-twin weight difference, lower Apgar score of the twins, and higher intrauterine fetal death (IUFD) than the non-sIUGR group (all p < 0.001). The same trend was found in the sIUGR type II group compared to type I and III groups. A significantly lower gestational diabetes rate (p = 0.01) and placenta weight (p < 0.001), and higher proportions of abnormal placental umbilical cord insertion (p < 0.001), and ultrasound Doppler monitoring indicators (p = 0.006) were found in the sIUGR group than the non-sIUGR group.

CONCLUSIONS

The MCDA twins with sIUGR showed poorer outcomes than the non-sIUGR group. Doppler interrogation was a useful clinical marker for fetal outcome.

Selective fetal growth restriction in dichorionic diamniotic twin pregnancy: systematic review and meta-analysis of pregnancy and perinatal outcomes

OBJECTIVE

Most of the published literature on selective fetal growth restriction (sFGR) has focused on monochorionic twin pregnancies. The aim of this systematic review was to report on the outcome of dichorionic diamniotic (DCDA) twin pregnancies complicated by sFGR.

METHODS

MEDLINE, EMBASE and The Cochrane Library databases were searched. The inclusion criteria were DCDA twin pregnancies complicated by sFGR. The outcomes explored were intrauterine death (IUD), neonatal death and perinatal death (PND), survival of at least one and both twins, preterm birth (PTB) (either spontaneous or iatrogenic) prior to 37, 34, 32 and 28 weeks' gestation, pre-eclampsia (PE) or gestational hypertension, neurological, respiratory and infectious morbidity, Apgar score < 7 at 5 min, necrotizing enterocolitis, retinopathy of prematurity and admission to the neonatal intensive care unit (NICU). A composite outcome of neonatal morbidity, defined as the occurrence of respiratory, neurological or infectious morbidity, was also evaluated. Random-effects meta-analysis was used to analyze the data, and results are reported as pooled proportion or odds ratio (OR) with 95% CI.

RESULTS

Thirteen studies reporting on 1339 pregnancies with sFGR and 6316 pregnancies without sFGR were included. IUD occurred in 2.6% (95% CI, 1.1-4.7%) of fetuses from DCDA pregnancies with sFGR and 0.6% (95% CI, 0.3-9.7%) of those from DCDA pregnancies without sFGR, while the respective values for PND were 5.2% (95% CI, 3.5-7.3%) and 1.7% (95% CI, 0.1-5.7%). Spontaneous or iatrogenic PTB before 37 weeks complicated 84.1% (95% CI, 55.6-99.2%) of pregnancies with sFGR and 69.1% (95% CI, 45.4-88.4%) of those without sFGR. The respective values for PTB before 34, 32 and 28 weeks were 18.4% (95% CI, 4.4-38.9%), 13.0% (95% CI, 9.5-17.1%) and 1.5% (95% CI, 0.6-2.3%) in pregnancies with sFGR and 10.2% (95% CI, 3.1-20.7%), 7.8% (95% CI, 6.8-9.0%) and 1.8% (95% CI, 1.3-2.4%) in those without sFGR. PE or gestational hypertension complicated 19.9% (95% CI, 12.4-28.6%) of pregnancies with sFGR and 12.8% (95% CI, 10.4-15.4%) of those without sFGR. Composite morbidity occurred in 28.2% (95% CI, 7.8-55.1%) of fetuses from pregnancies with sFGR and 13.9% (95% CI, 6.5-23.5%) of those from pregnancies without sFGR. When stratified according to the sFGR status within a twin pair, composite morbidity occurred in 39.0% (95% CI, 11.1-71.5%) of growth-restricted fetuses and 29.9% (95% CI, 3.5-65.0%) of appropriately grown fetuses (OR, 1.9 (95% CI, 1.7-3.1)), while the respective values for PND were 3.0% (95% CI, 1.8-4.5%) and 1.6% (95% CI, 0.9-2.6%) (OR, 2.1 (95% CI, 1.0-4.1)). On risk analysis, DCDA pregnancies complicated by sFGR had a significantly higher risk of IUD (OR, 5.2 (95% CI, 3.2-8.6)) and composite morbidity or admission to the NICU (OR, 3.2 (95% CI, 1.9-5.6)) compared to those without sFGR, while there was no difference in the risk of PTB before 34 weeks (P = 0.220) or PE/gestational hypertension (P = 0.210).

CONCLUSIONS

DCDA twin pregnancies complicated by sFGR are at high risk of perinatal morbidity and mortality. The findings of this systematic review are relevant for counseling and management of complicated DCDA twin pregnancies, in which twin-specific, rather than singleton, outcome data should be used. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Neurological morbidity in monochorionic twins with selective fetal growth restriction

The increased risks of various obstetric, maternal and fetal comorbidities of monochorionic twin pregnancies are widely known. However, despite its high prevalence and significance, the assessment of neurological morbidity as more commonly in selective fetal growth restriction (sFGR) is concerned with more health care. This literature review aims to provide more information about such an assessment. To this end, retrospective cases of sFGR were studied in monochorionic twins, already diagnosed, classified and who had the recommended management, published between 2001 and 2018 in 17 scientific articles. In the assessment of fetal mortality, the highest risk of death of the restricted fetus was found in type 3 of sFGR, while type 2 sFGR was responsible for the highest death rates of both fetuses and also the lowest mean gestational age at delivery, 30.9 weeks. Regarding neurological morbidity, however, studies have shown a higher risk of brain damage in the habitually growing twin compared to the restricted one in the case of sFGR. This may be due to prematurity or intermittent diastolic flow on Doppler in type 2 and 3 of sFGR, however, statements about its pathophysiology still lack further studies.

Monochorionic Twins: TTTS, TAPS, and Selective Fetal Growth Restriction

With an increasing incidence of twin gestations, understanding the inherent risks associated with these pregnancies is essential in modern obstetrics. The unique differences in placentation in monochorionic twins leads to unique complications, including twin-to-twin transfusion syndrome, the twin anemia-polycythemia sequence, and selective fetal growth restriction. Not only does the understanding of the monochorionic placenta lead to an understanding of the pathophysiology of the complications of monochorionic twins, but it also has led to the development of highly effective directed fetal therapy via fetoscopic laser coagulation used in twin-to-twin transfusion syndrome.

