Diagnostic accuracy of cell-free DNA in maternal blood in detecting chromosomal anomalies in twin pregnancies: systematic review and meta-analysis.

OBJECTIVES: To report the diagnostic accuracy of cell-free DNA (cfDNA) in maternal blood in detecting chromosomal anomalies in twin pregnancies. METHODS: Medline, Embase and Cochrane databases were searched. The inclusion criteria were twin pregnancies undergoing cfDNA screening for Trisomies 13, 18, 21, monosomy X0 and other sex chromosomal anomalies (SCA). The index test was represented by a positive results of cfDNA test. The reference standard was represented by the karyotype results (obtained either pre or postnatally) or, in case of negative cfDNA result, by a normal neonatal phenotype. The quality of the studies was assessed using the revised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2). Summary estimates of sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-) and diagnostic odds ratio (DOR), with the corresponding 95% Confidence Intervals (95% CI), were computed using the bivariate random-effects model. RESULTS: Thirty-five studies were included. cfDNA had an overall high accuracy in detecting Trisomy 21 in twin pregnancies with a sensitivity of 98.8% (95% CI 96.5-100), a specificity of 100% (95% CI 99.9-100). Sensitivity and specificity were of 94.9% (95% CI 75.6-99.1) and 100 (95% CI 99.9-100) for Trisomy 18, and 84.6% (95% C% 54.6-98.1) and 100% (95% CI 99.9-100) for Trisomy 13 . We could not compute the diagnostic accuracy of cfDNA in detecting monosomy X0 in twins, while cfDNA had a sensitivity of 100% (95% CI 71.5-100) and a specificity of 99.8% (95% CI 99.7-99.9) in detecting other SCA (11 cases). The accuracy of cfDNA in detecting Trisomy 21, 18 and 13 was similar in dichorionic and monochorionic twin pregnancies. CONCLUSION: cfDNA has a high diagnostic accuracy in detecting Trisomy 18 and 21 in twin pregnancies, irrespective of chorionicity. Accuracy in the detection of Trisomy 13 and SCA was limited by the small number of affected cases and the difficulties in the confirmation of false negative cases in case of SCA and requires confirmation in larger studies. This article is protected by copyright. All rights reserved.

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.

Maternal vitamin D status and risk of gestational diabetes mellitus in twin pregnancies: a longitudinal twin pregnancies birth cohort study.

BACKGROUND: Gestational diabetes mellitus (GDM) is a common complication of pregnancy, with significant short-term and long-term implications for both mothers and their offspring. Previous studies have indicated the potential benefits of vitamin D in reducing the risk of GDM, yet little is known about this association in twin pregnancies. This study aimed to investigate maternal vitamin D status in the second trimester and examine its association with the risk of GDM in twin pregnancies. METHODS: We conducted a prospective cohort study based on data from the Chongqing Longitudinal Twin Study (LoTiS). Peripheral blood serum was collected from the mothers in the second trimester to measure 25(OH)D concentrations. GDM was diagnosed at 23-26 weeks of gestation using a 75-g 2-h oral glucose tolerance test. We used multivariable logistic regression analyses to examine the correlations between vitamin D status and the risk of GDM. RESULTS: Of the total participants, 93 (29.9%) women were diagnosed with GDM. The mean serum 25(OH)D concentration in the second trimester was 31.1 ± 11.2 ng/mL, and the rate of vitamin D insufficiency and deficiency were 23.5% and 18.7%, respectively. Compared to women with a 25(OH)D concentration < 30 ng/mL, those with a 25(OH)D concentration ≥ 30 ng/mL had a significantly lower risk of GDM (RR 0.61; 95% CI: 0.43, 0.86), especially those who were overweight before pregnancy (RR 0.32; 95% CI: 0.16, 0.64). The restricted cubic splines model showed an inverted J-shaped relationship between vitamin D concentrations and GDM risk. CONCLUSIONS: The risk of GDM was significantly reduced in twin pregnant women with vitamin D concentrations ≥ 30 ng/mL in the second trimester. TRIAL REGISTRATION: ChiCTR-OOC-16,008,203. Retrospectively registered on 1 April 2016.

The efficacy of expanded non-invasive prenatal testing (NIPT) in a high-risk twin pregnancies cohort.

