This past summer I began to worry that I was going to die prematurely and leave my four children motherless. There, I’ve said it: These are anxious and narcissistic fantasies even by Upper West Side standards.

I’m not exactly sure what triggered this fear. I’m hardly the type to angst over weighty issues such as life and death. And even so, I asked myself, why this worry? I rarely even catch a cold.

Was it something as practical as realizing I hadn’t been for a physical exam in five years? Was it because my friend —a mother with three young children — was the latest of my acquaintances to be diagnosed with breast cancer in the course of a year? Was it the tragic story of an Upper East Side mother who died of a virulent cancer only a month after she noticed bruises on her body while swimming with her two sons?

I don’t know.

But in quiet moments I found myself wondering how my children would fare without me. Would my eldest — restrained and reserved as first-borns tend to be — be coaxed into talking about his feelings? Would my second child, stormy and creative, be able to manage the tides of emotion? Would my younger children understand what had happened?

What surprised me most about this line of thought was that when I finally confided my feelings in a friend, another mother of four young children, she told me that she, too, spends more time than she would like worrying about the exact same thing.

“I never worry about it when I’m around my kids, of course,” she said. “When I’m with them I’m in control, even invincible. But when they’re safely tucked into their beds and out of sight, all my inner demons come out and I think of all the ways I might be dying without knowing it. I know my mind is just playing tricks, but please, please, please, just let me live long enough to raise my kids.”

It turns out that almost every mother I spoke with has the same fear of leaving her children motherless, and her own fantasies about how she might die, or might actually be dying as this very moment. “You know when you’re driving behind a truck that has all those metal beams piled up,” a mother of three said. “I’m always convinced that one of them is going to fall off the truck and somehow decapitate me. I know, it’s absurd.”

“I’m convinced I’m dying of ovarian cancer,” another mother said. “Anytime I gain a pound or two around my middle, it’s not the dinners out or glasses of wine or crème brûlée. It’s ovarian cancer.”

Interestingly, though, not a single mother mentioned the fear of dying in relation to her own life being cut short. All the fantasies were related to how her death would impact her children — and her husband.

“My husband would be remarried in two seconds,” one woman told me. “I always tell him, go for sweet and pretty. As long as she’s kind to the kids, she can be as tall and thin and gorgeous as he wants.”

Happily married middle-age widowers typically remarry very quickly. Some studies indicate that the median amount of time is less than 2 years, which is why a woman jumping from fantasizing about her premature death to her husband’s remarriage is hardly unreasonable.

“For me the worst part of the fear of dying and leaving my children involves this new woman who can’t possibly see, let along bring out, the best in my children,” the mother of four said. “Maybe this is politically incorrect, but I just think it’s worse for children if their mothers die, than if their fathers die. Mothers kiss boo-boos and give hugs and pick up kids from school and cook favorite meals. It must be terrible to have your mother die when you’re 6 or 8 or 13 years old.”

“But then, on top of that, to have to deal with a stepmother?,” she added. “You know, they’re not a nightmare in every Disney movie for no reason.”

I know plenty of people who have wonderful relationships with their stepparents, those they gained after a parent’s divorce or death. But of course, it’s the nefarious activities of the cool and aloof stepparents that stand out in my mind.

“My stepmother definitely liked her own kids better,” an acquaintance told me about her experience after her mother died and her father remarried. “She tried really hard to make things appear equal, but is that really possible? She made our house a happy one, though. And she made my father happy.”

Once I knew that so many mothers around me were also worrying about what would happen if they kicked the bucket, I felt much better. I was also reassured after I had the long-overdue checkup.

“You’re the picture of health,” the doctor told me. Fixations, phobias, and neuroses apparently included.