Baby mattresses (or other sleeping surfaces) that are too soft can be dangerous for babies. A firm mattress may help prevent sudden infant death syndrome (SIDS). You can test the safety of the mattress with two cartons of milk and a stack of CDs. In addition to making sure the mattress is secure, you should take other steps to ensure your baby's safety when sleeping. A safe sleep environment is vital to your well-being.
Steps
Part 1 of 3: Testing the mattress

Step 1. Gather your supplies
You can use a few simple household items to test the safety of a baby's mattress. If you don't have all the items, you can get most of them at a department store. You will need the following:
- a rule
- a pen or marker
- plastic wrap or a thin plastic bag
- two full (or 1/4 gallon) cartons of milk or juice with square bottom
- a stack of 12 CDs or DVDs

Step 2. Draw a ring around one of the boxes
Take a pen or marker, and the ruler. Place the ruler on the bottom edge of the box. It measures 40 mm (1.5 inches). Make a mark there and then draw a line parallel to the bottom edge.
- Draw similar lines on the other three sides of the box. Now you should have a box with a ring drawn around it.
- You don't need to repeat it with the other box.

Step 3. Wrap the CDs in the plastic wrap (or thin plastic bag) and place them on the mattress
Wrapping them up will ensure that they stay stacked. This will also prevent damage to the CDs. Put the 12 CDs in a neat pile and wrap them securely.
- Make sure to remove the CDs from their cases.
- When you're done, place them on the mattress. Take the softest part of the mattress. This is important. The baby could roll over at any point on the mattress during the night, so it is important that you try the softest part and, above all, the point where the head is going to be placed.

Step 4. Place the boxes on the stack of CDs
Start with the box with the ring. Line up the edge of the CD stack with the ring you drew earlier. The boxes should lie on their side.
Lay the second box on top of the first, also on its side. Position it however you need so that the boxes and CDs are balanced horizontally

Step 5. Determine the safety of the mattress
The mattress must be firm enough so that the baby does not run the risk of suffocation if he sinks into it. Look at the hanging part of the bottom box. This is the part under the hoop that you drew earlier. It should not touch the mattress.
- If the hanging part of the box does not touch the mattress, it will be safe to use.
- If the hanging part touches the mattress, it is very soft. You must replace it. Make sure the mattress you use is safe for the baby.
Part 2 of 3: Prepare a Safe Crib

Step 1. Verify that the mattress has been tested
Testing is not always a requirement, but some mattresses are tested before they are sold. Check the packaging of every mattress you buy. See if anywhere on the packaging indicates that its strength has been tested for security purposes.
Keep in mind that you should still try every mattress you buy. They could test the mattresses at the factory, but there is still a chance that a soft mattress was overlooked

Step 2. Make sure the crib bars and rails are secure
The crib mattress is not the only essential part for the baby's health. You should also check that the handrails and bars are secure enough to prevent the baby from rolling or slipping out of the crib.
- The bars of a crib should be no more than 6 cm (2 3/8 inches) apart. It is better to prevent the baby from being able to put his head through the bars.
- The top of a crib rail should be a minimum of 26 inches (65 cm) from the top of the mattress. You may have to lower the mattress from time to time as your baby gets taller.

Step 3. Do not put pillows, duvets, or toys in the crib
The baby could choke on these objects while sleeping. He may also use the toys to get up and out of the crib as he gets older.
- Don't use padded crib bumpers either.
- If you want the baby to stay warm, it is better to layer them. This is safer than covering it with a blanket.
- However, babies don't always need extra clothing. A room temperature of 21 or 22 ° C (70 to 72 ° F) is usually enough to keep them warm at night.
Part 3 of 3: Take Other Safety Precautions

Step 1. Lay the baby on his back
Many people believe that it is dangerous to lay a baby on his back, as he could choke on saliva. Babies can clear fluids easily, even if they are placed on their back. It is safer to lay them down this way.
- Babies can breathe most easily if you lie on their back. There will be no obstructions preventing them from breathing.
- If they spit in their sleep, they can easily swallow their saliva on their back.
- Consult with your doctor to determine if your baby has health problems that could change his or her safer sleeping position.

Step 2. Put the baby in the crib alone
You should not sleep next to him or make two babies sleep in the same crib. Babies should always sleep alone.
Don't nap with your baby on the couch or bed

Step 3. Use the blankets with care
The fewer things you put in the crib, the better. If you put a blanket on, just use a thin one. Do not extend the blanket beyond the height of the baby's chest.
- Keep your baby's arms off the blanket.
- Tuck the blanket into the sides and bottom of the crib. This will keep it safe, which will prevent the baby from pulling it over your head at night.

Step 4. Make sure your family members and caregivers know the safety precautions
Everyone who cares for the baby should know the safe conditions for the baby to sleep. Family members and caregivers should know how to put the baby to sleep. This is especially important if you are going to leave it with them overnight.