Hi Alea......
Unfortunately they have a lunar calendar,their women
as all women have their lunar periods & the sun rises
& sets every day there as well.........
They would also
probably notice every bride to be was showing & that
babies born a certain time after wedlock meant the bride
was pregnant before the marriage.....
This is similar reasoning to saying a man suffering from
a disease that disables the ability to feel pain is able to pass a sword through his chest without death,damage or blood.
In other words fit the observation into your existing
belief system rather than changing your belief system
to fit the observation.