OBJECTIVE In early pregnancies, miscarriages and inconclusive ultrasound scans considering location and viability are very common. In several previous studies, serum progesterone levels predicted viability of pregnancy and, in recent ones, failed Pregnancies of Unknown Location (PUL), completion of miscarriage and complications. Corpus luteum, secreting progesterone in early pregnancy, was less studied. Some publications showed correlations between corpus luteum aspects and diagnosis of miscarriage but it was not evaluated for other outcomes in early pregnancy, such as failed PUL, completion of miscarriage or complications. We aimed to assess if Doppler examination of corpus luteum could also predict all these outcomes: failed PUL, diagnosis and completion of miscarriages and complications. METHODS A single operator prospectively described and/or collected pictures of Doppler signal in the wall of the corpus luteum at most consultations in our early pregnancy unit and established a three-level score. All suspected or confirmed non-viable pregnancies with this score or/and serum progesterone levels were registered retrospectively. With logistic regressions, AIC/BIC, likelihood ratios, ROC curves, Mann-Whitney and Fisher exact tests, we evaluated the ability of the score, alone, to predict failed PUL, diagnosis and completion of miscarriages and the complications, and, combined, to improve previously published predictions. RESULTS From 277 included pregnancies, 186 (67.1 %) miscarried. Of these, 159/186 (85.5 %) fully evacuated without surgery: 114/186 (61.3 %) within 20 days after the first diagnosis and 45/186 (24.2 %) after more than 20 days. Twenty-seven patients (14.5 %) underwent surgical evacuation, including ten complications, five haemorrhages and five suspected infections. Logistic regression correlated strongly the corpus luteum score with failed PUL (p < 0.0001) and miscarriages (p < 0.0001). Moreover, rates of complications and swift non-surgical completions of miscarriage were respectively 0 % and 92 % with scores of 0, versus 6 % and 44 % with scores of 1, versus 16 % and 0 % with scores of 2. Combined with serum progesterone levels, this score improved most predictions. Adding parity or history of miscarriage in predictive models even increased these performances. CONCLUSIONS Corpus luteum score, alone, can predict failed PUL, diagnosis and completion of miscarriages and their complications. Combining this score with other factors (mainly serum progesterone levels) improves most predictions.