A staggering one in 16 women said they were raped by force or coercion the first time they had sexual intercourse, according to a new study of government survey data.

Survivors reported higher rates of unwanted first pregnancy, abortion and an array of other physical and mental health problems, study authors wrote in an analysis published Monday in the Journal of the American Medical Association.

What does the study say?

Between 2011 and 2017, researchers for the Centers for Disease Control and Prevention questioned a nationally representative sample of 13,310 women, ages 18 to 44 about marriage, divorce, family life, reproductive health and more. Men were not asked about the first time they had sexual intercourse, and women with no history of vaginal intercourse and girls 17 or younger were not included in this study.

Among women who responded, 6.5 percent said their first time having sex was forced upon them. That equates to an estimated 3.3 million women nationwide. If the survey had included girls younger than 17 or women older than 45, “certainly that absolute number would be higher,” said Laura Hawks, a primary care doctor at Cambridge Healthcare for the Homeless and the study’s lead author.

“Quite honestly, that’s the tip of the iceberg.”

“Quite honestly, that’s the tip of the iceberg,” said Hawks, who is also a research fellow at Harvard Medical School.

The trauma of this first sexual experience left a legacy of negative health outcomes for survivors, the study suggested. Among these survey respondents, 30 percent of women reported an unwanted first-time pregnancy, compared to 18 percent of women who said they chose to have sex the first time.

Women who were forced to have sex the first time were also more likely to report having had an abortion and have had problems ovulating or menstruating, significantly higher than women who described their first sexual experience as consensual.

Often, the sexual violence happened when the women were girls. Among respondents, 7 percent said they were younger than 10 at the time of the assault, while another 29 percent said they were between the ages of 11 and 14. The largest segment, at 39 percent, said the assaults happened between the ages of 15 and 17.

While women of all racial and socioeconomic groups reported these assualts, women of color and women in poverty reported higher rates of first-time forced sex.

Why is this important?

One out of five women and one out of 71 men will be raped in their lifetime, according to the CDC’s 2010 National Intimate Partner and Sexual Violence Survey. Among those who had been raped, 81 percent of women and 35 percent men reported post-traumatic stress disorder of varying duration, according to the National Sexual Violence Resource Center.

These first-time experiences are important for physicians to understand and monitor with trauma-informed care, Hawks said. This includes requesting permission to ask difficult questions and being sensitive when performing any genital exams.

“Any physical exam can be traumatizing for someone who has encountered physical or sexual violence in the past,” Hawks said.

A patient’s exposure to sexual violence “needs to be top of mind for medical professionals, particularly those serving teenagers and young adults, said said Scott Berkowitz, president of the Rape, Abuse and Incest National Network.

“Any physical exam can be traumatizing for someone who has encountered physical or sexual violence in the past.”

Nearly half of all victims of sexual violence who call RAINN’s national hotline are under age 18, Berkowitz said. Younger people are at greater risk and while there is no guaranteed prevention he said there are steps children and young adults can take to lower risk.

Caregivers can empower their children to speak out by discussing personal boundaries so children know what kinds of behavior are appropriate. It is also important for parents to reassure their child that if someone ever mistreats them, the parent or caregiver remains a safe person for the child to talk to.

If an act of sexual violence has already occurred, Berkowitz said family and friends should be supportive, let the victim lead the conversation, and remember that the “reaction of the first person they tell is going to have a big effect on everything that happens next, on their healing process, how long it takes, or whether or not they report to police.”

If you have been sexually assaulted, call the National Sexual Assault Hotline at 800.656.HOPE (4673), available 24 hours, seven days a week. You will be connected with a trained staff member from a sexual assault service provider in your area.