When parents come for their one month visit they're most interested in feeding issues. Feeding issues, peeing issues, and pooping issues are all the popular one month visit issues. So, a one month should be feeding every three to four hours during the day. In the evening a one month old might feed every three hours, but they might sleep three to five hours. If they do then you're really lucky. You don't have to wake a one month old baby up every three hours to feed any more unless your doctor tells you that your baby is not gaining enough weight and needs to be woken up every two to three hours let's say.
Breast-fed babies wake more often, because they just don't get as much volume when they breast feed. Often, a baby's put on the breast, and when they hear the mom's heartbeat and they feel the mom's warmth they just fall right back to sleep. They don't finish that full feed like a bottle-fed baby might get three or four ounces before bed.
Babies often cluster feed, and that's normal. So, a baby might feed every hour during the day, especially a breast-fed baby, and in the evening that baby might sleep longer. That's fine.
Babies should have anywhere between three to five wet diapers a day, and poop can range. Some breast-fed babies poop with every feed, whereas some babies don't poop for five days. That's totally normal. I would say that the majority of the phone calls I get are parents worrying about a baby being constipated. There's a wide range of normal, and that's OK.
At one month the baby should be regarding your face, looking at you while they're feeding. What the baby is seeing is the contrast of you against the wall behind. So, sometimes parents feel that the baby is looking past them because their vision is about 20/400. It's very out of focus. What they're looking at is a contrast of you against the wall behind them, and that's OK.
Between one month and three months the baby is going to start to recognize you, regard your face, know your voice. A baby should be responding to sound of course. They still have the startle reflex, so if a loud car drives by or somebody honks a horn they'll startle. That's the Moro reflex. That's normal.
Babies should be sleeping on their back. I recommend that parents rotate the baby's head from side to side. I almost make the analogy of a rotisserie chicken. You want it cooked all the way around. So with the baby's head, because we are preventing SIDS by having a baby lie on their back, we are creating a flat back of their head. That's called postural plagiocephaly. To prevent postural plagiocephaly I recommend that the parents rotate the baby's head from side to side when they put them to sleep.
Then during the day time when the baby's awake you can give the baby tummy time. Parents ask how much tummy time does a baby need. There's no set menu for tummy time. Five minutes for a baby is eternity. You often put your baby on their tummy and they're supposed to lift their head up but they smush their head back down. That's fine, but you want to keep on practicing with the baby because they're sleeping on their back for so long some of their milestones are delayed, and we want them to learn to push up when they're awake. So, whenever the baby's awake you can put the baby on a firm surface like the mattress in a crib or a play mat on the floor and let the baby learn to push up and hold their head up.
Babies don't need water at this age. Water starts at four months. On warm days you just have to keep your baby cool and well hydrated with formula or with breast milk.
As far as smiling, smiling develops between six weeks to two and a half months. A baby will start smiling when they're happy or when they're soothed. A baby should also, between one and three months, be calmed by your voice when you come in the room and be consoled. If a baby has excessive crying where they cannot be consoled whatsoever then you should contact your physician.