INTRODUCTION: Our objective was to evaluate the efficacy of expanded non-invasive prenatal testing (NIPT) that includes both trisomies and copy number variants (CNVs) in high-risk twin pregnancies. MATERIAL AND METHODS: A prospective, double-blinded cohort study was conducted, enrolling 73 high-risk twin pregnancies characterized by increased risk of genetic disorders due to factors such as increased nuchal translucency, structural anomalies, fetal growth restriction, and other factors associated with chromosomal abnormality. Participants underwent invasive karyotyping and chromosomal microarray analysis, alongside separate expanded NIPT for research purposes. The sensitivity, specificity, positive predictive value, and negative predictive value of expanded NIPT were calculated. RESULTS: The cohort included 24 monochorionic and 49 dichorionic twin pregnancies. The median cell-free fetal DNA concentration in expanded NIPT was 16.7% (range 3.86%-49.1%), with a test failure rate of 1.4% (1/73). High-risk findings for trisomy 21/13/18 were identified in five cases (6.8%), Turner syndrome in one case (1.4%), and CNVs indicative of high risk for clinically significant microdeletion/microduplication syndromes (MMS) in ten cases (13.7%). Of these, 56 cases (76.7%) tested NIPT negative, revealing one false-negative for 45, X and five false-negatives for CNVs. Expanded NIPT achieved a detection rate of 100% (5/5) for trisomy 21/13/18 with a false-positive rate of 0% (0/5), a detection rate of 33.3% (1/3) for sex chromosome abnormalities with a false-positive rate of 0% (0/3), and a detection rate of 66.7% (4/6) for MMS with a false-positive rate of 3.0% (2/67). The positive predictive values for trisomy T21/13/18, sex chromosome abnormalities, and known MMS were 100% (5/5), 100% (1/1), and 66.7% (4/6) in the expanded NIPT, respectively. CONCLUSIONS: The expanded NIPT demonstrated high detection rates for common trisomies and moderate detection rates for prenatal MMS in high-risk twin pregnancies. Further studies with large sample sizes in low-risk populations are needed.

Maternal and neonatal outcomes of dichorionic twin pregnancies achieved with assisted reproductive technology: meta-analysis of contemporary data.

PURPOSE: Assisted reproductive technology (ART) is commonly used to achieve pregnancy and often results in dichorionic diamniotic (DCDA) twin pregnancies. However, the potential risks of ART on maternal and neonatal outcomes in these pregnancies are not well understood. The objective is to compare the maternal and neonatal outcomes in DCDA twin pregnancies between those achieved through ART and those spontaneously conceived (SC). METHODS: We carried out a systematic comprehensive search of electronic databases; namely, PubMed, Embase, Scopus, and the Cochrane Library, from inception to March 2023 with a study period of recruitment between 2003 and 2023. We included all studies comparing the maternal and neonatal outcomes of DCDA twin pregnancies between those achieved by ART and those SC. RESULTS: We analyzed data from 18 cohort studies involving 10,485 women with DCDA twin pregnancies. The meta-analysis showed that ART-conceived pregnancies had a significantly higher risk of preeclampsia or gestational hypertension (GH), gestational diabetes mellitus (GDM), placenta previa (PP), placental abruption (PA), postpartum hemorrhage (PPH), and elective and emergency cesarean sections than SC twin pregnancies. The absolute risks of these complications remained relatively low. We also found a slightly higher risk of respiratory distress syndrome (RDS) and congenital malformations in ART-conceived infants compared to the risks in SC infants. Finally, the risk of neonatal intensive care unit (NICU) admissions was significantly higher in ART-conceived infants than in SC infants, but with high heterogeneity. CONCLUSION: We found associations between DCDA twin pregnancies conceived through ART and increased frequencies of adverse maternal outcomes. However, the absolute risks of these complications remained low, and the benefits of ART for achieving successful pregnancies may well outweigh the potential risks. Additionally, ART-conceived DCDA twin pregnancies may pose higher risks of RDS, congenital malformations and NICU, admissions than SC DCDA twin pregnancies.

First-trimester serum biomarkers in twin pregnancies and adverse obstetric outcomes-a single center cohort study.

