You do have to read this story pretty carefully to pick up the central theme of abortion and how it is presented. Hemmingway seems to focus on this theme and how terrible it is by actually only including very oblique references to it, so we have to read between the lines to identify what is being talked about. Have you every had a conversation with somebody when the most important thing you need to discuss, is actually never referred to or only referred to in passing? In a sense, this only serves to emphasise the importance of the topic, as the silence and avoidance only highlights its power and strength. Hemmingway uses this strategy in this short story.
Let us consider what references there are to abortion. It is, of course, the man who brings up the first reference to abortion. After making some small talk about the coolness of the beer, he finally can restrain himself no longer, and says:
"It's really an awfully simple operation, Jig," the man said. "It's not really an operation at all."
He doesn't seem to pick up the body language of Jig, who obviously doesn't want to talk about it, and looks at the ground, to avoid his gaze. So he continues:
"I know you wouldn't mind it, Jig. It's really not anything. It's just to let the air in."
The girl did not say anything.
"I'll go with you and I'll stay with you all the time. They just let the air in and then it's all perfectly natural."
This is actually the last reference directly to the medical prodecure, though of course the rest of this short story is dominated by it, as Jig seeks to learn what will be the impact on their relationship and bows to the inevitable dominion of her partner. Key to considering how the theme of abortion is presented is how it is linked with the theme of power. The man deliberately presents abortion in a way that minimises how invasive and destructive the procedure is, and the way that he keeps coming back to the topic, even when Jig does not want him to, indicates his manipulation and determination to ensure that Jig has this operation.