Getting Answers
Ultrasound is the most commonly used test to determine if a uterine problem is to blame for recurring miscarriages, because it can evaluate both the cavity of the uterus and its outer contour. Three-dimensional ultrasound is more accurate than its two-dimensional counterpart, but not all fertility centers have the more advanced machine.
To rule out problems in the fallopian tubes, doctors often do a hysterosalpingogram (HSG) as well, though an HSG isn’t very good at distinguishing one type of abnormality from another, and it can be uncomfortable and expensive. Sonohysterography, the procedure Sue DiMatteo underwent, can also find abnormalities. If all else fails, doctors can turn to MRI, which provides a more detailed look inside.
How you’ll be treated—including decisions about the best ways to increase your odds of carrying a healthy baby to term—depends on the kind of uterine problem you have. There are seven types, as defined by the American Society for Reproductive Medicine. Here’s information you need to know about each, including how it can be treated to allow a healthy pregnancy.
Septate
What Goes Wrong?
In this type of uterine abnormality—believed to be the most common kind—fibrous tissue extends partially down the middle of the uterus, or all the way to the cervix, giving the uterus a Y shape. Some 44 percent of pregnant women with a septum will miscarry. “We think the high risk is because this [uterine] tissue doesn’t have a good blood supply,” explains Dr. Park. The placenta depends on the uterus for food and oxygen, and the fetus needs this strong and steady blood supply to grow. If implantation occurs in the septum, “the developing placenta will not be well-nourished,” Dr. Park concludes.
Can it be Fixed?
Luckily, the septate uterus isn’t just the most common type of uterine abnormality, it’s also the easiest to correct, says Dr. Park. You won’t have to do any hospital time during the minimally invasive procedure, called a hysteroscopic metroplasty, that alleviates the problem. The surgeon inserts a tiny telescope-like device through the cervix and into the uterus and then releases a liquid or gas to expand the uterus. The unwanted tissue is then removed and the uterine cavity is left a normal shape and size. Recovery time is several days, and after the procedure delivery rates are about 80 percent. The embryo can now implant in the blood-rich walls of the uterus, and the baby has enough room to grow.
Unicornuate
What Goes Wrong?
Only one Mullerian duct forms, resulting in a one-sided horn- or crescent-shaped uterus with a single fallopian tube. In three-quarters of cases, a remnant of the other duct remains, leaving behind an incomplete second horn. If the partial horn isn’t connected to the uterus, as happens in the vast majority of cases, and an embryo lodges there, there’s a 50 percent chance the horn will rupture. Usually this happens in the first or second trimester, when the embryo runs out of space.
Can it Be Fixed?
Ideally, the incomplete duct should be removed. But even after surgery there’s still a one-third chance of miscarriage because the remaining uterine cavity is smaller than normal. Even so, almost half of women with a unicornuate uterus will carry a baby to term. Cervical cerclage, a surgical procedure to sew the cervix shut to retain a pregnancy, may help them get to 37 weeks.
Bicornuate
What Goes Wrong?
The tubes fail to fuse at the top, resulting in two separate horn-shaped uterine bodies that share a single cervix, which gives the uterus a heart shape. Because there’s a deep indentation at the top of the uterus, the fetus has less space in which to grow; about one-third of women with a bicornuate uterus will miscarry. If the uterine bodies are completely fused, leaving two small spaces, two-thirds of women will have a preterm delivery due to the small uterine cavities and a weakened cervix that’s prone to open too early.
Can it Be Fixed?
Surgery—in the form of a procedure called a Strassman metroplasty—can restore the uterus to normal, but this major abdominal procedure requires a hospital stay of several days and four to six weeks of recovery. “This is something you don’t want to fix unless a woman has had several miscarriages,” cautions Dr. Rackow. Cervical cerclage may also be an option.
Didelphys
What Goes Wrong?
Both Mullerian ducts develop, but they fail to fuse to form the uterus. Instead, each creates its own separate but narrower-than-usual crescent-shaped uterus, each with its own cervix. Due to the small size of each uterus, pregnant women with a didelphys uterus face a one-third chance of miscarriage, and a more than one in four chance of a preterm delivery
Can it Be Fixed?
A Strassman metroplasty may help repair this abnormality, too, increasing a couple’s chances of taking home a baby from 56 percent to over 80 percent.
Des-Related
What Goes Wrong?
Women born to mothers who used the drug diethylstilbestrol (DES) during pregnancy are at a higher risk of uterine abnormalities, most commonly a T-shaped uterine cavity. Ten to 20 percent of women born to a mom who took DES have preterm deliveries, and they have an increased risk of first-trimester miscarriages.
Can it Be Fixed?
No, but cervical cerclage may be an option to hold off an early delivery.
Arcuate
What Goes Wrong?
The uterus has a normal shape, but there’s a small indentation in the top of the uterine cavity where the fused ducts weren’t completely reabsorbed. Not all doctors consider an arcuate uterus an abnormality since there seem to be few negative effects on pregnancy: In fact, nearly two-thirds of women with this condition carry babies to term. “An arcuate uterus has the highest chance of a full-term vaginal delivery and the lowest risk of miscarriage,” of all types of uterine abnormalities, says Dr. Park.
Can it Be Fixed?
Since it’s not always considered a problem and so many women do fine without any intervention, an arcuate uterus usually isn’t corrected.
Agenesis or Hypoplasia
What Goes Wrong?
In very rare cases, a woman is born without a vagina, cervix, fallopian tubes, and/or her entire uterus. Because these women don’t have a full uterine cavity, they can’t carry a fetus.
Can it Be Fixed?
No, but it may be possible for a surrogate to carry an embryo using eggs harvested from a woman’s ovaries.
If you have an uncommon uterus and have had corrective surgery but are still struggling to conceive, you may be a good candidate for fertility treatments, including in vitro fertilization (IVF). Research published in 2007 in Reproductive Medicine Online found that women who had surgery to correct a septate uterus and then underwent IVF had the same pregnancy rates (about 47 percent) as IVF patients without uterine abnormalities.
And if you have a history of unexplained miscarriages and are concerned that an uncommon uterus might be responsible, talk to your doctor. Chances are you’re in the clear, since uncommon uteruses are exactly that: uncommon. But if it does turn out that you’re one of the few, remember, as Sue DiMatteo says, that “these doctors can work miracles.” She wakes up to two of them every day.
A version of this article originally appeared in the March/April 2009 issue of Conceive Magazine.
Related Topics: Fertility Basics; Fertility Health; Fertility Threats; Miscarriage Causes
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