PURPOSE: This study aimed to determine the association of first-trimester maternal serum biomarkers with preterm birth (PTB), fetal growth restriction (FGR) and hypertensive disorders of pregnancy (HDP) in twin pregnancies. METHODS: This is a retrospective cohort study of twin pregnancies followed at Maternidade Dr. Alfredo da Costa, Lisbon, Portugal, between January 2010 and December 2022. We included women who completed first-trimester screening in our unit and had ongoing pregnancies with two live fetuses, and delivered after 24 weeks. Maternal characteristics, pregnancy-associated plasma protein-A (PAPP-A) and ß-human chorionic gonadotropin (ß-hCG) levels were analyzed for different outcomes: small for gestational age (SGA), gestational hypertension (GH), early and late-onset pre-eclampsia (PE), as well as the composite outcome of PTB associated with FGR and/or HDP. Univariable, multivariable logistic regression analyses and receiver-operating characteristic curve were used. RESULTS: 466 twin pregnancies met the inclusion criteria. Overall, 185 (39.7%) pregnancies were affected by SGA < 5th percentile and/or HDP. PAPP-A demonstrated a linear association with gestational age at birth and mean birth weight. PAPP-A proved to be an independent risk factor for SGA and PTB (< 34 and < 36 weeks) related to FGR and/or HDP. None of the women with PAPP-A MoM > 90th percentile developed early-onset PE or PTB < 34 weeks. CONCLUSION: A high serum PAPP-A (> 90th percentile) ruled out early-onset PE and PTB < 34 weeks. Unless other major risk factors for hypertensive disorders are present, these women should not be considered candidates for aspirin prophylaxis. Nevertheless, close monitoring of all TwP for adverse obstetric outcomes is still recommended.

Meta-analysis comparing different ultrasound detection methods to accurately assess wound healing and scar formation after caesarean section.

The accurate assessment of wound healing post-caesarean section, especially in twin pregnancies, remains a pivotal concern in obstetrics, given its implications for maternal health and recovery. Traditional methods, including conventional abdominal ultrasonography (CU), have been challenged by the advent of transvaginal ultrasonography (TU), offering potentially enhanced sensitivity and specificity. This meta-analysis directly compares the efficacy of TU and CU in evaluating wound healing and scar formation, crucial for optimizing postoperative care. Results indicate that TU is associated with significantly better outcomes in wound healing, demonstrated by lower REEDA scores (SMD = -20.56, 95% CI: [-27.34.20, -13.77], p < 0.01), and in scar formation reduction, evidenced by lower Manchester Scar Scale scores (SMD = -25.18, 95% CI: [-29.98, -20.39], p < 0.01). These findings underscore the potential of integrating TU into routine post-caesarean evaluation protocols to enhance care quality and patient recovery.

The risk factors of procedure-related complications after amniocentesis in twin pregnancies: a retrospective analysis.

BACKGROUND: There is an increasing demand for prenatal diagnostic testing in twin pregnancies, however, anecdotally there is a higher incidence of procedure-related complications after amniocentesis than that in singleton pregnancies. There is a paucity of data regarding risk factors of amniocentesis in twin pregnancies. METHODS: Women with twin pregnancies who underwent amniocentesis between January 2016 and December 2020 were enrolled in this retrospective study. Procedure-related complications including spontaneous miscarriage, intrauterine fetal death, spontaneous preterm delivery, preterm premature rupture of membranes, and placental abruption in one or both fetuses after amniocentesis were assessed. Meanwhile, potential risk factors related to amniocentesis including chorionicity, gestational age, conception, number of needle insertions, parity, history of miscarriage, indications, and pregnancy-related complications (pregnancy-induced hypertension and gestational diabetes) were also recorded. RESULTS: A total of 811 women with twin pregnancies underwent amniocentesis were included, with a procedure-related complications rate of 3.83%. Risk factors associated with increased risk of procedure-related complications after amniocentesis in twin pregnancies were chorionicity (adjusted odds ratio [aOR]: 4.06), gestational age at the procedure (aOR: 2.76), and numbers of needle insertions (aOR: 3.26). In the monochorionic twin pregnancy, hemorrhage during this pregnancy (aOR: 12.01), polyhydramnios (aOR: 5.03), and numbers of needle insertions (aOR: 3.15) were risk factors after amniocentesis. In the dichorionic twin pregnancy, gestational age at the procedure (OR:4.47) affected the risk of procedure-related complications after amniocentesis. In the subgroup of gestational age at the procedure ≤ 24+ 0 weeks, risk factors associated with increased risk of procedure-related complications after amniocentesis in twin pregnancies were chorionicity (aOR: 5.14), and numbers of needle insertions (aOR: 3.76). CONCLUSION: The procedure-related complications rate is 3.83% in our institution during the study period. The present study has emphasized the significance of certain risk factors for adverse outcome and will be useful in counseling patients with twin pregnancies.

Noninvasive prenatal testing, ultrasonographic findings and poor prenatal diagnosis rates for twin pregnancies: a retrospective study.

