03/25/2013 12:33 pm ET Updated May 25, 2013

Every Mother Counts: Blood Clot Awareness Month -- What That Means to Pregnancy

Most of the time, our blood's ability to clot is nothing short of a miracle. Without that mad skill, we could bleed to death from something as minor as a shaving nick. Sometimes, however, blood clots in ways and places we don't want it to, which can lead to serious health problems. In the case of maternal health, blood clots can sometimes lead to pulmonary embolus, a leading contributor to maternal death.

This month, more than 25 organizations are participating in Deep-Vein Thrombosis (Blood Clot) Awareness Month, a national effort to raise awareness among health professionals and consumers about this potentially fatal medical condition. Deep vein thrombosis is a blood clot that forms in one of the large veins, usually in the lower limbs, that partially or completely blocks circulation. If part of that blood clot breaks free and migrates to the lungs, it can block a pulmonary artery and cause a pulmonary embolism, which is serious and often deadly. Pulmonary embolism may be responsible for as many as 200,000 deaths annually in the United States. Most of these deaths are preventable, because when doctors and their patients are aware of the signs, symptoms, and factors that contribute to clot formation, they can stop the clot from forming or treat it before it's too late.

The One in a Thousand campaign is designed to raise awareness of the risks of blood clot/deep vein thrombosis development during pregnancy and they've produced a Public Service Announcement that demonstrates their message. During pregnancy and the six-week postpartum period after birth women are at increased risk for blood clot development. One pregnant woman in a thousand may develop a potentially life threatening blood clot. The good news is that blood clots are almost always preventable. By knowing your own and your family's health history, practicing prevention measures and knowing what symptoms to look out for, your chance of not becoming one in a thousand is excellent.

While the statistic 1:1000 is ominous, it's not something most women should panic about. Dr. Shilpi Mehta-Lee, MD Assistant Professor of Maternal Fetal Medicine at NYU Medical Center says, "We actually know the risks are between 1:500 and 1:2000, which makes 1:1000 about average. When you put the statistic that way, it sounds pretty bad, but what that really breaks down to is about a 0.25 to 0.1 percent risk. That means more than 99.5 percent of women won't have this problem. Still, pregnancy and the postpartum period are among the highest risk times of a woman's life for developing clots, even if those risks are still pretty low."

What is it about pregnancy that increases the risks? Dr. Mehta-Lee says it comes down to two factors. "First, women have more blood volume during pregnancy that moves less efficiently through blood vessels. Second, pregnant women have increased blood-clotting factors (chemicals) to prevent them from hemorrhaging. They are important protective factors we need to help our blood coagulate otherwise, delivery itself would be extremely dangerous." In most cases (more than 99.5 percent of all pregnancies), our blood and veins work in harmony. Blood clots form when they're supposed to and don't when they're not. That's especially important during the post partum period when uterine bleeding tends to be heaviest, but that's also when risks for dangerous clots are highest.

Who's at risk for developing blood clots during pregnancy? According to the American Society of Hematology, the risk during pregnancy is increased by the following:
• Obesity
• Prolonged bed rest
• Prolonged inactivity (long trips by plane or car)
• Surgical deliveries (C-sections)
• Genetic predispositions to blood clots (personal or family history of dangerous blood clots)

In addition, women with a history of smoking, high blood pressure, diabetes, lupus and other autoimmune disorders, heart disease, sickle cell disease, and African American women and women over age 35 are at increased risk.

How do you avoid getting a blood clot? Dr. Mehta-Lee says it's fairly easy, "It comes down to hydration and mobility. Water makes up the biggest percentage of our blood and mobility keeps our blood pumping through our veins. That's why exercise is so important throughout pregnancy and during labor. After delivery, getting up and walking is really important. In the case of cesarean deliveries where we know our patients are going to be down for a while, we always put on compression boots that squeeze the lower legs automatically and keep blood circulating. Of course, women with known risk factors for blood clots require more specific medical care."

Mehta-Lee says, "Knowing what symptoms to look out for is also essential. If a patient develops one-sided leg pain that is dull, achy and constant, if there's swelling, redness, or a hard knot, or if the foot or leg is cold, any of those symptoms might signal something is very wrong that requires immediate medical attention."

Blood clots may be a physiologic miracle, but there nothing to mess around with when they're up to no good. For more information on risk factors, signs, symptoms and treatments, log on to One in a Thousand.