Miscarriage, Pregnancy Loss, and Fertility: What to Know

There’s no question: Having a miscarriage can be devastating, so it’s natural to be concerned about the possibility if you’re pregnant or trying to conceive. But there’s a lot of misinformation about the primary causes of pregnancy loss, which can ratchet up your worries unnecessarily. Also called a spontaneous abortion, a miscarriage occurs when an embryo or fetus dies before the 20th week of pregnancy. Pregnancy loss after 20 weeks is called a stillbirth. (1,2)

More Common Than Many Know: The Prevalence of  Miscarriage

Miscarriages are fairly common occurrences: In the United States, the miscarriage rate ranges from 11 to 22 percent of pregnancies, with the highest proportion occurring within the first 13 weeks. (3) The rate may be higher than that because some women miscarry before they even discover they’re pregnant; they may just think their period is late. (4,5)

The Emotional Effects of Experiencing Miscarriage

If a miscarriage happens after a woman knows she’s pregnant, feelings of sadness and loss are bound to occur. “The minute a woman hears or realizes she’s pregnant, that’s a baby to her — she’s thinking about names and a nursery,” explains Alice Domar, PhD, an associate professor of obstetrics, gynecology, and reproductive biology at Harvard Medical School in Boston and the author of Finding Calm for the Expectant Mom. “So if there’s a miscarriage at any point, there’s a potential for it to be perceived as a death, and the grieving process can be intense.”

Seeking Answers, Someone to Blame, After Miscarriage or Pregnancy Loss

After a miscarriage, it’s not unusual for women to retrace their recent histories to try to pinpoint what may have gone wrong. “It’s common for women to blame themselves — people want to find a reason; it’s hard for them to accept having something terrible happen so randomly,” Dr. Domar says. “But a miscarriage is almost never because of something the woman did.”

Why Miscarriages and Pregnancy Loss Happen

In most cases, it’s difficult to figure out exactly why a particular miscarriage occurred. “The most common cause of miscarriages is a chromosomally abnormal pregnancy,” says Mary Ellen Pavone, MD, an associate professor of obstetrics and gynecology in the division of reproductive endocrinology and infertility at the Northwestern University Feinberg School of Medicine in Chicago. In a 2018 study, researchers examined the “products of conception” (aka, the tissue derived from the placenta or fetus) in 1,000 first-trimester miscarriages and found that 50 percent had chromosomal abnormalities. (6)

Pregnancy and Miscarriage Basic Facts

A brief refresher: Chromosomes are the gene-containing structures inside the nucleus of each cell. In human beings, each cell normally contains  46 chromosomes (or 23 pairs of chromosomes). Each egg and sperm normally have 23 chromosomes, so when they fuse during fertilization, the two sets of chromosomes come together to form a complete set of 46. If the fertilized egg has an abnormal number of chromosomes — or duplicated, missing, or incomplete ones — this can cause problems with implantation or early miscarriage, Dr. Pavone explains.

In other cases, uterine abnormalities like fibroids or structural problems in the mother can lead to miscarriage. And certain medical conditions like poorly controlled diabetes, hypothyroidism, or celiac disease can increase the risk.

And with a disorder called antiphospholipid syndrome (APS), which affects mostly women, the immune system makes it much easier for someone to form blood clots. “These clots can form in the placenta and cause miscarriage,” Pavone explains. (However, APS is quite rare, with only 1 to 50 cases per 100,000 people, according to a 2021 study.) Fortunately, some of these conditions can be treated with medication or corrective surgery so that a subsequent pregnancy can be carried to term.

Age-Related Risks for Miscarriage and the Biological Clock Factor

Another common risk factor: A woman’s age. Simply put, the risk of miscarriage increases as a woman gets older, according to the American College of Obstetricians and Gynecologists (ACOG), and after the age of 40, more than a third of pregnancies result in miscarriage. (1)

Miscarriage Risk Factors That You Can Reduce

Meanwhile, certain risk factors are under your control: Smoking increases the risk of miscarriage, probably because it interferes with blood and oxygen flow to the fetus, Pavone says. Exposure to other detrimental environmental factors — such as lead, certain pesticides, solvents, or arsenic — may increase the chances of miscarriage, she adds.