BACKGROUND: Noninvasive prenatal testing (NIPT) is increasingly used in the clinical prenatal screening of twin pregnancies, and its screening performance for chromosomal abnormalities requires further evaluation. For twin pregnancies with indications for prenatal diagnosis, there is a lack of clinical data to assess the prenatal diagnosis rate (PDR). The aim of this study was to evaluate the screening performance of NIPT for foetal chromosomal abnormalities in twin pregnancies and the PDR in the second and third trimesters. METHODS: Ultrasound scans were carried out for all twin pregnancies between 11 and 13+ 6 gestational weeks. For twin pregnancies with nuchal translucency thickness˂3.0 mm and no foetal structural malformations, NIPT was performed after blood sampling, followed by routine ultrasound monitoring. Women with twin pregnancies who underwent NIPT at the prenatal diagnostic centre of Xiangya Hospital from January 2018 to May 2022 were included in the study. Genetic counselling was offered to each pregnant woman when the NIPT result indicated a high risk of abnormalities or abnormal ultrasonographic (USG) findings were detected. We followed up twin pregnancies for NIPT results, USG findings, prenatal diagnosis results and pregnancy outcomes. RESULTS: In 1754 twin pregnancies, the sensitivity, specificity and positive predictive value of NIPT for trisomy 21 were 100%, 99.9% and 75%, and the corresponding values for sex chromosome aneuploidy (SCA) were 100%, 99.9% and 50%, respectively. For the 14 twin pregnancies for which the NIPT results indicated a high risk of abnormalities, the PDR was 78.6% (11/14). For the 492 twin pregnancies for which the NIPT results indicated a low risk of abnormalities, the rate of USG findings in the second and third trimesters was 39.4% (194/492); of these pregnancies, prenatal diagnosis was recommended for 16.7% (82/492), but it was actually performed in only 8.3% (41/492), and the PDR was 50% (41/82). There was no significant difference in the PDR between the NIPT high-risk and low-risk groups. CONCLUSIONS: The screening performance of NIPT for SCA in twin pregnancies needs to be further evaluated. When abnormal NIPT results or USG findings are used as the main prenatal diagnostic indicator in the second and third trimesters, the PDR is poor.

Associations between velamentous or marginal cord insertion and risk of adverse perinatal outcomes in twin pregnancies: a retrospective cohort study.

BACKGROUND: Velamentous cord insertion (VCI) and marginal cord insertion (MCI) are well-known risk factors for adverse perinatal outcomes in singleton pregnancies. However, the potential links between VCI or MCI and perinatal outcomes in twin pregnancies have yet to be systematically evaluated. This study aimed to investigate the relationships between VCI or MCI and perinatal outcomes in twin pregnancies. METHODS: This retrospective single-center cohort study included women with twin pregnancies who gave birth in a tertiary hospital in Southwest, China between January 2017 and December 2022. VCI and MCI were identified by abdominal ultrasound and confirmed after placental delivery. Logistic regression, multinomial logit regression and generalized estimation equation models were used to evaluate the association between VCI or MCI and perinatal outcomes. RESULTS: A total of 3682 twin pregnancies were included, including 100 (2.7%) pregnancies with VCI and 149 (4.0%) pregnancies with MCI. Compared to pregnancies with normal cord insertion, both monochorionic and dichorionic pregnancies with VCI were associated with an increased risk of preterm delivery 32-34 weeks (aRRR 2.94, 95% CI 1.03-8.39; aRRR 2.55, 95% CI 1.19-5.46, respectively), while pregnancies with MCI were not associated with preterm delivery. VCI was associated with a higher incidence of placental previa (aOR 6.36, 95% CI 1.92-21.04) in monochorionic pregnancies and placental accreta (aOR 1.85, 95% CI 1.06-3.23) in dichorionic pregnancies. MCI was associated with an increased risk of preeclampsia (aOR 3.07, 95% CI 1.49-6.32), intertwin birthweight discordance ≥ 20% (aOR 2.40, 95% CI 1.08-5.60) and selective fetal growth restriction (aOR 2.46, 95% CI 1.08-5.60) in monochorionic pregnancies and small-for-gestational age neonates (aOR 1.97, 95% CI 1.24-3.14) in dichorionic pregnancies. CONCLUSIONS: VCI was associated with an increased risk of preterm delivery in twin pregnancies irrespective of chorionicity, whereas MCI was associated with an increased preeclampsia risk, significant intertwin birthweight discordance in monochorionic pregnancies and small-for-gestational age neonates in dichorionic pregnancies.

Outcomes of vertex-vertex vs. vertex-breech presentation in twin pregnancy after vaginal delivery in China.

