What Causes Premature Birth

While most of us think of a pregnancy as lasting nine months, the actual term of a pregnancy is around 40 weeks. When a baby is born before 37 weeks, that baby is said to have been born prematurely. Or, if you’re carrying twins, full term is considered to be 38 weeks and premature birth is a delivery before 35 weeks. Finally, if you’re carrying higher order multiples, the full term length will vary according to the number of babies you’re carrying. In general, slightly more than 10 percent of babies are born prematurely.

Babies continue to grow and develop inside their mother's body right up until the time they’re born. Therefore, the more premature a baby is, the more growth and development time it’s missed and the less likely it is to be prepared to adapt to life outside the mother's body without assistance. For example, many babies who are born prematurely have trouble breathing on their own without assistance, and some have difficulty sucking, which makes it difficult for them to nurse or take a bottle.

Unfortunately, there’s no hard and fast answer to the question of what causes premature birth in every case. In fact, in about half of the cases of premature birth, there’s no answer at all. In the remaining half of the cases, there are a variety of causes.

One, as mentioned before, is multiple gestation, particularly of higher order multiples – that is to say, triplets and above. In a higher order multiple pregnancy, greater demands are placed on the mother's body, particularly her uterus. When the uterus has expanded beyond its usual capacity, it begins to become irritable and begins contracting. Often, labor and delivery can be prevented for a period of time, allowing the babies additional time to grow and develop and the administration of medications that helps lung development. However, a point will be reached when attempts at stopping labor are unsuccessful and the babies will born, however prematurely.

In other cases, labor begins prematurely because of an infection – particularly an infection in the amniotic fluid or amniotic membranes. Infections of the kidneys, bladder, urinary tract and vagina can also trigger premature labor. Any infection that causes a high fever can trigger premature delivery. Women whose amniotic membranes break early in pregnancy, known as PPROM or preterm premature rupture of membranes, are at a higher risk for infection and for premature delivery.

In addition, women who suffer from chronic diseases, such as high blood pressure and diabetes, are at a higher risk of having a premature delivery. Other risk factors include clotting disorders, kidney disease, sexually transmitted diseases, drinking alcohol, smoking, using illegal drugs, being subjected to domestic violence (physically, sexually or emotionally), or being subject to high levels of stress.

Fortunately, most of the conditions described above are preventable. If you have a chronic disease, talk to your doctor about the best way to manage your condition during pregnancy. Or, if you are currently engaged in a risky behavior, such as drinking or smoking, seek out the assistance you need to quit. Your baby is depending on you!