Premature babies’ development
By definition, a premature birth is when a baby is born before 37 weeks of gestation. In humans, a normal gestational period is from 38-42 weeks. Ideally, babies remain in the womb until they are full-term but for all sorts of reasons, this does not always happen.
For every day and week that a baby is left to grow in the womb, important size, growth and developmental changes occur. Not all of these are as obvious but they are no less important.
When babies are born before they are due, they can have a range of health and developmental problems, which need to be carefully managed. Though it’s important to remember that each and every baby is an individual, and although two babies may be born at the same gestation period, they may not share the same complications.
Likewise, being born at full-term is not in itself a guarantee that everything will be fine; every pregnancy, mother and baby is unique.
The more premature a baby is, the more likely they are to have health and developmental concerns. This is why early surveillance and good ante-natal care and monitoring are so important for all mothers, but particularly to those who fit into a high-risk category.
Babies are classified as being
- Extremely premature if they are born before 25 weeks of gestation
- Moderately premature if they are born between 32-35 weeks of gestation
- Having late prematurity if they are born between 34-37 weeks
Around 85% of premature births occur after 32 weeks of gestation. Currently an estimated 15 million babies (more than 1 in 10) are born too soon every year.
Common problems with prematurity:
- Low birth weight – A normal birth weight is around 3,500 grams/3.5 kg
- Breathing difficulties, especially before 28 weeks of gestation. It is common for premature babies to have apnoeic episodes, where they stop breathing for short periods
- Bradycardia or a slowing down of their heart rate (medication can be given to help regulate both their heartbeat and breathing patterns)
- Jaundice – due to liver immaturity
- Low levels of calcium and blood glucose
- Underdeveloped organs or body systems
- Difficulty feeding and problems with digestion
- Delay in establishing breastfeeding
- Longer stays in hospital
- Higher risk of infections and less immunity
- Difficulty maintaining their own temperature
- Cerebral Palsy
- Vision and hearing problems
- Intellectual disability and learning difficulties
- Prematurity contributes to a higher risk of having emotional and behavioural problems throughout childhood and adolescence
- Potential problems with emotional attachment and bonding
- Sometimes premature babies die because they are simply too immature to survive
Common long-term problems of prematurity:
- Respiratory infections
- More prone to asthma
- More chance of admissions to hospital
- Increased risk of Sudden Infant Death Syndrome – SIDS
Why does premature labour happen?
Often we do not know the cause, but in some instances, it can be identified:
- There is some research which suggests the rising rates of obesity both before and during pregnancy have contributed to the increase in prematurity numbers in later years.
- Assisted fertility technology has meant that there are more numbers of multiple births and older mothers conceiving. This combination has also added to the increase in premature births.
- Some mothers go into spontaneous labour and despite all medical attempts to stall or halt it, labour still progresses.
- Some maternal health conditions make the uterine environment risky and it is safer for the baby to be born early than to remain in the womb. In these cases, the health benefits for the baby versus the risks of being born early are carefully weighed up.
- There are also occasions when it is safer for the mother to have her baby earlier than when she is due.
Can I still have a normal delivery?
Premature babies can be born either vaginally or by caesarean section. If the mother has had a spontaneous rupture of her membranes (her water breaks) and there are no other complications, she may progress to deliver vaginally. But if there are concerns that vaginal delivery could be too traumatic and stressful for the baby because of their degree of prematurity, then a caesarean section delivery is often done.
Risk factors for premature birth
- A past history of premature delivery
- Gestational Diabetes
- Hypertension and/or Pregnancy Induced Hypertension PIH
- Multiple births
- Having had four or more babies in the past
- Placenta Praevia, placental abruption or placental insufficiency
- Maternal obesity
- Abnormal cervix or womb
- An acute maternal illness
- Premature rupture of the membranes
Respiratory Distress Syndrome
This is a common condition in premature babies and is caused by the underdevelopment of their lungs. The more premature the baby, the more likely they are to experience Respiratory Distress Syndrome or RDS. A substance called surfactant is produced from around 28 weeks of gestation and for babies who are born before this time, breathing difficulties are more common. Surfactant helps to keep the tiny air sacs open in the baby’s lungs and without sufficient quantities; the airways cannot adequately exchange oxygen and carbon dioxide.
There are increased chances for babies who have had RDS to develop asthma in their early years.
What does corrected age mean?
It is standard practice for healthcare professionals to “correct for age” when a child was born prematurely. For example, if a baby was born 10 weeks premature their corrected age would be 30 weeks. Until the child is two years of age, correcting for their weight, head circumference and length are generally done. After this time, they are managed in the same way as their full-term peers.
Research has shown that by pre-school years, most premature babies have caught up with children of the same age in terms of their development. They may take longer and need more practice and support but eventually, most get to where they need to be.
What are the chances for a premature baby?
Again, this depends on the weeks of prematurity and the baby’s birth-weight. For a baby who is born at 24 weeks the chances of survival are around 58%, though by 32 weeks, these chances increase to 97% or more.
Specialist neonatal intensive care units are located within most large metropolitan maternity hospitals. Caring for premature babies requires highly specialised care, with medical and nursing expertise. Keeping the baby warm in an incubator is important and intravenous fluids and antibiotics are often necessary.
When a baby is too young to breathe on their own, they need to have a tube inserted into their mouth or nose which goes down their trachea (wind pipe). A ventilator does the breathing for the baby by regularly pushing oxygen into their lungs.
A premature baby may also be attached to heart and temperature monitors, and have a drip inserted into their arm or through their umbilicus. Alarms are set so that staff can be alerted to any change in the baby’s condition.
Some babies need to stay in special care or intensive care units for many weeks. If they have been very premature they may need to remain in hospital for many months.
With good care, chances are increased for premature babies to lead healthy and full lives. Early detection and management of developmental delay generally means the outcomes are much better for babies and their families.
All neonatal units have follow up programmes and assessment processes in place. Depending on the extent of the prematurity, regular check-ups occur throughout childhood. Teams including paediatricians, neonatologists, nurses, physiotherapists, occupational and speech therapists, and dieticians are all involved in the care of premature babies.