The White House staff secretary replaces David Warrington, who is leaving for the private sector.
The Democratic congresswoman, 36, said she made the decision to undergo the fertility procedure to “feel more in control of my life.”
The left-hander, a former protégé of the departed Foster Griffin, delivered a solid performance in Washington’s 8-2 victory over Cincinnati.
Todd Blanche formally takes the reins at the Justice Department and faces pressure from the president to go after his critics, including former FBI director James B. Comey.