I often hear "I can't use a sling; I have a bad back" from moms, as they stand there with a toddler perched on their hip, their other hip thrown out to counter-balance. I ask these women, "Do you EVER hold your baby?"
If you plan to hold you baby at all, and in particular, walk more than a few steps while holding baby (from bedroom to kitchen is a few steps; from car to mall is more than a few steps), then a sling will be a lifesaver. If you will never hold your baby, then don't bother reading; you have bigger issues, LOL. Even when sitting, a sling is useful. Simply put, a sling will take the weight of the baby/toddler, and spreads it out over your body where ever the sling makes contact. So, instead of your arm and front shoulder 'taking the weight', you will now spread the same weight over the shoulder, across the larger back muscles, and around to the front again (one shoulder or two---more on that to come). Also, other people in the baby's life can wear baby....children as young as seven can even wear the baby once taught how. Maybe not for two mile hikes, but if you have a 'bad back' you're probably not going on a two mile hike.
There are many forms of 'bad back', but that is never a medical diagnosis. Different diagnosis will suit different carriers. Someone with poor muscle strength in the lower back should look for a carrier with a good padded waist, like the Ergo. Milder muscle weakness could tolerate a Mei Tai, and many of them come with padded waists, just not structured like the Ergo (name brands are not to be taken as a recommendation; just as an easy-to-Google-suggestion). Weak upper backs would do well with woven wraps or Mei Tai's, and in the early days, even ring slings and pouches. Wrapping yourself with 5 yards of fabric will actually make your back feel supported and is an easy and loving way to gradually build up strength. Think of this---if you hold a 10lb baby in one arm with no sling, the weight is supported entirely by that arm...which is connected to your back. But if you wrap yourself and baby with a 5 yard woven wrap, that's not many pounds per yard of contact! And, remember, a stretchy sling will feel comfy and conform to baby and you easily, but you lose support and the fabric has 'give'. Think of stretchy clothes that feel comfy because they move with you....but don't hold anything in, vs. your favourite jeans that compress your softness and keep it in place, LOL.
If your back issue is something like degenerative discs, you should try every option, but be prepared for limited babywearing. Same with arthritis (like I have). Your muscles might feel fine, but the extra load on the spine/pelvis might shorten your babywearing experience. I could not tolerate a low back carry with the MT....even though everyone says to transfer the weight to your hips by using a low back carry. I could do high back, front, and hip carries though. However, lack of flexibility made it difficult for me to learn wraps and soft-structured carriers.
But, what about carrying the baby in the carseat, or in a stroller? Aren't strollers good for exercise too? When you babywear, the baby's weight is added to your own, and you get the metabolic and weight-bearing results for that combined weight. Pushing a stroller--esp. one with large wheels--does not have that advantage. Your arms and shoulders might get some workout, but that's about it. Not to mention I see women with very poor posture while pushing strollers, particularly up hills. By leaning into the angle, they are losing a potentially awesome ab workout. And strong abs mean a stronger back; but it comes at a price of being hard on the shoulders. Babywearing encourages good posture for safety's sake, as well as pride. You're connected to your baby physically and emotionally and will take pride in that.
And don't forget the convenience of babywearing compared to the increasingly popular double stroller. I recently saw a woman trying to push a double stroller into Shopper's Drug Mart. There was a 90degree turn in the vestibule....shorter than the length of her stroller. She couldn't swing the stroller to go through the second door. I see moms at the library, lined up for the elevator with their strollers while I go up the stairs. What about strollers in small public bathrooms? Do you really want to push 50lbs of children and 25lbs of stroller around? That's pretty hard on your back! Compare to tying a 8lb newborn onto your upper chest....your body was already used to being heavier, and pushing the single stroller that you're already used to.
"My baby doesn't mind the carseat and it's convenient" is an argument to 'support' using the carseat as a carrier. I see these 'cocoon babies' all the time. Just because baby doesn't mind it, doesn't make it 'good'. Baby is isolated, can't see mom or smell her, not exposed to other adults or kids or noises. Even at 4 months, a baby is seeing only about 2ft in front of themselves. How far is it from mom's face as she pushes a stroller, to the baby's eyes?
