Recommandations françaises pour les critères diagnostiques d'arrêt de grossesse au premier trimestre et stratégie de prise en charge des patientes présentant une menace de fausse couche ou une grossesse arrêtée (hors évacuation utérine)

First trimester nonviable pregnancy is established with gestational sac mean diameter and embryo crown-rump length. Mean sac diameter ≥ 25 mm without embryo (LE2) or embryo crown-rump length ≥ 7 mm without heartbeat (LE2) by transvaginal sonography allows to diagnose pregnancy failure. Intrauterine pregnancy of uncertain viability is defined by intra-uterine gestational sac without embryo with heartbeat or without pregnancy diagnosis failure and requires a new transvaginal sonography. The delay for this second sonography depends on the aspect of intrauterine picture (i.e. presence of yolk sac or not, presence of embryo or not) (LE4). Human chorionic gonadotropin (hCG) and progesterone are useful for pregnancy of unknown location (i.e. no gestational sac at transvaginal sonography): hCG ratio < 15% between two-day serum samples when first hCG is < 2000 UI/mL (LE2) or low serum progesterone level (< 3.2 ng/mL) (LE2) exclude viable intrauterine pregnancy. There is not known prevention strategy for threatened miscarriage.