What is preterm labour?
Going into labour before your 37th week of pregnancy is called preterm labour, or premature labour. Preterm labour can cause your baby to be born too soon. This can lead to a number of health problems that may affect your baby.
Symptoms of preterm labour
If you believe you are having preterm labour, get medical help right away. If in doubt, get checked early. Once labour is established it is very difficult to stop. Contractions alone do not mean you are in preterm labour, however. What matters more are the changes in your cervix (the lower end of your uterus). Symptoms of preterm labour include:
- 4 or more contractions per hour;
- strong contractions;
- constant menstrual-like cramping;
- low back pain;
- pelvic presure (feeling that the baby is pushing down;
- watery, mucous, or bloody vaginal discharge; or
- bleeding or blood spotting after 3 months into your pregnancy.
Evaluating preterm labour
Your doctor or obstetrician will try to find out whether you are in preterm labour or whether you are just having contractions. They may keep watch on you for a few hours. The following tests may be done:
- pelvic exam to see if your cervix has effaced (thinned) and dilated (opened);
- uterine activity monitoring to detect contractions; or
- fetal monitoring to check the health of your baby.
In addition, there is a biochemical test that can identify women at risk of preterm delivery. The test involves the measurement of fetal fibronectin, a type of glue created by the body to help the pregnancy bind to the inside lining of the uterus. This substance leaks through the cervix early in the process of preterm labour, and can be detected in vaginal fluid using a simple swab test.
The fetal fibronectin test is not 100 per cent reliable, but if you are experiencing symptoms of preterm labour it can help determine your risk of delivering the baby in the next one to 2 weeks.
Caring for yourself at home
If you have contractions preterm but your cervix is still thick and closed, your doctor or obstetrician may ask you to do the following at home:
- do fewer activities, including heavy lifting; or
- rest in bed, lying on your side.
If you need hospital care
Preterm labour often requires hospital care and complete bed rest. You may need an intravenous line through which fluids are given. You may also be given pills or an injection to help prevent contractions.
Are you at risk?
Any pregnant woman can have preterm labour. It may start for no reason. But these risk factors can increase your chances:
- previous preterm labour or early birth;
- some abnormalities of the baby, cervix, uterus or placenta;
- a lack of prenatal medical care;
- some infections, such as urinary tract infections or vaginal infections (e.g. bacterial vaginosis);
- having certain medical problems, such as diabetes, high blood pressure or clotting disorders;
- being underweight or overweight before becoming pregnant;
- being under 17 or over 35 years old;
- smoking, drug or alcohol use during pregnancy; or
- multiple fetuses (twins or more).
The dangers of preterm birth
A baby born too soon may have health problems. This is because the baby did not have enough time to mature. The baby is then at risk of a variety of problems, such as:
- not breastfeeding well;
- having immature lungs, and not being able to breathe on their own;
- bleeding in the brain;
- life-threatening infections;
- inflammation of the bowel;
- long-term health problems, such as cerebral palsy; or
Your goal is to get as close to term (40 weeks) as you can before giving birth. The closer you get to term, the greater your chances of having a healthy baby. Work with your doctor or obstetrician. Together you can take steps to keep you from giving birth too early.
Last Reviewed: 05/08/2009
myDr. Adapted from original material sourced from MediMedia.
1. MayoClinic.com. Preterm labor: take prevention seriously [updated 2009, May 23; accessed 2009, Aug 7]. Available at: http://www.mayoclinic.com/health/preterm-labor/PR00118 2. MayoClinic.com. Vaginitis [updated 2009, Feb 6; accessed 2009, Aug 7]. Available at: http://www.mayoclinic.com/health/vaginitis/DS00255 3. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists. Use of cervical fetal fibronectin as a screening test for preterm birth [published 2008, Nov; accessed 2009, Aug 7]. Available at: http://www.ranzcog.edu.au/publications/statements/C-obs26.pdf
Video: Preterm labour
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.
Symptoms of preterm labour can include waters breaking and regular contractions.
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.
The length of the cervix can indicate a 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.
Video: Cholestasis of pregnancy
Cholestasis is a condition in which the flow of bile from a pregnant woman’s liver is slowed, causing a build-up of bile acids in the bloodstream. It may occur in the later stage of pregnancy and the most notable symptom is intense itching.
Labour is the process through which a baby is delivered from a woman’s womb to the outside world. Stages of labour that pregnant women commonly experience include uterine contractions, dilation of the cervix and the rupturing of foetal membranes to release amniotic fluid, or ‘water breaking’.
Video: Low lying placenta
Low-lying placenta (also called placenta praevia) occurs when the placenta attaches to the uterus in a position that is too low down in the uterus. This can block the passage for delivery of the baby and if labour occurs, cause severe bleeding.
Video: Premature birth
A birth is defined as premature if it occurs before 37 weeks’ gestation. Although the risk of complications for premature babies increase the earlier they are born, survival rates are continuing to improve as treatments evolve and develop.