What to Expect When You're Expecting is a pregnancy guide, now in its fifth edition, authored by Heidi Murkoff and Sharon Mazel and published by Workman Publishing. Its first edition, authored by Murkoff, Arlene Eisenberg, and Sandee Hathaway, was originally published in 1984. The book consistently tops The New York Times Best Seller list in the paperback advice category, is one of USA Todays "25 Most Influential Books" of the past 25 years and has been described as "the bible of American pregnancy". , per the publisher and the author's agent, over 22 million copies were in print in . According to USA Today, 93 percent of all expectant mothers who read a pregnancy guide read What to Expect When You're Expecting. In 2005, WhatToExpect.com launched. The What to Expect mobile app launched on iOS in 2009 and Android in 2014. In 2012, What to Expect When You're Expecting was adapted into a film released by Lionsgate. History Author Heidi Murkoff cites her own quest for reassuring information during her first pregnancy as being the motivation for developing What to Expect When You're Expecting. Murkoff collaborated with her mother Arlene Eisenberg, a freelance journalist, and her sister Sandee Hathway, a nurse, when writing the first three editions of the pregnancy guide. Its iconic title emerged when an employee of the publisher suggested it as a subtitle for the temporarily titled manuscript, "Pregnancy:" By publication, the subtitle had claimed the top spot. Although the book's initial print run was small, word of mouth and innovative promotion led to sales that increased in every subsequent year. What to Expect books What to Expect When You’re Expecting The book presents advice in a question-and-answer format. It proceeds chronologically from the time a woman first begins to suspect pregnancy, through each of the nine months (with one chapter devoted to each), and into the postpartum period. The beginning of each chapter includes a section called “Your Body This Month,” which succinctly lists common physical and emotional changes and symptoms a woman may be experiencing, and gives information on what a woman can expect when visiting her doctor or nurse midwife during checkups. Also included early in each chapter is a section entitled "Your Baby This Month" which displays pictures of the growing embryo then fetus. An additional section titled "What You May Be Concerned About" is designed to address a wide range of concerns,