Preterm Labor: Symptoms and Causes

Preterm labor can be life threatening for both mother and baby. Let's see how to identify it and why it occurs.
Preterm Labor: Symptoms and Causes

Last update: 16 January, 2023

Most pregnancies last about 40 weeks. According to the National Institute of Child Health and Human Development (USA), it’s said that you’re dealing with preterm labor when labor begins before 37 weeks. When the baby is born just before this timescale, it’s said to have been born prematurely.

Preterm labor is a major cause of death, and surviving babies can have long-term developmental disabilities in their central nervous system. Experts stipulate that between 5% and 18% of deliveries are premature and the spontaneity of these sometimes makes it difficult to determine what caused them. We show you its symptoms and main causes.

What are the symptoms of preterm labor?

Preterm labor is nothing more than labor that hasn’t reached its full term. Therefore, its symptoms are identical to those experienced in normal labor. The difference is that this time they do it before 37 weeks, which can confuse the pregnant woman and lead her to miss them.

Indeed, as the signs don’t correspond to the stipulated labor date, it isn’t uncommon for some women to ignore the signs thinking that it isn’t possible that they’re about to give birth. This attitude is much more frequent in women with a first pregnancy, since they don’t know first-hand what the symptoms of labor are:

  • Frequent and painful uterine contractions
  • Very intense pelvic pressure sensation
  • Expulsion of the mucous plug
  • Loss of amniotic fluid

If you do experience these, then don’t hesitate to seek medical attention, as this can make a notable difference in the prognosis of birth.

Don’t be afraid if it’s a false alarm – it’s better this way than risk endangering the baby’s life. Always be on the lookout for these signs, especially when they stray from the signs you’ve experienced so far during your pregnancy. Not all preterm labor is the same, so you can develop mild symptoms too.

What are the causes of preterm labor?

Preterm labor has many causes.
In many cases, the origin of preterm labor cannot be determined. In others, obvious pathologies can be related as causative agents.

Most preterm labor is spontaneous. That is, it arrives without prior notice and without any medical evidence that it’s about to happen. In other cases, there may be alerts that it could happen, so the professional will notify the pregnant woman of the symptoms that point to premature labor.

There’s no consensus among specialists as to why this event happens. According to experts, 50% of deliveries of this type are spontaneous, 30% are associated with an early rupture of the membranes and the remaining 20% are induced by medical recommendation.

Since there are no known direct causes of preterm birth, it’s best to talk about risk factors, and we know about some of the factors that increase the chances of premature labor. Here are some of them.

Previous preterm labor

Researchers have found that the chances of having a preterm birth are between 41% and 68% in pregnant women who have a history of this type of labor. The reasons aren’t known, but they may be due to a series of genetic and physiological factors that cause the pregnancy not to go full term.

Shortened cervix

A shortened cervix is also a direct risk for premature delivery. The cervix is the lower part of the uterus that connects to the vagina. At the end of pregnancy, it softens and is trimmed, allowing the fetus to pass to the outside. When this happens prematurely, it leads to premature labor.

Presence of chronic conditions in the mother

These include hypertension, obesity, diabetes, autoimmune diseases, depression, stress, and more. All of these can combine to prevent the pregnancy from being carried to term. In general, the absence of chronic diseases and the commitment to a healthy life greatly reduces the probability of premature births.

Fetal birth defects

Researchers also warn that congenital fetal anomalies can also play against them. Congenital defects usually manifest during the first trimester of pregnancy, so they should be identified by the specialist in routine visits.

Mother’s age

Preterm labor is known to be more common in women under the age of 18 and over the age of 40. The chances are slightly higher in minors, especially those with a low gynecological age. This is pointed out by this evidence, which indicates that in these cases the risk of premature labor is close to 75%.

Of course, many other factors can prevent a pregnancy from reaching term. In addition to the previous triggers mentioned, we’ll point out other possible factors:

  • Presence of a larger volume of amniotic fluid (polyhydramnios)
  • Multiple pregnancies
  • Infections in the vaginal tract or amniotic fluid
  • Being overweight or underweight before or during pregnancy
  • Having become pregnant through in vitro fertilization
  • Getting pregnant too soon after having a baby
  • Family history of premature labor
  • Prenatal exposure to certain toxic chemical agents
  • Placenta previa
  • Preeclampsia

There are dozens and dozens of additional conditions that can cause premature birth. Sometimes the cause won’t be found, so your triggers will be idiopathic.

Can preterm labor be prevented?

Preterm birth and its prevention.
The better the life habits of the pregnant woman, the lower the risk of developing premature birth or other conditions.

Since we don’t know all the mechanisms behind preterm labor, you can’t prevent it 100%. Of course, you can include a series of habits that allow you to reduce your risk. Most important of all is following the prenatal care schedule.

Prenatal visits are very important to keep track of the development of the pregnancy. The specialist can determine warning signs of an early delivery, as well as managing actions to protect both the mother and the baby’s health. Apart from this, consider the following recommendations:

  • Eat a healthy diet
  • Avoid tobacco, alcohol, and recreational drugs
  • Keep chronic conditions in check
  • Avoid stressful situations
  • Stay hydrated during the hottest days
  • Get regular exercise
  • Try to meet the hours of sleep
  • Take the supplements indicated by the specialist (folic acid, among the most important)
  • If you have sex, be sure to use protection to reduce the risk of infection

In general, having a healthy lifestyle before and during pregnancy reduces the chances of preterm labor. The important thing is to carry out a good prenatal checkup and follow your doctor’s instructions. Preterm labor has unintended consequences for both mother and baby.

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