A study on the correlation of placental anastomosis and superficial vascular branches of selective fetal growth restriction in monochorionic diamniotic twins

INTRODUCTION

The main purpose of the present study was to investigate the correlation between placental anastomosis and superficial vascular branches in selective fetal growth restriction (sFGR) in monochorionic diamniotic twins.

MATERIALS AND METHODS

This was a retrospective analysis of the pregnancy data and placental perfusion of 395 patients with monochorionic diamniotic (MCDA) twin pregnancies delivered at our hospital from April 2013 to April 2020. We divided the patients into two groups and compared the number of placental superficial vascular branches in sFGR twins and normal MCDA twins. The correlation between the placental anastomosis and the number of superficial vascular branches in sFGR and normal MCDA twins was also investigated.

RESULTS

The number of umbilical arterial branches and umbilical venous branches was less than larger twins in sFGR, larger twins in normal MCDA and smaller twins in normal MCDA. (11.83 [4-44], 21.82 [7-50], 19.72 [3-38], 14.85 [0-31], p < 0.001, 6.08 [1-18], 9.60 [3-22], 9.96 [2-22], 8.38 [1-20], p < 0.00) For smaller twins in the sFGR group, the number of umbilical venous branches was positively associated with AA anastomosis overall diameter, AV anastomosis overall diameter and all anastomosis overall diameter. (r = 0.194, 0.182 and 0.211, p < 0.05) CONCLUSIONS: The risk of sFGR may arise when the placenta from MCDA twins shows a poor branching condition of placental superficial vessels. For the smaller twin of sFGR, regular ultrasound examination of the number of the umbilical venous branches may help to predict artery-to-artery (AA) overall diameter, artery-to-vein (AV) overall diameter and all anastomosis overall diameter.

Metabolic dynamics and prediction of sFGR and adverse fetal outcomes: a prospective longitudinal cohort study

BACKGROUND

Selective fetal growth restriction (sFGR) is an extreme complication that significantly increases the risk of perinatal mortality and long-term adverse neurological outcomes in offspring, affecting approximately 15% of monochorionic diamniotic (MCDA) twin pregnancies. The lack of longitudinal cohort studies hinders the early prediction and intervention of sFGR.

METHODS

We constructed a prospective longitudinal cohort study of sFGR, and quantified 25 key metabolites in 337 samples from maternal plasma in the first, second, and third trimester and from cord plasma. In particular, our study examined fetal growth and brain injury data from ultrasonography and used the Ages and Stages Questionnaire-third edition subscale (ASQ-3) to evaluate the long-term neurocognitive behavioral development of infants aged 2-3 years. Furthermore, we correlated metabolite levels with ultrasound data, including physical development and brain injury indicators, and ASQ-3 data using Spearman's-based correlation tests. In addition, special combinations of differential metabolites were used to construct predictive models for the occurrence of sFGR and fetal brain injury.

RESULTS

Our findings revealed various dynamic patterns for these metabolites during pregnancy and a maximum of differential metabolites between sFGR and MCDA in the second trimester (n = 8). The combination of L-phenylalanine, L-leucine, and L-isoleucine in the second trimester, which were closely related to fetal growth indicators, was highly predictive of sFGR occurrence (area under the curve [AUC]: 0.878). The combination of L-serine, L-histidine, and L-arginine in the first trimester and creatinine in the second trimester was correlated with long-term neurocognitive behavioral development and showed the capacity to identify fetal brain injury with high accuracy (AUC: 0.94).

CONCLUSIONS

The performance of maternal plasma metabolites from the first and second trimester is superior to those from the third trimester and cord plasma in discerning sFGR and fetal brain injury. These metabolites may serve as useful biomarkers for early prediction and promising targets for early intervention in clinical settings.

Establishment of a model for predicting preterm birth based on the machine learning algorithm

BACKGROUND

The purpose of this study was to construct a preterm birth prediction model based on electronic health records and to provide a reference for preterm birth prediction in the future.

METHODS

This was a cross-sectional design. The risk factors for the outcomes of preterm birth were assessed by multifactor logistic regression analysis. In this study, a logical regression model, decision tree, Naive Bayes, support vector machine, and AdaBoost are used to construct the prediction model. Accuracy, recall, precision, F1 value, and receiver operating characteristic curve, were used to evaluate the prediction performance of the model, and the clinical application of the model was verified.

RESULTS

A total of 5411 participants were included and were used for model construction. AdaBoost model has the best prediction ability among the five models. The accuracy of the model for the prediction of "non-preterm birth" was the highest, reaching 100%, and that of "preterm birth" was 72.73%.

CONCLUSIONS

By constructing a preterm birth prediction model based on electronic health records, we believe that machine algorithms have great potential for preterm birth identification. However, more relevant studies are needed before its application in the clinic.

Selective intrauterine growth restriction without concomitant twin-to-twin transfusion syndrome, natural history, and risk factors for fetal death: A systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the natural history of selective intrauterine growth restriction in monochorionic twin pregnancies based on the Gratacós classification, including progression of, improvement in, or stability of umbilical artery Dopplers and progression to twin-to-twin transfusion syndrome or twin anemia polycythemia syndrome. We also aimed to investigate risk factors for smaller twin demise.

DATA SOURCES

A systematic search was performed to identify relevant studies published in English up to June 2022 using the databases PubMed, Scopus, and Web of Science STUDY ELIGIBILITY: We used retrospective and prospective studies published in English that reported on selective intrauterine growth restriction without concomitant twin-to-twin transfusion syndrome.

STUDY APPRAISAL AND SYNTHESIS METHODS

Articles that investigated selective intrauterine growth restriction progression and outcomes by umbilical artery Doppler end-diastolic flow (Gratacós classification) were included. Type I included selective intrauterine growth restriction cases with positive end-diastolic flow, type II included those cases with persistently absent end-diastolic flow, and type III included cases with intermittent absent or reversed end-diastolic flow. Pregnancies in which a diagnosis of twin-to-twin transfusion syndrome or twin anemia polycythemia sequence was made before the diagnosis of selective intrauterine growth restriction were not included in the analysis. A random effects model was used to pool the odds ratios and the corresponding 95% confidence intervals. Heterogeneity was assessed using the I2 value.

