So next time the aunt is away from her desk at a meeting or something, call the hospital and get connected to the niece. Tell her that her aunt has been in a meeting, and you haven’t had an update for at least 20 minutes. Ask her how many centimeters she is dilated now, how regular her contractions are, etc. You might also ask her if, after the birth, she is planning to have herself stitched up some, to be tight enough to satisfy her husband – tell her the poll of the women in the office is strongly in favor of that.
She might then tell her aunt to be more discreet.