Samantha Blackwell was working her way through a master's degree at Cleveland State University when she found out she was pregnant.

"I was 25, in really good health. I had been an athlete all my life. I threw shot put for my college, so I was in my prime," she says with a laugh.

Though it wasn't planned, Blackwell's pregnancy was embraced by her large and loving family and her boyfriend, who would soon become her husband. Her labor was quick, and she gave birth to a healthy baby boy.

Yet just days after she was discharged, Blackwell was back in the hospital, in a medically induced coma, fighting a runaway infection that left her hovering between life and death.

"It was like 'I fell asleep at that hospital and woke up the next day' kind of thing," she says. She was in a coma for more than a month.

Blackwell's story of reaching the brink of death is one that happens much too often, say researchers.

Over the past year, NPR and ProPublica have been investigating why American mothers die in childbirth at a far higher rate than in all other developed countries.

A mother giving birth in the U.S. is about three times as likely to die as a mother in Britain and Canada.

In the course of our reporting, another disturbing statistic emerged: For every American woman who dies from childbirth, 70 nearly die. That adds up to more than 50,000 women who suffer "severe maternal morbidity" from childbirth each year, according to the Centers for Disease Control and Prevention. A patient safety group, the Alliance for Innovation on Maternal Health, came up with an even higher figure. After conducting an in-depth study of devastating complications in hospitals in four states, it put the nationwide number at around 80,000.

"It's referred to as the tip of the iceberg because for every woman we lose, there are lots of other women that we come very close to losing," says obstetrician Peter Bernstein, the director of the Maternal-Fetal Medicine division at Montefiore Medical Center in New York.

But surviving can come with a cost.

"An experience that we would hope and expect would be natural, beautiful, uplifting, becomes one that's terrifying," Bernstein says. "Women can wind up losing their uterus and therefore becoming infertile. They can wind up with kidney problems. They can have heart attacks. They can have brain damage from all the blood that they've lost."

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And that is just a partial list of what can go wrong. Also on that list: Women develop pregnancy-induced high blood pressure known as pre-eclampsia, which can lead to a stroke and organ failure; parts of the placenta can be left behind, which can lead to infection; and a woman giving birth is more prone to blood clots that can be life-threatening.

The cost, though, is not just medical. The treatment for these complications can become an ongoing financial burden, and the trauma suffered from physical complications can lead to persistent emotional and psychological pain.

It is still rare for childbirth to involve truly severe complications, but in the U.S., say researchers, many of these worst-case scenarios need not have happened at all.

Samantha Blackwell doesn't remember much about her ordeal. It began 11 days after giving birth, when she sat up in bed with a terrible pain. By the time she got to the emergency room, her medical records show, she was in septic shock from a massive infection. For weeks, her doctors couldn't promise her family that she would live.

"They just knew that it was bad," she says, "to a point of 'expect the worst. We don't know if she's going to come out of this.' "

When Blackwell did emerge from her coma, she discovered she had undergone an emergency hysterectomy, a last-ditch effort to stop the infection that had originated in her uterus.

"I don't think I'm the type to overreact"

In the U.S., the rate of severe complications from childbirth has been rising faster than the rate of women who died. The rate of women nearly dying almost tripled between 1993 and 2014, according to the CDC. To help explain those dire statistics, experts point to risk factors that have increased in recent years: American women are giving birth at older ages and are more likely to have problematic conditions like obesity, high blood pressure and diabetes.

Early in our reporting, NPR and ProPublica launched an online call-out asking for stories of deaths and near deaths due to childbirth, and the tales of catastrophic complications and deaths poured in, ultimately more than 5,000 in all.

Alicia Nichols was among the thousands who wrote about their own experience. At 39, she and her husband had been trying hard to have a baby. She finally succeeded in getting pregnant through in vitro fertilization and gave birth in March 2017, just after she turned 40.

At her home outside of Boston, in a spacious, airy room strewn with baby toys, Nichols spoke of an easy pregnancy. It was how many stories we heard began. The birth, though, was different: a painful 42 hours of labor, until the baby's "failure to descend" led to an emergency cesarean section.

Then, after healing well for four weeks, she was surprised to feel a gush of blood.

"I was rocking Diana in my rocking chair here in the living room, and when I stood up, blood [had] soaked through me onto the chair," she says.

Her first reaction was to call an ambulance. "I don't think I'm the type to overreact. It was just so foreign to me," she says.

In the emergency room, the obstetrics resident who came over quickly chalked it up to natural postpartum bleeding, something that didn't merit the ultrasound Nichols was requesting.

"I felt that she was just dismissing me, annoyed, a new mother being paranoid of some blood. I felt like she was not listening at all," Nichols says.

Throughout our NPR/ProPublica investigation, we heard many variations on the perception by postpartum mothers that their physical concerns were not taken seriously. In Nichols' case, she was familiar with a medical environment. She worked as an aesthetician and office administrator for a plastic surgeon in the same building as her obstetrician.

In the weeks following her first scare, her obstetrician assured Nichols — in both an office visit and on phone calls — that the episodes of bleeding were most likely the beginning of her menstrual period.

For her part, Nichols pointed out to her doctor that she had never experienced a period like that.

"I had no cramping," she says. "It was just bright red blood. And, we all know, we're women. I don't want to be graphic, but we know it's different."

"Denial and delay"

It was before dawn two months after giving birth, that Nichols — up with baby Diana — had another episode of sudden bleeding.

By chance, her own doctor was on call that early morning and picked up the phone. She remembers him saying, "You're going to be fine. Check back later in the day if this continues."

Instead, she went to his office right after it opened.

