Week 15

Days 99 to 105 · 14 weeks 0 days to 14 weeks 6 days old · about 3 months This week your baby measures about 61 cm (24 in) and weighs roughly 6.3 kg (13.9 lb). Babies vary widely, and a steady curve on the growth chart matters more than any single number. Your baby is exploring with hands and mouth, napping in shorter and more varied chunks and may be laughing out loud for the first time. For you, the return to work or the start of childcare may be getting closer, along with mixed feelings about it. This week covers mouthing, naps at this age, fever and how to take a temperature, settling into daycare, belly laughs and the emotional side of going back to work.

Day 99 · 14 weeks 0 days old

Everything goes in the mouth

Hands, toys, blankets, your finger, the edge of a book: if your baby can reach it, it is probably heading for their mouth. This is not hunger, and it is not always teething. It is one of the main ways babies learn.

The mouth has a huge number of nerve endings, and at this age it is far more sensitive than the fingertips. When your baby gums a toy, they are finding out about its shape, texture, hardness and temperature. Mouthing also helps them practise moving the tongue and jaw, skills that will matter later for eating and talking.

There is no need to stop it. Instead, make sure what is within reach is safe to mouth. Good toys are too big to fit fully inside the mouth, have no small parts that can come loose, and are washable. Wash teethers and toys regularly in warm, soapy water, particularly if other children have been playing with them, but there is no need to sterilize everything at this age. Keep a close eye on older siblings' toys, coins, button batteries, magnets and anything with a detachable piece. If it fits through a toilet paper tube, it is small enough to choke on.

Try this: Gather three safe objects with different textures, such as a fabric square, a wooden ring and a silicone teether, and let your baby explore them one at a time.

Day 100 · 14 weeks 1 day old

Naps at 3 to 4 months

At this age, daytime sleep is often messy. Many babies take three to four naps a day, some long and some only 30 to 45 minutes, one sleep cycle. Total daytime sleep is often somewhere between three and five hours, and most babies sleep around 12 to 16 hours across the whole day and night. Your baby may need more or less.

A useful idea is the wake window: the length of time your baby can comfortably stay awake between sleeps. At 3 to 4 months, this is often about 1 to 2 hours. Past that point, many babies become overtired, which can make it harder, not easier, for them to settle.

Watch for early sleepy signs: staring into space, losing interest in play, rubbing eyes, pulling at ears, yawning or getting fussy. Starting the wind-down when you see them tends to work better than waiting for full tears. Short naps are very common and usually not a problem. Some babies are simply catnappers at this age, and nap length often stretches as the months go by. Naps on the move, in a carrier or stroller, are fine too. If your baby falls asleep in a car seat, move them to a firm, flat sleep surface once you arrive, as car seats are not for routine sleep outside the car.

Try this: For the next two days, note when your baby wakes and when they first show sleepy signs, to find their usual wake window.

Day 101 · 14 weeks 2 days old

Understanding fever by age

A fever is a temperature of 38.0 °C (100.4 °F) or higher. It usually means the body is fighting an infection, most often a virus. What to do depends a great deal on your baby's age.

Under 3 months: any fever of 38.0 °C or more needs a doctor the same day, right away, even if your baby seems well. If your baby was born early, ask whether this rule applies for longer.

3 to 6 months: call your baby's doctor for any fever, especially one of 38.9 °C (102 °F) or higher, or if your baby seems unwell, is feeding poorly or the fever lasts more than a day.

Over 6 months: behaviour matters more than the number. Call if the fever lasts more than two or three days or your baby seems ill.

Fever medicine can make a miserable baby more comfortable. Some is suitable from about 2 to 3 months, some only from 6 months. Ask your pharmacist or follow the dose for your baby's weight on the package. Never give a baby aspirin.

Get help right away if your baby is hard to wake, floppy, struggling to breathe, has a rash that does not fade when you press a glass against it, has a seizure, or cries in a high-pitched way you cannot settle.

Try this: Save your baby's doctor's number and your local after-hours health line in your phone today.

Day 102 · 14 weeks 3 days old

How to take your baby's temperature

Touching a forehead is not a reliable way to check for fever. A digital thermometer gives you a number you can share with a doctor or nurse. Avoid old glass mercury thermometers.

