First pillar
Medical prevention
At the visit: follow growth, examine the baby, watch development, support caregiver wellbeing, assess family needs, and give the second round of routine vaccines.
Academy · Prevention · Pediatrics
4months
Preventive visit
A visit for a baby who is more alert, more social—and beginning to move.
Use this guide to understand what the doctor will check, which vaccines usually continue, how development is changing, and what matters at home as rolling and feeding decisions approach.
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Start here · Five useful questions
Begin with what matters to your family today.
Second pillar
Lifestyle prevention
Every day: support feeding, protect sleep as rolling begins, make room for floor play and connection, care for caregivers, and reduce unsafe exposures.
What the doctor does
The visit follows one simple arc: listen, check, protect, plan.
The order may change, but these are the major parts a family can expect.
01
Listen
Your concerns, feeding, sleep, wet diapers and stools, development, family wellbeing, childcare, exposures, and safety.
02
Check
Weight, length, head size, growth pattern, vision and hearing responses, movement, head control, and a complete examination.
03
Protect
The second round of routine vaccines, caregiver mood screening, family-needs review, and early attention to any concern.
04
Plan
Vitamin D and iron when relevant, feeding readiness, rolling and safe sleep, floor play, home safety, and the next visit.
Growth and examination
The pattern matters more than one measurement.
Weight, length, and head size are plotted over time. The doctor also checks the baby from head to toe, with special attention to head control, movement on both sides, vision, hearing, hips, heart, skin, and head shape.
What if something worries me?
Bring it up at this visit. Concerns about growth, feeding, movement, interaction, hearing, or vision should be assessed now rather than saved for a later screening visit.
Prepare for the visit
A small list you can actually use.
0 of 5 ready
Vaccines and safety
The vaccine series continues at 4 months.
Most babies receive the second doses of the same five protections started at 2 months. The exact products and earlier record still matter.
Usually given at this visit
DTaP
Protects against diphtheria, tetanus, and whooping cough.
Injection · second dose
Hib
Protects against serious illness caused by haemophilus influenzae type b.
Injection · second dose
Pneumococcal
Protects against serious pneumococcal illness.
Injection · second dose
Polio
Protects against poliomyelitis.
Injection · second dose
Rotavirus
Protects against rotavirus stomach and intestinal illness.
By mouth · second dose
One visit
The routine vaccines can be given together.
There is no benefit to separating the vaccines that are due. The oral rotavirus vaccine is given by mouth; the others are injections and may be combined into fewer products.
Usually short-lived
What is common
Fussiness, soreness or swelling where a shot was given, lower appetite, sleepiness, or fever may occur during the next 1–3 days. Rotavirus vaccine may also cause brief diarrhea or vomiting.
Products can differ
The record matters
The brand used for Hib and rotavirus determines how many doses remain. A combination vaccine may also include hepatitis B. The care team should use the complete record to plan the next doses.
A later or individual decision
Not routine at 4 months
Influenza vaccination begins at 6 months. Routine anemia and lead blood tests are not scheduled at this visit. RSV protection depends on season and individual circumstances.
When a reaction needs urgent attention
Get emergency help for hives with facial or mouth swelling, breathing difficulty, a seizure, or a baby who is limp or hard to wake. After rotavirus vaccine, severe waves of crying with the legs pulled up, repeated vomiting, bloody stool, or unusual sleepiness need urgent assessment.
Growth and development
At 4 months, connection and movement become easier to see.
These are abilities the doctor watches for around this age—not a test your baby has to perform on command.
Connection
Smiles to gain attention, chuckles, and looks toward a caregiver.
Communication
Coos, makes sounds back to another person, and turns toward voices.
Hands and attention
Looks at the hands, reaches for objects, and brings objects toward the mouth.
Movement
Holds the head steadier, holds a toy placed in the hand, and pushes up on the forearms during tummy time.
Timing varies
Rolling may begin
Some babies begin rolling from front to back around this age. Whether or not it has happened yet, signs of trying to roll should change swaddling and fall-prevention plans.
But concerns do not wait
No formal screen today
A standardized developmental screen is not routine at 4 months. If you or the doctor has a concern, the baby can be screened and referred for support now.
