<P> In the fall of 1960, Peggy rips her skirt trying to pick something up off the floor . Soon afterward, she begins wearing oversize suits and baggy dress - and - jacket outfits, and she gains weight (Elisabeth Moss wore increasingly bigger padding and had makeup artists apply prosthetics to make her face and neck appear bigger.) Account executive Ken Cosgrove jokes to his male co-workers that Peggy looks like a lobster, because all her "meat" is in her "tail". Despite having coldly ended a brief affair with Peggy, Pete reacts strongly to Ken's remark and punches him in the face . </P> <P> Office manager Joan Holloway makes snide remarks to Peggy about her weight gain, joking that she will remain a virgin because of her appearance . Peggy calls Joan out on her condescending attitude, and states that she is not, in fact, a virgin . Joan is surprised to learn that Peggy is genuinely interested in copywriting, having believed she was using her opportunity on Belle Jolie to get close to Paul Kinsey . </P> <P> At the end of Season 1, which takes place just before Thanksgiving 1960, Peggy is promoted to Junior Copywriter, heading up the new Clearasil account . Just after receiving the promotion, Peggy begins experiencing severe abdominal pain; she attributes it to a "bad sandwich" from the office cart and heads to St. Mary's Hospital in Brooklyn . She is shocked and in denial when informed she's actually in labor . As she gets up to leave, she collapses, and the hospital staff moves her into a hospital room in labor and delivery . She gives birth to a healthy baby boy, whom she refuses to hold or look at . </P> <P> Season 2 begins 15 months later, on February 14, 1962, with a slim Peggy and no mention of the birth . Her long absence (not shown) is a mystery to Sterling Cooper's employees . One co-worker jokes during a meeting that "Draper knocked her up and she's dropped nine pounds, eight ounces ." Pete has heard through office gossip that Peggy went to a fat farm . </P>

In which episode does peggy have her baby