Human reproduction
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An essential prerequisite for the future widespread application of human induced pluripotent (hiPSCs) and embryonic stem cells (hESCs) is the development of efficient cryopreservation methods to facilitate their storage and transportation. ⋯ This method is an effective cryopreservation procedure for single dissociated hESCs in feeder-free culture, which is also applicable for single dissociated hiPSCs using a ROCK inhibitor. The cloning efficiency of hiPSCs and hESCs improves when ROCK inhibitor is added both in Matrigel and in medium in comparison with conventional addition to medium. Therefore, we believe this method would be useful for current and future applications of the pluripotent stem cells.
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The optimal timing of an ultrasound scan to assess the location and viability of an early pregnancy.
The objective of this study was to determine the optimal gestational age at which to establish the location and viability of an early pregnancy using transvaginal ultrasonography (TVS). ⋯ The ability to confirm viability or non-viability is significantly related to gestational age. In asymptomatic women with no previous ectopic pregnancy TVS should be delayed until 49 days. Our data suggest that this would reduce the number of inconclusive scans, without an associated increase in morbidity from missed ectopic pregnancies.
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Although elective single embryo transfer (eSET) minimizes the multiple birth rate after in vitro fertilization (IVF)/intra cytoplasmic sperm injection (ICSI), there remain concerns in many countries that it is less effective and more expensive than conventional double embryo transfer (DET). ⋯ This study shows that eSET with cryopreservation is more effective and less expensive than DET and should be adopted as a treatment of choice.
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Despite the widespread use of highly effective contraceptive methods in France, one in every three pregnancies is unintended. Among women experiencing an unintended pregnancy leading to an abortion, half had changed their contraceptive method in the 6 months preceding the abortion, in most cases switching to a less-effective method or to no method at all. This study provides estimates of method-specific contraceptive discontinuation rates for any reason and for method-related reasons among French women. ⋯ Contraceptive discontinuation rates among French women are substantially lower than those reported for US women. Comparing the determinants of contraceptive discontinuation and the role of healthcare providers in helping women make these changes would improve our understanding of the reasons for such variation.
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Common knowledge of over a century has it that monozygotic and dizygotic twinning events occur by unrelated mechanisms: monozygotic twinning 'splits' embryos, producing anomalously re-arranged embryogenic asymmetries; dizygotic twinning begins with independent ovulations yielding undisturbed parallel embryogeneses with no expectation of departures from singleton outcomes. The anomalies statistically associated with twin births are due to the re-arranged embryos of the monozygotics. Common knowledge further requires that dizygotic pairs are dichorionic; monochorionicity is exclusive to monozygotic pairs. ⋯ Dizygotic twinning and monozygotic twinning have the same list of consequences of anomalous embryogenesis. Those include an unignorable fraction of dizygotic pairs that are in fact monochorionic, plus many more sharing co-twins' cells in tissues other than a common chorion. The idea that monozygotic and dizygotic twinning events arise from the same embryogenic mechanism is the only plausible hypothesis that might explain all of the observations.