Over the next week, the nausea hits her most mornings, like a flash. It stays for 10 or at most 15 minutes them its gone again.
Sometimes she vomits but mostly she just feels wretched, like she's going to hurl her stomach contents across the beach even if she doesn't.
Most days she goes into the jungle in the mornings to pick fruit. What Jack doesn't know can't hurt him she reasons.
Jack doesn't understand that she doesn't want this child, never wanted it, and to lose it would be a blessing and that would be best done alone, in the deep reaches of the jungle.
If she keeps throwing up at the beach sooner or later everyone else will guess what Jack already knows. She doesn't want them to know, because then inevitably there will be speculation and questions.
Jack feels like his world has tilted on its axis, and he can't find a firm foothold anymore.
Kate isn't his girlfriend or wife, or anything official to him.
And yet it feels like she is somehow his everything,though he's not willing to admit this publicly or even to himself.
Her being pregnant should be nothing to him personally, and only of interest on a professional level.
Yet he is so far from feeling impersonal about her situation it's not even funny.
He keeps checking in on her every couple of days when he's down at the beach.
He knows that she's started to avoid him if she can, because they're both playing a waiting game which neither of them are winning.
She hasn't given him the news he wants to hear over the past week, by telling him that she's not pregnant and it feels tortuous to both of them that they still don't know for sure, but every day that passes with her continuing to be not not pregnant feels a step closer to certainty that she is.
He always gives her an opening to let him know if it happens,by asking how she is.
But it's only bad news with more nausea and vomiting, and still no period.
Jack can't help but be snappier than usual with Sawyer.
Just looking at him he can feel himself grow angry.
This situation is further evidence Sawyer is purely motivated by his own selfish impulses - mainly in his pants. He's not going to have to deal with any of the consequences of his actions like Kate does.
Hell he himself will have to deal with the consequences of this himself, if he has to oversee another delivery on the island with no medical equipment or hospital.
And Kate - Kate isn't like Claire. Kate is smaller hipped and delicate and the birth is likely to be more difficult than Claire's straightforward delivery. She could even die, because that was a common outcome from childbirth going back a hundred years when they had the same level of care she'll be getting on this island.
One day he arrives down at the beach to see everyone building a new shelter.
Kate is hauling a heavy log and when he sees this it scares him.
Jack grabs it off her in a hurry.
"It's too heavy for you," he scolds.
"I was doing ok," Kate protests.
"Kate. No," Jack snaps back. "I've got it. Go do something else."
It's an order from Jack, not a discussion.
Kate looks annoyed, but the last thing she wants is a scene in front of people where they argue over this.
Sawyer is watching this whole situation from a few feet away, mildly bemused while he mutters something about Jack always having to be the hero.
Jack glares at him for the comment. "You of all people should know that was too heavy for her," he snaps at him, angrily.
Sawyer looks back at him, confusion all over his face. "She's stronger than she looks. And the log wasn't that heavy," he offers.
Jack watches him for a moment, and it clicks that Sawyer doesn't know.
He knows that who the father is is none of his business, and he keeps the situation as professional as he can with Kate over the next couple of days.
But one evening she's back at the caves and he's tired from treating too many patients, he's not thinking as straight as usual, and he just wants some clarity, because he needs to know.
Kate's packing up water she and Sayid will take back to the beach.
Jack looks at the two backpacks sitting in front of him and takes the opportunity to switch a water bottle out of Kate's and into Sayid's when she's not looking.
When Kate's doing up her backpack straps, he's still mulling over the whole situation in his head.
Jack uncharacteristically opens his mouth without thinking.
"Are you gonna tell Sawyer about being pregnant?"
Kate meets his eyes briefly then turns away from him, and her posture radiates pure tension.
There is a long pause before she replies.
Her voice sounds so muted, and strangled, he strains to hear.
"It's not Sawyers."
Jack stares at her, confused.
He wants to ask her the next most obvious question, then who?
But Kate's already moving off and away from him, while he's left behind trying to unpick another of Kate's many secrets.