For babies and young children, a rectal temperature is the most accurate. Clean a digital thermometer and put a little petroleum jelly on the tip. Lay your baby on their back with knees bent towards the chest, or tummy down across your lap. Gently insert the tip about 1 to 2.5 cm (half an inch to an inch), no further, and hold it still until it beeps. Label that thermometer for rectal use only.

An armpit temperature is easier and fine for a first check. Place the tip in the centre of the armpit, hold your baby's arm snugly against their side and wait for the beep. If it shows a fever, or your baby seems unwell, confirm it rectally if you can, and tell the doctor which method you used.

Ear thermometers are not reliable in babies under about 6 months. Forehead (temporal artery) thermometers can be useful if used carefully, but readings vary between devices. Whatever you use, read the instructions and wait at least 15 minutes after a bath or being bundled up.

Try this: Practise taking an armpit temperature today while your baby is well, so the steps feel familiar on a night when they are not.

Day 103 · 14 weeks 4 days old

Easing into daycare

Whether your baby will be with a daycare centre, a home provider, a nanny or a relative, the first weeks of childcare are a transition for everyone. Babies this young usually adapt well, especially when the change is gradual. If you can, plan a settling-in period before your first day of work. Start with an hour or two with you present, then leave for a short time, and build up over a week or two. This lets your baby get to know the new carer and lets you watch how they handle feeding, sleep and comfort.

Share what you know. A one-page note helps: how your baby likes to be held and soothed, feeding amounts and timing, sleepy signs, nap habits and any medical needs. Label bottles, clothing and anything that goes back and forth. Ask how they put babies to sleep, and expect to hear back to sleep, on a firm flat surface, with nothing loose in the crib.

Saying goodbye is easier if you keep it short and warm. Slipping away while your baby is distracted can feel kinder, but a consistent, cheerful goodbye builds trust over time.

Expect more colds in the first months of childcare. It is normal and usually eases with time.

Try this: Write your one-page "about my baby" note today, so it is ready for whoever looks after your baby next.

Day 104 · 14 weeks 5 days old

The sound of a real laugh

Somewhere between about 3 and 5 months, many babies give their first proper laugh, a deep, delighted chuckle that seems to surprise them as much as you. If you heard early giggles a few weeks ago, you may now notice longer, louder belly laughs.

Laughing is a social skill. Your baby is learning that some things are unexpected and funny, and that sharing that feeling with you is rewarding. It also shows they are starting to predict what comes next, which is why a game where something happens after a pause, such as a gentle tickle at the end of a rhyme, works so well.

Every baby finds different things funny. Silly noises, blowing raspberries on a tummy, a hat on your head, a dog's bark or a big "boo" can all set one off. What made them laugh yesterday may not work today. Some babies are more serious by temperament and laugh less often, which is fine. If your baby has not laughed out loud yet, give it time; this is one of those skills with a wide range.

Watch your baby's cues. Turning away, arching or fussing means they have had enough excitement for now, even if they were laughing a moment ago. Try this: Try three different sounds or faces today and note which one gets the biggest response.

Day 105 · 14 weeks 6 days old

Mixed feelings about going back

For many parents, the return to work brings a tangle of feelings: relief, guilt, excitement, sadness, worry and sometimes all of them before breakfast. There is no right way to feel about it, and both wanting to go back and dreading it are completely normal.

Some people miss adult conversation and the sense of who they were before the baby. Others feel they are leaving too early. Many worry that their baby will forget them or love the carer more. They will not. Babies form strong attachments to several caring adults, and you remain the person they know best.

It can help to plan the first weeks back with some slack. If your workplace allows it, a shorter first week, starting mid-week or flexible hours can ease the change. Lower your expectations at home for a while, and decide together what can slide. Plan something simple and close for the first evenings, such as a bath together or a long cuddle, so the reunion feels like a ritual rather than a rush.

If you will be the one staying at home while your partner returns to work, that is a big change too. Days alone with a baby can feel long, and it helps to name that and plan for company.

For your partner: Ask how they are feeling about the return to work, listen without trying to fix it, and take over one morning or evening task for the first two weeks.