Review of International Clinical Guidelines Related to Prenatal Screening during Monochorionic Pregnancies

Validation of Fetal Medicine Foundation charts for fetal growth in twins: nationwide Danish cohort study

OBJECTIVE

To assess the validity of the Fetal Medicine Foundation (FMF) chorionicity-specific models for fetal growth in twin pregnancy.

METHODS

This was an external validation study of the FMF models using a nationwide Danish cohort of twin pregnancies. The cohort included all dichorionic (DC) and monochorionic diamniotic (MCDA) twin pregnancies with an estimated delivery date between 2008 and 2018, which satisfied the following inclusion criteria: two live fetuses at the first-trimester ultrasound scan (11-14 weeks' gestation); biometric measurements available for the calculation of estimated fetal weight (EFW) using the Hadlock-3 formula; and delivery of two liveborn infants. Validation involved assessing the distributional properties of the models and estimating the mean EFW Z-score deviations. Additionally, the models were applied to pregnancies that delivered preterm and attended non-scheduled visits (complicated pregnancies).

RESULTS

Overall, 8542 DC and 1675 MCDA twin pregnancies met the inclusion criteria. In DC twins, 17 084 fetuses were evaluated at a total of 95 346 ultrasound scans, of which 44.5% were performed at scheduled visits in pregnancies carried to 37 + 0 weeks or later. The median number of growth scans per DC twin fetus from 20 + 0 weeks onwards was four. The model showed good agreement with the validation cohort for scheduled visits in DC twins delivered at 37 + 0 weeks or later (mean EFW Z-score, -0.14 ± 1.05). In MCDA twins, 3350 fetuses underwent 31 632 eligible ultrasound scans, of which 59.5% were performed at scheduled visits in pregnancies carried to 36 + 0 weeks or later. The median number of growth scans per MCDA twin fetus from 16 + 0 weeks onwards was 10. The model showed favorable agreement with the validation cohort for scheduled visits in MCDA twins delivered at 36 + 0 weeks or later (mean EFW Z-score, -0.09 ± 1.01). Non-scheduled visits and preterm delivery before 37 + 0 weeks for DC twins and before 36 + 0 weeks for MCDA twins corresponded with smaller weight estimates, which was consistent with the study's definition of complicated pregnancy.

CONCLUSIONS

The FMF models provide a good fit for EFW measurements in our Danish national cohort of uncomplicated twin pregnancies assessed at routine scans. Therefore, the FMF models establish robust criteria for subsequent investigations and potential clinical applications. Future research should focus on exploring the consequences of clinical implementation, particularly regarding the identification of twins that are small-for-gestational age, as they are especially susceptible to adverse perinatal outcome. © 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.

Like and share: A mixed-methods cross-sectional survey of social media use during monochorionic diamniotic twin pregnancies

PROBLEM

Monochorionic-diamniotic (MCDA) twin pregnancies are high-risk, requiring specialized monitoring and procedures to screen for and treat potential complications.

AIM

This study examined decisions to use social media among those who have experienced MCDA pregnancies and how these groups influenced treatment and management decisions for these rare, complicated pregnancies.

METHODS

An online mixed-methods, retrospective survey, was completed in 2021 by 624 participants who experienced MCDA pregnancies within 5 years of the study; participants were recruited from online MCDA pregnancy groups on Facebook and Twitter. Data was analyzed using descriptive statistics and thematic analysis.

FINDINGS

Sixty-nine percent of participants used social media to communicate during their MCDA pregnancies, an 18 increase from before pregnancy, and most (74.2 %) used online support groups during pregnancy. Thematic analysis revealed participants used social media primarily to find others with similar experiences, learn more about MCDA pregnancies, and obtain guidance. Most would also recommend joining social media during a similar pregnancy. Nearly half indicated that social media influenced MCDA pregnancy management and treatment decisions - like decisions regarding birth plans, providers, and MCDA-related complications. Several participants cautioned that support groups can be triggering when negative stories are shared.

