Premature baby: Defined

A premature baby is defined as a baby born before 37 weeks of pregnancy are completed. There are 3 sub-categories of premature birth, depending on the week of pregnancy that your baby is born:

  • Extremely preterm (<28 weeks)
  • Very preterm (28 to <32 weeks)
  • Moderate to late preterm (32 to <37 weeks).

The following terms are commonly used terms when referring to premature babies;

Small for gestational age (SGA):
Babies who are smaller than the expected weight for the number of weeks of pregnancy.

Low birth weight (LBW):
Is used to define a baby that weighs less than 5 lb 8 oz (2,500 g) regardless of gestational age (the term used to describe how far along the pregnancy is).

Very Low Birth Weight (VLBW):
Babies weigh less than 3 lb 5 oz (1,500 g)

Extremely Low Birth Weight (ELBW):
Babies weigh less than 2 lb 3 oz (1,000 g).

Rate of premature birth                                                                                  

Globally over 15 million babies are born too early, too small and too sick each year: that’s “1 in 10 babies”.  Here in Ireland the figure stands around 4,500: that equates to “1 baby born prematurely every 116 minutes”. 

Causes of premature birth

  • Late maternal age
  • Obesity
  • In-Vitro-Fertility treatment
  • Multiple births
  • Infection
  • Preeclampsia
  • Gestational diabetes
  • PPROM-preterm premature rupture of membranes
  • Problems with the placenta
  • Problems with the cervix
  • Problems with the uterus
  • Problems with your baby’s development
  • Anti-Phospholipid Syndrome
  • A combination of medical conditions
  • One of more previous miscarriages or premature births
  • Previous delivery of 4 or more children
  • High level of stress
  • Age below 18 or over 34 years
  • Previous fertility treatment
  • Short time between pregnancies
  • Severe illness of the mother
  • Vaginal Bleeding

Reasons for increasing rates of premature birth

  • Progress in research and intensive care treatments
  • Increased number of multiple pregnancies as a result of increased use of assisted reproductive techniques i.e IVF.
  • Possibility of early and planned caesarean section for optimal medical care for your  premature baby
  • Increase in pregnancies of older women
  • Missing or insufficient education of pregnant women

Assessing your risk of a premature birth

Your antenatal checks will keep the medical team informed about the health of your growing baby and can determine your risk of a premature birth. If you are deemed to be at risk of a premature birth you may be offered additional tests that will aid your medical team spot potential problems and agree a care plan for the remainder of your pregnancy. These additional tests include:

  • Blood Tests
  • Urine Samples
  • Ultrasound Scans*
  • Vaginal Swabs

*Ultrasound scans can reveal a range of factors that have been linked to premature delivery.

  • These include:
  • The length of your cervix (cylinder-shaped neck of tissue that connect the vagina to the womb)
  • The size of your womb
  • The size and position of your baby
  • Whether you are carrying more than one baby
  • Whether there are any problems with your baby’s development
  • The size and position of the placenta (the organ that connects your baby to the womb wall to allow nutrient uptake, waste elimination and production of pregnancy supporting hormones)
  • The amount of amniotic fluid (the yellowish fluid that surrounds your baby in the womb)

You will be well looked after by your medical team if you are at risk of a premature birth. They will keep you informed of your progress as your pregnancy progresses. If you would like more information on premature baby’s please visit The Irish Neonatal Health Alliance  –