Preterm Birth 2025: Causes, Warning Signs, and Modern Treatment

Author photo
Zappelphilipp Marx•
Preterm infant in an incubator in a neonatal unit

Worldwide about one in ten babies is born before 37 weeks' gestation. Preterm birth is therefore a leading cause of health problems and mortality in early childhood. This guide explains in plain language what preterm birth is, which warning signs should be taken seriously, and how modern medicine protects preterm infants today.

What is a preterm birth?

A birth is considered preterm when a baby is born before the completion of 37 weeks' gestation. Professional societies distinguish several groups because prognosis and care differ significantly.

CategoryWeeks' gestationTypical features
Extremely pretermbefore 28 weeks' gestationImmaturity of all organs, frequent need for ventilation and intensive monitoring.
Very preterm28 to 31 weeks' gestationCare in a specialized neonatal unit, increased risk of brain and respiratory problems.
Moderate and late preterm32 to 36 weeks' gestationOften only short monitoring, but more frequent adaptation problems, low blood sugar, and neonatal jaundice.

In general: the earlier a baby is born, the more intensive the in-hospital care and the more important structured follow-up examinations after discharge are.

Causes and risk factors – why babies are born too early

Preterm birth rarely has a single cause. Multiple factors usually interact, and in some cases the trigger remains unclear. The most important known risk factors include:

  • Infections: for example bacterial vaginosis, urinary tract infections, or untreated gum disease.
  • Multiple pregnancy and assisted reproduction: twins or triplets, particularly after IVF or ICSI, have a significantly higher risk of preterm birth.
  • Cervical insufficiency: a too-short or early-opening cervix, for example after a conization.
  • Placental problems: placental insufficiency, premature separation, or a low-lying placenta.
  • Preexisting maternal conditions: chronic hypertension, preeclampsia, diabetes, autoimmune and kidney diseases.
  • Lifestyle: smoking, alcohol or drug use, severe underweight or obesity, and poor nutrition.
  • Social and psychological factors: high stress, violence, financial hardship, or lack of social support.

Detailed recommendations for assessing these risk constellations can be found, for example, in clinical guidelines on the prevention and treatment of preterm birth.

Warning signs of an impending preterm birth

Not every contraction indicates danger. However, there are symptoms that should always be promptly evaluated in a clinic or physician's office:

  • Regular, painful contractions before 37 weeks' gestation.
  • Suspected loss of amniotic fluid or premature rupture of membranes.
  • Vaginal bleeding, brownish or foul-smelling discharge.
  • Strong pressure downward or the feeling that the baby is "slipping down."
  • Marked cervical shortening measured on ultrasound.

In addition, tests such as detection of fetal fibronectin or certain inflammatory markers are used. They help better estimate the risk of delivery in the coming days but never replace clinical assessment.

Preventing preterm birth – Prevention 2025

Prevention ideally starts before a planned pregnancy and continues throughout pregnancy. Key elements are:

  • Optimal preparation: good control of chronic conditions, smoking cessation, and counseling on medication use before conception.
  • Regular prenatal care: consistent participation in prenatal visits, including ultrasound cervical checks for risk situations.
  • Progesterone for a short cervix: vaginal progesterone can reduce the risk of preterm birth in singleton pregnancies with a shortened cervix.
  • Cerclage or cervical pessary: with significant cervical insufficiency or recurrent late pregnancy losses, cerclage or silicone pessaries can help support the cervix.
  • Infection screening and treatment: promptly treated urinary tract infections, bacterial vaginosis, or other infections reduce the risk of complications.
  • Healthy lifestyle: balanced nutrition, exercise within recommended limits, sufficient sleep, and stress reduction support a stable pregnancy.

Many hospitals offer specialized clinics for high-risk pregnancies. There, individual preterm birth risks can be discussed and a tailored plan developed.

Acute treatment for threatened preterm birth

If preterm contractions, bleeding, or rupture of membranes occur, this is an emergency situation that should always be evaluated in a hospital. The further approach is individualized and may include:

  • Monitoring of mother and baby: CTG, ultrasound, laboratory tests, and swabs for infection diagnostics.
  • Tocolysis: labor-suppressing medications such as atosiban or calcium channel blockers often delay birth by a few days.
  • Antenatal corticosteroids: betamethasone or dexamethasone promote lung and other organ maturation, particularly between about 24 and 34 weeks' gestation.
  • Magnesium sulfate for neuroprotection: in very early births, magnesium sulfate can reduce the risk of severe brain injury.
  • Transfer to a perinatal center: when possible, the pregnant person is transferred before birth to a center with highly specialized neonatology.

