In Bereshit 31:35 we learn that Rachel was able to hide the Teraphim under her saddle by telling her father Lavan that "The way of women is upon me", presumably a euphemism for menstruation.
Just a few chapters later, though, while still travelling from Paddan-aram to Eprath, (Bereshit 35:16) we have her giving birth to Benjamin.
Since she would presumably have been well advanced in her pregnancy at the time the incident at Galeed occurred, and Lavan was a wily trickster, this successful deceit seems problematic.
Are there any traditional sources that discuss how Rachel Imeinu was able to deceive her father?