Premature Birth – Symptoms and Causes
What Is Premature Birth?
A premature birth occurs when a baby is born before completing 37 weeks in the womb. Normal pregnancies typically last around 40 weeks. Babies born too early often face health challenges, with risks increasing the earlier they arrive.
Premature babies fall into different categories based on timing:
- Late Preterm: Born between 34-36 completed weeks
- Moderately Preterm: Born between 32-34 weeks
- Very Peterm: Born between 28-32 weeks
- Extremely Preterm: Born before 28 weeks
Most premature births happen in the late preterm period. The health problems these babies experience vary widely, but earlier births generally mean more serious complications.
Each category represents different developmental stages and potential health concerns for the newborn.
Signs of Early Arrival
Babies born too early may show different signs. Some babies have mild symptoms, while others face more serious health issues.
Common signs of premature birth include:
- Small body size with a head that looks large compared to the body
- Less rounded features due to having fewer fat-storing cells
- Fine hair covering much of the body
- Low body temperature, especially right after birth
- Breathing difficulties
- Problems with feeding
Premature babies are typically smaller than full-term babies. The tables below show average measurements at different ages before full term.
Boys: Weight, Length and Head Size by Age
| Weeks | Weight | Length | Head Size |
|---|---|---|---|
| 40 weeks | 7 lbs, 15 oz (3.6 kg) | 20 in (51 cm) | 13.8 in (35 cm) |
| 35 weeks | 5 lbs, 8 oz (2.5 kg) | 18.1 in (46 cm) | 12.6 in (32 cm) |
| 32 weeks | 3 lbs, 15.5 oz (1.8 kg) | 16.5 in (42 cm) | 11.6 in (29.5 cm) |
| 28 weeks | 2 lbs, 6.8 oz (1.1 kg) | 14.4 in (36.5 cm) | 10.2 in (26 cm) |
| 24 weeks | 1 lb, 6.9 oz (0.65 kg) | 12.2 in (31 cm) | 8.7 in (22 cm) |
Girls: Weight, Length, and Head Size by Age
| Weeks | Weight | Length | Head Size |
|---|---|---|---|
| 40 weeks | 7 lbs, 7.9 oz (3.4 kg) | 20 in (51 cm) | 13.8 in (35 cm) |
| 35 weeks | 5 lbs, 4.7 oz (2.4 kg) | 17.7 in (45 cm) | 12.4 in (31.5 cm) |
| 32 weeks | 3 lbs, 12 oz (1.7 kg) | 16.5 in (42 cm) | 11.4 in (29 cm) |
| 28 weeks | 2 lbs, 3.3 oz (1.0 kg) | 14.1 in (36 cm) | 9.8 in (25 cm) |
| 24 weeks | 1 lb, 5.2 oz (0.60 kg) | 12.6 in (32 cm) | 8.3 in (21 cm) |
Extra Care Needs
Premature babies often need to stay in special hospital units. These babies require close watching and extra help after birth.
Many premature infants stay in a Neonatal Intensive Care Unit (NICU). This special area has staff who monitor babies around the clock. The NICU team includes doctors and nurses trained to care for early arrivals.
Some babies may stay in an intermediate care nursery instead. This provides less intensive care than the NICU but still offers specialized attention.
Your baby might need help with:
- Maintaining body temperature
- Breathing properly
- Learning to eat
The healthcare team will create a care plan for your baby. They can explain everything that’s happening and answer your questions. Don’t hesitate to ask about anything you don’t understand.
The length of hospital stay depends on how early your baby was born and what medical issues they have. Healthcare providers will work with you to prepare for taking your baby home when they’re ready.
Risk Factors
Several factors can increase the chance of having a premature birth. While doctors cannot always identify the exact cause, knowing these risk factors is important.
Pregnancy-Related Factors:
- Multiple pregnancies (twins, triplets)
- Short time between pregnancies (less than 6 months)
- Fertility treatments
- Previous premature births
- History of miscarriages or abortions
Health Conditions:
- Uterus, cervix, or placenta problems
- Certain infections, especially in the genital area
- Chronic conditions like high blood pressure or diabetes
- Physical trauma or injuries
Lifestyle Factors:
- Smoking, alcohol use, or drug use during pregnancy
- Weight issues (underweight or overweight before pregnancy)
- Age (younger than 17 or older than 35)
- High stress levels from difficult life events
Black and Native Americans have higher rates of premature births compared to other groups in the United States. However, premature birth can affect anyone regardless of background. Many women who deliver early have no known risk factors at all.
Experts recommend waiting 18-24 months between pregnancies to reduce risks. If you have any of these risk factors, talk with your healthcare provider about ways to help ensure a healthy, full-term pregnancy.
Health Issues in Premature Infants
Babies born too early may face several health issues in their first weeks of life. These problems vary based on how early the baby arrives and their birth weight.