RESULTS

A total of 17 studies encompassing 2748 monochorionic pregnancies complicated by selective intrauterine growth restriction were included in the analysis. The incidence of stable, deteriorating, or improving umbilical artery Dopplers in type I cases was 68% (95% confidence interval, 26-89), 23% (95% confidence interval, 7-40), and 9% (95% confidence interval, 0.0-100), respectively. In type II cases, the incidence was 40% (95% confidence interval, 18-81), 50% (95% confidence interval, 23-82), and 10% (95% confidence interval, 4-37), respectively, and in type III cases, the incidence was 55% (95% confidence interval, 2-99), 23% (95% confidence interval, 9-43), and 22% (95% confidence interval, 6-54), respectively. The risk for progression to twin-to-twin transfusion syndrome was comparable between type I (7%) and type III (9%) cases and occurred in 4% (95% confidence interval, 0-67) of type II cases with no significant subgroup differences. Progression to twin anemia polycythemia syndrome was highest in type I cases (12%) and comparable between type II (2%) and III (1%) cases with no significant subgroup differences. Risk factors for smaller twin demise were earlier gestational age at diagnosis (mean difference, -2.69 weeks; 95% confidence interval, -4.94 to -0.45; I2, 45%), larger intertwin weight discordance (mean difference, 34%; 95% confidence interval, 1.35-5.38; I2, 28%), deterioration of umbilical artery Dopplers for each of type II and III cases (odds ratio, 3.05; 95% confidence interval, 1.36-6.84; I2, 24%; and odds ratio, 4.5; 95% confidence interval, 2.31-8.77; I2, 0.0%, respectively), and absent or reversed ductus venosus a-wave for each of type II and III cases (odds ratio, 3.35; 95% confidence interval, 2.28-4.93; I2, 0.0%; and odds ratio, 2.36; 95% confidence interval, 1.08-5.13; I2, 0.0%, respectively). Progression to twin-to-twin transfusion syndrome was not significantly associated with smaller twin demise for each of type II and III selective intrauterine growth restriction cases.

CONCLUSION

These findings improve our understanding of the natural history of the types of selective intrauterine growth restriction and of the predictors of smaller twin demise in type II and III selective intrauterine growth restriction cases. The current data provide vital counseling points and support the need for modifications of the current selective intrauterine growth restriction classification system to include the variations in umbilical artery and ductus venosus Dopplers to better identify a cohort that might benefit from fetal intervention for which future multicenter prospective randomized trials are needed.

Outcome following laser surgery of twin-twin transfusion syndrome complicated by selective fetal growth restriction: systematic review and meta-analysis

OBJECTIVE

The published literature reports mostly on the outcome of twin pregnancies complicated by twin-twin transfusion syndrome (TTTS) without considering whether the pregnancy is also complicated by another pathology, such as selective fetal growth restriction (sFGR). The aim of this systematic review was to report on the outcome of monochorionic diamniotic (MCDA) twin pregnancies undergoing laser surgery for TTTS that were complicated by sFGR and those not complicated by sFGR.

METHODS

MEDLINE, EMBASE and Cochrane databases were searched. The inclusion criteria were studies reporting on MCDA twin pregnancies with TTTS undergoing laser therapy that were complicated by sFGR and those not complicated by sFGR. The primary outcome was the overall fetal loss following laser surgery, defined as miscarriage and intrauterine death. The secondary outcomes included fetal loss within 24 h after laser surgery, survival at birth, preterm birth (PTB) prior to 32 weeks of gestation, PTB prior to 28 weeks, composite neonatal morbidity, neurological and respiratory morbidity, and survival free from neurological impairment. All outcomes were explored in the overall population of twin pregnancies complicated by sFGR vs those not complicated by sFGR in the setting of TTTS and in the donor and recipient twins separately. Random-effects meta-analysis was used to combine data and the results are reported as pooled odds ratios (OR) with 95% CI.

RESULTS

Five studies (1710 MCDA twin pregnancies) were included in the qualitative synthesis and four in the meta-analysis. The overall risk of fetal loss after laser surgery was significantly higher in MCDA twin pregnancies with TTTS complicated by sFGR (20.90% vs 14.42%), with a pooled OR of 1.6 (95% CI, 1.3-1.9) (P < 0.001). The risk of fetal loss was significantly higher in MCDA twin pregnancies with TTTS and sFGR for the donor but not for the recipient twin. The rate of live twins was 79.1% (95% CI, 72.6-84.9%) in TTTS pregnancies with sFGR and 85.6% (95% CI, 81.0-89.6%) in those without sFGR (pooled OR, 0.6 (95% CI, 0.5-0.8)) (P < 0.001). There was no significant difference in the risk of PTB prior to 32 weeks of gestation (P = 0.308) or prior to 28 weeks (P = 0.310). Assessment of short- and long-term morbidity was affected by the small number of cases. There was no significant difference in the risk of composite (P = 0.506) or respiratory (P = 0.531) morbidity between twins complicated by TTTS with vs those without sFGR, while the risk of neurological morbidity was significantly higher in those with TTTS and sFGR (pooled OR, 1.8 (95% CI, 1.1-2.9)) (P = 0.034). The risk of neurological morbidity was significantly higher for the donor twin (pooled OR, 2.4 (95% CI, 1.1-5.2)) (P = 0.029) but not for the recipient twin (P = 0.361). Survival free from neurological impairment was observed in 70.8% (95% CI, 45.0-91.0%) of twin pregnancies with TTTS complicated by sFGR and in 75.8% (95% CI, 51.9-93.3%) of those not complicated by sFGR, with no difference between the two groups.

CONCLUSIONS

sFGR in MCDA pregnancies with TTTS represents an additional risk factor for fetal loss following laser surgery. The findings of this meta-analysis may be useful for individualized risk assessment of twin pregnancy complicated by TTTS and tailored counseling of the parents prior to laser surgery. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Cervical cerclage for prevention of preterm birth and adverse perinatal outcome in twin pregnancies with short cervical length or cervical dilatation: A systematic review and meta-analysis

BACKGROUND

The optimal approach to prevent preterm birth (PTB) in twins has not been fully established yet. Recent evidence suggests that placement of cervical cerclage in twin pregnancies with short cervical length at ultrasound or cervical dilatation at physical examination might be associated with a reduced risk of PTB. However, such evidence is based mainly on small studies thus questioning the robustness of these findings. The aim of this systematic review was to determine the role of cervical cerclage in preventing PTB and adverse maternal or perinatal outcomes in twin pregnancies.