If you have a 'bad back' you should be carrying the carseat (with baby in it) as little as possible. Ideally, for all babies, the carseat should remain in the car. There are better options. Let's take a look at the issues with carseats as carriers. First, they aren't light, often weighing 7-10lbs. Add that to an ever-growing baby...second...many babies hate them because the safe angle it gives baby in the car, is a poor angle for digestion. They are cold, hard, and unyielding. Things that a parent is not. Carrying a carseat....you can either use one hand, so you have the other hand free, but it means a seriously unequal weight load for your body. This is a very serious problem even if you don't have a bad back. You can use both arms and carry the seat high and in front, like the instruction manuals tell you to, but then your hands are occupied, and it's still a heavy load to carry in front of you. Instead, using a simple sling like a pouch, to get baby to and from the vehicle will save your sanity, your back, and keep your arms the same length.
"I won't be able to carry baby around at all". That's a tough spot to be in. As you get larger during pregnancy, your body is probably going to have a harder time supporting the weight gain, and you'll probably be on bed rest....weakening muscles even more. After the birth, you will be dependant on 24hr assistance, and I imagine it will be emotionally rough to see someone else carrying your baby around so much. A sling can be useful even when sitting. Newborns spend a lot of time sleeping....let them do it in the sling while you're sitting. They get to hear your heart again, feel your warmth, and learn your smell. You can nurse in a sling (although new moms should perhaps try nursing without the sling at first, as there's a lot going on), and this will give your arms and back a break. You can wear baby while you eat, even while you sit in a shower. I'd recommend a pouch or ringsling for these types of situations...it might be hard to tie a wrap or MT if you can't get up, not to mention a knot at the base of your back digging into a chair. If the other primary caregiver is over 8, they can also learn about the benefits of babywearing....and then they'll have their hands free to care for you :) A ring sling or pouch is also much easier to deal with when you're out in a wheelchair.
"My baby weighs too much" drives me crazy. Parents carry around toddlers all the time. Piggyback rides, on the hip, etc. If you put on 30lbs while pregnant, why would carrying a 8lb newborn be a problem? The weight gain in pregnancy is hard on your back because it is below your center of gravity. Babywearing keeps the baby up high, snuggled on your chest. You can easily carry weight up high or on your back, that you can't carry lower down. And, remember, the weight is spread out across all the contact points of the sling. Hold your toddler on your hip, your back is instantly pushed out of alignment to balance yourself. And, your hands are occupied holding the toddler. Use a ring sling and a hip hold....you can walk straight and tall and have both hands free to pay the cashier, drink your coffee, or hold another child's hand. A healthy person, babywearing from the start, can usually carry a 35lb toddler with little difficulty. A person with back issues might need to call it quits earlier, or limit sling use in the higher end. I could carry Meg on my back for the two mile 'get the kids at school' walk until she was 33lbs, but I could carry her on my front surprisingly, still, and in the ring sling on my hip. But only for short trips now or I get a flare-up in my neck. I have felt very lucky that my SI joints have not flared up significantly since her birth, almost 3 years ago. The pregnancy was very painful, but birth solved that flare up, LOL. I think wearing her from day 3 has helped my fitness tremendously and strengthened otherwise unused muscles in my back.
"I have a Bjorn/Snugli and it KILLS my back" Take a look at the narrow straps on a Bjorn style carrier, compared to the wide straps on a mei tai, ring sling or wrap. All the baby's weight is supported by where the straps touch you---high heels sexy shoes, or low, comfortable wedges? A Bjorn also places baby away from your body so the load is not connected to you. A traditional sling keeps baby snug against you, preventing 'baby sway' (when the baby moves away from you, pulling you with him). Let's not forget the financial and practical issues with Bjorn style carriers. They are usually limited to about 22lbs...for many babies, that's reached by 6 months, and usually by one year at the latest. You can't do back or hip carries. There are issues about spine and pelvis development when baby is suspended (instead of sitting). A $90 Bjorn will be in the yardsale pile by baby's first birthday, but a $60 Mei Tai will go strong for another two to three YEARS.
If you have a particular health issue and want to know more about babywearing, there is http://www.thebabywearer.com/ and a yahoo group "Babywearing". Remember---if you can hold your baby in your arms, a sling will make life easier, NOT hurt you; as long as you choose the right sling and use it correctly. Babies should be held by people, not things :)