שמואל ב, פרק י״א, פסוק ה׳

The encounter between David and Bathsheba leads to an immediate consequence that sets a new chain of events into motion. Bathsheba quickly realizes her situation and sends an urgent, clear message to the king. The timing of their meeting occurred at the most optimal moment for conception [ביאור שטיינזלץ]. Her awareness of her condition was unusually fast. She felt the pregnancy right away because she experienced a distinct physical change; immediately following the act, fluids cleared from her womb, serving as a direct bodily sign that she had conceived [רלב״ג, מלבי״ם].

Upon sending word to David, Bathsheba makes it entirely clear that the child is undoubtedly his [ביאור שטיינזלץ]. This absolute certainty is based on a strict timeline. Uriah the Hittite had left her a bill of divorce months earlier, in the month of Sivan, while her encounter with David took place at the end of the month of Elul. This significant gap in time provided the necessary waiting period required to distinguish between a husband's child and another man's. Because of this clear separation of time, there was no question that the pregnancy belonged to David [מלבי״ם].