Hi, thanks for using healthcare magic
If the period is delayed this month then she may want to repeat the pregnancy
tests. Pregnancy tests
are accurate at determining pregnancy if done at least 11 to 14 days after probable conception. Her tests may have indicated she did not conceive last month but she would need another to determine if she conceived since they were taken.
If you and your partner are not currently trying to conceive then you should consider the use of some form of contraception
I hope this helps