Premature Labor- Causes, Risk Factors, Signs, Prevention And Treatment

7 min read

Written by Editorial Team

Editorial Team

Premature Labor

If Pregnancy is a period of joy and great expectations. However, it can also be a period of uncertainty. Therefore, staying watchful all through pregnancy is vitally important. One of the vital events that can pop up (mostly) during the third trimester of pregnancy is premature labor.

Premature labor occurs in approximately 12% of all pregnancies. Nevertheless, by understanding and recognizing the signs and staying away from risk factors, an expecting mother can lessen her chances of going into labor before time.

In This Article

What Is Premature Labor?

A normal pregnancy keeps going 38 to 40 weeks. Labor that starts around the 38th week of pregnancy is considered normal. Preterm labor happens if the labor begins before the 37th week of pregnancy. The uterine contractions and the dilation and thinning out of the cervix will start.

This can be considered as a medical emergency, and immediate medical attention is inevitable, because, if no necessary steps are taken to delay the labor, the baby will bear before completing its development- as a preemie. The preemies experience several health issues, and some problems can be fatal too.

What Are The Causes Of Premature Labor?

What Are The Causes Of Premature Labor_

There is no specified reason for preterm labor, though research is still on in this field. However, there are some medical issues, which can trigger preterm labor. 50% of preterm labor is spontaneous, which can occur out of the blue when you are least expecting it.

Preterm labor is mainly (but not limited to) caused due to:

  • Uterine bleeding that occurs due to the rupture of the fetal membrane because of the issues like placental abruption or placenta previa (when the placenta fully or partially covers the cervix) will trigger preterm labor.
  • Physical and emotional stress can tamper with the endocrine system and result in the release of hormones, which trigger uterine contractions.
  • Overly stretched uterus due to, multiple pregnancies, polyhydramnios, etc. can start the uterine contraction much earlier than the due date.
  • As a consequence of some infections and associated inflammation, which happens in or progresses to the uterus, uterine contractions occur which can end in preterm labor.

Hence, it is really significant to know the signs of preterm labor, mainly if you belong to the “50%” who hold a medical risk (mentioned below) of undergoing labor far before the due date.

Am I At The Risk Of Premature Labor?

Am I At The Risk Of Premature Labor_

Although the specific causes of premature labor are not yet known, certain factors (like some unhealthy lifestyles and medical conditions) may increase a woman’s risk of having early labor. What you have to keep in mind is that just because a few risk factors explained below are closely connected to you or are experienced by you, it does not mean that you are definitely going to undergo premature labor.

Similarly, having no apparent reason for preterm labor does not mean that you are on the safe side either. You are at the highest risk for premature labor if:

  • You have a case of multiple pregnancies.
  • If you are underweight.
  • If you have experienced multiple inexplainable abortions during the first and second trimesters.
  • You have high blood pressure.
  • You have unhealthy habits like smoking, drinking alcohol, etc.
  • If you experienced preterm labor during your previous pregnancy.
  • You develop anemia in the course of pregnancy.
  • You are experiencing polyhydramnios.
  • If you got pregnant soon after your last delivery.
  • You put on too much weight or didn’t achieve optimum weight in the course of pregnancy.
  • You are experiencing stress due to domestic abuse or other emotional issues that can trigger preterm labor.
  • Your career demands physical and mental strain (like standing for a long time, unachievable targets, unsolvable financial issues, etc.)
  • You have other medical conditions like preeclampsia, UTI, abnormally structured uterus, gestational diabetes, cervical incompetence, etc.
  • Preterm births run in your family.

If you experience any of the above risk factors, it is significant to recognize the symptoms of premature labor and what to do if it happens.

What Are The Signs Of Premature Labor?

Early recognition of preterm labor is hard as the initial symptoms are often gentle and normally take place in the course of normal pregnancy too. Therefore, usually, women wait until their next appointment to mention it to the doctor, or, even dismiss the early warning signs as “normal occurrence” in pregnancy. The warning signs include:

  • Abnormal cramps
  • Increased vaginal discharge with or without a change in its appearance
  • Diarrhea without any known reasons
  • Persisting lower backache, which will not ease even after changing your position
  • More than four contractions per hour
  • Vaginal bleeding or spotting
  • Water break
  • Feeling the pressure in the pelvic area

Are There Any Tests That Can Predict Premature Labor?

