Pregnancy outcomes in infertility patients diagnosed with sleep disordered breathing with wireless wearable sensors

Objective To study the feasibility of home-based assessment of sleep disordered breathing (SDB) on early pregnancy success after in vitro fertilization with novel wearable sensors. Design Prospective observational study. Setting Patients 18 to 45 years old undergoing autologous IVF at an academic infertility center. Patients 30 women (24–44 years old) Intervention Participants provided medical history, completed sleep surveys, and a single night of home sleep monitoring prior to IVF with a novel, FDA-cleared wireless sensor system (ANNE® Sleep, Sibel Health), to collect continuous measurements of heart rate, respiratory rate, pulse oxygenation, respiratory effort/snoring, peripheral arterial tonometry, pulse arrival time, and pulse transit time, an accepted surrogate of continuous blood pressure generated by pulse arrival time and pulse transit time. Sleep nights were reviewed to derive the apnea hypopnea index (AHI), defined as the average number of apnea or hypopnea events per hour. An AHI of greater than or equal to 5 events/hour was considered abnormal. Main outcome measure Rate of clinical pregnancy (defined as intrauterine gestational sac with a yolk sac) after IVF. Logistic regression models were used to estimate the unadjusted and adjusted odds ratio. Results The overall rate of sleep disordered breathing of any severity was 57%. Participants with SDB had a mean AHI of 13.4 compared to 2.7 events/hr (p<0.01), were younger, and more likely to have polycystic ovary syndrome. Of the 29 patients undergoing an embryo transfer, clinical pregnancy and livebirth occurred in 35% of women with SDB compared to 58% without SDB (p = 0.22). After adjusting for age, SDB reduced pregnancy rates but was not statistically significant (aOR 0.23, 95% CI: 0.04–1.5, p = 0.12). Though polycystic ovary syndrome was associated with higher rates of SDB it was not independently associated with lower pregnancy rates. Conclusion Screening for sleep disordered breathing using home-based wireless, wearable sensors was well accepted and easily performed by infertile patients in this cohort. Sleep disordered breathing of any severity was associated with an 77% (95% CI: 0.08–1.8) lower likelihood of clinical pregnancy and live birth independent of underlying diagnosis. Future larger studies will be needed to understand the role of sleep disordered breathing and IVF outcomes

Effect of orographic gravity wave drag on Northern Hemisphere climate in transient simulations of the last deglaciation

Long transient simulations of the last deglaciation are increasingly being performed to identify the drivers of multiple rapid Earth system changes that occurred in this period. Such simulations frequently prescribe temporal variations in ice sheet properties, which can play an important role in controlling atmospheric and surface climate. To preserve a model’s standard performance in simulating climate, it is common to apply time dependent orographic variations, including parameterised sub-grid scale orographic variances, as anomalies from the pre-industrial state. This study investigates the causes of two abrupt climate change events in the Northern Hemisphere extratropics occurring between 16 and 14 thousand years ago in transient simulations of the last deglaciation from the Hadley Centre coupled general circulation model (HadCM3). One event is characterized by regional Northern Hemisphere changes comprising a centennial scale cooling of ~ 10 °C across Fennoscandia followed by rapid warming in less than 50 years as well as synchronous shifts in the Northern Annular Mode. The second event has comparable but temporally reversed characteristics. Sensitivity experiments reveal the climate anomalies are exclusively caused by artificially large values of orographic gravity wave drag, resulting from the combined use of the orographic anomaly method along with a unique inclusion of transient orography that linearly interpolates between timesteps in the ice sheet reconstruction. Palaeoclimate modelling groups should therefore carefully check the effects of their sub-grid scale orographic terms in transient palaeoclimate simulations with prescribed topographic evolution

A multi-model assessment of the early last deglaciation (PMIP4 LDv1): a meltwater perspective

The last deglaciation (∼20–11 ka BP) is a period of a major, long-term climate transition from a glacial to interglacial state that features multiple centennial- to decadal-scale abrupt climate variations whose root cause is still not fully understood. To better understand this time period, the Paleoclimate Modelling Intercomparison Project (PMIP) has provided a framework for an internationally coordinated endeavour in simulating the last deglaciation whilst encompassing a broad range of models. Here, we present a multi-model intercomparison of 17 transient simulations of the early part of the last deglaciation (∼20–15 ka BP) from nine different climate models spanning a range of model complexities and uncertain boundary conditions and forcings. The numerous simulations available provide the opportunity to better understand the chain of events and mechanisms of climate changes between 20 and 15 ka BP and our collective ability to simulate them. We conclude that the amount of freshwater forcing and whether it follows the ice sheet reconstruction or induces an inferred Atlantic meridional overturning circulation (AMOC) history, heavily impacts the deglacial climate evolution for each simulation rather than differences in the model physics. The course of the deglaciation is consistent between simulations except when the freshwater forcing is above 0.1 Sv – at least 70 % of the simulations agree that there is warming by 15 ka BP in most places excluding the location of meltwater input. For simulations with freshwater forcings that exceed 0.1 Sv from 18 ka BP, warming is delayed in the North Atlantic and surface air temperature correlations with AMOC strength are much higher. However, we find that the state of the AMOC coming out of the Last Glacial Maximum (LGM) also plays a key role in the AMOC sensitivity to model forcings. In addition, we show that the response of each model to the chosen meltwater scenario depends largely on the sensitivity of the model to the freshwater forcing and other aspects of the experimental design (e.g. CO2 forcing or ice sheet reconstruction). The results provide insight into the ability of our models to simulate the first part of the deglaciation and how choices between uncertain boundary conditions and forcings, with a focus on freshwater fluxes, can impact model outputs. We can use these findings as helpful insight in the design of future simulations of this time period