OBJECTIVE: To compare the maternal and neonatal outcomes of twin pregnancies between vertex and nonvertex presentations of the second twin in vaginal delivery. METHODS: In this unicentric retrospective cohort study, we collected data from 213 cases of vaginal twin deliveries from January 2016 to July 2020. Participants were divided into the vertex-vertex presentation group (VV) and vertex-breech presentation group (VB). Data on maternal and neonatal outcomes were compared between groups. RESULTS: Among the 213 mothers and 426 infants (213 twin pairs), there were 140 women in the VV group and 73 women in the VB group (65.73% vs. 34.27%). Infants in the VB group had a higher incidence of admission to NICU (51.43% vs. 68.49%, p = 0.017), lower 1-min (11.43% vs. 28.77%, p < 0.001) and 5-minute Apgar scores (1.43% vs. 4.11%, p = 0.043) for the second twin. However, after the adjustment for sex of the twin, birth weight, chorionicity, and gestational age, the greater risk of admission to NICU and low 5-min Apgar score was no longer significantly different. CONCLUSION: VB twins are at no greater overall risk of a poor outcome due to breech presentation in the second twin. However, the presentation of the second fetus represents a risk factor for a low 1-min Apgar score. Obstetricians and midwives should consider appropriate interventions for second twins who present breech versus vertex.

Velamentous cord insertion in monochorionic twin pregnancies: a step forward in screening for twin to twin transfusion syndrome and birthweight discordance?

OBJECTIVES: Two major complications of monochorionic diamniotic (MCDA) twin pregnancies are twin to twin transfusion syndrome (TTTS) and birthweight discordance. The current screening ultrasound test for these pathologies combines the detection of nuchal translucency discrepancy and abnormal ductus venosus in at least one twin, in the first trimester. We aim to determine whether combining the presence of velamentous cord insertion in at least one twin increases screening efficiency. METHODS: This was a retrospective cohort with a sample of 136 MCDA twin pregnancies followed at Centro Hospitalar Universitário São João, during a 16-year period. RESULTS: The combination of abnormal ductus venosus in at least one twin and nuchal translucency discrepancy is associated with the development of TTTS with an OR of 10.455, but not with birthweight discordance. The combination of these first trimester markers with velamentous cord insertion is not associated with the development of either outcome. CONCLUSIONS: The presence of velamentous cord insertion in MCDA pregnancies is not associated to TTTS development. Therefore, the addition of this marker to the first trimester screening would not effectively predict the development of birthweight discordance or TTTS. However, a positive currently used screening test increases the risk of developing TTTS by about ten times.

Performance of noninvasive prenatal testing for twin pregnancies in South China.

OBJECTIVE: The purpose of this study was to evaluate the performance of noninvasive prenatal testing (NIPT) for the detection of chromosomal aneuploidies and copy number variations (CNVs) in twin pregnancies. METHOD: A cohort of 2010 women with twin pregnancies was recruited. 1331 patients opted for NIPT, and 679 patients opted for expanded NIPT (NIPT-plus). All high-risk patients were advised to undergo invasive prenatal diagnosis. All participants were followed up until 6 months after birth. RESULTS: Twenty-two cases were predicted to have a high risk of chromosome abnormalities by NIPT, of which 14 pregnant women underwent invasive prenatal diagnosis. The 14 cases included 3 cases of trisomy 21, 1 case of trisomy 18, 1 case of trisomy 7, 2 cases of sex chromosome aneuploidies (SCAs), and 7 cases of CNVs, of which the confirmed cases numbered 2, 1, 0, 1, and 0, respectively. Twenty cases were predicted to have a high risk of chromosome abnormalities by NIPT-plus, of which 16 pregnant women underwent invasive prenatal diagnosis. The 16 cases included 1 case of trisomy 21, 1 case of trisomy 7, 7 cases of SCAs, and 7 cases of CNVs, of which were confirmed in 1, 0, 3, and 2, respectively. No false-negative result was reported during the follow-up period. CONCLUSION: The NIPT/NIPT-plus has excellent performance in the detection of chromosome aneuploidies in twin pregnancies. But for CNVs, the effectiveness of NIPT is poor, and the NIPT-plus have a certain detection efficiency. It is worth noting that pre- and post-genetic counseling is especially important, and the chorionicity, mode of conception, clinical indications, and fetal fraction should be considered as influencing factors.

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.

Arabin pessary to prevent adverse perinatal outcomes in twin pregnancies with a short cervix: a multicenter randomized controlled trial (PESSARONE).

