The actual question from the 15 April 1984 edition of the Watchtower on page 29 in the article "Respect Jehovah, Urges the Book of Numbers" is:
Q: What actually happened to a wife guilty of adultery? Numbers 5:11-31
A: No affliction was brought on by the water itself. But it was drunk before Jehovah, who knew whether the woman was guilty of adultery. If she was, he would make her belly swell and her thigh fall away. Evidently the thigh is used here euphemistically for the procreative organs. (Compare Genesis 46:26.) 'Fall away' suggests that these organs atrophied, making conception impossible. This would harmonize with the fact that if the woman was innocent her husband was to make her pregnant.
That's all folks!
DarK SpilveR