METHODS AND FINDINGS

Key databases searched and date of last search: MEDLINE, Embase, and CINAHL were searched electronically on 20 April 2023. Eligibility criteria: Inclusion criteria were observational studies assessing the risk of PTB among twin pregnancies undergoing cerclage versus no cerclage and randomized trials in which twin pregnancies were allocated to cerclage for the prevention of PTB or to a control group (e.g., placebo or treatment as usual). The primary outcome was PTB <34 weeks of gestation. The secondary outcomes were PTB <37, 32, 28, 24 weeks of gestation, gestational age at birth, the interval between diagnosis and birth, preterm prelabor rupture of the membranes (pPROM), chorioamnionitis, perinatal loss, and perinatal morbidity. Subgroup analyses according to the indication for cerclage (short cervical length or cervical dilatation) were also performed. Risk of bias assessment: The risk of bias of the included randomized controlled trials (RCTs) was assessed using the Revised Cochrane risk-of-bias tool for randomized trials, while that of the observational studies using the Newcastle-Ottawa scale (NOS). Statistical analysis: Summary risk ratios (RRs) of the likelihood of detecting each categorical outcome in exposed versus unexposed women, and (b) summary mean differences (MDs) between exposed and unexposed women (for each continuous outcome), with their 95% confidence intervals (CIs) were computed using head-to-head meta-analyses. Synthesis of the results: Eighteen studies (1,465 twin pregnancies) were included. Placement of cervical cerclage in women with a twin pregnancy with a short cervix at ultrasound or cervical dilatation at physical examination was associated with a reduced risk of PTB <34 weeks of gestation (RR: 0.73, 95% CI [0.59, 0.91], p = 0.005 corresponding to a 16% difference in the absolute risk, AR), <32 (RR: 0.69, 95% CI [0.57, 0.84], p < 0.001; AR: 16.92%), <28 (RR: 0.54, 95% [CI 0.43, 0.67], 0.001; AR: 18.29%), and <24 (RR: 0.48, 95% CI [0.23, 0.97], p = 0.04; AR: 15.57%) weeks of gestation and a prolonged gestational age at birth (MD: 2.32 weeks, 95% [CI 0.99, 3.66], p < 0.001). Cerclage in twin pregnancy with short cervical length or cervical dilatation was also associated with a reduced risk of perinatal loss (RR: 0.38, 95% CI [0.25, 0.60], p < 0.001; AR: 19.62%) and composite adverse outcome (RR: 0.69, 95% CI [0.53, 0.90], p = 0.007; AR: 11.75%). Cervical cerclage was associated with a reduced risk of PTB <34 weeks both in women with cervical length <15 mm (RR: 0.74, 95% CI [0.58, 0.95], p = 0.02; AR: 29.17%) and in those with cervical dilatation (RR: 0.68, 95% CI [0.57, 0.80], p < 0.001; AR: 35.02%). The association between cerclage and prevention of PTB and adverse perinatal outcomes was exclusively due to the inclusion of observational studies. The quality of retrieved evidence at GRADE assessment was low.

CONCLUSIONS

Emergency cerclage for cervical dilation or short cervical length <15 mm may be potentially associated with a reduction in PTB and improved perinatal outcomes. However, these findings are mainly based upon observational studies and require confirmation in large and adequately powered RCTs.

The High-Risk Profile of Selective Growth Restriction in Monochorionic Twin Pregnancies

The present review aims to provide a critical appraisal of the sonographic diagnosis and follow-up and to evaluate the optimal clinical management of monochorionic twin pregnancies where one of the twins is complicated by selective fetal growth restriction (sFGR). The classification is based on the umbilical artery (UA) diastolic flow reflecting the outcome. If the sFGR twin has positive diastolic flow (Type I) then the prognosis is good, and it does not require close surveillance. Biweekly or weekly sonographic and Doppler surveillance and fetal monitoring are recommended strategies to detect unpredictable complications in type II and type III forms, which are defined by persistently absent/reverse end-diastolic flow (AREDF) or cyclically intermittent absent/reverse end-diastolic flow (iAREDF) in the umbilical waveforms, respectively. The latest forms are associated with an increased risk of unexpected fetal demise of the smaller twin and 10-20% risk of neurological injury in the larger twin in addition to the overall risk of prematurity. The clinical course can be affected by elective fetal therapy ('dichorinization' of the placenta with laser or selective fetal reduction) or elective delivery in the presence of severe fetal deterioration. The prediction of the clinical outcome in complicated cases of type II and III sFGR cases remains elusive. Novel routines in fetal and placental scans in order to predict neurological impairments and unexpected fetal death to optimize the delivery time-point are needed.

Natural evolution and risk factors for adverse outcome in selective intrauterine growth restriction under expectant management: A retrospective observational study

OBJECTIVE

To evaluate the natural evolution of and risk factors for the adverse outcome of monochorionic twins with selective intrauterine growth restriction (sIUGR) under expectant management.

METHODS

Retrospective study conducted in a single tertiary referral center. The clinical characteristics and neonatal outcomes of 153 patients with sIUGR under expectant management were evaluated, and the risk factors leading to adverse outcomes were explored.

RESULTS

Fifty-one patients (33.3%) showed a changed pattern in umbilical artery Doppler at the last examination, occurring in all types of sIUGR. Compared with type Ia, the gestational age of diagnosis was earlier, the estimated fetal body weight difference at diagnosis was greater, and the rate of severe neonatal complications in both fetuses was significantly higher in type Ib (P < 0.05). Univariate and multivariate logistic regression analyses showed that type II (odds ratio [OR] 5.41, 95% confidence interval [CI] 2.34-12.51; P < 0.001) and type III (OR 9.11, 95% CI 3.02-27.50; P < 0.001) were associated with adverse perinatal outcomes in sIUGR.

CONCLUSION

Type II and III sIUGR are independent risk factors predicting adverse outcomes of sIUGR. Different types of sIUGR could convert to each other. The outcome of type Ib is poorer than that of type Ia.

Does Fetal Growth Adequacy Affect the Nutritional Composition of Mothers' Milk?: A Historical Cohort Study

OBJECTIVE

The study aimed to assess the association between intrauterine growth of preterm infants and energy and macronutrient contents in their mothers' milk.

STUDY DESIGN

A historical cohort of mothers of preterm infants was assessed according to offspring's intrauterine growth. Fetal growth restriction (FGR) was defined as small-for-gestational age or appropriate for gestational age with fetal growth deceleration. During the first 4 weeks after delivery, the composition of daily pool samples of mothers' milk was measured by using a mid-infrared human milk analyzer. Explanatory models for milk energy, true protein, total carbohydrate, and fat contents were obtained by generalized additive mixed effects regression models.