BACKGROUND: The number of twin pregnancies continues to increase worldwide as both the number of pregnancies obtained by medically assisted reproduction and age at first pregnancy keep rising. Preterm delivery is the major complication associated with twin pregnancies. The effectiveness of preventive treatments such as progesterone or cervical cerclage for women with a short cervix is doubtful in twin pregnancies. The effectivity of cervical pessaries in preventing preterm birth and its associated morbidity and mortality is also controversial. OBJECTIVE: We sought to investigate if the Arabin pessary reduces adverse neonatal outcomes in twin pregnancies with a short cervix. STUDY DESIGN: This open-label, multicenter, randomized controlled trial on twin pregnancies with a cervical length of <35 mm compared pessary placement at 16+0 to 24+0 weeks' gestation with standard care alone. The primary endpoint was a composite of adverse neonatal outcomes, namely peripartum or neonatal death or significant neonatal morbidity before hospital discharge, defined as at least 1 of the following complications: bronchopulmonary dysplasia, intraventricular hemorrhage grade III to IV, periventricular leukomalacia, necrotizing enterocolitis grade II or higher, culture-proven sepsis, and retinopathy requiring treatment. A sample size of 308 pregnancies was planned to ensure 80% power to compare the proportions of women with at least 1 infant with an adverse neonatal outcome. The intention-to-treat analysis after multiple imputation of missing data, was supplemented with a secondary analysis that controlled for gestational age and cervical length, both at inclusion. The primary endpoint was also compared between randomization groups in the per-protocol population, which excluded patients with prespecified major protocol violations (mostly cervical cerclage and/or progesterone after inclusion). Secondary endpoints included preterm birth, spontaneous preterm birth, and pessary side effects. RESULTS: In total, 315 women were randomized to either receive a pessary (n=157) or standard management (n=158). Overall, 10.8% (34 women) of participants had a missing value for the primary endpoint, mostly (79%) because of the lack of paternal consent for neonatal data collection. In the intention-to-treat analysis, the adverse neonatal outcome occurred in 16.8% of the pessary group vs in 22.5% of the control group (risk ratio, 0.69; 95% confidence interval, 0.39-1.23; P=.210). The per-protocol analysis did not show any significant difference between groups (risk ratio, 0.78; 95% confidence interval, 0.47-1.28; P=.320). The occurrence of preterm birth or spontaneous preterm birth did not differ significantly between groups. No serious side effects were associated with pessary use. CONCLUSION: Pessary use in our study did not significantly reduce adverse neonatal outcomes in twin pregnancies with a short cervix.

Selective vs complete fetoscopic coagulation of vascular equator: a matched comparative study.

BACKGROUND: Complete coagulation of the vascular equator (as in the Solomon technique) has been suggested to reduce postoperative complications such as twin anemia polycythemia syndrome and the recurrence of twin-twin transfusion syndrome following fetoscopic laser coagulation of chorionic vessels for twin-twin transfusion syndrome. OBJECTIVE: We aimed to evaluate the benefit of this technique on perinatal outcomes compared with selective ablation of anastomoses. STUDY DESIGN: We conducted a monocentric retrospective study comparing selective laser coagulation of anastomoses to the Solomon technique from January 2006 to August 2020. To adjust for potential confounders, the cases operated by selective surgery were matched to the cases operated with the Solomon technique according to the gestational age at laser therapy, placental localization, and Quintero stage using propensity score matching. RESULTS: With a total of 994 cases, 399 matched pairs were included in the analysis. Compared with selective ablation, the Solomon technique was associated with significantly improved survival: the overall twin survival at delivery and discharge was 72% vs 79% (P=.003) and 69% vs 75% (P=.006), respectively; the double twin survival rate at discharge was 55% vs 65% (P=.02), respectively, and the rate of intrauterine death dropped from 18% to 12% (P=.003), respectively. The Solomon technique significantly reduced the rate of twin anemia polycythemia syndrome (10% vs 4%; P=.02), leading to fewer secondary rescue procedures (13% vs 7.3%; P=.01). However, the Solomon technique was associated with an increased risk of preterm rupture of membranes, especially at early gestational ages (3.8% vs 11%; P<.001 for preterm rupture of membranes <24 weeks). Among the survivors at delivery, both the groups had similar gestational ages at birth. Both neonatal mortality and severe neurologic morbidity were similar in both the groups. However, an increased risk of bronchopulmonary dysplasia was found in the Solomon group (4.5% vs 12%; P<.001). CONCLUSION: Although the risk of preterm premature rupture of membranes has increased, the introduction of the Solomon technique has significantly improved perinatal outcomes in pregnancies affected with twin-twin transfusion syndrome.

