OBJECTIVES: To assess the optimal mode of delivery in women with, or carriers of, bleeding disorders.
SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the Cochrane Pregnancy and Childbirth Group's Trials Register as well as trials registries and the reference lists of relevant articles and reviews. Date of last search of the Group's Trials Registers: 21 June 2021.
SELECTION CRITERIA: Randomised controlled trials and quasi-randomised controlled clinical trials investigating the optimal mode of delivery in women with, or carriers of, any type of bleeding disorder during pregnancy were eligible for the review.
DATA COLLECTION AND ANALYSIS: No trials matching the selection criteria were eligible for inclusion.
MAIN RESULTS: No trials matching the selection criteria were eligible for inclusion.
AUTHORS' CONCLUSIONS: The review did not identify any randomised controlled trials investigating the safest mode of delivery and associated maternal and foetal complications during delivery in women with, or carriers of, a bleeding disorder. In the absence of high quality evidence, clinicians need to use their clinical judgement and lower level evidence (e.g. from observational trials, case studies) to decide upon the optimal mode of delivery to ensure the safety of both mother and foetus. Given the ethical considerations, the rarity of the disorders and the low incidence of both maternal and foetal complications, future randomised controlled trials to find the optimal mode of delivery in this population are unlikely to be carried out. Other high quality controlled studies (such as risk allocation designs, sequential design, and parallel cohort design) are needed to investigate the risks and benefits of natural vaginal and caesarean section in this population or extrapolation from other clinical conditions that incur a haemorrhagic risk to the baby, such as platelet alloimmunisation.
METHODOLOGY/PRINCIPLE FINDINGS: The D. siamensis monovalent antivenom displayed extensive recognition and binding to proteins found in D. siamensis venom, irrespective of the geographical origin of those venoms. Similar immunological characteristics were observed with the Hemato Polyvalent antivenom, which also uses D. siamensis venom as an immunogen, but binding levels were dramatically reduced when using comparator monovalent antivenoms manufactured against different snake species. A similar pattern was observed when investigating neutralization of coagulopathy, with the procoagulant action of all four geographical venom variants neutralized by both the D. siamensis monovalent and the Hemato Polyvalent antivenoms, while the comparator monovalent antivenoms were ineffective. These in vitro findings translated into therapeutic efficacy in vivo, as the D. siamensis monovalent antivenom was found to effectively protect against the lethal effects of all four geographical venom variants preclinically. Assessments of in vivo nephrotoxicity revealed that D. siamensis venom (700 μg/kg) significantly increased plasma creatinine and blood urea nitrogen levels in anaesthetised rats. The intravenous administration of D. siamensis monovalent antivenom at three times higher than the recommended scaled therapeutic dose, prior to and 1 h after the injection of venom, resulted in reduced levels of markers of nephrotoxicity and prevented renal morphological changes, although lower doses had no therapeutic effect.
CONCLUSIONS/SIGNIFICANCE: This study highlights the potential broad geographical utility of the Thai D. siamensis monovalent antivenom for treating envenomings by the Eastern Russell's viper. However, only the early delivery of high antivenom doses appears to be capable of preventing venom-induced nephrotoxicity.