RESULTS

In total, 127 milk samples were analyzed from 73 mothers who delivered 92 neonates. Energy content was significantly higher in mothers with chronic hypertension (average: +6.28 kcal/dL; 95% confidence interval [CI]: 0.54-12.01; p = 0.034) and for extremely preterm compared with very preterm infants (average: +5.95 kcal/dL; 95% CI: 2.16-9.73; p = 0.003), and weakly associated with single pregnancies (average: +3.38 kcal/dL; 95% CI: 0.07-6.83; p = 0.057). True protein content was significantly higher in mothers with chronic hypertension (average: +0.91 g/dL; 95% CI: 0.63-1.19; p < 0.001) and with hypertension induced by pregnancy (average: +0.25 g/dL, 95% CI: 0.07-0.44; p = 0.007), and for extremely preterm compared with very and moderate preterm infants (average: +0.19; 95% CI: 0.01-0.38; p = 0.043 and +0.28 g/dL; 95% CI: 0.05-0.51; p = 0.017, respectively). Fat content was weakly and negatively associated with FGR, both in SGA infants and AGA infants with fetal growth deceleration (average: -0.44 g/dL; 95% CI: -0.92 to -0.05; p = 0.079 and average: -0.36 g/dL; 95% CI: -0.74 to -0.02; p = 0.066, respectively).

CONCLUSION

Energy and macronutrient contents in mothers' milk of preterm infants was significantly and positively associated with the degree of prematurity and hypertension. The hypothesis that the composition of milk is associated with FGR was not demonstrated.

KEY POINTS

· Energy and protein are higher for more immature infants.. · Energy and/or protein is higher in hypertension.. · Fat may be lower for infants with intrauterine growth restriction..

Solomon technique vs selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome: systematic review and meta-analysis of maternal and perinatal outcomes

OBJECTIVE

To ascertain maternal and perinatal outcomes of monochorionic twin pregnancies complicated by twin-twin transfusion syndrome (TTTS) treated with the Solomon technique compared with selective fetoscopic laser photocoagulation (SFLP) of placental anastomoses.

METHODS

MEDLINE, EMBASE and The Cochrane Library were searched to identify relevant studies. The outcomes observed were perinatal loss and survival, preterm prelabor rupture of membranes (PPROM), preterm birth (PTB), gestational age (GA) at delivery, interval between laser treatment and delivery, maternal bleeding, septostomy or chorioamniotic separation, placental abruption, twin anemia-polycythemia sequence (TAPS), recurrence of TTTS, neonatal morbidity and neurological morbidity. Random-effects head-to-head meta-analyses were used to analyze the data. Pooled odds ratios (OR) and mean differences (MD) and their 95% CIs were calculated.

RESULTS

Nine studies were included in the systematic review. There was generally no difference in the main maternal and pregnancy characteristics between pregnancies treated using the Solomon technique and those treated using SFLP of placental anastomoses. The risks of fetal loss (pooled OR, 0.69 (95% CI, 0.50-0.95); P = 0.023), neonatal death (pooled OR, 0.37 (95% CI, 0.16-0.84); P = 0.018) and perinatal loss (pooled OR, 0.56 (95% CI, 0.38-0.83); P = 0.004) were significantly lower in pregnancies treated using the Solomon technique than in those treated with SFLP. Likewise, pregnancies treated using the Solomon technique had a significantly higher chance of survival of at least one twin (pooled OR, 2.31 (95% CI, 1.03-5.19); P = 0.004) and double survival (pooled OR, 2.18 (95% CI, 1.29-3.70); P = 0.001). There was no difference in the risk of PPROM (P = 0.603), PPROM within 10 days from laser surgery (P = 0.982), PTB (P = 0.207), maternal bleeding (P = 0.219), septostomy or chorioamniotic separation (P = 0.224) or chorioamnionitis (P = 0.135) between the two groups, while the risk of placental abruption was higher in pregnancies treated using the Solomon technique (pooled OR, 2.90 (95% CI, 1.55-5.44); P = 0.001). In the Solomon technique group, pregnancies delivered at a significantly earlier GA than did those treated with SFLP (pooled MD, -0.625 weeks (95% CI, -0.90 to -0.35 weeks); P < 0.001), while there was no difference in the interval between laser treatment and delivery (P = 0.589). The rate of recurrence of TTTS was significantly lower in pregnancies undergoing the Solomon technique (pooled OR, 0.43 (95% CI, 0.22-0.81); P < 0.001), while there was no difference in the risk of TAPS between the two groups (P = 0.792). Finally, there was no difference in the overall risk of neonatal morbidity (P = 0.382) or neurological morbidity (P = 0.247) between the two groups.

CONCLUSIONS

Monochorionic twin pregnancies complicated by TTTS undergoing laser treatment using the Solomon technique had a significantly higher survival rate and lower recurrence rate of TTTS but were associated with an increased risk of placental abruption and earlier GA at delivery compared to those treated with SFLP. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Placenta accreta spectrum disorders in twin pregnancies as an under reported clinical entity: a case series and systematic review

Recent reports suggested a potential association between twin pregnancy and the occurrence of placenta accreta spectrum (PAS) disorders. Despite this, scarce data on PAS disorders in twins has been reported in the published literature. We present a series of twelve twin pregnancies complicated by PAS from two large institutions over 5 years. A systematic review of the literature was also conducted in order to find studies reporting on the risk factors, prenatal diagnosis using ultrasound and clinical outcomes of PAS in twin pregnancies.

Gestational Age at Birth and outcome in Monochorionic Twins with Different Types of Selective Fetal Growth Restriction: A Systematic Literature Review

This systematic review aims to assess the gestational age at birth and perinatal outcome (intrauterine demise (IUD), neonatal mortality and severe cerebral injury) in monochorionic (MC) twins with selective fetal growth restriction (sFGR), according to Gratacós classification based on umbilical artery Doppler flow patterns in the smaller twin. Seventeen articles were included. Gestational age at birth varied from 33.0-36.0 weeks in type I, 27.6-32.4 weeks in type II, and 28.3-33.8 weeks in type III. IUD rate differed from 0-4% in type I to 0-40% in type II and 0-23% in type III. Neonatal mortality rate was between 0-10% in type I, 0-38% in type II, and 0-17% in type III. Cerebral injury was present in 0-2% of type I, 2-30% of type II and 0-33% of type III cases. The timing of delivery in sFGR varied substantially among studies, particularly in type II and III. The quality of evidence was moderate due to heterogenous study populations with varying definitions of sFGR and perinatal outcome parameters, as well as a lack of consensus on the use of the Gratacós classification, leading to substantial incomparability. Our review identifies the urgent need for uniform antenatal diagnostic criteria and definitions of outcome parameters. This article is protected by copyright. All rights reserved.

