At six weeks, it is very common for a fetal heartbeat not to be detected yet. This often happens if the pregnancy is slightly earlier than calculated or if ovulation occurred later than expected. The injection you were prescribed contains human chorionic gonadotropin (hCG). This hormone supports your pregnancy by encouraging your body to produce progesterone, a vital hormone that maintains the uterine lining and helps secure the pregnancy. Please try not to worry; prescribing this hormone and scheduling a repeat scan in two weeks is a standard, supportive approach to give your pregnancy the best possible start.