When babies are born, fear of teething tends to take the place “sleep now while you can!” held during pregnancy. It's a warning from everyone who’s been there and a few people who haven’t, and a warning that definitely has some truth to it, but also turns out to be a bit of overkill for plenty of babies. In rare cases, teething can start when your baby is as young as a couple of months old, or as late as 12 months, but it generally starts between 6 and 9 months. The age when teething starts is determined by genetics, so there might be a clue to when teething will start in finding out what age you or your partner started teething at.
Teething can definitely be painful for babies, but because it's known for being painful, it can also become a catch-all reason for your baby's discomfort around this time, when there are many other reasons why she might be uncomfortable or upset.
On the one hand, teething can go easily enough that the first sign of teething is when you notice a tooth. On the other, though, most babies do show some other signs of teeth on their way.
As your baby’s new teeth try to push their way up to cut through her gums, those gums are going to have a little bit of a hard time adjusting, and often swell and become puffy. If you reach in to touch them gently, you can often feel the outlines of the new teeth beneath as they fight their way through. Swollen gums sometimes come with dark, squishy blood-blisters on them.
Yes, your baby may have already drooled, and yes, if your baby is around 4 to 6 months old, an increase in saliva tends to happen whether she is teething yet or not, just as a way of getting ready to process solid foods a few months down the road, so drooling isn’t a sure sign of teething, but it can often accompany teething.
One of the other common signs that goes with drooling is the facial rash on your baby’s cheeks and chin where her skin dries out from the drool, which is often even more obvious than the increased drooling itself. Like diaper rash, the best way to get these rashes under control is to wipe them gently with a damp cloth and then pat them dry. Sometimes a mild, unscented moisturizer can help as well.
Many babies, when they begin teething, start by drawing everyone’s attention to their mouths as often as possible - by putting everything they can into their mouths, and by biting down, even on the literal "hand that feeds them." Again, this isn’t a sure sign, since babies like to explore the world with their mouths anyway, but teething inspires a more goal-oriented type of gumming on things, since biting hard, or chewing or gnawing with their gums, can help babies to manage some of the pain and pressure on those gums as the teeth try to push their way up and through.
No matter how predictable and reliable your baby has or has not been up until this point, teething can easily disrupt eating and sleeping schedules temporarily. It’s no wonder that your baby’s swollen gums and achey jaw might cut into her usual appetite, though she is more likely to eat anyway if the food you offer her is cool enough to soothe her gums. She might have trouble sleeping because even if her teething pain is reasonably manageable during the day, at night, when she has nothing to distract herself with, she could get significantly fussier when she is supposed to be sleeping.
Some parents and doctors believe a low fever can also be a sign of teething, but there is no medical proof that fever or diarrhea can be caused by teething. And even if your baby is teething, that doesn’t mean she is any less likely to pick up a virus than at any other time, so doctors generally recommend against dismissing these symptoms as only signs of teething. Teething pains also tend to only last a few weeks, so if symptoms last for longer than that, they may be worth checking out with a doctor.