SIX MYTHS ABOUT MISCARRIAGE

Miscarriage is a heartbreakingly common experience, ending 15 percent to 20 percent of confirmed pregnancies. Although many women experience miscarriage, this loss has often been shrouded in secrecy, and couples often grieve alone.

Even the common advice that people should wait until the end of the first trimester to announce a pregnancy to family and friends can inadvertently confer stigma, said Dr. Zev Williams, an obstetrician at the Albert Einstein College of Medicine and the Montefiore Health System in New York.

"We tell people when they're pregnant, you know, don't tell anyone," Williams told Live Science. "What we're really telling people is you shouldn't tell anyone." Perhaps due to the stigma surrounding it, myths about miscarriage persist. Here are some of the most pervasive misconceptions — and the truth about pregnancy loss.

Myth 1: It's mom's fault

Many women who experience miscarriage blame themselves. They shouldn't. The majority of miscarriages — 60 percent — are caused by abnormal numbers of chromosomes, according to Williams.

When sperm and egg meet, they each bring 23 DNA-carrying chromosomes to the table, which pair up to create the new embryo's genome. Sometimes, this process goes wrong, causing aneuploidy, or abnormal chromosome numbers instead of pairs. The most well-known type of aneuploidy is probably Down syndrome, which occurs when the embryo has three copies of chromosome 21 instead of two.

Some types of aneuploidy, like Down syndrome, are survivable. Others, like trisomy 18 or trisomy 13, are often fatal after birth. But still other aneuploidies have such a big impact on a fertilized egg that the embryo can't progress in development.

These genetic errors cause most sporadic miscarriages, and have nothing to do with the mother's behavior or choices during pregnancy. [7 Ways Pregnant Women Affect Babies]

Myth 2: If the chromosomes are okay, then something's wrong with mom

In cases where an embryo or fetus has the correct number of chromosomes, then it's often assumed that there is something wrong with the mother's health that is causing pregnancy loss, Williams said. But in reality, although aneuploidy is the most common explanation for miscarriage, it is not the only genetic problem that can cause pregnancy loss.

In about 10 percent to 15 percent of cases where the chromosome number is normal, an optical scope in the uterus reveals the fetus to be malformed, Williams said. The problem is that testing a fetus for aneuploidy is a very crude way to measure genetic problems: Problems within chromosomes (as opposed to problems with the number of chromosomes itself) aren't picked up.

A fetus's genome could be missing "10 million nucleotides, and those results would come back as normal," Williams said.

Thus, fetal genetic problems can still cause miscarriages, even if the fetus has the correct number of chromosomes. Detecting these cases requires more sophisticated testing than is typically done (if genetic testing is done at all).

Myth 3: Multiple miscarriages signal infertility

Most women who miscarry will do so only once or twice. A small percentage, though, go on to have three or more miscarriages — and may despair of ever carrying a baby to term.

But there's lots of reason to hope. A 35-year-old woman who has had three miscarriages in a row still has a 70 percent chance of a successful pregnancy, said Dr. Ruth Lathi, a professor of obstetrics and gynecology at the Stanford University School of Medicine.

"We have the benefit of seeing a lot of women through this diagnosis to the other side," Lathi told Live Science.

Many underlying health causes of miscarriage, such as thyroid issues, uterine growths called fibroids or blood-clotting disorders, are treatable, Lathi said.

Myth 4: The body needs to rest after a miscarriage

Common sense might suggest that a woman should wait awhile to get pregnant after having a miscarriage — the body needs to rest, right?

In fact, research suggests the opposite. A 2010 study of more than 30,000 women who had a miscarriage and a subsequent pregnancy found that those who got pregnant six months or less after the miscarriage were less likely to have another miscarriage than those who waited longer, according to the findings published in the journal BMJ.

The women who got pregnant sooner also had a lower chance of ectopic pregnancy, which occurs when a fertilized egg implants in the fallopian tube or elsewhere within the abdominal cavity, rather than the uterine lining, according to the study.

The study involved Scottish women, who, like many women in other developed countries, tend to have babies later in their reproductive years, the researchers cautioned. Thus, the results might not generalize to countries where women tend to get pregnant younger.

Myth 5: Miscarriage is caused by physical or emotional stress

A survey of Americans released in May 2015 revealed that 64 percent of respondents thought that lifting a heavy object could cause miscarriage. In fact, heavy lifting does not cause miscarriage at all. Nor does exercise.

In the same survey, 76 percent of people said a stressful event could cause a miscarriage, and 74 percent said chronic stress might cause pregnancy loss. Neither is true, Williams said. [7 Baby Myths Debunked]

A single study of women in Israel found a 2 percent difference in the miscarriage rate between women living in a town under constant threat of rocket attack and women in a nearby town that was not under frequent attack. That's "barely a perceptual difference," Williams said. Constant fear of sudden death is about as extreme as stress gets, and very few American women live with that kind of danger. Common stressors such as a hectic job or a death in the family are not causes of miscarriage. 

Myth 6: Miscarriage should stay secret

People may hesitate to talk about their experiences of miscarriage for fear of alienating others. But in fact, talking about miscarriage can be enormously helpful to others.

The 2015 survey about miscarriage asked people whether they had ever experienced a pregnancy loss. Fifteen percent had, and 46 percent of those said they'd gained comfort from a friend who revealed a miscarriage of her own.

Even celebrities can help. Just over a quarter (28 percent) of respondents said they'd felt less isolated after hearing miscarriage stories from public figures.

Seventy-four percent of people who talked about their miscarriages said they'd gotten support from people they'd told. But there is still a way to go: Less than half (45 percent) said they received support from a health care worker.