One sided acceptance sampling by variables : the case of the Laplace distribution

National audienceThe theory of acceptance sampling by variables is well known when the underlying distribution is normal. When the normality assumption is not true, using the usual normal case method can be quite misleading. In this paper we deal with the Laplace distribution for both the standard deviation known and then unknown. We establish a decision rule for accepting a lot of product containing a defective proportion p. We determine the density function of the decision rule statistic, for small and large sample sizes. We give some pratical ways to choose the sample size and the acceptance constant to obtain a desired operating characteristic curve

Placental lesions and SARS-Cov-2 infection: Diffuse placenta damage associated to poor fetal outcome

International audienceINTRODUCTION: Pregnant women with covid-19 are more likely to experience preterm birth. The virus seems to be associated with a wide range of placental lesions, none of them specific. METHOD: We collected cases of Covid-19 maternal infection during pregnancy associated with poor pregnancy outcomes, for which we received the placenta. We studied clinical data and described pathological findings of placenta and post-mortem examination of fetuses. We performed an immunohistochemical study and RT-PCR of SARS-Cov-2 on placenta samples. RESULTS: We report 5 cases of poor fetal outcome, 3 fetal deaths and 2 extreme premature neonates, one with growth restriction, without clinical and biological sign of SARS-Cov-2 infection. All placenta presented massive perivillous fibrin deposition and large intervillous thrombi associated with strong SARS-Cov-2 expression in trophoblast and SARS-CoV-2 PCR positivity in amniotic fluid or on placenta samples. Chronic histiocytic intervillositis was present in 4/5 cases. Placental ultrasound was abnormal and the sFLT1-PIGF ratio was increased in one case. Timing between mothers' infection and the poor fetal outcome was ≤10 days in 4 cases. The massive placental damage are directly induced by the virus whose receptors are expressed on trophoblast, leading to trophoblast necrosis and massive inflammation in villous chamber, in a similar way it occurs in diffuse alveolar damage in adults infected by SARS-Cov-2. DISCUSSION: SARS-Cov-2 can be associated to a rare set of placental lesions which can lead to fetal demise, preterm birth, or growth restriction. Stronger surveillance of mothers infected by SARS-Cov-2 is required