Intracranial KCl injection--an alternative method for multifetal pregnancy reduction in the early second trimester

Fetal Outcomes and Prognostic Factors After Radiofrequency Ablation for the Selective Reduction in Complicated Monochorionic Multiple Pregnancies

RATIONALE AND OBJECTIVES

Monochorionic pregnancies are responsible for some severe complications, and selective reduction of a single fetus can improve pregnancy outcomes. This study evaluated the fetal outcomes and procedure-related prognostic factors after radiofrequency ablation (RFA) in complicated monochorionic multiple pregnancies.

MATERIALS AND METHODS

This prospective cross-sectional study was conducted in an academic center from June 2020 to January 2022. The participants were 70 women with monochorionic multiple pregnancies who were candidates for selective fetal reduction by RFA. All participants' demographic data, RFA-related information, and pregnancy outcomes were evaluated and reported.

RESULTS

The RFA procedure was successful in all participants. The most frequent RFA indications were twin-to-twin transfusion syndrome following selective intrauterine growth restriction. The mean gestational age at birth was 33.60 ± 5.62 weeks. Also, 11 (15.7%) of the cases had preterm delivery up to 30 days after RFA. The total pregnancy loss rate was 12 (17.14%), and the total fetal survival rate after RFA was 82.85%. The mean time of the RFA procedure was 130.8 ± 83.3 seconds. The procedure was conducted easily in 31 (44.2%) cases. Although the meantime of RFA procedure was longer in the not-easy group, the difference in surgery time was not significant (P = .296). There was no significant relationship (P = .623) between RFA indications and the gestational age of the remained fetus at delivery. The RFA needle was passed through the placenta in 18 (25.7%) cases. The mean gestational age at the delivery time was significantly lower in this group compared to their counterparts' gestational ages without needle placental passage (P = .030). Also, there was no significant correlation between gestational age at pregnancy termination and RFA cycles (P = .219).

CONCLUSION

RFA is a relatively safe and minimally invasive procedure for the selective reduction of complicated monochorionic fetuses. Although mortality, premature membrane rupture, and preterm delivery are the potential risk factors for the remaining co-twin. According to this study, gestational age at the time of the procedure and passing the needle through the placenta can affect the outcome. Other procedure-related factors like easy- or hard-access procedures, and the number of RFA cycles are not significantly associated with gestational age at birth.

Dynamics of histone acetylation during human early embryogenesis

It remains poorly understood about the regulation of gene and transposon transcription during human early embryogenesis. Here, we report that broad H3K27ac domains are genome-widely distributed in human 2-cell and 4-cell embryos and transit into typical peaks in the 8-cell embryos. The broad H3K27ac domains in early embryos before zygotic genome activation (ZGA) are also observed in mouse. It suggests that broad H3K27ac domains play conserved functions before ZGA in mammals. Intriguingly, a large portion of broad H3K27ac domains overlap with broad H3K4me3 domains. Further investigation reveals that histone deacetylases are required for the removal or transition of broad H3K27ac domains and ZGA. After ZGA, the number of typical H3K27ac peaks is dynamic, which is associated with the stage-specific gene expression. Furthermore, P300 is important for the establishment of H3K27ac peaks and the expression of associated genes in early embryos after ZGA. Our data also indicate that H3K27ac marks active transposons in early embryos. Interestingly, H3K27ac and H3K18ac signals rather than H3K9ac signals are enriched at ERVK elements in mouse embryos after ZGA. It suggests that different types of histone acetylations exert distinct roles in the activation of transposons. In summary, H3K27ac modification undergoes extensive reprogramming during early embryo development in mammals, which is associated with the expression of genes and transposons.

[Clinical effect of fetal reduction by intracranial and intrathoracic KCl injection]

OBJECTIVE

To evaluate the feasibility and effectiveness of fetal reduction by transabdominal intracranial KCl injection for multifetal pregnancies in the early second trimester.

METHODS

The data of 363 patients who underwent transabdominal fetal reduction in the Reproductive Medical Center of Peking University Third Hospital from January 2006 to December 2019 were analyzed retrospectively. According to the location of fetal reduction, they were divided into two groups: Intracranial injection group (n=196) and intrathoracic injection group (n=167). The process of fetal reduction and pregnancy outcome of the two groups were compared.

