Vaginal birth after cesarean: New insights on maternal and neonatal outcomes
ABSTRACT To systematically review the evidence about maternal and neonatal outcomes relating to vaginal birth after cesarean (VBAC).
Relevant studies were identified from multiple searches of MEDLINE, DARE, and the Cochrane databases (1980 to September 2009) and from recent systematic reviews, reference lists, reviews, editorials, Web sites, and experts.
Inclusion criteria limited studies to the English-language and human studies conducted in the United States and developed countries specifically evaluating birth after previous cesarean delivery. Studies focusing on high-risk maternal or neonatal conditions, including breech vaginal delivery, or fewer than 10 patients were excluded. Poor-quality studies were not included in analyses.
We identified 3,134 citations and reviewed 963 articles for inclusion; 203 articles met the inclusion criteria and were quality rated. Overall rates of maternal harms were low for both trial of labor and elective repeat cesarean delivery. Although rare in both elective repeat cesarean delivery and trial of labor, maternal mortality was significantly increased for elective repeat cesarean delivery at 0.013% compared with 0.004% for trial of labor. The rates of maternal hysterectomy, hemorrhage, and transfusions did not differ significantly between trial of labor and elective repeat cesarean delivery. The rate of uterine rupture for all women with prior cesarean was 0.30%, and the risk was significantly increased for trial of labor (0.47% compared with 0.03% for elective repeat cesarean delivery). Perinatal mortality was also significantly increased for trial of labor (0.13% compared with 0.05% for elective repeat cesarean delivery).
Overall the best evidence suggests that VBAC is a reasonable choice for the majority of women. Adverse outcomes were rare for both elective repeat cesarean delivery and trial of labor. Definitive studies are lacking to identify patients who are at greatest risk for adverse outcomes.
Article: [Uterine rupture].[Show abstract] [Hide abstract]
ABSTRACT: Uterine rupture may be defined as a disruption of the uterine muscle extending to and involving the uterine serosa or disruption of the uterine muscle with extension to the bladder or broad ligament . Uterine dehiscence is defined as disruption of the uterine muscle with intact uterine serosa . Uterine rupture is associated with severe maternal and perinatal morbidity and mortality, and it remains one of the most catastrophic obstetrical emergencies. It has consequences not only for the index pregnancy but also, if it is possible to conserve the uterus, for further fertility and pregnancy outcomes. In the developed world, most cases occur in women with a uterine scar [2–4]. In less and least developed countries, cephalopelvic disproportion causing obstructed labor is the major cause of uterine rupture [5–7]. The prevalence of uterine rupture is likely to increase in the developed world reflecting increasing rates of cesarean section, and it continues to contribute significantly to maternal mortality among women giving birth in the developing world.Sanfujinka no jissai. Practice of gynecology and obstetrics 11/1967; 16(10):951-4.
Conference Paper: Novel current mode AC/AC converters with high frequency AC link[Show abstract] [Hide abstract]
ABSTRACT: A novel circuit topologies family of the current mode AC/AC converter with high frequency ac link, based on flyback converter, are proposed. These circuit topologies which can transfer one unregulated sinusoidal voltage with high THD into another regulated constant frequency sinusoidal voltage with low THD, are constituted of input cycloconverter, high frequency storage transformer and output cycloconverter. The circuit topologies family include single four-quadrant power switch mode, push-pull mode, half-bridge mode, and full-bridge mode circuit. The single four-quadrant power switch mode and push-pull mode converter are suit for low input voltage fields, but the half-bridge mode and full-bridge mode converter are suit for high input voltage fields. The operational mode, steady principle and transient voltage feedback control strategy of the kind of converter are investigated. The output characteristic curve, its relation to internal resistance, and the design criterions for the key circuit parameters are given. The current mode AC/AC converters with high frequency ac link have the advantages such as simple topology, two-stage power conversions, bi-directional power flow, high frequency electrical isolation, good line current waveform, strong load adapting ability. The correction and advance of the converters are verified by the Pspice simulation and test resultsPower Electronics Specialists Conference, 2005. PESC '05. IEEE 36th; 02/2005
- Annales d Endocrinologie 10/2006; 67(5):457-457. DOI:10.1016/S0003-4266(06)72797-4