Why it happens

Obstructive sleep apnea is a disorder characterized by loud snoring and brief, involuntary breathing pauses during sleep. (The Greek word apnea means "want of breath.")

Sleep apnea sufferers may briefly stop breathing and then wake with a gasp, start, or snort as many as a hundred times a night or more. People with sleep apnea rarely remember these episodes in the morning, although they may wonder why they feel so tired all the time.

Obesity is a major risk factor for sleep apnea, and some experts believe that pregnancy may also make you more susceptible, particularly in the third trimester. The heavier you are to begin with and the more weight you gain during pregnancy, the more likely you are to have trouble breathing at night because of the extra tissue in your neck and throat.

Other factors that make you more likely to snore during pregnancy, such as swollen nasal passages, may also put you at a higher risk for sleep apnea. Higher levels of estrogen during pregnancy contribute to swelling in the mucous membranes lining the nose and can even cause you to make more mucus.

Also, the amount of blood in your body increases and your blood vessels expand during pregnancy. This can lead to swollen nasal membranes as well.

What you can do about it

If your partner notices that you're snoring a lot and making periodic snorting or gasping sounds in your sleep, be sure to mention it to your doctor or midwife so you can be evaluated for sleep apnea.

When you periodically stop breathing, the amount of oxygen in your blood drops temporarily. If left untreated, sleep apnea can take a toll on your health. Some research suggests it may affect your baby's growth too.

Sleep apnea is also linked to high blood pressure and other cardiovascular disorders. And feeling tired during the day increases your risk of falling asleep at work, while you're driving, or while you're caring for your other children.

If you're diagnosed with sleep apnea, you may be given a special mouth guard to wear at night to keep your airway open. If the apnea is severe, your doctor may have you wear a mask that's hooked up to a machine that provides a steady flow of air while you sleep.

The mask device helps keep you breathing normally. Most people are amazed by how much better they feel during the day soon after they begin using this device at night.

NOTE: Medically reviewed by Donna Arand, PhD at the Ohio Sleep Disorders Center Kettering Hospital in Dayton, OH