Pre-pregnancy check-ups are promoted as a way to improve pregnancy outcomes by identifying risk factors…
What is preterm labour?
Preterm labour is labour that occurs before 37 weeks of pregnancy have passed. It is a concern because babies born prematurely are at higher risk of serious health complications.
If there are indications that preterm labour might occur, your doctor will use a range of medications to delay delivery for as long as possible, as every week that delivery can be delayed greatly reduces the risk of complications and increases the chances of survival for your baby.
Causes of preterm labour include:
- Placental abnormalities - placental abruption or low-lying placenta;
- Infection and inflammation - these can produce substances that can trigger birth contractions;
- Physical or psychological stress - stress can result in the production of hormones that trigger contractions, and;
- Stretching of the uterus - having a multiple pregnancy can cause stretching of the uterus, which can trigger contractions.
Risk factors for preterm labour include:
- Preterm birth in the past;
- Preterm rupture of the fetal membranes;
- Surgery on the cervix;
- A short cervical length;
- Cervical incompetence;
- Placental abruption - where your placenta detaches from the wall of the uterus;
- Smoking and drug use;
- Vaginal bleeding, and;
- Polyhydramnios - having too much amniotic fluid in the uterus.
Signs and symptoms
Signs and symptoms of preterm labour include:
- Pelvic pressure;
- Lower abdominal cramping and back pain;
- Your waters breaking;
- Changes in cervical discharge such that it is watery, bloody or mucus-like;
- Dilation of the cervix;
- Vaginal spotting, and;
- Regular contractions of the uterus.
Methods for diagnosis
If contractions are frequent and intense enough to cause the dilation of the cervix between 24-37 weeks' pregnancy, it is a sign of preterm labour. A test called the vaginal fetal fibronectin test is performed on a swab of secretions near your cervix. The test detects fibronectin, which is a protein attached to the amniotic sac that surrounds your baby within the uterus. A positive result indicates an increased risk of preterm labour.
Sometimes a transvaginal ultrasound will also be performed to check your cervical length, since a short cervical length increases your risk of preterm labour.
Types of treatment
Labour can be delayed or stopped using medications known as tocolytic therapy. However, this is not used if labour is too advanced, or if your pregnancy is past 34 weeks. Tocolytic medications are intended to delay delivery for 48 hours. If by this time labour has stopped, you will be monitored until labour recommences.
Corticosteroids are given to reduce complications for your baby by helping the lungs mature faster. They are given between 24-34 weeks of pregnancy, often in conjunction with tocolytic medications.
For the baby, potential complications of preterm labour include:
- Immature lungs, which can result in breathing difficulties;
- Bleeding in parts of the brain;
- An immature digestive system that is unable to properly absorb nutrients, and;
- Difficulty feeding, as the swallowing reflex has not yet developed. Premature babies may need to be fed through a tube inserted into their stomach.
If no complications occur, the prognosis is good for preterm birth beyond 34 weeks' pregnancy. The earlier you give birth, the greater the risk of complications. Even an extra week can make a big difference in reducing the risk of complications.
You can reduce the risk of preterm labour by not smoking, not using recreational drugs and maintaining low stress levels. If you have a history of preterm labour, you might be given progesterone in the form of an injection or vaginal gel to help prevent it. This preventative treatment has not been proven to be effective for pregnant women who do not have a history of preterm labour.