This is not the first time Trump has questioned a woman's appearance.
In the primary, Trump attacked rival Republican presidential hopeful Carly Fiorina on her looks.
"Look at that face! Would anyone vote for that?" Trump said in an interview with Rolling Stonein 2015. "Can you imagine that, the face of our next president."
RELATED: See photos of Carly Fiorina
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WAUKEE, IA - APRIL 25: Former business executive Carly Fiorina speaks to guests gathered at the Point of Grace Church for the Iowa Faith and Freedom Coalition 2015 Spring Kickoff on April 25, 2015 in Waukee, Iowa. The Iowa Faith & Freedom Coalition, a conservative Christian organization, hosted 9 potential contenders for the 2016 Republican presidential nominations at the event. (Photo by Scott Olson/Getty Images)
TIFFIN, IA - APRIL 24: Former business executive Carly Fiorina (L) poses for a selfie with Ashlynn Dale at the Johnson County Republicans Spaghetti Dinner at Clear Creek Amana High School on April 24, 2015 in Tiffin, Iowa. Fiorina is considered a potential contender for the 2016 Republican presidential nomination. (Photo by Scott Olson/Getty Images)
Chair of the American Conservative Union Foundation Carly Fiorina speaks about the 'War on Women' on Capitol Hill in Washington, DC, March 16, 2015. AFP PHOTO/JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images)
WASHINGTON, DC - MARCH 16: Chair of the American Conservative Union Foundation Carly Fiorina speaks speaks during a forum on Capitol Hill March 16, 2015 in Washington, DC. Ms. Fiorina spoke about what she calls the War on Women in politics. (Photo by Mark Wilson/Getty Images)
WASHINGTON, DC - DECEMBER 18: Carly Fiorina, former CEO of the Hewlett-Packard Company, speaks at the Heritage Foundation December 18, 2014 in Washington, DC. Fiorina joined a panel discussion on the topic of 'And Now for a Congressional Growth Agenda'.
(Photo by Win McNamee/Getty Images)
IRVINE, CA - NOVEMBER 03: Republican candidate for U.S. Senate and former head of Hewlett-Packard Carly Fiorina kisses daughter of Kristin Vellandi, Coalitions Director of the Carly for California campaign, Raquell Vellandi, 9, after she conceded defeat to her rival Sen. Barbara Boxer (D-CA) during news conference at her Irvine campaign headquarters on November 3, 2010 in Irvine, California. Boxer, the democratic incumbent was re-elected to her senate seat and California's attorney general, Jerry Brown was elected Californiaï¿½s governor replacing Arnold Schwarzenegger. (Photo by Kevork Djansezian/Getty Images)
Former Hewlett Packard CEO, California Republican candidate for US Senate Carly Fiorina answers a question as she debates US Senator Barbara Boxer, D-CA, who is in the NPR studio in Washington DC, at the Mohn Broadcast Center in Pasadena on September 29, 2010. AFP PHOTO / Pool / Anne Cusack (Photo credit should read ANNE CUSACK/AFP/Getty Images)
GARDEN GROVE, CA - NOVEMBER 4: Former Hewlett-Packard chief executive officer Carly Fiorina announces to the media her candidacy for U.S. Senate at Earth Friendly Products on November 4, 2009 in Garden Grove, California. Fiorina will face off against Assemblyman Chuck DeVore (R-Irvine) for the Republican nomination and if won, challenge Democratic incumbent Barbara Boxer. Fiorina battled a nine-month bout with breast cancer and lost her hair during chemotherapy treatment. (Photo by Michal Czerwonka/Getty Images)
SAN FRANCISCO - DECEMBER 6: Hewlett-Packard CEO Carly Fiorina delivers a keynote address at the 2004 Oracle OpenWorld Conference on December 6, 2004 in San Francisco. The annual technology conference runs through Thursday December 9, 2004. (Photo by Justin Sullivan/Getty Images)
LAS VEGAS - JANUARY 7: (L-R) HP CEO Carly Fiorina takes a photo with musician Gwen Stefani during Fiorina's keynote address at the 2005 Consumer Electronics Show January 7, 2005 in Las Vegas, Nevada. The 1.5 million square foot electornic gadget show runs through January 9 and is expected to attract over 120,000 attendees. (Photo by Justin Sullivan/Getty Images)
(FILES) This file photo shows Hewlett-Packard CEO Carly Fiorina (L) and Compaq CEO Michael Capellas (R) answering questions during a press conference announcing the merger of their companies 04 September 2001 in New York. The combined US 87 billion USD merger is in doubt after the David and Lucile Packard Foundation, the biggest share holder of Hwelett-Packard stock, voiced its opposition to the union. AFP PHOTO/Doug KANTER (Photo credit should read DOUG KANTER/AFP/Getty Images)
LAS VEGAS, NV - NOVEMBER 18: Carly Fiorina, Chairman and CEO of Hewlett-Packard, talks about HP technology in outer space with NASA during her keynote address at the COMDEX Fall 2002 computer technology trade show November 18, 2002 in Las Vegas, Nevada. COMDEX, one of the largest conventions of it kind, is in its 23rd year. (Photo by David McNew/Getty Images)
TAIPEI, TAIWAN - JUNE 12: Carly Fiorina, president and chief executive officer of Hewlett-Packard, speaks on 'Invent/Reinvent: Strategic Imperatives for the Internet Era' following the opening of the three-day World Congress on Information Technology in Taipei 12 June, 2000. The forum draws some 15,000 IT company executives from worldwide incuding Microsoft head Bill Gates. AFP PHOTO (Photo credit should read STEVEN WANG/AFP/Getty Images)
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After the death of former first lady Nancy Reagan in March, media organizations dredged up disparaging remarks Trump had made about her in 2004, when he said, "She was never very beautiful."
Trump has also gotten into spats with female journalists, including Fox News' Megyn Kelly, whom he suggested was menstruating when she launched into a tough line of questioning against Trump during a primary debate.
Polling shows Trump at a steep deficit among women voters — a crucial voting bloc he needs to perform better with if he wants a shot at the White House in November.