Outcome of fetal echogenic bowel: A systematic review and meta-analysis

The main aim of this systematic review was to explore the outcome of fetuses with isolated echogenic bowel (EB) on antenatal ultrasound. Inclusion criteria were singleton pregnancies with isolated EB no associated major structural anomalies at the time of diagnosis. The outcomes observed were: chromosomal anomalies, cystic fibrosis (CF), associated structural anomalies detected only at follow-up scans and at birth, regression during pregnancy, congenital infections, intra-uterine (IUD), neonatal (NND) and perinatal (PND) death. Twenty-five studies (12 971 fetuses) were included. Chromosomal anomalies occurred in 3.3% of the fetuses, mainly Trisomy 21 and aneuploidies involving the sex chromosomes. Cystic fibrosis occurred in 2.2%. Congenital infections affected 2.2%, mainly congenital Cytomegalovirus (CMV) infection. The majority of fetuses with EB experienced regression or disappearance of the EB at follow-up scans. Associated anomalies were detected at a follow-up scan in 1.8%. Associated anomalies were detected at birth and missed at ultrasound in 2.1% of cases. IUD occurred in 3.2% of cases while the corresponding figures for NND and PND were 0.4% and 3.1%. Fetuses with EB are at increased risk of adverse perinatal outcome, highlighting the need for a thorough antenatal management and postnatal follow-up. Assessment during pregnancy and after birth should be performed in order to look for signs of fetal aneuploidy, congenital infections and associated structural anomalies.     

Antenatal screening for fetal trisomies using microarray-based cell-free DNA testing: A systematic review and meta-analysis

Objective

To evaluate the test accuracy of non-invasive prenatal testing (NIPT) for fetal trisomy 21, 18, and 13 using cell-free (cf) DNA analysis in maternal plasma with microarray quantitation.

Method

Systematic review and meta-analysis. Searches in MEDLINE, Pre-MEDLINE, EMBASE, Web of Science, and the Cochrane Library to 09.07.2018.

Results

Five studies analyzing 3074 samples, including 187 trisomy 21, 43 trisomy 18, and 19 trisomy 13 cases, were identified. Risk of bias was high in all studies, introduced particularly by exclusions from analysis and by the role of the sponsor. Sensitivity of microarray-based cfDNA testing was 99.5% (95%CI 96.3%-99.9%) for trisomy 21, 97.7% (95%CI 87.9%-99.6%) for trisomy 18, and 100% (95%CI 83.2%-100%) for trisomy 13. Specificity was 100% (95% CI 99.87%-100%) for trisomy 21, 99.97% (95%CI 99.81%-99.99%) for trisomy 18, and 99.97% (95%CI 99.81%-99.99%) for trisomy 13. Pooled test failure rate was 1.1%. A direct comparison of microarray- and sequencing-based cfDNA found equivalent test accuracy.

Conclusion

Included studies suggest that NIPT using microarray-based cfDNA testing has high sensitivity and specificity for detecting fetal trisomy 21, 18, and 13. However, the evidence base is small and at high risk of bias.     

Association between low fetal fraction in cell-free DNA screening and fetal chromosomal aberrations: A systematic review and meta-analysis

Objective

To perform a systematic review and meta-analysis of the available literature on low fetal fraction (LFF) in cell-free DNA (cfDNA) screening and the risk of fetal chromosomal aberrations.

Method

We searched articles published between January 2010 and May 2021 in PubMed and EMBASE databases. Risk of bias was assessed using QUADAS-2.

Results

Twenty-seven studies met the inclusion criteria, comprising data of 243,700 singleton pregnancies. Compared to normal fetal fraction, LFF was associated with a higher risk of trisomy 13 (OR 5.99 [3.61–9.95], I ² of heterogeneity = 0%, n = 22 studies), trisomy 18 (OR 4.46 [3.07–6.47], I ² = 0%, n = 22 studies), monosomy X (OR 5.88 [2.34–14.78], I ² = 18%, n = 10 studies), and triploidy (OR 36.39 [9.83–134.68], I ² = 61%, n = 6 studies), but not trisomy 21 (OR 1.25 [0.76–2.03], I ² = 36%, n = 23 studies). LFF was also associated with a higher risk of various other types of fetal chromosomal aberrations (OR 4.00 [1.78–9.00], I ² = 2%, n = 11 studies). Meta-analysis of proportions showed that absolute rates of fetal chromosomal aberrations ranged between 1% and 2% in women with LFF. A limitation of this review is the potential risk of ascertainment bias because of differences in outcome assessment between pregnancies with LFF and those with normal fetal fraction. Heterogeneity in population characteristics or applied technologies across included studies may not have been fully addressed.

Conclusion

An LFF test result in cfDNA screening is associated with an increased risk of fetal trisomy 13, trisomy 18, monosomy X, and triploidy, but not trisomy 21. Further research is needed to assess the association between LFF and other specific types of fetal chromosomal aberrations.     

