A premature baby’s survival rate and development may vary depending on how early they are born before the due date. Nearly 15 million babies are born prematurely, and in the US, one in every 10 babies are preemies (1) (2).
Significant developments occur in the fetus during each week of pregnancy; hence, prematurely born babies may lack a few of these developments, even though they can survive outside the womb. However, babies born near the due date may have better growth and development.
Read on to learn more about a preterm baby’s survival rates and risk factors.
Definition Of Premature Birth
According to the World Health Organization, preterm or premature birth is defined as when babies are born alive before the completion of 37 weeks of pregnancy (1). Based on the gestational age or age of the pregnancy, preterm birth can be further divided into the following categories (1).
- Extremely preterm: When a baby is born before 28 weeks
- Very preterm: When a baby is born between 28 and 32 weeks
- Moderate or late preterm: When a baby is born between 32 and 37 weeks
It is usually recommended that unless there is a medical emergency or a serious health condition, cesarean birth or induced labor (induction) should not be planned before 39 weeks of gestation. However, with advances in medical sciences, it is estimated that about 9 out of 10 babies born prematurely survive and have normal growth (3).
Factors Affecting Survival Of Preterm Babies
A National Institutes of Health study that observed 4,000 newborns found that the following factors affect the survival and disability in preterm babies (4).
- Baby’s gender
- Maternal age
- Birth weight
- multiple pregnancies
- Whether the mother was given medication to stimulate the development of fetus
- Infections and chronic conditions (eg. diabetes, hypertension, etc.)
The researchers found that there were better chances of survival without a disability when the baby was a female, was of older gestational age, had higher birth weight, was born as a single baby, and the mother received medication, such as antenatal steroids, to stimulate fetal growth (4).
Since preterm babies are not able to meet growth milestones during pregnancy, they may have serious health problems. In 2018, preterm birth and low-birth weight accounted for 17% mortality in newborns (2). However, babies who survive may develop respiratory problems, digestive problems, or bleeding issues in the brain.
What To Expect After An Extremely Premature Birth?
The extremely preterm babies require advanced care from specialized experts, including obstetricians, neonatologists, maternal-fetal-medicine specialists, and other specialized pediatricians (6).
The first thing to consider after an extremely premature birth is whether the baby is capable of breathing and whether the parents and doctors decide to resuscitate the baby. When resuscitation doesn’t work, doctors try to make the baby comfortable instead of using treatment to help them survive (7).
The treatment, in such cases, is dependent on the following factors (7).
- Whether the brain of the baby has incurred any damage, which can occur due to lack of oxygen or bleeding in the brain
- Physical health of the baby
- Gestational age at which the baby is born
The first month after birth is the most crucial period because that is when the baby experiences major problems (7).
Very rarely, babies born before 23 weeks survive. Babies born between 23 and 25 weeks may survive but may experience long-term disabilities (6). This happens because the vital organs are not completely formed.
Preterm Survival Rates
Below are the survival rates for preterm babies born at different gestational ages.
- Babies born less than 24 weeks: Babies born before 24 weeks have a rare chance of survival, their chance of survival is usually less than 50% However, if they do survive, they may have life-long health complications.
The graph illustrates the survival rates of premature babies born at 24 weeks in different high income countries. According to the study, Japan has the highest survival rate and France the lowest (16).
Survival of preterm infants born at 24 weeksSource: Preterm birth and sustained inflammation: consequences for the neonate. Seminars in Immunopathology.
- Babies born at 26 weeks: Babies born at 26 weeks have about a 78% chance of survival. Moreover, in the long-term 4 out of 10 children develop problems with vision, hearing or, intellectual development (8) (9).
- Babies born at 28 weeks: Babies born at 28 weeks have an 80% to 90% chance of survival. Statistically, they only have a 10% chance of developing long-term health problems, which include breathing problems, infections, digestive problems, and blood-related problems (8).
- Babies born at 30 to 32 weeks: When a baby is born at 32 weeks, the chances of survival can be as high as 95%. Also, the chances of mortality and development of long-term health problems decrease drastically (8).
- Babies born at 34 to 36 weeks: A baby born at or after 34 weeks has similar health outcomes as that of a baby born after a complete gestation period of 40 weeks. Thus, the baby is more likely to be as healthy as the baby who was not born prematurely. Also, in the long-term, the babies do well and are generally as healthy as full-term babies. However, doctors may still recommend hospital (neonatal) care for one or two more weeks (8).
It is important to note that statistics may not apply to all babies. Every baby is different. Also, survival rate factors, mentioned earlier, have a significant role to play in the prognosis.
Risk Of Disabilities At Each Stage
Due to immature organs, babies who survive preterm birth develop both short-term and long-term complications. Preterm babies may develop various health problems, including (7):
- Respiratory problems: May range from transient tachypnea of newborns to bronchopulmonary dysplasia.
