Musar do Izajasza 30:22

From all this we learn how careful a husband has to be to keep his distance from his wife while she is menstruating, so as not to defile himself additionally. The impurity associated with a menstruating woman is viewed so gravely by our sages that they compare it to idol worship. We know this from Shabbat 82a, where Rabbi Akiva compares the impurity conferred upon a person who carries some object that has been used for idol worship with the impurity of a menstruating woman, basing himself on Isaiah 30,22: תזרם כמו דוה, "You will cast them away like a menstruous woman." Rachel may well have had this interpretation in mind so as not to be guilty of lying; her father, however, accepted her words at face value, and that is why he did not reply.