1. Poor production environment: In the process of anchovy production, if it is disturbed or the environment changes, it may affect its production. At this time, we should keep the environment quiet and don't disturb them too much.

2. Lack of nutrition: If anchovies lack sufficient nutrition during pregnancy, it may lead to production difficulties or fetal dysplasia. At this time, they need to supplement nutrition in time to promote fetal development.

3. Diseases: Anchovies will suffer from some diseases in the production process, such as inflammation of swim bladder, which will also lead to production difficulties. At this time, it is necessary to diagnose and treat diseases in time to ensure the health of anchovies.

In short, we need to check these aspects to determine the reasons why anchovies don't give birth, and take corresponding measures to solve the problem.