The reasons of premature birth

Babies born before 37 weeks gestation are considered premature, and according to Tommy's the baby charity, around 7% of all babies born in the UK in the years 2001/2002 were born prematurely.In the United States about 12% of all babies, about 1-in-8, are born prior to 37 weeks gestation. Preterm birth is the leading cause of death in a newborn. It is also the leading cause of death for infants in many states. Unfortunately the trend is expected to get worse.

We are still trying to understan why preterm labor happens, causing babies to be born before their time. However, currently we only know what has caused the preterm labor in about half of all of the labors being effected.Some babies born early are fine; they are just small. But often when a baby is born preterm, his organ systems may not have had time to fully develop.

According to Tommy's, the majority of preterm births occur without any obvious cause or known risk factors. However, there are some known risks for premature births:

• Infection.

About 40-50% of all preterm labor can be traced to infection. Many women do not show classic signs of infection, like fevers. One good note here is that with antibiotic treatement for Group B Strep, we have seen a reduction. Other than for Group B Strep, antibiotics usually lead only to antibiotic resistance and not a reduction in preterm labor rates.

• Bleeding.

This does include placental abruption, where the placenta tears away from the uterine wall too early. It also includes bleeding disorders that may be genetic or acquired. Bleeding of any sort should be reported to your doctor or midwife.

• Stretching of the uterus.

The stretching or overdistension of the uterus has also been linked to preterm labor and birth. This can be caused by fibroids, multiple pregnancies (twins, triplets, etc.), or even having too much amniotic fluid (polyhydramnios).The overstretching of the womb that occurs in the case of twin or triple pregnancies is thought to increase the risk of premature labour.

• Maternal age:

Not a major factor, but it is recognised that mothers under 20 or over 35 years old have a slightly higher risk of preterm labour.

• Fetal development:

If the baby is not thriving in the womb, for example, if the placental blood supply is impaired or there is evidence of growth retardation, then this can lead to premature birth.

• Lifestyle factors:

The mother's lifestyle can increase the risk of having a premature baby. For example, smoking, using recreational drugs, having a high caffeine intake, having a poor diet or being underweight, and engaging in over-strenuous physical activity.

• Previous gynaecological history:

Women who have had surgery on their cervix may have suffered damage to the opening of the womb. This can cause the cervix to open too soon in pregnancy, resulting in premature labour.

• Pregnancy-specific maternal disease:

Examples of this include pregnancy-induced diabetes and pre-eclampsia (itself a cause of at least 15% of all pre-term births) and obstetric cholestasis (liver disease characterised by extreme itching).

• Maternal medical conditions:

Certain pre-existing medical conditions in the mother have been linked to an increased risk of premature labour. They include systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), or renal disease.

• Cervical incompetence:

In some women the cervix, the opening to the womb, will shorten and open too soon and labour will spontaneously follow.

Research is ongoing as to the causes of preterm labor and how to prevent this dangerous complication. The biggest thing to be aware of are the signs of preterm labor and what risk you are at with your current pregnancy.