Guidance is provided, among others, by the WHO on antenatal corticosteroids as well as national guidelines from professional societies.

Modern neonatology and the role of parents

Perinatal centers combine high-tech medicine with developmentally supportive care. This includes:

  • Gentle ventilation strategies with the lowest possible pressure peaks to protect the lungs.
  • Modern incubators with stable temperature and noise regulation.
  • Consistent promotion of breast milk, including donor milk banks and individualized nutrient fortification.
  • Strict hygiene standards and infection prevention.

At the same time, parent–infant bonding plays a central role. Kangaroo care (skin-to-skin contact), early involvement of parents in caregiving tasks, and psychological support help families cope with the intensive time on the unit and promote the child's development.

Long-term consequences and structured follow-up

Many moderately or late preterm infants reach a normal school and working life with good support. Nevertheless, certain health issues are more common among preterm infants:

  • Fine and gross motor developmental delays.
  • Vision and hearing disorders that require regular screening.
  • Chronic respiratory conditions such as bronchopulmonary dysplasia or asthma.
  • Attention and learning difficulties, sometimes accompanied by emotional challenges.

Many children benefit from interdisciplinary early intervention, for example through pediatric specialty centers, physical, occupational, or speech therapy. It is important that parents stay attentive, raise concerns, and seek support if needed.

Research and future prospects

Research teams worldwide are working on new ways to better predict preterm birth risks and to care for preterm infants even more safely:

  • Biomarkers and immune profiles: blood tests aim to help identify individual preterm birth risks early.
  • Microbiome approaches: studies are investigating whether specific probiotics can reduce the risk of serious intestinal diseases such as NEC.
  • "Artificial womb": experimental systems aim to provide extremely preterm infants with additional maturation time outside the uterus.
  • Digital support: apps and telemedicine can help monitor high-risk pregnancies more closely and detect warning signs early.

Support for parents of preterm infants

In addition to medical care, parents of preterm infants primarily need reliable information and psychosocial support. Organizations such as the European Foundation for the Care of Newborn Infants (EFCNI) provide informational materials, checklists, and contact points for families. Many hospitals also collaborate with preemie initiatives, lactation consultants, psychologists, and pediatric specialty centers to support the transition home.

Conclusion

Preterm births cannot be completely prevented. However, knowing the main risk factors, taking warning signs seriously, and ensuring guideline-based care in an experienced perinatal center improve the chances of a stable start to life. Good follow-up and appropriate support help preterm infants and their families navigate this special path step by step.

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Frequently Asked Questions (FAQ)

Estimates suggest that about one in ten babies worldwide is born preterm. The exact rate varies by region and year, but overall preterm birth remains one of the most common complications of pregnancy.

A markedly shortened cervix on ultrasound is one of the most important measurable risk factors for preterm birth. The shorter the cervix and the earlier the cervix opens, the greater the likelihood that the baby will be born prematurely.

In certain situations, such as a singleton pregnancy with a shortened cervix, vaginal progesterone can reduce the risk of preterm birth. Whether treatment is appropriate is decided by the treating clinician based on the overall situation.

A cerclage or cervical pessary is mainly considered for significant cervical insufficiency or repeated late pregnancy losses. The goal is to mechanically support the cervix to prevent or delay premature opening.

Tocolytics are medications that can slow or temporarily stop preterm labor. They typically prolong pregnancy by a few days to allow time for corticosteroid injections for lung maturation and a possible transfer to a specialized center.

Antenatal corticosteroid injections support maturation of the baby's lungs and other organs. They have been shown to reduce the risk of severe respiratory problems and improve survival when a very early birth cannot be prevented.

Modern neonatal units use as gentle methods as possible, for example respiratory support with nCPAP or high-flow oxygen and ventilation with low pressure peaks to protect the delicate lungs of infants.

In the kangaroo method, preterm infants are held skin-to-skin on a parent's chest. This helps stabilize breathing, temperature, and heart rate, strengthens bonding, and often supports breastfeeding and parental well-being.

A negative fetal fibronectin test makes it much less likely that delivery will occur in the next few days. This can help avoid unnecessary hospital stays and focus monitoring, but it never replaces medical assessment.

Preterm infants are somewhat more likely to have problems with motor skills, breathing, vision, hearing, or attention. With regular checkups and early intervention, many children can largely overcome these initial disadvantages and lead normal lives.

Research projects are currently investigating blood tests that measure specific inflammatory and immune signals. They aim to indicate preterm birth risk early, but they are not yet established as routine tests in clinical practice.

The composition of gut bacteria appears to influence the risk of intestinal diseases such as NEC. Early studies suggest targeted probiotics might be protective, but definitive recommendations are not yet available.