Does the divorce I intended in my heart, and did not utter to my wife, but said to her father with the words "Yes, I divorced her with a single pronouncement," take effect, bearing in mind that she was menstruating at the time I intended the divorce?

As long as you uttered the phrase: (Okay, consider everything between us over) in response to your wife's question about divorce, and you intended divorce by this phrase; then a revocable divorce has occurred. An explicit pronouncement is not a condition, nor does menstruation prevent the occurrence of divorce. Therefore, one divorce has occurred to your wife, and you may take her back before the expiration of her waiting period without a new contract or her consent.