Pregnancy losses are substantial in lactating dairy cattle. The majority of pregnancy losses occur during embryonic development (before d 45 post-insemination), before rectal palpation can be utilized effectively for pregnancy diagnosis. Earlier determination of pregnancy status can benefit producers by allowing for earlier re-insemination and can benefit researchers seeking to understand the physiological causes of pregnancy losses. This presentation will explore current methods used to predict pregnancy status and likelihood of pregnancy loss before d 45 of gestation. Transrectal ultrasonography is the ‘gold standard’ for detecting embryos, amnionic sacs and embryonic heart beats by d 24–28 post-insemination. However, this method requires technical skill and up-front equipment costs. An alternative to ultrasonography is to examine circulating concentrations of pregnancy-associated glycoproteins (PAGs). These placenta-produced proteins can be detected in the maternal circulation from d 24–28 onward. Cow-side tests are not currently available for PAG testing, but local and regional labs permit rapid turnaround times for pregnancy determination (usually 1–2 d). Quantifying circulating PAG concentrations is also being used in research settings to predict impending pregnancy losses. Earlier prediction of pregnancy status is possible. Plasma and milk progesterone concentrations at d 17–24 post-insemination are used to identify open cows. Commercially available qualitative progesterone kits are available for on-farm testing. A more recent development is the use of peripheral blood leukocyte gene expression to predict pregnancy status. Conceptus production of interferon-tau in early pregnancy alters interferon-stimulated gene (ISG) expression within maternal cells, including circulating immune cells. These pregnancy-dependent ISG responses can be detected at d 17–22 post-insemination in cattle. However, these same gene responses are also observed in disease states, thus ISG-based tests predict open cows with greater accuracy than pregnant cows. Collectively, these technologies benefit dairy herd fertility by increasing the number of breeding opportunities during early and mid-lactation, thus reducing days open.