CONCLUSION

Social media can provide information, support, and improve advocacy for those experiencing MCDA pregnancies. Providers may consider online groups as another source of support for pregnant people and be prepared to address questions that may arise. This study also reveals opportunities for increased and/or improved patient educational materials and patient-provider communication related to MCDA pregnancies.

Evaluation of the efficacy of intrauterine treatments of twin-to-twin transfusion syndrome using myocardial performance index

Background

Prognosis of twin-to-twin transfusion syndrome (TTTS) varies depending on the Quintero stage and fetal cardiac function. The purpose of our study was to evaluate fetal cardiac function before and after different intrauterine treatments of TTTS through myocardial performance index (MPI).

Methods

In this retrospective study, data were collected from August 2016 to December 2022. Totals of 68 cases of TTTS and 68 monochorionic diamniotic (MCDA) twins without TTTS were included. MPI was collected and compared between TTTS and MCDA twins without TTTS before intrauterine treatments. TTTS cases were divided into 3 groups according to different intrauterine treatments: (I) amnioreduction (34 cases), (II) fetoscopic laser photocoagulation (FLPC; 20 cases), and (III) selective reduction (14 cases). The MPI of the left ventricle (LV) and right ventricle (RV) in each surviving fetus were measured 48 hours before and after treatments by pulse Doppler ultrasound. One-way analysis of variance (ANOVA) was employed to assess whether there were statistical differences in LV-MPI and RV-MPI among the donors, recipients, and the control group. Paired t-test analysis was used to compare whether there were differences in MPI before and after intrauterine treatments.

Results

The MPIs of the LV and RV in the recipients were significantly higher than those in the MCDA twins without TTTS (P<0.05). After the amnioreduction treatment of TTTS, no significant differences were observed in the MPI of either the LV or the RV before and after treatment. At 48 hours after FLPC treatment, the value of the LV-MPI in donors was 0.25±0.08, and the value of the RV-MPI in recipients was 0.58±0.17. Both of them were significantly lower than those before the treatment (P<0.05). In the selective reduction group, the value of the RV-MPI in surviving recipients significantly decreased compared to that before treatment (P<0.05).

Conclusions

MPI is an effective indicator to evaluate fetal cardiac function of TTTS and assess the efficacy of intrauterine treatments of TTTS.

Ultrasonographic Prenatal Diagnosis: Unveiling the Path to Improved Antenatal Care

The realm of prenatal diagnosis has witnessed remarkable advancements in recent years, primarily due to the widespread use of ultrasonography [...].

Comparison of International Guidelines on the Management of Twin Pregnancy

OBJECTIVES

To review current international clinical guidelines on the antenatal and intrapartum management of twin pregnancies, examining areas of consensus and conflict.

METHODS

We conducted a database search using Medline, Pubmed, Scopus, Academic Search Complete, CINAHL and ERCI Guidelines website. Guidelines were screened for eligibility using our inclusion and exclusion criteria. Those deemed eligible were quality assessed using the AGREE II tool and relevant data was extracted.

RESULTS

We identified 21 relevant guidelines from 16 countries including two international society guidelines. There was consensus in determination of chorionicity and amnionicity within the first trimester, fetal anomaly scan between 18 and 22 weeks and the recommended screening for twin-to-twin transfusion syndrome (TTTS). For those that provided intrapartum guidance, there was agreement in recommending caesarean section to deliver monochorionic monoamniotic (MCMA) twins, epidural anaesthesia for intrapartum analgesia and the use of cardiotocography (CTG) for intrapartum fetal monitoring. The main areas of conflict included cervical length screening, frequency of ultrasound surveillance, timing of delivery of dichorionic twin pregnancies and circumstances for recommending vaginal delivery. There was a lack of advice on intrapartum management.

CONCLUSIONS

This review has highlighted the need for unified international guidance on the management of twin pregnancy. Comparisons of current guidance demonstrates a lack of confidence in the management of labour in twin pregnancies. Further evidence on intrapartum care of twin pregnancies is needed to inform practice guidelines and improve both short and long term maternal and fetal outcomes.

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.