RESULTS

There was no significant difference between the two groups in the average age and the proportion of type of infertility before assisted reproductive technology, conception method, indication for fetal reduction, starting number of fetuses, reduced number of fetuses, and finishing number of fetuses (P>0.05). There was no significant difference between the two groups in the proportion of the number of puncture ≥ 2 times (12.1% vs. 8.6%, P=0.249) and the incidence of replacing puncture site (10.7% vs. 6.4%, P=0.161). The next day after fetal reduction, color Doppler ultrasound was rechecked. In the intracranial injection group and intrathoracic injection group, the incidence of fetal heartbeat recovery [3.6% (8/224) vs. 1.1% (2/187), P=0.188], the volumes of KCl used [(2.6±1.0) mL vs. (2.8±1.1) mL, P=0.079], and the abortion rate within 4 weeks after fetal reduction (1.0% vs. 0.6%, P=0.654) were of no significant difference. In addition, there was no significant difference in the total abortion rate after fetal reduction, premature delivery rate, cesarean section rate, delivery gestational week and neonatal birth weight between the two groups (P>0.05).

CONCLUSION

Intracranial KCl injection can be an effective alternative to intrathoracic KCl injection for multifetal pregancy reduction.

Fetal reduction for everyone?

Infertility treatments have benefited millions of couples to have their own children; however, the complication of multiple pregnancies with their increased morbidity and mortality has created significant problems. Fetal reduction (FR) was developed to ameliorate these issues. Over 30 years of publications show that FR has been highly successful in substantially reducing both mortality and morbidity. As with most radically new techniques, initial cases were in the "nothing to lose" category. With experience, indications liberalize, and quality of life issues increase as a proportion of cases. Overall risks for twins are not twice as those for singletons, but they are approximately 4- to 5-fold higher. In experienced hands, the combination of genetic testing by CVS followed by FR has made most multiples behave statistically as if they were originally the lower number. The use of microarray analysis to better determine fetal genetic health before deciding on which fetus(es) to keep or reduce further improves pediatric outcomes. With increasing experience and lower average starting numbers, the proportion of FRs to a singleton has increased considerably. Twins to a singleton FR now constitute an increasing proportion of cases performed. Data on such cases show improved outcomes, and we believe FR should be at least discussed and offered to all patients with a dichorionic twin pregnancy or higher. eSET is not a panacea because of the resultant monochorionic twins.

Fetal reduction and twins

Infertility treatments have allowed millions of couples to have their own children, but resultant multiple pregnancies with their increased morbidity and mortality have been a significant complication. Fetal reduction was developed to ameliorate this issue. Over 30 years of publications show that fetal reduction has been highly successful in substantially reducing both mortality and morbidity related to multiple pregnancies. As with most radically new techniques, initial cases were in the "nothing to lose" category. With experience, indications liberalize, and quality of life issues gain relevance. The overall risks of twin pregnancy are not twice that of singleton pregnancy; they are about 4 to 5 times higher. In experienced hands, the combination of genetic testing by chorionic villus sampling followed by fetal reduction has made the outcomes of most multiple pregnancies statistically equivalent to those of pregnancies with lower fetal numbers. Use of microarray analysis to better determine fetal genetic health before deciding on which fetus(es) to keep or reduce further improves pediatric outcomes. With increasing experience and lower average starting numbers, the proportion of fetal reductions to a singleton has increased considerably. Twins to a singleton fetal reductions now constitute an increasing proportion of cases performed. Data on such cases show improved outcomes, and we believe fetal reduction should be at least discussed and offered to all patients with a dichorionic twin pregnancy or higher. With the increasing reliance on elective single-embryo transfers, monochorionic twins, which have much higher complication rates than dichorionic twins, have increased substantially. Furthermore, monochorionic twins cannot be readily and safely reduced, so the adverse perinatal statistics of elective single-embryo transfer are a major setback for good outcomes. Although elective single-embryo transfer is appropriate for some, we believe that for many couples, the transfer of 2 embryos is generally a more rational approach.

Screening and Invasive Testing in Twins

Prenatal screening and testing for trisomy 21 in twin pregnancies poses a number of challenges: the exact estimate of the a priori risk of trisomy 21, the choice of prenatal screening test and/or invasive techniques to employ for the diagnosis and the impact of the result on the options of treatment in case of discordant results within a twin pair or among multiples. These different aspects are discussed below while recognizing that many issues remain unresolved.