Seasonal prediction of the boreal winter stratosphere.

The predictability of the Northern Hemisphere stratosphere and its underlying dynamics are investigated in five state-of-the-art seasonal prediction systems from the Copernicus Climate Change Service (C3S) multi-model database. Special attention is devoted to the connection between the stratospheric polar vortex (SPV) and lower-stratosphere wave activity (LSWA). We find that in winter (December to February) dynamical forecasts initialised on the first of November are considerably more skilful than empirical forecasts based on October anomalies. Moreover, the coupling of the SPV with mid-latitude LSWA (i.e., meridional eddy heat flux) is generally well reproduced by the forecast systems, allowing for the identification of a robust link between the predictability of wave activity above the tropopause and the SPV skill. Our results highlight the importance of November-to-February LSWA, in particular in the Eurasian sector, for forecasts of the winter stratosphere. Finally, the role of potential sources of seasonal stratospheric predictability is considered: we find that the C3S multi-model overestimates the stratospheric response to El Niño-Southern Oscillation (ENSO) and underestimates the influence of the Quasi-Biennial Oscillation (QBO). Supplementary Information: The online version supplementary material available at 10.1007/s00382-021-05787-9.

Nomograms for predicting adverse obstetric outcome in IVF pregnancy: A preliminary study.

BACKGROUND: In a previous study, we showed that the obstetric complication rate after in vitro fertilization (IVF) pregnancy was 40%. The main objective of our study was to determine maternal prognosis factors that influence the IVF pregnancy outcome. METHODS: We conducted an observational retrospective monocentric study between January 2014 and January 2018. Pregnancy over 22 gestational weeks (GW) obtained after IVF in our infertility clinic was included. Maternal characteristics and pregnancy outcome were collected. RESULTS: Data from 498 IVF pregnancies were analyzed. The most significant maternal prognosis factors for obstetric complications were maternal age above 40 years (OR 3,0 [95% IC 1,30-7,09], P = 0,010), twin pregnancies (3.8 [95% IC 1.49-9.99], P = .005), daily maternal smoking above 10 cigarettes (7.1 [95% IC 1.22-41.74], P = .029), maternal obesity (2.2 [95% IC 1.19-4.07], P = .012), endometriosis stages III and IV (6.4 [95% IC 1.52-27.04], P = .011), and history of ovarian hyperstimulation syndrome (OHSS) in early pregnancy (5.7 [95% IC 1.29-24.74], P = .021). Risk increase was independent of pregnancy type (singleton or twin) and allowed the elaboration of 2 nomograms. CONCLUSIONS: Our study showed a link between some maternal factors and increase in obstetric complications after IVF. Screening of these factors during preconceptional visit is essential to identify at high-risk pregnancies and adapt their monitoring.