Breathing Difficulties
Breathing difficulties are common in premature infants. Their lungs may lack surfactant, a substance that helps lungs expand properly, leading to respiratory distress syndrome.
Many preemies experience apnea—brief pauses in breathing. Some develop bronchopulmonary dysplasia, requiring oxygen support for weeks or months.
Heart Issues
Heart issues frequently affect premature babies. Patent ductus arteriosus (PDA) occurs when an opening between two major blood vessels fails to close naturally. Without treatment, PDA can cause heart failure.
Low blood pressure is another concern, often requiring intravenous fluids, medications, or blood transfusions.
Brain Bleeding
Brain bleeding risks increase with earlier births. While most cases of intraventricular hemorrhage are mild with minimal short-term effects, severe bleeding can cause lasting brain damage.
Temperature Regulation
Temperature regulation presents a significant challenge for premature infants. With limited body fat and inability to generate sufficient heat, preemies can quickly develop hypothermia—dangerously low body temperature.
This condition may trigger breathing problems and low blood sugar. Many premature babies initially need incubators or warmers to maintain proper body temperature.
Digestive System Complications
Digestive system complications include necrotizing enterocolitis (NEC), a serious condition where intestinal tissue becomes damaged. This typically occurs after feeding begins. Breast milk significantly reduces NEC risk in premature infants.
Blood-Related Issues
Blood-related issues affect many preemies:
- Anemia: Insufficient red blood cells, often more severe in premature babies.
- Jaundice: Yellowing of skin and eyes due to excess bilirubin in the blood.
Metabolism Problems
Metabolism problems make it difficult for premature babies to maintain normal blood sugar levels. Their limited glucose stores and trouble converting stored sugar into usable forms contribute to this issue.
Immune System Weakness
Immune system weakness leaves premature infants vulnerable to infections. Without fully developed defenses, infections can rapidly progress to sepsis, a life-threatening condition.
Lasting Health Effects
Premature birth can lead to health issues that persist beyond infancy. These long-term effects may include:
Cerebral Palsy
Cerebral palsy, a group of movement disorders, occurs more frequently in premature babies. It can result from infection, poor blood flow, or brain injury during pregnancy or early infancy.
Learning Challenges
Learning challenges are more common among children born prematurely. They may reach developmental milestones later than full-term peers and face a higher likelihood of learning disabilities during school years.
Vision Complications
Vision complications, particularly retinopathy of prematurity, affect some preemies. This condition involves abnormal blood vessel growth in the retina. Without treatment, it can lead to retinal detachment and potential blindness.
Hearing Deficits
Hearing deficits occur more frequently in premature infants. All preemies should undergo hearing screenings before leaving the hospital.
Dental Problems
Dental problems in children born early may include:
- Enamel defects
- Delayed tooth development (especially in very or extremely premature babies)
| Complication | Description | Risk Factors |
|---|---|---|
| Cerebral palsy | Movement and coordination disorders | Earlier gestational age |
| Learning difficulties | Delayed milestones, possible learning disabilities | Extremely premature birth |
| Vision problems | Retinopathy of prematurity, potential visual impairment | Very low birth weight |
| Hearing loss | Partial or complete hearing deficits | Infection, certain medications |
| Dental issues | Enamel defects, delayed development | Very early birth |
Behavioral and Mental Health Concerns
Behavioral and mental health concerns appear more frequently in children born prematurely. These may include developmental delays and various psychological challenges.
Ongoing Health Vulnerabilities
Ongoing health vulnerabilities often affect premature babies throughout childhood. They face higher risks of:
- Recurrent illnesses
- Asthma
- Feeding difficulties
- Sudden infant death syndrome (SIDS)
Not all premature babies experience these complications. Healthcare providers closely monitor premature infants to identify and address potential issues early. Many premature babies grow up healthy with appropriate medical care and support.
Prevention
There are ways to reduce the chance of having a baby too early. Even though doctors don’t always know what causes premature births.
Medical treatments that can help:
- Progesterone Supplements – This hormone occurs naturally during pregnancy. If you’ve had a premature baby before or have a short cervix, your doctor might recommend taking artificial progesterone to lower your risk.
-
Cervical Cerclage – This surgical procedure may be recommended if you have both a short cervix and previous premature births. The doctor stitches the cervix closed with strong sutures to provide extra support for the uterus.
These stitches are removed when it’s time for delivery. Your healthcare provider might advise limiting strenuous activities afterward.
What doesn’t work:
Bed rest is not recommended for preventing premature birth. In fact, staying in bed for extended periods can actually cause problems like:
| Risks of Bed Rest |
|---|
| Blood clots |
| Weakened bones |
| Decreased muscle strength |
| Possible increased risk of premature birth |
If you’re concerned about having a premature birth, talk with your healthcare provider about prevention strategies that might work for your specific situation. The best approach will depend on your medical history and current pregnancy conditions.
