Natural Cycles App: Contraceptive Outcomes and Demographic Analysis of UK Users

Objective: Digital fertility awareness-based contraception offers an alternative choice for women who do not wish to use hormonal methods or are unable to use hormones due to medical reasons. It is also popular among women who may be planning a pregnancy over the coming years and wish to educate themselves about their individual menstrual cycle and fertility. The aim of this study was to investigate the key demographics of current users of the Natural Cycles app and assess the effectiveness of the app at preventing pregnancy for a cohort of women from the United Kingdom. Setting: Users of the Natural Cycles mobile application. Participants: 12,247 women in the UK who used Natural Cycles as their primary method of contraception. Outcome Measures: Cohort demographics and risk of unintended pregnancy. Study Design: Observational prospective real-world cohort study. Results: Users contributed an average of 9.9 months of data for a total of 10,066 woman years of exposure. The mean age of the cohort was 30, mean BMI 23.4, the majority were in a stable relationship (83.2%) and had a university degree or higher (83%). The most common form of contraception used prior to natural cycles was combined oral contraceptive (COC)(39.3%). The one year typical use, PI was 6.1 (95% CI: 5.6, 6.6) and with perfect-use was 2.0 (95% CI: 1.3, 2.8). 13 cycle pregnancy probability was 7.1%. Age was found to be associated with contraceptive outcomes, those between 29-34 had a significantly higher pregnancy probability than those aged 34-45 (8.9% vs 5.0%; p=0.0005). In total 41.9% of users were still using the app at the end of the study. Conclusion: This is the first study which describes the use of a digital contraceptive by women in the UK. It describes the demographics of users and how they correlate with the apps effectiveness at preventing pregnancy. Its findings support previously published effectiveness rates for Natural Cycles in a number of countries

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements