Babies born weighing less than two kilogrammes are considered to be of low birth weight, an average new-born usually weighs about 3.6 kg.

Although a low-birth-weight baby may be healthy even though they are small, medics note that some might need some special attention, including treatment depending on the situation of the infant.

Dr Iba Mayale, an obstetrician and gynaecologist, says when babies are born, they are categorised in normal birth weight, which is between 2.4 kg and 3.9.

Low birth weight is considered to be less than 2.4 kilogrammes while very low birth weight is normally 1.5 kg. Also, a high birth weight is normally more than 3.9 kg.

Dr Mayale says that babies are born with a low birth weight because they arrive early or because they have poor growth during pregnancy or a combination of both.

Poor growth during pregnancy, known as intrauterine growth restriction, happens when a foetus is below the 10th percentile for their gestational age.

What causes this?

Dr Silvain Muzungu, a gynaecologist at Kibagabaga Hospital, says there are several potential causes for low birth weight.

One of them he says is preterm birth, globally, he says it’s estimated that about two-thirds of all low birth weight babies are preterm or born before the 37th week of pregnancy, and nearly all very low birth weight babies are premature.

Also, about one-third of a baby’s birth weight is determined by genes, so if you and/or your partner was a small baby, there’s a greater chance your baby will be born small too.

Another common cause that might bring about low birth weight in children, Dr Muzungu says, is problems with the placenta.

He explains that if the placenta doesn’t get enough oxygen or nutrients to a baby or the placenta’s blood supply is impaired, the baby may grow at a slower rate during pregnancy.

Dr Mayale says another cause is if the mother is carrying multiples, that is, more than one baby. For instance, he says if one is carrying more than one baby, the space inside the uterus can get cramped quickly, which is why 60 per cent of twins are born early and frequently at low birth weight, according to studies.

On average, twins are delivered at around 35 or 36 weeks and weigh about 2.4 kg.

According to Dr Mayale, he says women should pay attention to how much weight they gain during pregnancy as both low and excess weight is not good for the mother or infant.

For instance, he mentions that not gaining enough weight during pregnancy, less than the recommended amount of weight during pregnancy, can result in a baby who’s born with low birth weight.

In the short-term, low birth weight babies especially those who are born premature or are very underweight are more likely to have complications. 

Rene Tabaro, a nutritionist at King Faisal Hospital, says kids born underweight normally have issues when it comes to feeding, especially those born before 34 to 36 weeks.

This infant, Tabaro says, often struggles with breastfeeding or bottle-feeding because of immature or underdeveloped sucking reflex breathing problems. 

Babies who are born early sometimes haven’t had enough time in the womb for their lungs to develop, which can lead to treatable breathing problems like respiratory distress syndrome (RDS).

Tabaro says such babies are also likely to suffer from a condition known as jaundice, which is a common condition that happens when a baby’s liver isn’t fully formed or isn’t working correctly.

Dr Muzungu notes that babies born with low birth weight are also likely to get infections quite easily because their immune systems aren’t fully developed, so they’re at greater risk.

Baby management in the hospital may include IV fluids feeding for babies who struggle to feed, an IV or a small tube placed in the stomach via the mouth ensures delivery of the vital nutrients, vitamins, minerals, and fluids necessary to grow and thrive. 

In light therapy, it’s recommended that babies with jaundice may be placed under special lamps that help the body process and excrete bilirubin.

If light therapy doesn’t work, other more intensive treatments involving blood exchange transfusions or IV injections of antibodies may be required, on rare occasions though.