One woman goes down an elevator, then three women go down a different elevator.
A reviewer pointed out that the only important woman in the series who is conspicuously absent from an episode about women is Trudy (even Jane and Carla are name-checked). Trudy, who is pregnant.
Joyce is a lesbian and is unlikely to have children (not in those days). Let’s look at the other elevator:
Joan has had two abortions, wants to get pregnant, but her husband isn’t available to her. Peggy has given up a child for adoption and has since then been very careful indeed about birth control. Faye spends the entire episode proving she has no maternal instinct whatsoever, and fiercely defends her choice.
Ironically, Joan is pregnant in this shot, as we will learn in the next episode. Ultimately, she’ll decide not to have a third abortion. By Tomorrowland, Joan will have chosen motherhood, and Don will have rejected the woman unable to mother his children. (Even without all the visual framing of Megan with the kids, Don fell in love with her while she was working, not as his secretary, but as his nanny.)
But at this moment, in The Beautiful Girls, a theme of the episode is “not a mother.” A complicated theme for women, even today.