Introduction:
To generate a prediction model for miscarriage in women with a viable single pregnancy from first-trimester ultrasound findings and maternal characteristics.

Material and Methods:
A prospective, cross-sectional study of 415 singleton pregnancies was performed. The initial ultrasound parameters were crown-rump length (CRL), mean gestational sac diameter (MGSD), yolk sac diameter (YSD), and the sum of the differences between gestational ages and embryonic heart rate (EHR). Potential predictors for spontaneous miscarriage occurring prior to 20 weeks were evaluated.

Results:
Fifty-three (12.8%) patients had miscarriages and 362 (87.2%) had normal outcomes. Forty-three (81.2%) miscarriages occurred in the first trimester, 5 (9.4%) in the second trimester, and 5 (9.4%) represented fetal anomalies. EHR, CRL, and MGSD were decreased in the miscarriage group (p<0.001); YSD showed no difference (p=0.21). Gestational age by CRL and by MGSD were different between the groups (p<0.001). The proposed sum of differences was higher in the miscarriage group (p<0.001). Maternal age, indication for scan, gestational age by MGSD and CRL, heart rate, and proposed sum of differences were found to be potential predictors. Predictive ability of our proposed model was calculated sensitivity as 0.509, and specificity as 0.975 with a cut-off=0.5. The prediction model’s false positive rate is 0.025, and its false negative rate is 0.491.

Conclusions:
Miscarriage can be predicted via maternal characteristics and ultrasound findings. Advancing maternal age, low EHR, and high proposed sum of differences increase the probability of miscarriage.