Solomon versus selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome: A systematic review and meta-analysis

This meta-analysis aims to compare the perinatal outcome of twin-twin transfusion syndrome (TTTS) pregnancies undergoing selective versus vascular equator (Solomon) fetoscopic laser photocoagulation (FLP). We performed a systematic search in PubMed and Web of Science from inception up to 25 July 2021. Studies comparing the Solomon and selective techniques of FLP for treatment of TTTS pregnancies were eligible. Random-effects or fixed-effect models were used to pool standardized mean differences (SMD) and log odds ratio. Seven studies with a total of 1664 TTTS pregnancies (n = 671 undergoing Solomon and n = 993 selective techniques) were included. As compared to the selective FLP, Solomon was associated with a lower risk of recurrent TTTS compared to the selective technique (Log odds ratio [OR]: −1.167; 95% credible interval [CrI]: −2.01, −0.33; p = 0.021; I²: 67%). In addition, Solomon was significantly associated with a higher risk of placental abruption than the selective technique (Log [OR]: 1.44; 95% CrI: 0.45, 2.47; p = 0.012; I²: 0.0%). Furthermore, a trend for the higher risk of preterm premature rupture of membranes was observed among those undergoing Solomon (Log [OR]: 0.581; 95% CrI: −0.43, 1.49; p = 0.131; I²: 17%). As compared to selective FLP, the Solomon technique for TTTS pregnancies is associated with a significantly lower recurrence of TTTS; however, it significantly increases the risk of placental abruption.     

Fetoscopic laser photocoagulation versus expectant management for stage I twin-to-twin transfusion syndrome: A systematic review and meta-analysis

To investigate the outcomes of asymptomatic stage I twin-to-twin transfusion syndrome (stage I TTTS) among patients treated with fetoscopic laser photocoagulation (FLP) versus expectant management. Databases such as PubMed, Web of Science and Scopus were systematically searched from inception up to March 1st, 2022. The primary outcome was at least one fetal survival at birth and secondary outcomes included gestational age at delivery, preterm premature rupture of membranes < 32 weeks, preterm birth < 32 weeks, and single and dual fetal survival. Five studies were included in the meta-analysis. There was no significant difference in terms of at least one survival (odds ratio (OR) = 1.40, 95%CI= (0.26, 7.43), P = 0.70), single survival (OR = 0.87, 95%CI= (0.51, 1.48), P = 0.60) and dual survival (OR = 1.63, 95%CI= (0.74, 3.62), P = 0.23) among FLP and expectant groups. Gestational age at delivery (mean difference = 1.19, 95%CI= (−0.25, 2.63), P = 0.10), the risk of PTB<32 weeks (OR = 0.88, 95%CI= (0.50, 1.54), P = 0.65), and pPROM<32 weeks (OR = 1.80, 95% CI= (0.41, 7.98), P = 0.44) were also comparable between the groups. Routine FLP of the placental anastomoses before 26 weeks of gestation is unlikely to be beneficial among asymptomatic stable stage I TTTS patients without cervical shortening as the procedure does not offer a survival advantage compared with expectant management.     

Non-invasive prenatal testing (NIPT) in twin pregnancies affected by early single fetal demise: A systematic review of NIPT and vanishing twins

The screening performance of non-invasive prenatal testing (NIPT) in vanishing twin (VT) pregnancies is relatively unknown. To close this knowledge gap, we conducted a systematic review of the available literature. Studies describing the test performance of NIPT for trisomy 21, 18, 13, sex chromosomes and additional findings in pregnancies with a VT were retrieved from a literature search with a publication date until October 4, 2022. The methodological quality of the studies was assessed with the quality assessment tool for diagnostic accuracy studies-2 (QUADAS-2). The screen positive rate of the pooled data and the pooled positive predictive value (PPV) were calculated using a random effects model. Seven studies, with cohort sizes ranging from 5 to 767, were included. The screen positive rate of the pooled data for trisomy 21 was 35/1592 (2.2%), with a PPV of 20% (confirmation in 7/35 cases [95% CI 9.8%–36%]). For trisomy 18, the screen positive rate was 13/1592 (0.91%) and the pooled PPV 25% [95% CI 1.3%–90%]. The screen positive rate for trisomy 13 was 7/1592 (0.44%) and confirmed in 0/7 cases (pooled PPV 0% [95% CI 0%–100%]). The screen positive rate for additional findings was 23/767 (2.9%), of which none could be confirmed. No discordant negative results were reported. There is insufficient data to fully evaluate NIPT performance in pregnancies with a VT. However, existing studies suggest that NIPT can successfully detect common autosomal aneuploidies in pregnancies affected by a VT but with a higher false positive rate. Further studies are needed to determine the optimal timing of NIPT in VT pregnancies.     

Obstetrical outcomes following amniocentesis performed after 24 weeks of gestation: A systematic review and meta-analysis

To evaluate obstetrical outcomes for women having late amniocentesis (on or after 24 weeks). Electronic databases were searched from inception to January 1st, 2023. The obstetrical outcomes evaluated were gestational age at delivery, preterm birth (PTB) < 37 weeks, PTB within 1 week from amniocentesis, premature prelabor rupture of membranes (pPROM), chorionamnionitis, placental abruption, intrauterine fetal demise (IUFD) and termination of pregnancy (TOP). The incidence of PTB <37 weeks was 4.85% (95% CI 3.48–6.56), while the incidence of PTB within 1 week was 1.42% (95% CI 0.66–2.45). The rate of pPROM was 2.85% (95% CI 1.21–3.32). The incidence of placental abruption was 0.91% (95% CI 0.16–2.25), while the rate of IUFD was 3.66% (95% CI 0.00–14.04). The rate of women who underwent TOP was 6.37% (95%CI 1.05–15.72). When comparing amniocentesis performed before or after 32 weeks, the incidence of PTB within 1 week was 1.48% (95% CI 0.42–3.19) and 2.38% (95% CI 0.40–5.95). Amniocentesis performed late after 24 weeks of gestation is an acceptable option for patients needing prenatal diagnosis in later gestation.