Yes, though not with 100% accuracy, there are some tests, which can predict the chances of premature labor. However, only when your doctor thinks that your chances of preterm labor are high, they conduct these tests.

Monitoring Uterine Contractions

Even though on certain occasions, some doctors go for it, this is not a well-accepted procedure to predict preterm labor. Usually, the medical team monitors uterine contractions by wrapping a belt around the abdomen and being connected to a machine called a tocodynamometer.

Uterine monitoring depends on the possibility that the recurrence of contractions (per hour) increases as the labor begins. Its drawback is that it cannot read mild contractions, which are relevant in predicting the possibility of preterm labor.

Cervical sonography during pregnancy can detect cervical effacement. It will happen around the 32nd week of normal pregnancy (a delivery that takes place around the 38th week of gestation) and as early as 16–24 weeks for preterm deliveries. Getting the measure of the cervix will also assist. A short cervix increases the risk of preterm labor.

Detecting the Amount of Fetal Fibronectin

Fetal Fibronectin

Fibronectin acts like a paste that joins the fetal membranes to the underlying uterine decidua – the thick layer of the reformed mucous membrane, which covers the uterine lining during pregnancy and is shed with the fetal membrane during delivery.

Fibronectin is usually found in the cervicovaginal secretions prior to 16–18 weeks of pregnancy, and again towards the end of normal pregnancy (as labor approaches). It is not normally found in the cervicovaginal secretions in between the 22nd and 37th weeks. They test vaginal discharge. An increased level of fibronectin indicates the chances of preterm labor.

What Are The Possibilities Of Treating Premature Labor?

No environment invented by modern science could be as perfect as the mother’s womb. Hence, the priority of the treatment of preterm labor will be delaying the delivery as late as possible. Every second the baby spends in the uterus counts.

It significantly increases the chance of the survival of the baby. It also decreases the chances and the intensity of the possible lifetime health challenges. You necessarily do not have to experience all the symptoms. A lot of times Braxton Hicks contractions are mistaken for preterm labor.

  • The doctor will first check whether you are onto real labor.
  • Once the signs are of labor, the doctors will try their best to find a fast solution, thereby, stopping the labor from progressing more.
  • If the water breaks and you are not having a contraction, antibiotics will be given to prevent the possible infection.
  • The doctor will order a strict rest. He will ask you to lie down on your left side for unhindered blood flow.
  • The doctor will order to increase the intake of fluid; if needed, he will start an IV. Staying well-hydrated is significant to delay labor.
  • If the water does not break and the contractions start, the doctor conducts a fetal fibronectin test. Once the result is positive,  your medical team will try to stop the contractions.
  • If the preterm birth is inevitable, Tocolytics drugs will be given, which will help to delay the delivery for another 48 hours, which will give ample time to transfer the women to a hospital specializing in neonatal care.

In between proceeding with the treatments to delay the labor and delivery, doctors administer certain medicines to make the baby strong enough to survive a preterm birth.

The most common medicines are:

Magnesium sulfate

To reduce the risk of the particular type of damage that can happen to the brain, which increases the chances of issues like cerebral palsy.


To speed up the process of lung development.

How Can A Possible Premature Labor be Prevented?


During your meeting with your doctor in the course of pregnancy, if your doctor detects that you are prone to undergo preterm labor, there are some preventive measures. Preventive measures include:


Cervical incompetence is a condition in which the cervix dilates without any pain. The doctor usually discovers it during the routine monthly visit. If not recognized at the right time, it can result in pregnancy loss or preterm labor, which ends with premature delivery.

In such cases, the doctor will place a stitch around the cervix – cerclage. If they diagnose cervical incompetence for the first time, they do cerclage during the second trimester. Whereas, if you have a previous history, they do the placement of cerclage to the end of the first trimester itself.


Weekly progesterone injections (starting between the 16th and the 21st week of gestation) are very helpful in delaying the pregnancy until the 37th week.

No to Sex and Travel

Restricting sexual activities and long travels (especially on bumpy roads) are other preventive measures

Lie Down on Your Side

Never lie down on your back, especially if you are at the risk of preterm labor. Lie down, preferably inclining towards the left side

Preterm labor does not necessarily mean premature birth. Around 30% to 50% of woman who develops preterm labor may complete their pregnancy successfully with appropriate medical care.

Editorial Team,

With a rich experience in pregnancy and parenting, our team of experts create insightful, well-curated, and easy-to-read content for our to-be-parents and parents at all stages of parenting.Read more.

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