Never purchase an antique or used crib or bassinet. It may be missing hardware that prevents it from collapsing or failing in some other way. Some older cribs have cutouts in the headboard or footboard. Whether old or new, your crib shouldn't have any cutouts or openings that could entrap your child's head, neck, arms, or legs.

Even if an old crib is in good shape, safety standards have improved over the years, so it's best to buy a new one if you can. A crib should be the one place you feel comfortable leaving your child alone.

Check the condition of the crib's paint. If your crib is painted, make sure the paint isn't chipped or peeling. This is especially important with older cribs that may have been coated with paint that contains lead—another reason not to use old cribs.

Check the crib for splinters. If you use an older crib, be sure to check it over thoroughly for cracks, splinters and rough edges, which could harm your baby.

Remove ribbons. If your bassinet has ribbons or bows make sure your child can't pull them off or become entangled. It's best to remove them or cut them shorter than 8 inches. If you decide to keep these decorative features, you need to be sure they are tightly fastened.

Check slat spacing. The slats in a crib or bassinet should be no farther apart than 2 3/8 inches. If you can fit a can of soda through them, the opening is too large. You are more likely to find this problem in an older crib, but you can't be too safe when it comes to your baby, so check any crib you put him in. If you find you have purchased a crib that is unsafe, you should return it and report it to the Consumer Product Safety Commission (CPSC) at www.cpsc.gov .

Check corner posts. If your crib has corner posts or finial knobs they should stand at least 16 inches above the crib's end panels so that a child can't reach the top and get her pajamas caught. If the corner posts or finials are shorter than this, unscrew or saw them off so that the corners are no more than 1/16 of an inch higher than the crib ends or side panels. After sawing them off, you will need to sand the crib to eliminate splinters and sharp corners.

Inspect hotel cribs. When reserving a crib or a play yard at a hotel, try to find out the make and model number so you can check whether it has been recalled. Before you use either item, check thoroughly for loose screws or missing parts, and be sure the slats are no more than 2 3/8 inches apart. Make sure the sheet is designed for the crib or the play yard, and is not a bed sheet that has been tucked underneath. Best bet: Bring your own crib sheet or play-yard sheet.

Check the hardware. Make it a habit to check the screws and bolts in your baby's crib to ensure nothing is loose, missing or damaged. Crib hardware can loosen over time and may need occasional tightening. If anything is missing or broken, contact the manufacturer for replacement parts.

Check mattress supports. Make sure that the system that supports the crib mattress isn't bent, broken or coming apart. Be sure it's secure and isn't in danger of falling. If the mattress is suspended on hangers attached to hooks on the end panels, check regularly to see that these are still connected. A handy time to look is when you are changing the crib sheet.

Make sure the mattress fits. Put your baby to sleep on her back on a firm mattress that fits tightly into the crib. There shouldn't be any cracks or openings between the crib and the mattress because a baby can get trapped in the smallest of spaces. A full-size crib has an interior surface of 28 inches by 52 inches. The mattress for a full-size crib should be 27 1/4 inches by 51 5/8 inches, and no more than 6 inches thick. If you can place more than two fingers between the mattress and the crib frame, the fit isn't snug enough and there's a risk of head entrapment.

Adjust the mattress to the right height. Most cribs have this feature, some with only three levels and some with several levels. The higher levels make it easier to take your infant out of the crib but become dangerous when your child is able to pull herself to a standing position. Before your child reaches that stage—at around 6 months—the mattress should be at its lowest setting. Bumper pads and large toys help your little escape artist climb out, which is another reason they don't belong in the crib.

Let your baby sleep unencumbered. Don't wrap your bundle of joy in blankets or comforters when he's in the crib. He can quickly become entangled and might not be able to free himself. Pillows, quilts, comforters, sheepskins, stuffed animals or dolls don't belong in the bassinet or crib. And remember that babies can quickly overheat. Put yours to sleep in lightweight clothes and set the thermostat at a comfortable 70 degrees.

Use safe sleepwear. Infant sleepwear should fit snuggly and be made of flame-resistant fabric. There should be no drawstrings, ribbons or anything else that might catch on something. Buttons and snaps should be firmly attached to avoid becoming a choking hazard.

Remove the bottle. As your child gets older you may feel tempted to let him fall asleep with a bottle or sippy cup. Don't do this! Bottle nipples suffer from wear and tear over time and a small piece can break off and get caught in a baby's throat. Sleeping with a bottle or cup can also cause tooth decay and lead to ear infections.

Use the proper sheets. Use ones made to fit the mattress in your crib, bassinet or play yard. If a sheet isn't the correct fit, your baby may pull it up and become entangled. Test the sheet by pulling up on each corner to make sure it doesn't pop off the mattress corner.

Skip the crib gym. The safest crib is one that is free of gyms and other toys that stretch across the crib using strings, cords or ribbons. They can be dangerous for older or more active babies, and you have no way of knowing what your baby is doing in the middle of the night.

If you think you must use crib gyms or other crib toys, you can reduce the risks by following recommendations from the Consumer Product Safety Commission. Items should be free of points that your child's clothing could get caught on; they should be securely installed at both ends; they should be out of your child's reach; and they should be removed when your child is 5 months old or begins to push up on his hands and knees. Remove strings and cords from all toys and be sure there aren't any hanging into the crib or within reach of your baby.

Don't use a sleep positioner. Those wedge-shaped pieces of foam are designed to help babies sleep on their back. But the American Academy of Pediatrics says that none of these devices have been tested sufficiently to show that they are effective or safe.

Always put your baby to sleep on his back, not his stomach, to minimize the risk of sudden infant death syndrome (SIDS) and rebreathing, a sometimes fatal circumstance that can occur when a baby is sleeping on his stomach or trapped in soft bedding. As a result the child "rebreathes" his own carbon dioxide rather than breathing in oxygen-rich fresh air. The lack of oxygen can cause death.

Crib mobiles are for looking at, not for touching. They often have string or small attached pieces. Make sure your little one cannot reach the mobile so he can't become entangled or pull anything off. When he is able to push himself up on his hands and knees, the mobile should be removed from the crib.