Perhaps you already know, but initial vaccine trials are not performed against menstruation age (aka likely to become pregnant) women. It is considered medically unethical to do so. That is an obvious double edged sword:

1. It prevents birth defects from occurring with trial participants, because this product has not yet been fully studied and approved.

2. It reduces the initial knowledge of any female-specific issues with the product, and particularly limits knowledge around pregnancy issues.

https://www.path.org/articles/why-are-pregnant-people-left-o...

This also affected postmenopausal women who were included in the trials. To quote the paper: "66% of postmenopausal people reported breakthrough bleeding."

Then of course, menstruation age and pregnant women should not be told the vaccine is safe for them, as it was never tested on them. Similar to other pharmaceuticals, it should only be recommend after very careful consideration.

For example, the Tick-Borne Encephalitis Vaccine has a track record of decades, but still, the recommendation in pregnancy is [1] "The vaccine appears to be safe during pregnancy, but because of insufficient data the vaccine is only recommended during pregnancy and breastfeeding when it is considered urgent to achieve protection against TBE infection and after careful consideration of risks versus benefits."

[1] https://en.wikipedia.org/wiki/Tick-borne_encephalitis_vaccin...

That link says trials typically exclude pregnant woman, not all woman who menstruate.

> initial vaccine trials are not performed against menstruation age (aka likely to become pregnant) women

that's false.