Why late preterm babies born at 34 to 36 weeks need extra care

A late preterm baby is one born between 34 weeks and 36 weeks 6 days of pregnancy. These babies often look just like full term babies, but they are less mature inside. They have more feeding trouble, low blood sugar, jaundice and readmissions to hospital. Most do very well with a little extra watching in the first weeks.

What is a late preterm baby?

A baby born from 34 weeks 0 days to 36 weeks 6 days of pregnancy is called late preterm. The American Academy of Pediatrics recommended "late preterm" instead of the older "near term", to make clear that these babies carry higher risks.¹

A baby born at 36 weeks is still premature. The last weeks of pregnancy are a time of fast growth in the brain, lungs, liver and fat stores. Missing even a few of those weeks matters.

How common is late preterm birth?

Very common. In the United States, late preterm babies make up nearly three quarters of all preterm births.²

Worldwide, about 13.4 million babies were born preterm in 2020, close to 1 in 10 births. Southern Asia and sub-Saharan Africa together accounted for about 65 percent of them.³ India has a large share of these babies, so late preterm care is everyday work in our hospitals.

Why are some babies born early?

Preterm birth happens in three main ways: labour starting early on its own, the waters breaking early, or doctors delivering the baby early because of a problem in the mother or baby.⁴

Common medical reasons for an early planned delivery include high blood pressure in pregnancy (pre-eclampsia) and a baby who is not growing well in the womb. Spontaneous early labour can follow infection or inflammation, problems with blood vessels of the placenta, or an overstretched womb, as with twins. A previous preterm birth and a short cervix are strong warning signs.⁴ Often no single cause is found, and it is almost never something a mother did.

Is a premature baby the same as a small baby?

No. A baby can be small because they were born early, because they did not grow well in the womb, or both.

A baby who is small for the number of weeks of pregnancy is called small for gestational age (SGA). Global estimates for 2020 suggest about 13.4 million babies were born preterm and about 23.4 million were SGA.⁵ A late preterm baby who is also SGA has two sets of risks, especially low sugar and poor feeding, and needs even closer watching.

Why does a late preterm baby need extra care if they look healthy?

Because looks can be misleading. Late preterm babies are less mature than term babies in breathing, feeding, temperature control and blood sugar.¹

In a Massachusetts study of more than 400,000 births, late preterm babies were 7 times more likely than term babies to have a newborn health problem, 22 percent compared with 3 percent.² The risk doubled for each week born before 38 weeks.² The late preterm brain is also still developing and is more easily hurt.⁶ Dr Dutta sometimes calls these babies "great pretenders".

Why do late preterm babies have trouble feeding?

They tire quickly and often fall asleep at the breast after a few sucks. To a tired mother, this can look like a full, happy baby.

Their suck is weaker and less coordinated. Mothers who deliver early, often by caesarean, may also find their milk comes in later. Poor feeding then drives the other problems: low sugar, jaundice, dehydration and weight loss. In one American study, breastfed late preterm babies sent home early were about twice as likely as term babies to be readmitted.⁷ This is not a reason to stop breastfeeding. It is a reason to get extra feeding support.

How should I feed my late preterm baby?

Feed often, wake your baby for feeds, and check that milk is actually going in. Do not wait for strong hunger cries.

• Wake a sleepy baby for feeds rather than letting long gaps pass.
• Watch for steady sucking with swallows you can hear, not just fluttery sucks.
• If the baby feeds poorly, express milk after feeds and give it by cup or paladai.
• Hold your baby skin to skin between feeds. It keeps them warm and more awake.
• Give no water, honey, ghutti or gripe water.

Ask for a lactation counsellor before you go home.

Why do late preterm babies get low blood sugar?

They have smaller energy stores and are slower to make their own sugar between feeds. Low blood sugar (hypoglycaemia) can harm the developing brain if it is severe or long lasting.

In a New Zealand study of babies at risk, including late preterm babies, about half had at least one low sugar reading, and most episodes happened in the first 24 hours.⁸ American guidance recommends identifying at-risk babies early, checking their sugar and taking steps to prevent low levels.⁹ Low sugar often has no signs, though some babies become jittery, sleepy, floppy or feed poorly. Early, frequent feeding is the first line of treatment.

Why do late preterm babies get more jaundice?

Their livers clear bilirubin (the yellow pigment from old red blood cells) more slowly. If feeding is poor, more bilirubin is taken back up from the gut.

NICE lists birth before 38 weeks as a risk factor for serious jaundice.¹⁰ In late preterm babies jaundice often peaks after they have gone home. Jaundice and infection were the most common reasons for readmission in late preterm babies sent home early.⁷ Ask for a bilirubin check before discharge and a follow-up check soon after.

Can sunlight treat jaundice in my baby?

No. NICE advises against using sunlight to treat jaundice.¹⁰ It is unreliable and can overheat or burn a baby.

Also, do not judge jaundice by eye alone. NICE says looking at the skin is not enough to estimate the bilirubin level, and jaundice is harder to see in darker skin.¹⁰ A skin meter or blood test gives the real number.

How do I keep a late preterm baby at the right temperature?

Keep the baby skin to skin as much as possible, use a cap, and dress them in one more layer than you. Avoid both chilling and overheating.

Late preterm babies have less fat, so they lose heat faster. A cold baby burns sugar, which makes low sugar and poor feeding worse. WHO recommends kangaroo mother care for all preterm and low birth weight babies, in hospital or at home.¹¹ In an air conditioned room, keep the baby covered. In the summer heat, do not bundle them in blankets.

Do late preterm babies have breathing problems?

Some do. Fast breathing in the first hours or days is more common than in term babies, especially after a caesarean before labour.

Most of this is from slow clearing of lung fluid, and it settles. A few babies have RDS (surfactant shortage) or an infection. In a large trial, steroid injections given to mothers at risk of delivery at 34 to 36 weeks lowered serious breathing problems, but more babies had low blood sugar.¹² European guidelines advise against routine steroids after 34 weeks in spontaneous preterm labour.¹³

When can a late preterm baby go home from hospital?

Only when feeding is going well, sugar and temperature are stable, and jaundice has been checked. Late preterm babies should not be sent home as early as healthy term babies.

In a Massachusetts study, late preterm babies who went home after less than two nights had nearly twice the readmission rate of term babies sent home just as early.⁷ The American Academy of Pediatrics has set out guidance on checking and caring for late preterm babies after birth.¹ Make sure you have a review appointment very soon after going home.

Will my late preterm baby do well at school?

Most late preterm children do well. As a group, they have slightly lower scores on thinking and school tests than children born at term.¹⁴

A review found late preterm children had a higher risk of lower general ability, but the differences were small.¹⁴ Use corrected age for milestones in the first year or so, keep up with check-ups, and ask for an assessment early if you are worried.

When should I bring my late preterm baby back to the doctor?

Come back the same day if you notice any of these.

• Too sleepy to wake for feeds, or feeds lasting only a few minutes.
• Fewer wet nappies than usual, or dry nappies for many hours.
• Yellow colour spreading to the tummy, legs, palms or soles.
• Pale stools or dark urine.
• Feels cold or hot, or a temperature below 35.5 degrees C or 37.5 degrees C or more.¹⁵
• Fast or hard breathing, grunting or chest drawing in.¹⁵
• Jittery, floppy, or simply unwell to you.