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.

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 10^th 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.

Prediction of Fetal Growth Restriction for Fetal Umbilical Arterial/Venous Blood Flow Index Evaluated by Ultrasonic Doppler under Intelligent Algorithm

The empirical wavelet transform (EWT) algorithm was applied in ultrasound to explore the predictive value for fetal growth restriction (FGR) in fetal arteriovenous indexes. 142 pregnant women who received prenatal ultrasonic examination and delivered were selected. They were classified into control group and FGR group. There were 102 patients with normal pregnancy in the control group, and 40 patients with delayed fetal growth in the FGR group. The extended triple collocation (ETC) algorithm was employed to divide the Fourier spectrum of signals adaptively, and the constructed small filter banks were classified into corresponding intervals. The instantaneous frequency was analyzed, and the arterial blood flow indexes of the two groups were compared. The results showed that the time-frequency analysis method under EWT had lower normalization error and higher accuracy. The inner diameter and cross-sectional area of FGR were remarkably smaller than those of the control group, and the differences were statistically significant (P < 0.05). There were no significant differences in mean blood flow and mean blood velocity between the control group and FGR group (P > 0.05). The arterial blood flow parameters of the systolic flow velocity (VS) and the diastolic flow velocity (VD) in the FGR group were notably lower than those in the control group, and the differences were significant (P < 0.05). In conclusion, the frequency principal component extracted by EWT algorithm was less disturbed by noise, which could accurately and effectively evaluate fetal arteriovenous blood flow indexes and predict FGR.

Neonatal and Long-Term Prognosis of Monochorionic Diamniotic Pregnancies Complicated by Selective Growth Restriction

Background: There are few data concerning the neonatal and long-term prognosis of monochorionic biamniotic twin pregnancies (MCBA) complicated by selective intrauterine growth restriction (sIUGR). The aim of the study is to assess the neurological outcomes at two years of age of these newborns and compares these outcomes to those of newborns resulting from intrauterine growth restriction (IUGR) pregnancies. Methods: The study focuses on a cross-sectional prospective cohort of patients treated between 2012 and 2019 in Marseille, France. The primary endpoint is the overall score of the Ages and Stages questionnaires (ASQ) at two years, which assesses the global neurodevelopment. The secondary endpoint is the assessment of neonatal morbi-mortality for both groups (composite endpoint). Results: In total, 251 patients were included in the analysis: 67 in the sIUGR group and 184 in the IUGR group. There was no statistically significant difference in the overall ASQ score at two years but there was the finest motor skills impairment in the IUGR group. The areas most often impaired were communication and fine motor skills. There were no significant differences between the neonatal morbi-mortality of the two groups (adjusted OR = 0.95, p = 0.9). Conclusions: Newborns from MCBA pregnancies with sIUGR appear to have similar overall neurological development to IUGR. Notably, IUGR seems to have the most moderate neurobehavioral disorder (fine motor) as a consequence of impaired antenatal brain development due to placenta insufficiency leading to chronic hypoxia.

Neonatal management and outcome in complicated monochorionic twins: What have we learned in the past decade and what should you know?

Monochorionic (MC) twin pregnancies are at increased risk of neonatal morbidity and mortality due to the shared placenta with vascular connections that can give rise to various complications, including twin-twin transfusion syndrome, twin anemia polycythemia sequence (TAPS), selective fetal growth restriction, and other hematological imbalances at birth. Each complication presents its own challenges and considerations in the neonatal period. Measurement of hemoglobin levels and reticulocyte count is required to establish a correct diagnosis. Placenta dye injection is needed to properly distinguish between the various conditions. Risk factors for adverse outcome in MC twins include prematurity, severe cerebral injury, and the type of MC pregnancy complication. We, therefore, recommend cerebral ultrasound examinations in all complicated MC twins at birth to rule out a severe brain injury. Lastly, we strongly encourage screening for hearing loss using automated auditory brainstem response in all spontaneous TAPS donors to prevent permanent speech development delay.

Neonatal Morbidity of Monoamniotic Twin Pregnancies: A Systematic Review and Meta-analysis

OBJECTIVE

This study was aimed to report the incidence of neonatal morbidity in monochorionic monoamniotic (MCMA) twin pregnancies according to gestational age at birth and type of management adopted (inpatient or outpatient).

STUDY DESIGN

Medline and Embase databases were searched. Inclusion criteria were nonanomalous MCMA twins. The primary outcome was a composite score of neonatal morbidity, defined as the occurrence of at least one of the following outcomes: respiratory morbidity, overall neurological morbidity, severe neurological morbidity, and infectious morbidity, necrotizing enterocolitis at different gestational age windows (24-30, 31-32, 33-34, and 35-36 weeks). Secondary outcomes were the individual components of the primary outcome and admission to neonatal intensive care unit (NICU). Subanalysis according to the type of surveillance strategy (inpatient compared with outpatient) was also performed. Random effect meta-analyses were used to analyze the data.

RESULTS

A total of 14 studies including 685 MCMA twin pregnancies without fetal anomalies were included. At 24 to 30, 31 to 32, 33 to 34, and 35 to 36 weeks of gestation, the rate of composite morbidity was 75.4, 65.5, 37.6, and 18.5%, respectively, the rate of respiratory morbidity was 74.2, 59.1, 35.5, and 12.2%, respectively, while overall neurological morbidity occurred in 15.3, 10.2, 4.3, and 0% of the cases, respectively. Infectious morbidity complicated 13, 4.2, 3.1, and 0% of newborns while 92.1, 81.6, 58.7, and 0% of cases required admission to NICU. Morbidity in pregnancies delivered between 35 and 36 weeks of gestation was affected by the very small sample size of cases included. When comparing the occurrence of overall morbidity according to the type of management (inpatient or outpatient), there was no difference between the two surveillance strategies (p = 0.114).

CONCLUSION

MCMA pregnancies are at high risk of composite neonatal morbidity, mainly respiratory morbidity that gradually decreases with increasing gestational age at delivery with a significant reduction for pregnancies delivered between 33 and 34 weeks. We found no difference in the occurrence of neonatal morbidity between pregnancies managed as inpatient or outpatient.

