Did he kick her to death while she was pregnant?

Hello.

Yes, Nero reportedly did kick Poppaea to death while she was pregnant.

sources:

From San Jose State University:
"Nero kicked Poppaea to death while she was pregnant."
http://oldworld.sjsu.edu/ancientrome/emperor/nero/gossip.html

From the Bryn Mawr Classical Review:
"...Poppaea's violent death at the hands of Nero [kicked in the
stomach when she was seven months pregnant"
http://ccat.sas.upenn.edu/bmcr/1999/1999-03-03.html

From Porter Gaud School:
"Poppaea after bearing Nero a daughter who survived for only four
months became pregnant again.  This time Nero kicked her to death in a
temper tantrum."
http://www.portergaud.edu/cmcarver/jcii.html

From the Catholic Encylopedia:
"Poppaea too, who had been brutally kicked by her husband, died, with
her unborn child soon after."
http://www.newadvent.org/cathen/10752c.htm

From Microsoft Encarta:
"Poppaea was kicked to death by Nero"
http://www.bible-history.com/nero/NEROMicrosoft_Encarta_Online_Encyclo.htm

From TheFreeDictionary.com:
"Poppaea Sabina...
It is said that while she was awaiting the birth of her second child,
Nero flew into in a fit of rage and kicked her in the abdomen, so
causing her death."
http://encyclopedia.thefreedictionary.com/Poppaea

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search terms:
nero poppaea kicked 

I hope this helps.

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