A premature birth is a birth that takes place more than three weeks before the baby's estimated due date. In other words, a premature birth is one that occurs before the start of the 37th week of pregnancy.
Premature babies, especially those born very early, often have complicated medical problems. Typically, complications of prematurity vary. But the earlier your baby is born, the higher the risk of complications.
The cause of premature birth is unknown in about half of all cases. However, some of the reasons babies are born prematurely include:
- The mother gets an infection, particularly of the amniotic fluid and lower genital tract.
- Multiple pregnancy (twins or more).
- The mother has a medical condition that means the baby must be delivered early, such as pre-eclampsia.
- Problems with the placenta such as placental insufficiency, placenta praevia, placenta accreta or placental abruption.
- Preterm premature rupture of membranes, when the amniotic sac spontaneously ruptures.
- The mother has a health condition like diabetes.
- A history of premature birth, with the mother having had preterm babies easier.
- Problems with the cervix, when it is too weak to hold the weight of the baby and uterus so it starts to open prematurely (called cervical incompetence).
- An interval of less than six months between pregnancies.
- Conceiving through in vitro fertilisation.
- Smoking cigarettes or using drugs. Even e-cigarettes or vaping is a cause.
- Being underweight or overweight before pregnancy.
- Stressful life events, such as the death of a loved one or domestic violence.
- Multiple miscarriages or abortions.
- Physical injury or trauma.
Pregnant women also have an increased chance of delivering early if they are younger than 17 or older than 35.Research also suggests that you are slightly more likely to have a premature birth if you became pregnant less than 6 months after your last pregnancy.