For every five mothers dying in the United States from pregnancy and childbirth, three could have been saved if they had received better medical care, the federal Centers for Disease Control and Prevention said in a report published Tuesday.

The report details how mothers are dying needlessly before, during and up to a year after giving birth from pregnancy-related complications and health conditions aggravated by childbirth.

The agency's latest analysis of national maternal mortality data adds to the growing body of evidence that more than half of deaths are preventable. And it further illustrates how delayed and missed diagnoses by medical providers, failures to recognize warning signs, and a lack of patient access to healthcare are all fueling this country's status as the most dangerous place to give birth among developed nations.

The CDC's analysis also confirms "persistent racial disparities" in the risks faced by black women and American Indian/Alaska Native women, who are about three times as likely to die from pregnancy and childbirth than white women.

"Most deaths were preventable, regardless of race or ethnicity," the CDC found.

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"Our new analysis underscores the need for access to quality services, risk awareness, and early diagnosis, but it also highlights opportunities for preventing future pregnancy-related deaths," said Wanda Barfield, director of the CDC's reproductive health division.

Every year more than 50,000 U.S. women suffer serious complications related to childbirth and about 700 die. For years, hospitals and healthcare providers have blamed the country's rising rates of maternal deaths and injuries on mothers being too old, too fat or too unhealthy to have safe deliveries.

An ongoing USA TODAY investigation has revealed widespread failures by hospitals and providers to follow nationally recognized childbirth safety practices known to save mothers' lives from medical mistakes and poor care. Last month the bipartisan leadership of a congressional oversight committee sent letters to six federal health agencies, citing USA TODAY's investigation and asking for briefings on what they are doing to address what they called the alarming rate of mothers being harmed.

Tuesday's CDC report provides some additional new detail about when women are dying during their pregnancy and postpartum periods, and it reveals how their causes of death vary.

Of the 700 pregnancy-related deaths that occur each year, the CDC found that during 2011-2015 about one-third happened during pregnancy, about one-third happened during childbirth or the week after delivery, and about one-third happened in the following year.

Overall, heart disease and stroke were the most common causes of death. During delivery, causes were emergencies like hemorrhage and amniotic fluid embolism, where amniotic fluid enters a mother's blood stream, Problems from a weakened heart muscle, called cardiomyopathy, was the leading cause of death for moms from one week to one year after giving birth.

The CDC also analyzed data for 2013-2017 from 13 state maternal mortality review committees, expert panels that examine the circumstances of mothers' deaths. That data, the CDC said, reveals several areas where actions can be taken to prevent mothers' from dying.

The CDC said that health care providers can do more to help patients manage chronic health conditions and educate them about warning signs of dangerous complications. Hospitals and health systems can take actions to improve care, including standardizing the way their providers respond to obstetric emergencies.

The report called for states and communities to take actions to help address barriers to access to housing and transportation and develop policies to ensure high-risk women can receive care at hospitals with the specialized providers and equipment they need.

Women and families, the CDC said, can learn how to identify potential warning signs and communicate them to health providers.

"Though most pregnancies progress safely, I urge the public health community to increase awareness with all expectant and new mothers about the signs of serious pregnancy complications and the need for preventative care that can and does save lives," said CDC Director Robert Redfield.

Read USA TODAY's Deadly Deliveries series at maternal.usatoday.com.