Preterm labour

What is considered preterm labour?

Preterm labour is the presence of regular contractions that lead to changes in the cervix prior to term (37 weeks). This may lead to delivery. Preterm delivery is categorized as follows:

Extremely preterm (less than 28 weeks)
Very preterm (28-32 weeks)
Moderate to late preterm (32 to 37 weeks)

Preterm tightenings of the uterus are common and not all will lead to preterm birth. However, it is very important to go to the hospital if you have regular contractions at any time before 37 weeks that don’t go away when you change your activity. There are some important interventions to help prevent some of the consequences associated with preterm birth, but they have to be done early to be most effective. Staying home thinking that this couldn’t possibly be labour because it is too early is dangerous.

Why is preterm labour and birth a concern?

Preterm birth is one of the most common problems in pregnancy. Premature babies are more vulnerable to a host of health challenges and can have lifelong problems. Medical care of preterm babies has improved dramatically over the past several decades. However, babies born before 25 weeks still rarely survive without problems. Of all the babies who die in the newborn period, up to 75% will have been born preterm.

What causes preterm birth?

In about half of all preterm births, the reason is unknown – the mothers and infants were otherwise healthy. However, there are some factors that are known to increase the risk of going into labour early. Here are some of the known risk factors for preterm labour and how to reduce them:

Smoking. It is best not to smoke during pregnancy. Your baby can still benefit if you quit smoking before you reach 32 weeks.
Working too hard. Working long hours, doing strenuous kinds of work and being tired all the time can lead to a preterm birth. Work with your employer to try to reduce strenuous work.
Physical and emotional abuse. When someone hurts you they can also hurt your unborn baby. Even non-physical forms of abuse like psychological abuse can lead to a preterm birth by significantly raising your stress levels. If you are experiencing abuse within your household or relationship, a family crisis centre in your area can offer help and support.
Incompetent cervix. This is a rare condition in which the cervix dilates (opens) early and is associated with premature birth. This can sometimes be diagnosed during a vaginal examination or by measuring the size of the cervix during an ultrasound. Sometimes this can be treated by sewing the cervix closed with a “drawstring” stitch and removing the sutures when the baby is full term.
Bladder, vaginal or uterine infections. You may have a bladder or kidney infection if you have pain when you urinate, if you have to go often, and if when you do only a small amount of urine comes out. You may have an infection in your vagina or cervix if you notice an unusual vaginal discharge, have pain in your pelvis or groin area, or a fever. Notify your health care provider.
Being very overweight or underweight. Treatment depends on the cause of the problem. Sometimes this problem is helped by eating healthy, good food on a regular basis. Talk to your health care provider if you are underweight and having problems.
Placenta previa. This is a condition in which the placenta implanted and grew over the opening of the cervix (where the baby must come out). This can lead to hemorrhaging during labour. This problem is usually found during routine ultrasound testing. The baby is usually delivered by Caesarean section before labour has a chance to begin.
Premature rupture of membranes. This occurs when the sac of amniotic fluid breaks or leaks before your baby reaches full term. Some studies link this to infections in the uterus but further research needs to be done. If your membranes rupture early, treatment depends on how much amniotic fluid is lost and how close to your due date you are. Notify your health care provider.
Health conditions (gestational hypertension, diabetes). Some illnesses (diabetes, high blood pressure) may be less controllable during the pregnancy and in some situations the only way to stop the worsening condition is to deliver the baby. Sometimes the labour will begin too early on its own and in other cases the labour needs to be brought on (induced).

What are the signs of preterm labour?

Contact your health care provider right away if you are having any of the following:

Backache that comes and goes
Regular contractions less than 10 minutes apart
Cramping in your lower abdomen
Fluid leaking from your vagina
Pressure in your pelvis or vagina
Vaginal bleeding