- Neurologic outcomes: Neurosensory impairments such as deafness, blindness, hypo- or hypertonia, poorer cognitive performances, as well as neurodevelopmental abnormalities.
- Cerebral palsy: A non-progressive motor disability that results in plegias, spasticity and dystonia. Its signs may appear when the child is between one and three years old.
- Learning disabilities: These may appear when the child starts school.
- For babies born at 24 weeks, 60% of them may not have a disability at three years of age.
- For babies born at 25 weeks, 70% of them may not have a disability at three years of age.
- For babies born at 26 weeks, 80% of them may not have a disability at three years of age.
About 50% of babies born between 23 and 25 weeks may develop behavior- and attention-related problems by the age of six years. They may also have difficulty adjusting to school (7).
Nearly 40% of babies born between 25 and 26 weeks may develop problems related to hearing, vision, and intellectual development. These problems may carry on to adulthood (7).
What To Ask Your Doctor?
During pregnancy, you should make sure to visit your doctor for antenatal care during the first 12 weeks. The doctor can compute for your due date, using your last menstrual period or based on your earliest ultrasound, and perform necessary physical exams, and discuss risk factors or concerns, if any (8). The doctor can also monitor for presence of any infection or inflammation across the entire duration of pregnancy to avoid any risk factors that would greatly affect the baby.
Knowing about the following can help you prepare well for taking care of the baby. You may ask the following questions to the doctor to dispel your doubts.
- What is the gestational age at which my baby will be born?
- Does the baby have any developmental issues before birth? What are the associated complications of it? What tests were run to check the severity?
- What treatments will be used in my baby’s care before birth? What are the risks and benefits of each of these treatments? Are there any alternatives?
- What consequences should I look out for after discharge from the hospital? What can be the potential health problems in the first year or when the child starts school?
- What type of follow-up will my baby need after birth? How many revisits might be required after birth?
Frequently Asked Questions
1. What is the most common cause of premature birth?
Common causes of premature birth may include multiple pregnancies (more than one baby), infections, and underlying conditions such as diabetes and hypertension (10).
2. What is the earliest a baby can be born and survive?
A minimum of 24 weeks of gestation is required for a baby to be born and survive. Before this, many vital organs are not developed enough to support life (11).
3. How long do premature babies stay in hospital?
Premature babies may need to stay in the hospital until they reach their due date. However, the hospital stay may vary depending on the health condition of the baby (12).
4. At what weight can premature babies go home?
Though there is no defined protocol, some hospitals wait till babies are at least 4lb (2kg) before they are ready to come out of the incubator (13).
5. Do premature babies have mental problems?
Preterm babies with low birth weight may have a higher risk of developing psychological problems (14).
6. Are premature babies more likely to have autism?
Premature babies may have a higher risk of developing autism than the general prevalence, and the prevalence is about 2% (15).
The advancements in medical science and technology have allowed doctors to determine the possible risks associated with the baby’s premature birth and take the necessary precautions. The early period can be divided into various categories, and the duration for which the baby needs to be kept under observation after a premature delivery depends upon it. Therefore, it is advised that you take proper prenatal care, attend regular checkups, and refrain from performing activities that might increase the risks of premature delivery.
- Babies born beyond 28 weeks of gestational age have better survival rates than those born earlier.
- Birth weight, baby’s gender, and maternal age are a few important factors determining a premature baby’s survival rate.
- Babies born too early can survive with advanced medical support and care. However, there is a risk of them developing various disabilities in later stages.
2. Premature birth: Centers for Disease Control and Prevention
3. Premature baby: Pregnancy, Birth, and Baby
4. NIH Study Reveals Factors That Influence Premature Infant Survival, Disability: National Institute of Health
5. Preterm labor and birth FAQs: American College of Obstetricians and Gynecologists
6. Extremely preterm birth FAQs: American College of Obstetricians and Gynecologists
7. What to expect when you have an extremely premature infant: HealthLinkBC
8. When is it safe to deliver your baby?: University of Utah
9. Definition of premature birth: Irish Neonatal Health Alliance
10. Preterm Birth; WHO
11. You and your baby at 24 weeks pregnant; NHS
12. When can a premature baby leave the hospital; Nationwide Children’s Hospital
13. Neonatal weight gain and nutrition; MedlinePlus
14. Astrid M. W. Lærum et al.; Psychiatric symptoms and risk factors in adults born preterm with very low birthweight or born small for gestational age at term; Biomedcentral
15. Leora Allen et al.; Autism risk linked to prematurity is more accentuated in girls; NCBI
16. Tonse N. K. Raju; Moderately Preterm, Late Preterm and Early Term Infant: Research Needs; NCBI
17. Rates of survival increasing for extremely preterm infants, NIH network finds; NIH
18. CDC Grand Rounds: Public Health Strategies to Prevent Preterm Birth; CDC