Pietersen smashed a superb 53 against South Africa on Saturday to lead his side to a win that virtually secures a place in the last four.
The confident strokeplayer then said he would be making an 8,000-plus mile, 17-hour round-trip this week to be with pop singer and model wife Jessica.
"I'm flying in the next 24 hours and if there are no complications I'll come back a day before the semi," Pietersen said at the presentation ceremony.
"It's my first child so it's a hell of an exciting time for me. I'll be dashing across the Atlantic and hopefully dashing back," he added.
The only game Pietersen is scheduled to miss is Monday's match with New Zealand, a game that could be meaningless for England if Pakistan beat South Africa earlier the same day.
The semi-finals will be played on Thursday and Friday in St Lucia.
England all but ensured progress to the semis with victory over South Africa. They have a maximum four points in Group E.
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