Premature birth occurs when a baby is born before completing 37 weeks of gestation. These babies often have low birth weight and may require special medical attention to support their growth and development. Their weight gain and height increase vary depending on factors such as gestational age, overall health, and nutrition.
According to the American Academy of Pediatrics (AAP), babies develop at their own pace, and even premature babies gradually reach their growth milestones. Parents can track their child’s progress using a growth chart and tools like a height weight calculator to monitor physical development over time.
Understanding the weight of premature babies
The average weight of a full-term newborn is around 3.17 kg, while premature infants typically weigh 2.26 kg or less. The exact weight depends on how early the baby is born. For instance, babies born after 28 weeks may weigh around 1 kg.
- Gestational age – The earlier the baby is born, the lower their birth weight.
- Nutritional intake – Adequate breast milk or fortified formula helps improve weight gain.
- Medical conditions – Babies with complications such as respiratory distress syndrome may take longer to gain weight.
- Metabolism and energy needs – Premature babies often require more calories per kilogram than full-term infants.
Premature babies are usually kept in neonatal intensive care units, where their growth is carefully monitored. Parents can also track weight gain using a height weight calculator to understand whether their baby is following a healthy growth pattern.
Symptoms of premature birth
Premature babies may exhibit certain signs that indicate preterm labour or delivery. Some of these symptoms include:
- Frequent contractions before the 37th week of pregnancy
- Persistent lower back pain
- Abdominal cramps and pressure in the pelvis
- Unusual vaginal discharge, including blood or mucus
- Preterm rupture of membranes, where the water breaks earlier than expected
Recognising these symptoms early can help parents and doctors take preventive measures to improve the baby’s health outcomes.
Growth patterns of premature babies
Weight gain
Premature babies typically start gaining weight within a few days of birth. However, their growth rate differs based on gestational age:
- Babies born at 24 weeks may gain 5 grams per day.
- Those born at 33 weeks or later can gain up to 30 grams per day.
- Babies who weigh more than 2 kg at birth should gain 20-30 grams per day.
Height increase
- Premature babies grow by approximately 1.1 cm per week until reaching 40 weeks of gestational age.
- Their head circumference also increases by about 0.5 cm per week for the first three months.
- Between six to nine months, the head grows by two centimetres, and between nine to twelve months, by one centimetre.
While these figures serve as general guidelines, every baby grows at their own pace. Parents can monitor growth trends using tools like a BMR calculator to understand how many calories their child needs daily.
Growth chart for premature babies
Medical professionals rely on Fenton Growth Charts to assess the weight, height, and head circumference of premature babies. This tool helps compare a baby’s growth against standard percentiles for their gestational age.
Growth chart for premature baby girls
| Gestational age (weeks) | Weight (kg) | Height (cm) | Head circumference (cm) |
| 24 | 0.6 | 30 | 21.1 |
| 26 | 0.8 | 33 | 23.0 |
| 28 | 1.0 | 35.6 | 25.0 |
| 30 | 1.3 | 38.5 | 27.0 |
| 32 | 1.7 | 41.1 | 29.0 |
| 34 | 2.1 | 44.0 | 30.5 |
| 36 | 2.6 | 46.5 | 32.1 |
| 38 | 3.1 | 48.5 | 33.5 |
| 40 | 3.4 | 50.5 | 34.9 |
Growth chart for premature baby boys
| Gestational age (weeks) | Weight (kg) | Height (cm) | Head circumference (cm) |
| 24 | 0.65 | 31 | 22.0 |
| 26 | 0.83 | 34 | 23.5 |
| 28 | 1.1 | 36.5 | 25.8 |
| 30 | 1.4 | 39.0 | 27.5 |
| 32 | 1.8 | 42.0 | 29.5 |
| 34 | 2.25 | 44.9 | 31.0 |
| 36 | 2.7 | 47.0 | 32.8 |
| 38 | 3.2 | 49.5 | 34.0 |
| 40 | 3.6 | 51.0 | 35.0 |
Not all babies develop at the same pace, as growth depends on multiple factors. Doctors periodically assess a preterm baby in the neonatal intensive care unit to ensure they are meeting appropriate milestones.
Nutrition for a premature baby
Premature babies often experience feeding difficulties, so doctors determine their nutritional intake based on gestational age and health condition.
- Intravenous fluids – Early preterm babies who cannot breastfeed receive nutrients through IV solutions.
- Tube feeding – Once a baby’s digestive system develops, breast milk or formula is delivered through a nasogastric or orogastric tube.
- Breastfeeding – Late preterm babies (born between 34-37 weeks) may be able to breastfeed with some assistance.
- Fortified formula – Some premature babies require additional nutrients beyond breast milk to support weight gain.
A mother from India shared her experience helping her premature baby gain weight. She followed a feeding schedule of every two hours, used coconut oil for healthy fats, practised kangaroo care for warmth and bonding, and supplemented with formula when necessary. Tracking her baby’s feeding patterns and ensuring proper rest also contributed to steady weight gain.
Conclusion
Premature babies experience unique growth patterns that require careful monitoring. Using tools like a height weight calculator and a BMR calculator can help parents understand their baby’s progress and nutritional needs. While premature babies may take longer to reach certain milestones, they gradually catch up with full-term babies when given the right medical care and nutrition.
By following medical guidance and tracking their baby’s growth with reference charts, parents can ensure that their child develops healthily despite being born preterm.