Signs to discuss with the doctor
No social smile, no visual tracking or eye contact, poor head control, not bringing the hands together or toward the mouth, unusual stiffness or floppiness, no response to loud sounds, uneven movement, or loss of a skill.
Feeding and next foods
Milk still leads. Solid food is a readiness decision—not a deadline.
Human milk or iron-fortified formula remains the baby’s main nutrition. The 4-month visit is a good time to plan what comes next.
The short answer
For most babies, solid foods wait until about 6 months.
Do not begin before 4 months. Readiness—not the calendar alone—includes better head and trunk control, sitting with support, less tongue-thrusting, and interest in food.
Feed responsively
Continue human milk or iron-fortified formula. Follow hunger and fullness cues, and never prop a bottle or leave the baby alone while feeding.
Continue vitamin D
Give 400 IU each day when the baby is breastfed or drinks less than about 28 ounces of formula daily.
Ask about iron
For an exclusively breastfed term baby, discuss the iron plan at this visit. Premature or low-birth-weight babies need an individualized plan.
Keep a few foods out
Do not give honey, juice, cow’s milk, or plant-based milk at this age. Do not add food to a bottle.
What about allergenic foods?
Once a baby is developmentally ready, allergenic foods should not be deliberately delayed. A baby with severe eczema or an egg allergy may need a specific peanut-introduction plan between 4 and 6 months after appropriate evaluation. Discuss that plan before starting.
Life at home · Contrada second pillar
As movement changes, the environment has to change too.
At 4 months, daily prevention lives in feeding, sleep, floor play, relationships, caregiver wellbeing, and the spaces around the baby.
Daily practice 01
Stop swaddling at rolling attempts
At the first sign that the baby is trying to roll, stop swaddling. Do not use weighted swaddles.
Daily practice 02
Protect every sleep
Place the baby on the back on a firm, flat crib or bassinet surface. Room-share without bed-sharing and keep soft items and inclined sleepers out.
Daily practice 03
Make room for floor play
Use supervised, awake tummy time and interactive floor play each day. Encourage reaching and movement; tummy time is never a sleep position.
Daily practice 04
Talk and respond
Talk, read, sing, smile, and make sounds back and forth. Simple routines and responsive care support both learning and security.
Daily practice 05
Support the caregivers
Caregiver mood, fatigue, relationships, return to work, childcare, and practical support are part of the baby’s health.
Daily practice 06
Prepare for mobility
Use a rear-facing car seat, prevent falls from raised surfaces, reduce burn and choking hazards, and keep the home free of tobacco, nicotine, vaping, and smoke.
Once the baby can roll both ways
Keep placing the baby on the back at the start of every sleep. Once the baby can roll independently in both directions, you do not need to keep repositioning them.
When to get help
A few signs should change the plan quickly.
This is a focused guide, not a complete emergency manual. Trust a serious concern and contact your baby’s clinician.
Prompt assessment
Fever at this age
A rectal temperature of 100.4°F (38.0°C) or higher warrants prompt medical assessment.
Emergency now
Trouble breathing, blue color, seizure, severe allergic-reaction signs, a baby who is limp or hard to wake, or a severe injury.
Call the clinician
Poor feeding, fewer wet diapers, ongoing vomiting or diarrhea, unusual inconsolable crying, or a baby who seems noticeably less alert or active.
Developmental changes that should not wait
Contact the doctor for loss of a skill or a new concern about vision, hearing, interaction, head control, muscle tone, or movement on one side.
Looking ahead
Next routine visit: 6 months.
The next stage brings another round of vaccines and a more active conversation about complementary foods.
At 6 months
Bring the vaccine record—and what you have noticed.
Routine vaccine series continue, influenza vaccination begins, and feeding plans can be matched to the baby’s developmental readiness.
A little later
Developmental screening at 9 months.
The doctor watches development at every visit. A routine standardized developmental screen is scheduled at 9 months—but concerns can be assessed at any time.
References & review
This family guide was last reviewed September 12, 2026. It is educational and does not replace individualized clinical care.
Evidence reviewed includes guidance from current pediatric preventive-care, immunization, development, nutrition, and safe-sleep guidance documented for this topic. Where recommendations differ, those differences are identified explicitly.