Your baby will have achieved lots of little milestones from day one, but from this month things really start to take off, with some exciting developments taking place.
• Rolling over
Any time from now you may see your baby rolling over from her front to her back when you put her down to play on her tummy. Some babies manage to do this before they're four months old, but this is the typical stage for it to happen.
She might give you a warning sign that she's ready to attempt to roll: watch out for her rocking from side to side when she's on her tummy.
It's important you take some precautions to safeguard her when she does manage to flip over: make sure your floors are free from anything she might ingest or hurt herself on, as once she's rolled over she'll soon be rolling around the room!
Don't put her down on any raised surface, such as your bed or a sofa: chances are she'll roll straight off the edge, which could have dire consequences.
• Smiling and giggling
Now she'll beam broadly and even giggle, which is such a delightful sound! There's no better way to be greeted by your baby than with a winning smile.
Language starts to become more meaningful for your baby this month and you should see her listening intently when you read, talk or sing to her.
Expect to hear some cooing and babbling from your baby. She'll start with 'hard' sounds that are the easiest to make, like 'Babababa' or 'Dadadada'. Her dad may feel very privileged, but it's just easier for her to say 'B' than 'M. Don't worry - 'Mamamama' isn't too far off!
Once she's discovered her hands, she'll probably start to suck her fingers and fists, and she'll soon start to 'mouth' objects you hand her. Exploring things with her mouth is particularly enlightening to her as her tongue has very sensitive nerve endings so can tell her a lot about the shape and form of objects.
• Trying to sit
Your baby's natural instinct is to become mobile, so don't be surprised to see her trying to pull herself into a sitting position some time during this month. She might grasp her cot bars or practise leaning forwards in her baby seat or on your lap. You can encourage her by sitting her leaning forwards on your lap or propping her up with lots of cushions on the floor. Make sure you supervise this at all times, though: it's not yet safe to leave her 'sitting' without you there.
Remember, of course throughout reading these guides, that babies develop at different rates. Don't fall into competitive parenting with mothers of babies of similar ages - if your baby doesn't do something one week, you can bet she will within weeks. Each baby is unique.
Feeding your baby
Your baby will be in a good feeding routine now, but don't be surprised if you suddenly find it a struggle to keep him interested in breast or bottle. Partly it's because he's fascinated by the world around him and is easily distracted; partly it's because he's starting to be interested in what you and the family is eating.
Tempting though it may be to start him on solids, though, the Department of Health's recommendation is that you should continue with breastmilk or formula exclusively until your baby reaches six months.
It might be a struggle, and you may disagree and decide to introduce a little baby rice or pureed fruit and veg earlier than this. Don't attempt to do so until he's 17 weeks old at the very earliest, though, as his digestive system won't be well developed enough to cope properly before this time.
The Department of Health does acknowledge that some babies are more than ready for their first solids by 17 weeks, and in its most recently published guideline, it states: "Solid foods should not be offered before four months... However, if an infant is showing signs of being ready to start solid foods before six months, for example, sitting up, taking an interest in what the rest of the family is eating, picking up, and tasting finger foods then they should be encouraged".
There are some foods that you must avoid before your baby reaches six months.
• added sugar
• honey (which may contain a bacteria that can trigger botulism - a severe strain of food poisoning)
• foods containing gluten, such as breakfast cereals, bread and pasta
• unpasteurised cheese.
Entertaining your 4-month-old
Believe it or not, your young baby can become bored, and about now she'll be ready for slighty more complex games. There's a fine line between entertaining and over-stimulating her, though, so look for cues that she's had enough: you'll see her looking away, engaging less, showing signs of tiredness or irritability. That's the time to stop and let her have some down time.
Things she'll enjoy include:
• An activity play mat
She'll love the variety of textures, sounds, colours and shapes. She'll try to grab the dangling toys (although she may not grab accurately each time); roll from side to side; and smile and giggle as she discovers more and more play opportunities.
• Wrist and ankle rattles
These attach like bracelets and your baby will be delighted to be generating the tinkling sounds herself as she exercises her legs and arms.
• Hand-held rattles
Her hand-eye coordination is improving all the time and she'll love waving a rattle around.
• Stroller toys
Toys that attach to the stroller with curly cables mean your baby can grab and play with them independently as you wheel her along. Or choose a strap of toys that attaches across the front of the pram/pushchair that she can spin, squeeze, push and pull.
• Musical toys
Your baby will be fascinated by toys that make sounds, especially if she has to produce the sound herself by hitting the right button. Musical activity balls are a good bet for this age group. She may try to emulate the noises or giggle in response.