| 1. |
- Ahlström, A., et al.
(författare)
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No major differences in perinatal and maternal outcomes between uninterrupted embryo culture in time-lapse system and conventional embryo culture
- 2023
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Ingår i: Human Reproduction. - : Oxford University Press. - 0268-1161 .- 1460-2350. ; 38:12, s. 2400-2411
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Tidskriftsartikel (refereegranskat)abstract
- STUDY QUESTION: Is embryo culture in a closed time-lapse system associated with any differences in perinatal and maternal outcomes in comparison to conventional culture and spontaneous conception?SUMMARY ANSWER: There were no significant differences between time-lapse and conventional embryo culture in preterm birth (PTB, <37 weeks), low birth weight (LBW, >2500 g) and hypertensive disorders of pregnancy for singleton deliveries, the primary outcomes of this study.WHAT IS KNOWN ALREADY: Evidence from prospective trials evaluating the safety of time-lapse incubation for clinical use show similar embryo development rates, implantation rates, and ongoing pregnancy and live birth rates when compared to conventional incubation. Few studies have investigated if uninterrupted culture can alter risks of adverse perinatal outcomes presently associated with IVF when compared to conventional culture and spontaneous conceptions.STUDY DESIGN, SIZE, DURATION: This study is a Swedish population-based retrospective registry study, including 7379 singleton deliveries after fresh embryo transfer between 2013 and 2018 from selected IVF clinics. Perinatal outcomes of singletons born from time-lapse-cultured embryos were compared to singletons from embryos cultured in conventional incubators and 71 300 singletons from spontaneous conceptions. Main perinatal outcomes included PTB and LBW. Main maternal outcomes included hypertensive disorders of pregnancy (pregnancy hypertension and preeclampsia).PARTICIPANTS/MATERIALS, SETTING, METHODS: From nine IVF clinics, 2683 singletons born after fresh embryo transfer in a time-lapse system were compared to 4696 singletons born after culture in a conventional incubator and 71 300 singletons born after spontaneous conception matched for year of birth, parity, and maternal age. Patient and treatment characteristics from IVF deliveries were cross-linked with the Swedish Medical Birth Register, Register of Birth Defects, National Patient Register and Statistics Sweden. Children born after sperm and oocyte donation cycles and after Preimplantation Genetic testing cycles were excluded. Odds ratio (OR) and adjusted OR were calculated, adjusting for relevant confounders.MAIN RESULTS AND THE ROLE OF CHANCE: In the adjusted analyses, no significant differences were found for risk of PTB (adjusted OR 1.11, 95% CI 0.87-1.41) and LBW (adjusted OR 0.86, 95% CI 0.66-1.14) or hypertensive disorders of pregnancy; preeclampsia and hypertension (adjusted OR 0.99, 95% CI 0.67-1.45 and adjusted OR 0.98, 95% CI 0.62-1.53, respectively) between time-lapse and conventional incubation systems. A significantly increased risk of PTB (adjusted OR 1.31, 95% CI 1.08-1.60) and LBW (adjusted OR 1.36, 95% CI 1.08-1.72) was found for singletons born after time-lapse incubation compared to singletons born after spontaneous conceptions. In addition, a lower risk for pregnancy hypertension (adjusted OR 0.72 95% CI 0.53-0.99) but no significant difference for preeclampsia (adjusted OR 0.87, 95% CI 0.68-1.12) was found compared to spontaneous conceptions. Subgroup analyses showed that some risks were related to the day of embryo transfer, with more adverse outcomes after blastocyst transfer in comparison to cleavage stage transfer.LIMITATIONS, REASONS FOR CAUTION: This study is retrospective in design and different clinical strategies may have been used to select specific patient groups for time-lapse versus conventional incubation. The number of patients is limited and larger datasets are required to obtain more precise estimates and adjust for possible effect of additional embryo culture variables.WIDER IMPLICATIONS OF THE FINDINGS: Embryo culture in time-lapse systems is not associated with major differences in perinatal and maternal outcomes, compared to conventional embryo culture, suggesting that this technology is an acceptable alternative for embryo incubation.
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| 2. |
- Farage, P. K., et al.
(författare)
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The potential for soil carbon sequestration in three tropical dryland farming systems of Africa and Latin America: A modelling approach
- 2007
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Ingår i: Soil & Tillage Research. - : Elsevier BV. - 0167-1987. ; 94:2, s. 457-472
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Tidskriftsartikel (refereegranskat)abstract
- Historically, agriculturally induced CO2 release from soils has contributed to rising levels in the atmosphere. However, by using appropriate management, soils can be turned into carbon sinks. Many of the dryland regions of the world are characterised by degraded soils, a high incidence of poverty and a low capacity to invest in agriculture. Two well-proven soil organic matter models (CENTURY 4.0 and RothC-26 3) were used two explore the effects of modifying agricultural practices to increase soil carbon stocks. The changes to land management were chosen to avoid any significant increase in energy input whilst using technologies that would be available without radically altering the current agricultural methodology. Case studies were selected from dryland farming systems in Nigeria, Sudan and Argentina. Modelling showed that it would be possible to make alterations within the structure of the current farming systems to convert these soils from carbon sources to net sinks. Annual rates of carbon sequestration in the range 0.08-0.17 Mg ha(-1) year(-1) averaged over the next 50 years could be obtained. The most effective practices were those that maximised the input of organic matter, particularly farmyard manure (up to 0.09 Mg ha(-1) year(-1)), maintaining trees (up to 0.15 Mg ha(-1) year(-1)) and adopting zero tillage (up to 0.04 Mg ha(-1) year(-1)). Verification of these predictions will require experimental data collected from field studies. (C) 2006 Elsevier B.V. All rights reserved.
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