Survival and other outcomes for babies born at 24 or 25 weeks

Outcomes of micro preemies

“Is my baby going to live?” and “How is my baby going to do in the future” are the two most frequent questions asked of me after the birth of a premature baby. These questions are even more crucial closer to viability thresholds when we expect higher mortality rates or higher incidence of developmental disabilities among babies who will survive. 

In this article, I will talk specifically about preemies born at 24 or 25 weeks of gestational age. Before I go into more details, I want to emphasize that you should treat my post only as general educational material and not use it to make any medical decisions. Your child’s situation may be very different, and the birth hospital of your baby may have different outcomes from described here. Furthermore, medical knowledge and results in neonatology are changing and evolving constantly.

What are survival rates for babies born at 24 and 25 weeks?

According to the article published in 2015 by Rysavy in the New England Journal of Medicine, the survival rate for 24 weeker babies is 56.6% and for 25 weekers is 72%. This data set came from an analysis of 5000 babies born before 27 weeks in the USA between 2006 and 2011. We could expect that current results might be a little better. I want to emphasize that these numbers should give you only a general idea about the mortality and survival of those premature babies. 

Different countries, hospitals, and races may have different results. In fact, we are aware of significant racial disparities in health outcomes in the USA among various ethnic and racial groups. 

To learn your situation better, you should ask your obstetrician or neonatologist some additional questions beyond just mortality or survival rate. You should know whether your baby is likely to have average outcomes, worse or better than average. For example, if your baby was born by emergency cesarean section, in a very poor condition, required prolonged resuscitation, and its weight was extremely small, such a baby will probably have worse than average outcomes. 

On the other hand, if your baby was born under more controlled conditions, did not need resuscitation, and had good weight for its gestational age, this baby is likely to have better than average outcomes. 

What are the short-term outcomes of preemies born at 24 and 25 weeks?

I define short-term outcomes as mortality or survival rates (described above) and rates of various complications occurring in babies treated in NICU. I will briefly talk about these conditions below, and if interested, you can read more extensive articles on those subjects in my book “Babies Born Early.”

How big are babies born at 24 and 25 weeks of gestation?

Size of the baby after birth is different depending on the sex. Usually, boys are a little heavier and longer than the girls. However, girls are stronger, and survival rates are somewhat better for them compared to boys. You can see the average weight and height for each gestational age in tables below. Remember, that actual weight and height of your baby will be either above or below that average value (Resource).

Table 1: Measurements for girls born at 24 and 25 weeks of gestation

Weeks at birthWeight in gmWeight in lbHeight in cmHeight in inch
24 weeks600 gm1 lb 5.2 oz30.2 cm11.9 inch
25 weeks700 gm1 lb 8.7 oz31.5 cm12.4 inch

Table 2: Measurements for boys born at 24 and 25 weeks of gestation

Weeks at birthWeight in gmWeight in lbHeight in cmHeight in inch
24 weeks650 gm1 lb 6.9 oz31 cm12.2 inch
25 weeks750 gm1 lb 10.5 oz32 cm12.6 inch

What are the rates of Respiratory Distress Syndrome (RDS) in 24 and 25 weeker babies

The vast majority of newborns born that early suffer from Respiratory Distress Syndrome (RDS). RDS is a pulmonary condition that preemies develop due to the chemical and anatomical immaturity of their lungs. It results in them needing respiratory support. 

Most babies affected by the disease will need supplementary oxygen and respiratory support such as ventilators, CPAP machines, or nasal cannulas. You can read more about these therapies in my article here. Most preemies will eventually recover from RDS. However, in many cases, RDS first will evolve into another pulmonary condition called Bronchopulmonary Dysplasia or BPD (sometimes also called Chronic Lung Disease). 

The rates of Bronchopulmonary Dysplasia (BPD) in babies born at 24 and 25 weeks of gestational age.

Without getting into scientific controversies, we can define BPD as a condition that develops following the RDS and results in a baby requiring supplementary oxygen at the corrected age of 36 weeks. In other words, it is a case when a baby born at 24 or 25 weeks still needs additional oxygen for breathing 14 or 13 weeks later. For this definition, it does not matter if extra oxygen is being delivered by a ventilator, CPAP device, or nasal cannula. 

Among babies born at 24 weeks, about 30% will develop severe BPD, and 70% will develop mild BPD. Among babies born at 25 weeks, about 26% will have a severe form of BPD and 56% milder version. 

The need for oxygen is a frequent cause of delayed discharge home for babies with BPD. Sometimes, we can send some babies home on oxygen. However, for that to be possible, the baby can’t need a large amount of oxygen, and that support must be stable so parents can manage it at home. 

Apnea of Prematurity among preemies born at 24 and 25 weeks

Apnea of prematurity is defined as a situation in which babies stop breathing for 15-20 seconds or a shorter pause in breathing accompanied by abnormal heart rate or oxygen levels. 

