Wendy Becker already had three daughters when she miscarried at 14 weeks. That she was already a mother didn't lessen her grief.

"What people didn't understand was that having my other children and realizing how unique they are made it harder for me," said Becker, who lives in Highland Ranch, Colo.

At first, her husband was understanding of her need to talk through the loss and the hours she spent online searching for support groups. But as the months wore on, he became frustrated at what seemed to be her inability to get over it.

"At a time you would think you would be able to help each other, we were going totally separate directions," Becker said. "I was grieving. He was moving on."

The Beckers aren't alone in experiencing strain in a relationship in the aftermath of miscarriage; their marriage remains intact. New research finds that couples who have experienced miscarriage or stillbirth are more likely to break up even years after the loss than couples whose pregnancy ended with the birth of a child.

For miscarriage, or pregnancy loss prior to 20 weeks, the likelihood of breaking up is 22% higher than for couples who have a successful pregnancy. The rate of splitting up peaks between 18 months and three years afterward, before falling back to rates similar to that of other couples, according to the study.

For stillbirth, or pregnancy loss at 20 weeks and beyond, the risk of breakup or divorce is heightened by as much as 40% for as long as a decade after the loss, according to the study.

The researchers say this is the first nationwide study of the fallout on relationships, both among married partners and couples living together, from miscarriage and stillbirth. The study analyzed the results of 7,770 pregnancies using data from the National Survey of Family Growth.

"The findings were quite surprising at how strong they were and how long they lasted," said study author Dr. Katherine Gold, an assistant professor in the departments of family medicine and obstetrics and gynecology at the University of Michigan, in Ann Arbor.

The study is published in the May issue of Pediatrics.

Miscarriage can cause grief, anger and guilt, Gold said. Those feelings may fade in time, but not nearly as quickly as friends and family may expect them to, and can crop up again on the anniversary of the due date or the loss itself.

Becker, whose miscarriage occurred three years ago, remembers feeling alone in her grief. "No one else is grieving with you," Becker said.

The impact of stillbirth can be even worse, with some women becoming depressed or suffering from symptoms of post-traumatic stress or anxiety disorders, Gold said.

Yet pregnancy loss by no means dooms a relationship. Most women are resilient, Gold said.

"Most women after miscarriage actually do quite well, and most couples do well after miscarriage," Gold said. "But there is this subset of people who may be at higher risk for their relationship breaking up."

Researchers said it was possible that having a baby could help sustain relationships, rather than a miscarriage heightening the risk of a breakup. In addition, it's possible unknown factors could contribute to both risk of miscarriage and risk of divorce, such as mental illness or other chronic physical conditions.

After a miscarriage, men and women also experience the loss differently, said Dr. David Keefe, chairman of obstetrics and gynecology at New York University Langone Medical Center.

For women, the sense of loss lasts longer. While men can certainly bond emotionally with the fetus and the idea of being a father, women have also experienced physical changes that can intensify the attachment, Keefe said.

Men and women tend to grieve differently, with women wanting to discuss the loss and men tending to want to "close up and go play golf," Keefe said, though there are always exceptions.

For couples going through infertility treatment, who may have already heavily invested themselves in the pregnancy financially and emotionally, the loss can be especially difficult to bear.

"The study provides evidence scientifically of what a lot of us sensed was an issue, which is that following a major disappointment of a miscarriage or stillbirth, that marriages can fall apart," said Keefe, a fertility specialist who has also trained as a psychiatrist.

After the miscarriage, Becker had trouble sleeping, became depressed and wanted to "talk about what had happened to anyone who'd listen," she said.

Though she and her husband of 22 years never seriously considered divorce, "it did affect our relationship," Becker said.

Gradually, Becker found her own way of coping. Now 44, she started a website, miscarriagememories.com, where she offers support to other women going through similar loss and sells silver charms to memorialize the baby that could have been.

"People e-mail me all the time and say, 'Thank you for telling me I am not crazy for feeling this way,'" Becker said. "I would rather have the baby, but if I couldn't have that, I am happy that something positive has come out of this."