Consultant Paediatrician & Neonatologist, Indraprastha Apollo Hospital, New Delhi
What is a premature birth?
The duration of a normal pregnancy is 40 weeks. A premature birth is one that occurs before 37 weeks of pregnancy. A baby born at 28 weeks that is, after only 7 months of pregnancy can weigh as little as 1 Kg.
How is prematurity measured?
The duration of a pregnancy is measured as duration of gestation age or the length of time the baby spends in the womb. It is calculated from the first day of the last menstrual period. Ultrasound scan findings further help confirm the gestational age of the baby while still in the womb.
Another reflection of prematurity is the birth weight. The expected birth weight at term is 2.5 Kg or more. Premature babies are usually less than 2.5 Kg in weight, that is Low birth weight (LBW). The more premature the baby, the smaller it is. However, not all babies that are LBW are premature. Some time babies born at term may weigh less than 2.5 Kgs. Therefore, gestational age is a more accurate measure of prematurity than birth weight.
What are the common problems associated with prematurity?
The smaller the baby or the earlier the birth the more the associated problems.
Lungs: Respiratory distress syndrome is a common problem. This means that the baby’s lungs are immature due to lack of a substance called surfactant. Oxygen therapy is usually needed. If breathing is very poor, then a ventilator may be needed to help the baby to breathe and to maintain oxygen levels in the blood.
Heart: Premature babies may also have a problem related to the heart. One of the problems is patent ductus arteriosus (PDA) which is a communication between the pulmonary artery and aorta. This may require treatment.
Brain: Very small babies, especially those weighing less than 1 Kg are prone to bleeding into the brain, resulting in an intra-ventricular haemorrhage (IVH).
Feeding problems: The baby may need to be fed through a tube until he is strong enough to suck. Breast milk can also be fed through the tube.
Vision and hearing: Crossed eyes (strabismus) are more common in premature babies than in full term babies. Often, this problem goes away on its own as the baby grows up. Some babies have an eye disease called retinopathy of prematurity (ROP), a scarring of the retina due to exposure of the baby to excessive amounts of oxygen. ROP usually occurs in babies who are born very early, at 32 weeks of pregnancy or earlier. An eye doctor needs to be consulted to monitor any eye changes and allow any intervention. Premature babies are more likely to have hearing problems as well. All premature babies need regular growth and development checks with a very close watch for any developmental delay. Vision and hearing must be repeatedly assessed.