KEY POINTS

· MCMA pregnancies are at high risk of composite neonatal morbidity, mainly respiratory morbidity.. · Neonatal morbidity gradually decreases with increasing GA at delivery, mostly between 33 and 34 weeks.. · There is no difference in the occurrence of neonatal morbidity between in- or outpatient management..

Early- and late-onset selective fetal growth restriction in monochorionic twin pregnancy with expectant management

OBJECTIVE

This study aimed to identify selective fetal growth restriction (sFGR) in monochorionic twin (MCT) pregnancy with expectant management.

METHODS

We retrospectively analyzed cases of sFGR between January 2015 and December 2019 in Peking University Third Hospital. We included sFGR according to the International Society of Ultrasound in Obstetrics and Gynecology diagnostic criteria. We excluded those cases where a significant fetal structural abnormality, twin reversed arterial perfusion (TRAP), genetic syndrome or aneuploidy; cases terminated for maternal complications or for personal reasons; pregnancies that had a fetal intervention, such as fetoscopic laser photocoagulation (FLP) for vascular anastomoses, fetal reduction by radiofrequency ablation (RFA) and microwave ablation (MVA). We didn't excluded those cases that had amnioreduction therapy. According to the gestational age at onset (before 24 weeks or after), data were analyzed to identify the risk factors associated with fetal prognostic outcomes. Primary outcomes included survival of at least one twin and both twins. Secondary outcomes included gestational age of delivery, live birth weight, Apgar <7 in 5 min, admission to the neonatal unit and neonatal death. Kruskal-Wallis rank tests were used to compare non-normally distributed data, whereas categorical data were matched using Fisher's exact test or χ² tests. ANOVA was used to compare normally distributed data, followed by a post-hoc Bonferroni analysis. Multivariate binary logistic regression was used to identify the factors connected with intrauterine death.

RESULTS

There were 119 pregnancies that qualified for investigation, 75 (63.0%) were categorized as early-onset sFGR and 44 (37.0%) as late-onset sFGR. The rate of survival of at least one twin (82.7% vs. 95.5%), survival of both twins (73.3% vs. 88.6%) were all reduced in the early-onset sFGR group, compared to the late-onset sFGR group. Babies born alive of fetal growth restriction (FGR) and appropriate growth for gestational age (AGA) fetuses showed similar results in the two groups regarding birth weight, 5-min Apgar score <7, neonatal death, and 28-day survival rate. A multivariable model was used to predict the intrauterine death of at least one twin. The odds ratio were significantly higher for superimposed twin-twin transfusion syndrome (TTTS) (OR 17.915, 95%CI 3.699∼86.756) and Types Ⅱ/Ⅲ sFGR (OR 4.619, 95%CI 1.074∼19.869).

CONCLUSIONS

In MCT pregnancies, early-onset sFGR had a poorer survival of at least one or both twins, but there was no statistical difference in the prognosis after live birth, neither for FGR babies nor those of AGA. Superimposed TTTS and Types Ⅱ/Ⅲ sFGR had a worse perinatal outcome. This information could be provided to the parents during prenatal counselling.

Selective intrauterine growth restriction of monochorionic diamniotic twin pregnancies: What is the neonatal prognosis?

OBJECTIVE

This study compares the neonatal morbidity and mortality of the smallest twins of monochorionic diamniotic (MCDA) pregnancies complicated with selective intrauterine growth restriction (sIUGR) with newborns from singleton pregnancies with intrauterine growth restriction (IUGR).

METHODS

We conducted a retrospective cohort study of patients managed at the prenatal diagnosis center in a single tertiary care hospital between 2012 and 2019. MCDA twin pregnancies complicated with sIUGR (sIUGR group) were compared with singleton pregnancies with IUGR (IUGR group). The primary outcome was the comparison in neonatal morbidity and mortality between the two groups.

RESULTS

The analysis included 251 patients: 67 in the sIUGR group and 184 in the IUGR group. The two groups were comparable in gestational age and birth weight (p > 0.05). Multivariate analysis controlling for factors that may influence neonatal status showed no significant difference between the two groups in any of the neonatal morbidity criteria or the composite morbidity-mortality endpoint (adjusted OR = 0.946 [95% CI = 0.317-2.827]; p = 0.921).

CONCLUSION

Despite supposedly different pathophysiological mechanisms, neonates from MCDA pregnancies complicated with sIUGR and those from singleton pregnancies with IUGR appear to have identical neonatal morbidity and mortality .

Reference values for fetal Doppler-based cardiocirculatory indices in monochorionic-diamniotic twin pregnancy

Background

Placental anastomoses in monochorionic diamniotic (MCDA) twin pregnancy have a major impact on fetal circulation. This study was designed to define reference ranges of cardiac and vascular Doppler indices in MCDA twin pregnancies.

Methods

This cross-sectional study included 442 uncomplicated MCDA twin fetuses undergoing Doppler ultrasonography at 18–35 weeks of gestation. Left and right myocardial performance index (LV-MPI, RV-MPI), E/A ratio of atrioventricular valves, pulsatility indices of umbilical artery, middle cerebral artery (MCA), and ductus venosus (DV), cerebroplacental ratio, peak systolic velocity of MCA, S/a ratio of DV, and early diastolic filling time of ductus venosus (DV-E) were evaluated under standardized settings. The equation models between Doppler indices and gestational age (GA) were fitted. After adjustment for GA, the correlations between MPI and fetal heart rate (FHR), and between MPI and DV indices were analyzed.

Results

Estimated centiles of Doppler indices were derived as a function of GA, being distinct in values from those of singletons. There was no correlation between GA-adjusted MPI and FHR. DV-E was inversely related to LV-MPI.

Conclusions

MCDA twins showed significant changes in some Doppler indices throughout gestation with quantitative differences from singletons, emphasizing the importance of MC twin-specific reference values for clinical application. Further adjustment of MPI for FHR was unnecessary. DV-E is a vascular index indirectly representing fetal diastolic function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04255-w.

The accuracy of prenatal diagnosis of selective fetal growth restriction with second trimester Doppler ultrasound in monochorionic diamniotic twin pregnancies

BACKGROUND

Selective fetal restriction growth (sFGR) is one of the common diseases of monochorionic diamniotic (MCDA) twin pregnancies, resulting in many adverse outcomes. At present, second trimester ultrasonography is widely used in the prenatal diagnosis of sFGR, but the diagnostic effectiveness is still uncertain. The aim of this study is to assess the diagnostic accuracy of second trimester Doppler ultrasound measurements for sFGR.

