Kelly Wallace is CNN's digital correspondent and editor-at-large covering family, career and life. Read her other columns, and follow her reports at CNN Parents and on Twitter. Join Christy Turlington Burns at 2 p.m. ET Friday for a Facebook chat about " Giving Birth in America ."

(CNN) It's hard to comprehend how the United States, one of the wealthiest nations in the world, is now one of only eight countries -- including Afghanistan and South Sudan -- where the number of women dying as a result of pregnancy and childbirth is going up.

An increasing mortality rate for American mothers in 2015? How could that be?

First, the numbers: More than 25 years ago, in 1987, there were 7.2 deaths of mothers per 100,000 live births in the United States, according to the Centers for Disease Control and Prevention. In 2011, that number more than doubled, jumping to 17.8 deaths per 100,000 births.

What's going on? A range of experts made clear to me that there isn't any one factor to explain the increase, but a number of issues, including obesity-related complications such as hypertension and diabetes, the dramatic increase in the number of cesarean section births, a lack of access to affordable, quality health care and more women giving birth at older ages.

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"There were changes like this over time and this is why we believe that part of this increase is due to better methods of identification," she said.

But we don't know how much of the increase is due to better reporting methods, said Creanga. What we do know is there are still other factors that are likely pushing up the number of deaths during pregnancy and childbirth in the United States.

Obesity a 'tremendous piece' of the problem

Elise Turner , an associate professor of nursing at Mississippi's Belhaven University and a nurse midwife who has more than 35 years experience, says obesity is a "tremendous piece" of the problem.

"The body is already stressed by obesity and the other accompanying diseases, such as hypertension, diabetes and things that accompany that and then you put the demands of pregnancy on top of that and it's just very difficult," Turner said.

Obesity is one of the leading causes of mortality in the OB/GYN field, said Dr. Michael Brodman , chairman of the department of obstetrics, gynecology and reproductive science at the Mount Sinai Health System in New York.

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"We didn't specifically have protocols for dealing with obese patients. We didn't treat them differently and in reality, you have to treat them differently," said Brodman.

About two years ago, Brodman and about 50 other leaders in the OB/GYN profession came together after it was revealed that New York had one of the worst maternal mortality rates in the country. At first, the thinking was that New York, with one of the most diverse populations of any state, has more complicated patients than most other states and that explains the higher death rate for mothers during pregnancy and childbirth.

But as Brodman and his colleagues started meeting, they discovered a bigger issue: the wide range of health care offered at hospitals across the country.

"If you're in Sweden, everybody gets treated the same way. If you are in New York City, you get treated one way. If you're in Buffalo, you get treated another way and if you're in Missouri, you get treated another way," said Brodman. "This is that sort of U.S. individualistic kind of thing, 'I know what I'm doing. This is how I'll do it.' In health care, at the end of the day, that doesn't work."

So now, through programs such as the American Congress of Obstetrics and Gynecologists' Safe Mother Initiative , and the National Partnership of Maternal Safety , doctors are coming up with standardized care for pregnancy and childbirth complications where every hospital would follow the same protocols for dealing with issues such as a postpartum hemorrhage, which can result in death.

For instance, in New York, they've created hemorrhage teams and have done hemorrhage drills so "every little, big, medium-size hospital will all have the same protocol," said Brodman.

While different training and different procedures at hospitals account for some of the variations in care, medical egos are a big part of the problem too, he said.

In the United States, Brodman said, there's thinking such as, " 'No one tells me to wear a helmet when I'm riding my motorcycle. I am allowed to do what I want,' that kind of mentality. Well, doctors have that, too, and in reality, it doesn't work in health care."

Standardized guidelines are needed across every state and they have to be rigid, he said. "We can't allow for individuality because of whatever crazy reason people come up with," he said.

Improving care for pregnant women

African-American women are more than three times as likely to die as a result of pregnancy and childbirth than white women in the United States, according to the CDC.

"We know that black women dying from pregnancy-related causes are younger, less educated, more likely to be unmarried, more likely to start prenatal care in the second (or) third trimester of pregnancy or not at all, when compared to white women, but except for that, we don't know a lot," said Creanga of the CDC.

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Medical and nonmedical factors, such as poverty and insurance coverage, need to be considered as part of the research to figure out the reasons for this disturbing trend, she said.

There is no question that lack of access to affordable and good quality care is playing a role in the overall increasing maternal mortality rate, said Turner, the associate professor of nursing.

If a pregnant woman wakes up in the middle of the night with contractions at 28 weeks and isn't sure if she's in labor, she needs to go to the hospital, Turner said. No one can determine that over the phone. But even if you have private insurance, "You're still going to have a whopping co-pay for that hospital visit just to make sure you weren't really in preterm labor," she said. "So I know that people hesitate to seek care because there is an out-of-pocket expense every time you engage with the health care system."

Another factor likely contributing to the upward trend, experts say, is the dramatic increase in C-sections in the United States. Today, about one in three American mothers has a C-section. That's up from one in five 20 years ago.

"We, as providers, know that surgery carries more risk for mother and baby, " said Turner. She said the decision over whether to perform a C-section is a very difficult one for providers. "It's such a delicate balance to find that perfect razor's edge of the most benefit with the least risk and for some patients, there is risk in continuing to labor for the mom and for the baby."

Brodman of Mount Sinai Hospital also blames the climb in C-sections on the widespread fear among doctors of being sued. He believes those fears have come down in recent years based on changes in malpractice laws and a new generation of doctors who go into the OB/GYN profession knowing that being sued is part of the medical landscape.

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"People are not sitting on the labor floor thinking, 'If I make the wrong decision, I'm going to get sued,' so all of that hysteria and paranoia, I think, is abated, which is a good thing," he added.

In fact, the C-section rate dropped to 32.2% in 2014, down from a peak of 32.9% in 2009, according to the CDC.

"I hope in the last year or two, we've plateaued and now we're going to start seeing a trend downward," Brodman said. "How low it goes, that will remain to be seen."

The age of the mother may also play a role in the climbing maternal mortality rate, as American women have delayed childbearing.

While less than 15% of all births in the United States are to women 35 years and older, somewhere between 27% and 29% of all the pregnancy-related deaths are among that age group, according to the CDC's Creanga.

"Because women are delaying childbearing, a larger proportion of them are likely entering pregnancy with a burden of chronic disease conditions," she said. "Many studies have shown that an increasing number of pregnant women in the United States have chronic health conditions such as hypertension, diabetes, chronic heart disease and all these conditions can put a pregnant woman at higher risk of pregnancy complications."

What's the solution?

More access to more affordable and better quality care is one way to bring the maternal mortality rate down in the United States, said Turner.

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"We need to have quick, easy, 24/7 access to a skilled person that's not burdensome, that's not expensive, that's not difficult, that you don't have to drive an hour and a half to get to," she said.

More states implementing evidence-based guidelines and recommended practices for dealing with pregnancy and childbirth complications across every hospital in the state would also help bring the number of deaths down, said Creanga of the CDC.

These guidelines, which try to address the most preventable causes of maternal mortality, have been shown to decrease maternal mortality in other parts of the world, such as the United Kingdom, and will hopefully bring the U.S. rate down, too, she said.

Brodman of Mount Sinai Health System agreed. "We need to figure out the best way to do something and everybody should do it that way," he said.