Yes, dogs are likely able to sense when you're pregnant. This ability primarily comes from their extraordinary senses, especially their keen sense of smell. While there isn't definitive scientific proof, anecdotal evidence strongly suggests that dogs notice the subtle changes in their owner's body during pregnancy. Dogs have about 300 million scent receptors compared to 6 million in humans, allowing them to detect tiny differences, including hormonal changes that occur early in pregnancy. Some dog owners report their pets behaving differently even before they themselves know they are pregnant. Dogs may also pick up on changes in their owner's behavior and mood, which often change during pregnancy. Additionally, dogs' acute hearing might allow them to hear changes like a fetal heartbeat or other bodily sounds. Many pregnant dog owners notice increased affection or protectiveness from their dogs as a response to these sensed changes, although every dog may react differently. It's believed that dogs sense something is different but likely do not understand the reason or concept of pregnancy itself.