By Kristin Bendikson, MD

When a woman has a miscarriage, she often feels isolated and alone. Miscarriages are more common than most people realize, however; and when women start talking with their friends, they often find that they are not alone in coping with this difficult experience.

A miscarriage—the early loss of a pregnancy—occurs in approximately 15 percent of all clinically recognized pregnancies. If all pregnancies are accounted for, the statistic is closer to 50 percent ending in a loss. The increase is due to the fact that many women don’t even know they are pregnant and experience their period at the normal time or just a few days late. Sometimes a woman knows she is having a miscarriage because she has symptoms, which might include bleeding and cramping followed by the passage of the pregnancy. Other times a woman doesn’t sense there is anything wrong at all, and she finds out that the pregnancy has stopped growing only when she sees her doctor for an ultrasound.

It’s important to note that if a woman experiences bleeding during the first trimester, it doesn’t necessarily mean that she will miscarry. In fact, 25 to 30 percent of women will have some bleeding during their pregnancy, and less than half of those will have a miscarriage.

As a woman’s pregnancy progresses, she is less likely to miscarry. Approximately 80 percent of miscarriages occur in the first trimester. The chance of miscarriage also increases with maternal age: a 35-year-old woman’s chance of miscarriage is 15 percent; that number increases to 30 percent by age 40 and to 50 percent by age 45. After having one miscarriage, the chance of having another does increase slightly (up to 25 percent), although it is rare for a woman to have multiple consecutive losses (only 2 percent of women have two consecutive miscarriages, and only 0.4 to 1 percent of women have three consecutive miscarriages).

Inherited genetic causes, often involving specific alterations in chromosomes, which make up approximately 3 to 5 percent of women with recurrent miscarriages

An abnormality in the shape of the uterus caused by a congenital anomaly or exposure to a drug called diethylstilbestrol (DES)

Masses within the cavity of the uterus (where the embryo implants and the pregnancy grows) called fibroids or polyps, which have been shown to increase miscarriage rates

Scarring within the uterine cavity from an infection or a previous surgery (a hysterosalpingogram is a test of the uterus in which fluorescent dye and X-rays help doctors detect if there is some type of uterine abnormality or an issue within the cavity of the uterus)

Antiphospholipid antibody syndrome, a blood-clotting disorder, is also associated with recurrent first-trimester miscarriages. It is diagnosed by testing blood levels of particular antibodies that need to be positive at two different times. It is believed that this clotting disorder interferes with implantation of the egg. If diagnosed, treatment with both daily baby aspirin and a blood thinner will significantly decrease the chance of another miscarriage.

Additional factors leading to miscarriage include endocrine issues (such as thyroid illnesses), uncontrolled diabetes, obesity, and a hormone disorder called polycystic ovarian syndrome. Women with diabetes can decrease their risk of miscarriage by getting their blood glucose levels under control, and weight loss can decrease the risk of miscarriage for women who are obese. There is no known way to decrease miscarriage rates in women with polycystic ovarian syndrome.

Lifestyle issues may also play a role in causing miscarriages. Excessive smoking, drug use, caffeine intake, and exposure to radiation or toxic chemicals—all have been linked to increases in the incidence of miscarriage. In addition to eliminating negative lifestyle and environmental influences, women seeking to decrease their risk of miscarriage should optimize their health by eating well, exercising, managing stress, and taking prenatal vitamins.

Ensuring Emotional Well-Being

There is no doubt that having a miscarriage is physically and emotionally devastating. After suffering a miscarriage, it is important that women look after their emotional well-being by allowing themselves time to grieve their loss before preparing to conceive again. Women should seek support and comfort from family, friends, and their physician during this tumultuous time.

Though some lifestyle factors can decrease the risk of miscarriage, the unfortunate reality is that many factors leading to miscarriage are beyond a woman’s control. A visit to a physician can help answer questions, however, and in some cases can lead to testing that can determine the cause of a miscarriage as well as provide information about optimizing chances for a successful pregnancy. Remember that miscarriages are more common than most of us realize, and chances are good that if a woman does suffer a miscarriage, she will still be able to conceive and carry a healthy baby at a later time.

Kristin A. Bendikson, MD, joined USC Fertility after finishing her residency at Harvard Medical School and completing her subspecialty training in reproductive endocrinology and infertility at the internationally renowned Center for Reproductive Medicine and Infertility at Cornell University Medical College, under the direction of Zev Rosenwaks, MD. Kristin holds the title of assistant professor of obstetrics and gynecology in the Division of Reproductive Endocrinology and Infertility at the University of Southern California Keck School of Medicine. She is currently the principal investigator of several research projects, including the study of zygote intrafallopian tube transfer for women of advanced reproductive age, aging of the uterine endometrium, and vitamin D and its role in infertility. Her goal is to provide the highest-quality care for her patients and to help them fulfill their desire of having a healthy baby. In addition, she strives to guide her patients throughout what can be a trying and difficult journey by providing them with the support and the personal attention they need. A fertility expert, teacher, and researcher, Kristin is also a married mother of two.