{'fraction_non_alphanumeric': 0.021961086495858217, 'fraction_numerical': 0.0044307455210942015, 'mean_word_length': 5.144378698224852, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Re: Perinatal outcomes and intrauterine complications following fetal intervention for congenital heart disease: systematic review and meta‐analysis of observational studies. E. Araujo Júnior, G. Tonni, M. Chung, R. Ruano and W. P. Martins. Ultrasound Obstet Gynecol 2016; 48: 426–433.

The paper by Araujo Júnior and colleagues comprises a systematic review (and, where possible, a meta-analysis) of the literature regarding select in-utero procedures aimed at improving fetal cardiac status. They report on three types of procedure to treat structural heart disease (aortic and pulmonary valvuloplasty and atrial septoplasty/stent placement) and one aimed at improving fetal hemodynamics (pericardiocentesis with or without pericardioamniotic shunt placement), reporting rates of fetal death, live birth, preterm birth < 37 weeks and neonatal death for each. Intrauterine complications assessed included bradycardia requiring treatment and hemopericardium requiring drainage. This is a timely and comprehensive review of the literature on the topic of fetal cardiac intervention, and the authors are to be commended. Given the rarity of most of the conditions that might be amenable to these procedures and the wide range of expertise that exists in the relatively new field of invasive fetal therapy, pooling data regarding procedural complications and pregnancy outcomes in order to better inform both healthcare providers and patients regarding risk and likely outcomes becomes paramount. The paper itself has a lofty goal; its strength lies in a careful approach to inclusion of cases and limitation of conclusions to reporting on clear, measurable outcomes. That it falls short with regard to provision of guidance and answers is reflective of the field, not of the authors’ intentions or expertise. The findings that the authors present are not surprising, given our experience with invasive fetal therapies in general: fetal loss rates in relatively recent studies are around 11–17%, fetal instability is common but often recoverable, and membrane rupture and preterm delivery are problematic. As pointed out in the conclusion of the paper, neonatal death rates for the target cardiac diseases are high, and in-utero death is a major concern. The authors allude to the issue of experience, and it is probably true that fetal cardiac intervention should be performed only in select cases and in a few tertiary referral centers with highly experienced fetal teams; unfortunately, there are no real volume-to-outcome conclusions forthcoming from this dataset. In fact, in order to pool only data from centers experienced with these procedures and therefore potentially a similar degree of skill, only papers reporting at least 10 procedures were included in the analysis. However, even if all reports, regardless of center volume, had been included, the issue of reporting bias would still be difficult – centers are much more likely to report a success and a live birth than they are a procedure-related death. It is therefore quite possible that the complication rates are underreported in the cited literature. Furthermore, there are no data to support the efficacy of fetal cardiac intervention and no data to show that it is safer than expectant management. The authors do well to point out that, even with the current evidence, as summarized in their paper, we remain ‘unable to ascertain whether fetal cardiac interventions provide better, similar or poorer outcomes than do cardiac procedures performed only after birth’. There has in fact been only one report to date that looks at medium-term outcomes of fetal cardiac intervention (specifically for aortic stenosis); the intervention was apparently effective in only a minority of patients, and of these the majority required multiple procedures throughout childhood, with some requiring aggressive treatment for heart failure and pulmonary vascular disease1. In the end, it does seem that some answers are emerging. Can fetal cardiac intervention be performed in experienced centers with little risk to the mother? Probably2. Can the immediate risk to the fetus be quantified? Most definitely. Do the procedures change the natural history of the disease? Likely. But the real question remains: does intervening in the fetal period improve the functional and neurodevelopmental status and prolong the lifespan of the affected child in such a way as to justify the inherent risks of the fetal procedure? Lessons can be learned from other areas of fetal therapy, such as the tale of in-utero tracheal occlusion for diaphragmatic hernia, in which the procedural complications balanced against the improvement in postnatal care for the control arm led to a failure to demonstrate superiority of fetal intervention in a randomized controlled trial3 . . . after the fetal procedure had become all but adopted. We must continue to look critically at the here and now, as Araujo Júnior et al. have done; but to widen our lens to include the future will be critical, before time slips by and a procedure with proof-of-concept but without proven benefit becomes accepted as clinical care simply by virtue of having become commonplace.