Examining the effects of second-and third-trimester gestational weight gain rates on the perinatal outcomes among Chinese twin pregnancies: a retrospective cohort study.

BACKGROUND: This paper investigated how second- and third-trimester gestational weight gain relates to perinatal outcomes among normal weight women with twin pregnancies in Fujian, China. METHODS: A retrospective study examining the medical records of 931 normal weight twin-pregnant women was conducted in Fujian Maternity and Child Health Hospital from 2014 to 2018.The 2nd and 3rdtrimester weekly weight gain rates were calculated, and women were categorized as gaining below, within, or above the 2009 Institute of Medicine (IOM) recommended rates. The association between the trimester-specific weight gain rate and perinatal outcome was determined by traditional regression analysis among groups. RESULTS: A total of 25.9%, 19.8% and 54.3% of women had rates of weight gain across the 2nd and 3rd trimesters less than, greater than or within the recommended rates respectively. Multivariate logistic regression analysis showed that weight gain greater than the recommended rate in the 2nd trimester was associated with a decreased risk of preeclampsia (aOR:0.489,95%CI:0.289 ~ 0.974). Weight gain less than the recommended rate of weight gain in the 3rd trimester was associated with increased risks of premature delivery(aOR:2.079, 95%CI:1.467 ~ 2.968), gestational diabetes mellitus (aOR: 2.048, 95%CI:1.411 ~ 2.971), intrahepatic cholestasis syndrome (aOR:3.015,95%CI: 1.058 ~ 8.587), pre-labour rupture of membrane (aOR: 1.708,95%CI: 1.169 ~ 2.493), average twin birth weight < 2500 g(aOR:1.532,95%CI: 1.125 ~ 2.084) and neonatal respiratory distress syndrome (aOR:4.934,95%CI:1.626 ~ 15.083) and was associated with decreased risks of caesarean section (aOR:0.589,95%CI:0.386 ~ 0.898) and preeclampsia (aOR:0.471, 95%CI:0.274 ~ 0.808). In addition, weight gain greater than the recommended rate of weight gain in the 3rd trimester was associated with increased risks of premature delivery (aOR:1.589,95%CI:1.428 ~ 2.951) and gestational hypertension (aOR:2.137,95% CI:1.034 ~ 4.415) as well as preeclampsia (aOR:2.246, 95%CI:1.462 ~ 3.452). The stratified analysis of weight gain in the 3rd trimester showed that there was no significant difference in the incidence of adverse pregnancy outcomes compared to the 2nd trimester weight gain groups. CONCLUSIONS: While this study showed that a gestational weight gain rate above or below the recommendation in the 3rd trimester was associated with some adverse maternal and neonatal outcomes, further prospective and multicentre studies are required to explore alternate ranges of gestational weight gain rates in twin pregnancies.

The impact of assisted reproductive technology in twin pregnancies complicated by intrahepatic cholestasis: a five-year retrospective study.

BACKGROUND: Intrahepatic cholestasis of pregnancy is one of the common complications during pregnancy, and ursodeoxycholic acid has been recommended as the first-line drug. However, if the assisted reproductive technology may increase adverse perinatal outcomes of twin pregnancies complicated by intrahepatic cholestasis is disputed, we aimed to investigate perinatal outcomes between twin pregnancies by assisted reproductive technology versus spontaneous conception, based on these women accepted ursodeoxycholic acid treatment. METHODS: From January 2014 to January 2019, we retrospectively analysed the clinical data of twin pregnant women with intrahepatic cholestasis, excluding those who did not receive ursodeoxycholic acid treatment. In total, 864 women were included, among whom 500 conceived by assisted reproductive technology and 364 conceived by spontaneous conception. The primary assessment for perinatal outcomes included premature birth, meconium-stained amniotic fluid, low Apgar score, neonatal intensive care unit and still birth, and secondary indicators were serum bile acid and liver enzymes level during medication, so we also finished subgroup analysis based on different elevated bile acid level and drug usage. The statistical analysis was performed by SPSS 22.0. RESULTS: The study demonstrated that compared to spontaneous conception, assisted reproductive technology conceived twin pregnancies diagnosed as intrahepatic cholestasis earlier (p = 0.003), and lower birth weight (p = 0.001), less incidence of preterm delivery (p = 0.000) and neonatal intensive care unit admission (p = 0.001), but the rate of meconium-stained amniotic fluid, low Apgar score and still birth have no statistic differences. Moreover, the subgroup analysis showed no significant difference in elevated bile acid levels and medication between assisted reproductive technology and spontaneous conception groups. CONCLUSIONS: The assisted reproductive technology may increase the risk of early-onset intrahepatic cholestasis in twin pregnancies, but it does not seem to increase adverse effects on bile acid levels and perinatal outcomes. Regardless of ursodeoxycholic acid used alone or combination, the effect of bile acid reduction and improving perinatal outcomes in twin pregnancies is limited. Our conclusions still need more prospective randomized controlled studies to confirm.