"I got on the elevator, and the minute the elevator door opened, that's when I began to hemorrhage," she says.

The obstetrician immediately called an ambulance, but Nichols was already in the midst of a life-threatening emergency.

"I remember putting my hand down, and when I lifted up my hand, it was just, my whole left hand. I remember seeing my wedding ring, just blood. My left hand was soaked with blood," she says.

According to her medical records, Nichols lost nearly half the blood in her body.

As a last resort — as in the case of Samantha Blackwell in Cleveland — Nichols' doctors in Boston performed an emergency hysterectomy.

In an addendum attached to Nichols' records 24 hours later, her obstetrician stuck with his original theory about her bouts of bleeding. He wrote "patient came to office with onset of first period that seemed heavier than average," and she "suddenly hemorrhaged."

Though NPR received written permission for Nichols' obstetrician to share details of her case, he declined to be interviewed for this story.

But a pathology report included in her records found an entirely different cause for Nichols' on-and-off bleeding. The pathologist's diagnosis was placental site vessel subinvolution, or VSI.

That essentially means that the enlarged blood vessels in the lining of the uterus, which had sent nutrition and oxygen to the developing fetus, had failed to return to their pre-pregnancy state. They stayed enlarged and intermittently bled into Nichols' uterus.

Though rare, VSI can be detected early with a scan and treated before leading to a life-threatening hemorrhage.

Obstetrician Elliott Main, a national leader in the movement to reform maternal health care, says that because most mothers do well during and after pregnancy, obstetricians and nurses strongly tend to expect the best and often are not prepared for the worst.

"That sets up the opportunity for what we call the twin demons of denial and delay. Denial that it's actually something serious," says Main, "leading to delay before you get the care that's going to make the difference."

Indeed, NPR and ProPublica found a medical system that bases care on the idea that it's rare for a woman to die in childbirth. It's a system in which funding and resources are dedicated mostly at saving babies.

The price tag of life-threatening complications

Severe complications due to childbirth are not common in the U.S., where nearly 4 million babies are born each year.

Yet bringing down the rate of these complications would not only spare tens of thousands of mothers from nearly dying, but it would also bring down the cost of health care, points out obstetrician Barbara Levy. She oversees health policy at the American College of Obstetricians and Gynecologists.

"Severe morbidity is expensive. ICU care is expensive. Transfusions are expensive. Dialysis is expensive," she says. "We can actually save money by putting processes in place that reduce risk."

The cost of Samantha Blackwell's long hospital stay, rehabilitation and home care soared to nearly $540,000.

Because she was younger than 26, she was covered by her mother's insurance, which paid for most of that.

But the experience was still financially devastating.

Blackwell couldn't return to her job at Men's Wearhouse for months. Her husband, DeVon, spent so much time at the hospital that he lost his job at a car dealership. And Samantha Blackwell's mother never left her bedside. Cynthia Murphy is still thankful that the K-Mart distribution center where she worked gave her a two-month leave, even though it was unpaid.

"I would have moved from my house, lived on the street. I really would not have cared at that time," Murphy says. "Samantha was my No. 1 priority."

Alicia Nichols, whose hemorrhage led to an emergency hysterectomy, measures her financial burden by what she estimates it would take to have another baby via surrogate: at least $80,000.

No single study has tallied the total cost of America's high rate of severe complications. But there are clues that it runs into the billions. A report in the American Journal of Obstetrics and Gynecology found the cost of caring for mothers suffering from pre-eclampsia is more than a billion dollars each year.

And the federal Agency for Healthcare Research and Quality put a dollar figure on the average cost of a hysterectomy related to childbirth complications: In 2014, it was more than $95,000.

"I was just a wreck"

And then, of course, there is the human cost.

"I have a lot of anger. I do. I know that my obstetrician feels terrible that things went this way, but it just makes me so angry," says Alicia Nichols, "because I know I'm not the only one. There are so many women out there."

In Nichols' case, her troubles did not end with the massive hemorrhage. Just days later, while she and her baby were resting at her parents' home in Cape Cod, Nichols began feeling dizzy.

And this time, at a local hospital, the doctor paid close attention to her complaint.

"He knew my history, and he said something's not adding up," she recalls.

The results of a test that helps identify the presence of blot clots worried this new doctor enough to call for a CT scan, which proved his suspicion.

"He came back, and he's like, 'I'm sorry, you're not going home, you have multiple pulmonary emboli in both your right and left branches,' " she says.

Nichols remembers her shock at looking at the scan: "It was like someone splattered paint into my lungs."

Six days later, Nichols left the hospital with an anti-clotting drug, and a new fear: anticoagulants come with a risk of bleeding, leading her to imagine a nightmare scenario in which she hemorrhaged again.

"So I was just a wreck at that point," says Nichols, who is now being treated for post-traumatic stress disorder.

"It's funny, I remember speaking with the critical care pulmonologist, and I was sort of having a pity party and was just devastated," she says. "I said I'm so unlucky. And he said, 'No, you should go buy a lottery ticket, because you shouldn't be alive right now.' "

It is a common theme among the thousands of women we've heard from: Their trauma, both physical and emotional, is hard to shake and impossible to forget.

And that anxiety radiates out to the families who also survived a terrible time.

Two full years after Samantha Blackwell's son was born, she spoke of how she is continually reminded of the high fever from the raging infection that nearly killed her. That reminder comes from her mother, who nearly lost a daughter.

"My mom, I make fun of her, because she checks my temperature with her hand," says Blackwell. "Every time she hugs me goodbye, her hand is on my forehead."

ProPublica's Nina Martin and NPR's Meg Anderson contributed to this report.

Copyright NPR 2019.