METHODS

A retrospective study included 280 pregnant women (118 with and 162 without sFGR) with MCDA pregnancies was conducted in the fetal medicine center from Leiden University Medical Center from January 2008 to December 2013. The women participating had already undergone an ultrasound examination in the second trimester. The postnatal criteria of sFGR was a single birth weight (BW) < 3 rd percentile in a twin, or birth weight discordance (BWD)≥25% between two twins, while the BW of the smaller twin < 10th percentile. Early prenatal diagnosis of sFGR was defined as a single EFW < 3 rd percentile in a twin, or at least 2 of the following 4 parameters must be met (fetal weight of one fetus < 10th percentile, AC of one fetus <10th percentile, EFW discordance≥25%, UA pulsatility index (PI) of the smaller fetus > 95th percentile). According to the diagnosis of sFGR after birth, we evaluate diagnostic effectiveness of Doppler ultrasound in the second trimester for sFGR.

RESULTS

Of these 280 participants, the mean age was 32.06 ± 4.76 years. About 43.9% of pregnant women were primiparas. The ability of second trimester Doppler ultrasound to accurately diagnosed sFGR is 75.4%, missed diagnosis rate and the misdiagnosis rate were 24.6% and 10.5% respectively. The ROC curve indicated that the combination of AC discordance, EFW discordance, and small fetal UA blood flow was the best diagnostic indicator of sFGR in MCDA pregnancy with the AUC was 0.882 (95%CI, 0.839-0.926).

CONCLUSIONS

Second trimester Doppler and ultrasound measurements is an effective method for early prenatal diagnosis of sFGR. The combined indicator of AC discordance, EFW discordance, and the small fetal UA blood flow reaches highest diagnostic value.

Is growth restriction in twin pregnancies a double challenge? - A narrative review

BACKGROUND

Foetal growth restriction (FGR) complicates about 25-47% of twin pregnancies. One or both foetuses can be restricted. Pregnancies with discordant growth of foetuses are associated with a sevenfold increased risk of neonatal morbidity.

MATERIALS AND METHODS

This is a narrative or traditional literature review. A literature search was performed to present a comprehensive, critical and objective analysis of the current knowledge on growth restriction in twin pregnancies.

RESULTS

The definitions of FGR in twin pregnancies and selective FGR (sFGR) differ between international societies. In 2019, the Delphi procedure aimed to unify the definitions of sFGR in twin pregnancies. Several growth charts for twins have been published. However, most societies recommend singleton growth charts as better in detecting hypoxic complications of FGR in twin pregnancies. Discordant growth in twins results from placental insufficiency, congenital anomalies, chromosomal aberrations and TORCH infections.

CONCLUSIONS

Definitions and management of sFGR depend on chorionicity. The management aims to protect the properly growing foetus from ischemic complications or in utero death. In most cases, expectant management, strict surveillance and preterm labour are the methods of choice. Due to the co-existence of properly growing and small foetuses in one uterus, determining the appropriate time for delivery is challenging. In the case of preterm labour, even late preterm, antenatal corticosteroid therapy (ACT) in FGR twin pregnancies is beneficial because it decreases neonatal morbidity.

Placental characteristics in different types of selective fetal growth restriction in monochorionic diamniotic twins

INTRODUCTION

This study aimed to explore the differences in placental characteristics among three types of selective fetal growth restriction (sFGR) in monochorionic diamniotic twin pregnancies.

MATERIAL AND METHODS

A total of 123 placentas with sFGR between April 2013 and October 2019 were retrospectively analyzed after dye injection. Placental characteristics were compared among the three types.

RESULTS

The gestational age at diagnosis and delivery was less in sFGR II and III than in sFGR I (22.9 [21.7-33.6], 23.3 [20.0-26.1] and 25.7 [19.0-35.0] weeks, p < 0.001; 32.3 [31.6-35.1], 34.1 [29.9-34.7] and 35.5 [34.0-37.0] weeks, p < 0.001). The birthweight discordance ratio was less in sFGR I than in sFGR II (0.28 [0.14-0.43] and 0.30 [0.23-0.37], p < 0.001). The prevalence of a thick artery-artery anastomosis was higher in sFGR III than in sFGR I or II (81.8%, 44.9% and 48.6%, p = 0.010). The placental territory discordance ratio was higher in sFGR II and III than in sFGR I (0.60 [0.17-0.88], 0.60 [0.01-0.80] and 0.50 [0.01-0.71], p = 0.001).

CONCLUSIONS

Compared with sFGR I, the earlier onset time of sFGR II and III might be due to their higher placental territory discordance. The prevalence of thick artery-artery anastomoses was expected to be higher in sFGR III than in sFGR I or II.

Twin pregnancies

Twin pregnancies, resulting in 2-3 % of all deliveries, are high risk pregnancies which need specialized care. A correct dating of pregnancy and the assessment of the chorionicity/amnionicity in the first trimester (< = 13 + 6 gestational weeks, GW) is essential for further monitoring. During first trimester risk stratification of monochorionic pregnancies includes evaluation of discordance of crown-rump-lengths, nuchal translucencies and amniotic fluid. At 16 GW sonographic risk evaluation of monochorionic twins involves differences in amniotic fluid and abdominal circumferences and detection of a velamentous cord insertion. A screening for fetal malformations with cervical length measurement as screening for preterm birth (cut-off < 25 mm) should be offered all twin pregnancies around 20 GW. In uncomplicated dichorionic pregnancies US examination should be performed every 4 weeks onwards to check fetal growth and amniotic fluid. An intertwin weight discordance > 20 % identifies pregnancies at increased risk of adverse outcome. Monochorionic pregnancies should be followed at least every two weeks for screening of twin-twin transfusion syndrome (TTTS), twin-anemia-polycythemia-sequence (TAPS) and selective fetal growth retardation (sFGR) with a start at 16 GW. The type 1-3 classification of sFGR in monochorionic twins depends on the pattern of end-diastolic velocity at the umbilical artery Doppler. The diagnosis of TTTS requires the presence of an oligyohydramnios (deepest vertical pocket (DVP) < 2 cm) in the donor twin and a polyhydramnios (DVP > 8 cm) in the recipient twin. However, the diagnosis of TAPS is based on the finding of discordant MCA Doppler values with a delta-MCA PV > 0.5 MoM.