Twin Anemia-Polycythemia Sequence (TAPS): From Basic Research to Clinical Practice

Twin pregnancy is associated with an increased risk of perinatal and maternal complications, and early establishment of the chorionicity type defines this risk. In monochorionic (MC) pregnancies, the fetuses share the same placental mass and exhibit vascular anastomoses crossing the intertwin membrane, and the combination and pattern of anastomoses determine the primary clinical picture and occurrence of future complications. Twin Anemia-Polycythemia Sequence (TAPS) was first described in 2006 after fetoscopic laser surgery in twin-to-twin transfusion syndrome (TTTS) twins, and in 2007, the first spontaneous cases were reported, recognizing TAPS as an individualized vascular identity in fetofetal transfusion syndromes. There are two types of TAPS: spontaneous (3-5%) and iatrogenic or postlaser (2-16%). TAPS consists of small diameter arteriovenous anastomoses (<1 mm) and low-rate, small-caliber AA anastomoses in the absence of amniotic fluid discordances. There are certain antenatal and postnatal diagnostic criteria, which have progressively evolved over time. New, additional secondary markers have been proposed, and their reliability is being studied. The best screening protocol for TAPS in MC twins is still a matter of debate. This review provides a survey of the relevant literature on the epidemiology, vascular pathophysiology, underlying hemodynamic factors that regulate mismatched vascular connections, and diagnostic criteria of this condition. The aim is to increase awareness and knowledge about this recently identified and frequently unrecognized and misdiagnosed pathology.

Patient-Reported Monochorionic-Diamniotic Twin Pregnancy Management and Experiences During the COVID-19 Pandemic: A Mixed-Methods Cross-Sectional Survey

Monochorionic-diamniotic (MCDA) pregnancies are high-risk necessitating ongoing screening for serious complications and quick decision-making. COVID-19 pandemic protocols introduced unique challenges to pregnancy management and patient experience. In late 2021, an online, mixed-methods, cross-sectional survey recruited 561 participants who experienced an MCDA pregnancy within five years. Analyses included descriptive and bivariate statistics and thematic analysis. Findings suggest the pandemic did not negatively affect screening/diagnosis for these participants. Care consistent with guidelines was received by most, with care slightly better during the pandemic. Almost 80% (79.0%) received an MCDA diagnosis by gestational week 14 before the pandemic, 87.8% during. Most received biweekly ultrasounds, 88.0% prior to the pandemic, 88.9% during. Experiences were affected in other ways for almost 44% of participants pregnant during COVID-19; in ways likely shared by other high-risk pregnancies. Thematic analysis revealed management during COVID-19 impacted self-advocacy and emotions (eg, alienation, anxiety), made care seem impersonal, and resulted in delayed or canceled appointments. Policies should be considered, so future healthcare disruptions do not impact patients and preserve in-person health care with access to a support person.

Controlled amnioreduction for twin-to-twin transfusion syndrome

Background:

Twin-to-twin transfusion syndrome (TTTS) is a severe condition causing preterm delivery, fetal death, and neurodevelopmental disorders. This study presents a data-based controlled amnioreduction (AR) protocol composed of sequential amniodrainage in treatment of TTTS.

Methods:

A total of 18 procedures were performed in 11 TTTS pregnancies at 17 to 34 weeks of gestation. The amniotic pressure was measured along with sequential removal of the amniotic fluid, 500 mL each step. The umbilical artery systolic/diastolic (S/D) ratio for each twin was measured pre- and post-AR. Long-term neurodevelopmental outcomes of all TTTS survivors were evaluated from parental answers to a phone survey.

Results:

The amniotic pressure decreased exponentially with the increased volume of removed amniotic fluid until a plateau was obtained. Changes of the S/D ratio between pre- and post-AR procedure did not reveal a clear tendency. The survival rate was 86.4% although 91% of all twins were at Quintero stage III. Long-term neurodevelopment outcomes in the 19 surviving twins were 68.4% optimal, 26.3% suboptimal, and 5.3% abnormal.

Conclusion:

The controlled AR procedure resulted in a relatively high rate of twin survival with favorable long-term neurodevelopment outcomes.