Perinatal outcomes associated with ICP in twin pregnancies were worse than singletons: an almost 5-year retrospective cohort study.

BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP) is associated with an increased risk of adverse perinatal outcomes leading to high perinatal morbidity and mortality. However, few studies have examined twin pregnancies complicated by ICP. To assess the perinatal outcomes of twin pregnancies with ICP, a retrospective cohort study was conducted. METHODS: A total of 633 twin pregnancies and 1267 singleton pregnancies with ICP were included. In addition, a correlation study was performed on the matched total bile acid (TBA) levels from maternal serum, fetal umbilical venous blood, and amniotic fluid of 33 twin pregnancies from twin groups. RESULTS: When compared to singletons, twin pregnancies with ICP had a higher risk of cesarean section (CS) (96.4% vs. 76.1%), preterm birth (PTB) (82.6% vs. 19.7%), fetal distress (2.0% vs. 1.3%), and neonatal intensive care unit (NICU) admission (23.6% vs. 5.1%), which was significantly related to increasing TBA levels (P < 0.05). In twin pregnancies with TBA ≥100 µmol/L, the incidences of CS, PTB, fetal distress, neonatal asphyxia, and meconium-stained amniotic fluid were 94.4, 100, 11.1, 5.6, and 36.1%, respectively. Furthermore, the maximum maternal TBA levels were positively correlated with TBA levels in the amniotic fluid (r = 0.61, P < 0.05) and umbilical cord blood (r = 0.44, P < 0.05), and a similar correlation was found for maternal TBA levels at delivery. TBA levels in umbilical cord blood and amniotic fluid also had a significant and positive correlation (r = 0.52, P < 0.05). CONCLUSIONS: Twin pregnancies with ICP had a higher risk for adverse perinatal outcomes than singletons, which was associated with higher TBA levels. TBA can be transported through the placenta and is involved in uterus-placenta-fetal circulation.

Assessment of different thresholds of birthweight discordance for early neonatal outcomes: retrospective analysis of 2348 twin pregnancies.

BACKGROUND: The optimal threshold of birthweight discordance (BWD) remains controversial. This study aimed to evaluate the associations between BWD at different thresholds and early neonatal outcomes and to assess their predictive accuracy. METHODS: This was a retrospective cohort study using a birthweight data with the chorionicity information of 2348 liveborn twin pairs at a gestational age of ≥26 weeks, from 2012 to 2018. The percentage of BWD was calculated by dividing the actual birthweight difference by the weight of the larger twin and multiplying by 100. Outcomes of interest included neonatal intensive care unit (NICU) admission, neonatal respiratory distress syndrome (NRDS), ventilator support and a composite outcome combining major morbidities and neonatal death. Logistic regression models were performed to estimate the association between neonatal outcomes and BWD with different thresholds (≥15.0%, ≥20.0%, ≥25% and ≥ 30%). Generalized estimated equation (GEE) models were used to address intertwin correlation. Restrictive cubic spline (RCS) models were established to draw the dose-response relationship between BWD and the odds ratios of outcomes. Clustered receiver operating characteristic (ROC) curve analyses were performed to assess the predictive accuracy. RESULTS: Of 2348 twin pairs, including 1946 dichorionic twin pairs and 402 monochorionic twin pairs, BWD was significantly associated with NICU admission, regardless of the thresholds used. The incidence of NRDS, ventilator support and the composite outcome were significantly higher when a threshold of ≥20% or greater was chosen. The dose-response relationship showed nonlinear growth in the risk of adverse neonatal outcomes with increasing BWD. ROC analyses showed a low significant AUROC of 0.569 (95% CI: 0.526-0.612) for predicting NICU admission but no significant AUROCs for predicting other outcomes. A BWD of ≥30% provided a moderate increase in the likelihood of NICU admission [positive likelihood ratio (LR+) = 5.77]. CONCLUSION: Although BWD is independently associated with adverse neonatal outcomes, it is not a single predictor for neonatal outcomes given the weak discriminative ability to predict neonatal outcomes. A cutoff of 30% is more practical for risk stratification among twin gestations.