Being underweight, obese, or overweight carries a heightened risk of miscarriage. (7)

Deficiencies in certain vitamins, such as B and D, can increase a woman’s risk of miscarrying. (8) Consuming caffeine in moderation is nothing to worry about, but a high intake — more than 300 milligrams per day — could be risky, Pavone says. And certain sexually transmitted diseases — such as gonorrhea and chlamydia — can be problematic if they cause scarring in the fallopian tubes. Such scarring can be a risk factor for ectopic pregnancy, a potentially hazardous condition where a fertilized egg implants outside the uterus.

Drugs and Medications That Might Play a Role in Miscarriage

Taking nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil) around the time of conception confers a fourfold higher risk of miscarriage within the first eight weeks, according to a 2018 study. (9)

“If you’re taking any medications, please talk to your doctor to make sure they are safe to take when attempting pregnancy or while you’re pregnant,” Pavone advises. “And remember to start taking a prenatal vitamin, ideally before you start trying for pregnancy.” Research from 2014 found that women who have a higher intake of folate — which is known to prevent neural tube defects in the fetus — have a lower risk of miscarriage. (10)

6 Things to Cross Off the Miscarriage Worry List

Some other lifestyle factors women commonly worry about have been exonerated as possible causes of miscarriage. These include working hard, having sex, exercising while pregnant, and using the birth control pill before pregnancy, according to ACOG. (1) And contrary to what you may have heard, there’s no evidence that having had an abortion makes it more difficult to carry a subsequent pregnancy to term, Pavone says.

Does Psychological Stress Cause Miscarriage and Pregnancy Loss?

While it’s widely believed that psychological stress may play a role in miscarriage, “right now there’s no definitive evidence that stress contributes to miscarriage,” Domar says. So don’t stress about being stressed. But do learn good stress management or relaxation techniques so that you can cope well with the strains of modern life while you’re pregnant — and avoid turning to smoking, drinking alcohol, or using other substances that could be harmful to the pregnancy and your baby.

Signs and Symptoms of Miscarriage and Early Pregnancy Loss

The most common symptoms of a miscarriage are bleeding and cramping. But remember: Light bleeding (or spotting) and mild cramping in early pregnancy are relatively common and usually nothing to worry about. Often they stop on their own and the pregnancy continues normally. To be on the safe side, though, see your ob-gyn or healthcare provider if you experience these symptoms, especially if cramping is severe or bleeding is heavy.

Looking Forward and Planning Future Pregnancy

Having a single miscarriage doesn’t mean you’re destined to have more. Most women who have a miscarriage go on to have a successful pregnancy (or two or more) in the future.

If you have one miscarriage, your risk of having another one is 20 percent, according to the Miscarriage Association; if you’ve had two miscarriages, the risk of another is 28 percent; and if you’ve had three, the risk of having another one is 43 percent. (11) “You can have multiple miscarriages, and the odds that your next pregnancy will go to term and you’ll have a baby are in your favor,” Domar says. Even so, if you do have two or more miscarriages, it’s important to get thoroughly checked out by a reproductive endocrinologist.

After a miscarriage, “we say: nothing in the vagina for two weeks,” says Brooke Hodes-Wertz, MD, a reproductive endocrinologist and fertility specialist at the New York University’s Langone Fertility Center in New York City. That means no sexual intercourse and no tampons.

How Soon After a Miscarriage Can You Resume Trying to Get Pregnant?

In the past, women have been advised to wait two to three months before trying to become pregnant again, but the latest research suggests that may be unnecessary and counterproductive. A 2017 study found that women who became pregnant less than three months after having a miscarriage had a lower risk of having a subsequent miscarriage than those who waited six months or longer. (12)

“You can start trying after your next period,” Dr. Hodes-Wertz says. By then, the tissue from the miscarriage will have been expelled and your cervix will have had the opportunity to close. An added perk: Waiting until after your period makes it easier to calculate the due date of your next pregnancy.