It's every parent's worst nightmare. Sudden Infant Death Syndrome, or SIDS, is the leading cause of death in infants ages one month to one year, and is identified as the sudden death of a baby with no clear cause. SIDS occurs when a baby is sleeping, either at night or at nap time. In 2007, the death rate for SIDS was 6.75 deaths per 1,000 live births.

So, what causes SIDS? Research continues, but experts believe some babies have an immature respiratory system that raises their risk of SIDS, according to a 2007 study published in the Lancet. During deep sleep, these babies may simply "forget" to breathe.

Exposure to tobacco smoke, overheating and sleeping on soft bedding or soft sleep surfaces may also increase the risk. Premature babies and babies whose mothers experienced diabetes, high blood pressure or who smoked or used alcohol excessively during pregnancy may also be at increased risk, according to Jason Jarzembowski, MD, PhD, of the Children's Hospital of Wisconsin in Milwaukee.

So what can you do to keep your baby safe during sleep? Currently, most incidents of SIDS that occur in the U.S. happen when a baby is sleeping with an adult or another child, according to Charles Shubin, M.D., and director of Pediatrics at Mercy Medical Center in Baltimore. He urges parents to practice A, B, C, which stands for Alone, Back, Crib. Below are a few more tips on keeping your baby safe during sleep:

  • Back to basics. Always put your baby down for sleep laying on her back. In 1992, the American Academy of Pediatrics began a campaign warning parents against putting their little ones to sleep on their stomachs. Since then, the incidence of SIDS has dropped by 40 to 50 percent. From the time you bring your bundle of joy home from the hospital, always lay her to sleep on her back instead of her tummy. Some moms claim that infants sleep better on their tummies, but babies that go into deep, unresponsive sleep are more at risk for SIDS. It's better if your baby has light periods of arousal during sleep.
  • Stay close. Keeping your baby in your room to sleep may cut the risk of SIDS, probably because the sound of your breathing stimulates your little sleeper's respiratory processes. Don't run to arrange a spot in your family bed for your baby just yet though—co-sleeping with your baby may increase the risk of SIDS. Babies have smothered by a sleeping adult or by heavy bedding and pillows in an adult's bed, so the safest place for your baby is in a bassinet or co-sleeper next to your bed. That way, you have your little one close enough to tend to her midnight needs while keeping her safe from the accoutrements in your blissful bed. Win-win!
  • Use a pacifier. Many parents opt to avoid using a binky based on horror stories of kids kicking the habit or the risk it poses to tooth development, but sleeping with a pacifier has also been shown to cut the risk of SIDS. Using a paci creates an air pocket inside your little one's mouth, according to Charles Shubin, M.D. Buy several pacifiers designed with your baby's age in mind. Wash the pacifiers in warm, soapy water at least once each week to cut germs, and never force your baby to take a binky if she's uninterested. Breasfed babies shouldn't use a pacifier until they're at least one month old, to establish healthy feeding habits.
  • Optimal health. Healthy babies are less at risk for SIDS, says Jarzembowski, so follow your pediatrician's advice. Breastfeed if you can, keep immunizations current and maintain a healthy lifestyle for you and your baby both.
  • Non-smoking zone. A 2006 study by the U.S. Surgeon General and the U.S. Department of Health and Human Services found that chemicals in secondhand smoke may impair a baby's ability to regulate breathing. Babies whose mothers smoked during pregnancy or who are exposed to secondhand smoke during infancy have an increased risk of SIDS. Don't smoke around your baby, or better yet, quit altogether. What's good for your baby is good for your lungs and life span too!
  • Skip crib accoutrements. If bedding or pillows fall over a young baby's face, she can't move them and could potentially suffocate. Remove bumper pads, pillows, stuffed animals and any other objects from your baby's crib. Make sure the mattress fits snugly in the crib frame and cover it with tightly fitting sheets.
  • Cool factor. Although you might be tempted to bundle baby up on a cold winter night, don't! Babies have smothered in heavy blankets. Instead, dress your baby for sleep in a fleece sleeper or footed pajamas. Cover baby with a very light blanket or no blanket at all. Keep the thermostat set around 65 degrees for night-time sleeping and crack a window during the warmer months.

For many years, parents had little information on SIDS, its causes and prevention. Today, though, we know a lot about how to cut the risk of SIDS. Armed with this knowledge, you can give your baby the safest sleep environment possible. Talk with your pediatrician about SIDS, and rest easy, knowing you're doing everything you can to keep your baby safe.