Virtually all babies born at 24 or 25 weeks will suffer from this condition. While having symptoms, babies are frequently treated with a medicine called Caffeine and may need a ventilator, CPAP device, or nasal cannula to mitigate effects on their oxygen levels. 

The majority of premature babies will resolve their apnea by 34-36 weeks of corrected age. Some babies, particularly ones with complications in the central nervous system, may take much longer. Again, it may be frustrating because the presence of apnea may cause a significant delay in discharge home. 

What is Necrotizing Enterocolitis (NEC) incidence among babies born at 24 and 25 weeks?

Necrotic Enterocolitis is a severe condition that can develop in the bowels of premature babies. Its etiology is uncertain; probably infectious and inflammatory factors play a role in addition to the immaturity of the bowels and feeding intolerance.

Treatment involves stopping feedings for about two weeks, antibiotics, IV fluids, blood products as needed, and sometimes even surgery. Sadly, not all babies can recover from NEC. 

Approximately 10%-14% of newborns born at 24 and 25 weeks may develop NEC during their stay in NICU. The mortality rate among babies affected by NEC and with birth weights between 500-750 gm may reach even 42%.

What are the rates of Retinopathy of Prematurity (ROP) among babies born at 24 and 25 weeks?

Retinopathy of prematurity (ROP) is a condition that may develop in the eyes of premature babies and may lead in severe cases to blindness if not detected early or if too severe for successful treatment. Approximately 18% of 24 weekers and 12% of 25 weekers may develop severe ROP. 

A milder form of ROP affects about 95% of 24 weekers and 92% of 25 weekers. Depending on the stage of ROP disease, some babies will be only followed with regular eye exams, some will need laser or medical therapy, and some, despite all those measures, will have vision problems after discharge. 

The rates of Intraventricular Hemorrhage (IVH) among babies born at 24 and 25 weeks

Intraventricular Hemorrhage is defined as bleeding that may occur in a baby’s brain structures called ventricles. Factors such as degree of prematurity, clotting problems, traumatic delivery, an unstable condition may increase the risk of IVH in a baby. 

The severity of IVH is assessed by assigning a grade number. Grades 1 and 2 are considered milder forms, and grades 3 and 4 are considered severe bleeds. IVH may be associated with poor future developmental outcomes (mainly IVH grades 3 or 4). Of note, there is no specific treatment for IVH except for supportive therapy and treatment of complications. 

IVH grade 3 and 4 may be found in up to 26% of babies born at 24 weeks and 21% delivered at 25 weeks.

What is the long-term development of babies born at 24 and 25 weeks of gestational age?

After the baby goes home, all parents of premature babies are worried about their future. They ask questions: will they be able to talk, walk, go to school, and have a normal life? Let’s look at some data from the scientific literature. 

The French study that looked at babies born during 2011 in France found that preemies born between 24 to 26 weeks had a 6.4% incidence of cerebral palsy. Cerebral palsy is a condition affecting mainly a child’s motor abilities. 

Babies Born Early - Ebook on Amazon

The USA data reported by Rysavy in 2015 looked at rates of severe impairment. Severe impairment was defined as a score on standardized tests of motor and intellectual ability, which is below two standard deviations from the mean. In this study, severe cerebral palsy, bilateral blindness, and severe hearing deficit were also included as a severe impairment. 

For babies born at 24 and 25 weeks, survival rates without severe impairment were 46% and 61%. 

There is a lot of literature reporting on increased utilization of health resources, such as more frequent doctor visits and hospital admissions due to chronic problems associated with prematurity after discharge. 

New research is being conducted to find out how prematurity can affect one’s health late in life. Some doctors speculate that premature birth may affect our risk of developing chronic kidney disease, high blood pressure, or fertility problems. 

Final remarks:

Please understand that statistics, rates, probabilities are just numbers that can help you to get a general idea about answers to your questions. It will never give you 100% certainty about any outcome. If you have a child in the NICU right now, your child is a patient with its unique set of circumstances that are never fully understood even by their doctor-neonatologist. 

I have seen thousands of sick premature babies during my career. I have been in situations where I thought that baby would have a bad outcome, and it turned out that I was wrong. The opposite had happened as well. Many babies seemed to be doing well, and later on, they developed severe life-threatening complications. 

If you want to learn more about premature babies’ conditions, I encourage you to browse through articles included under the “prematurity” category above. If you have a premature baby born before 32 weeks receiving treatment in the NICU right now, you may want to explore my book “Babies Born Early,” which can be found here


This article is only for general information purposes. It should not be viewed as any medical advice. There is always a chance that information here may be inaccurate. It would be best if you always discussed all health-related matters with your doctor before making any decisions that may affect yours or your family members’ health.


Dr.Wisniewski is a board-certified pediatrician and neonatologist with over 20 years of clinical experience in the USA. He authored the book: "Babies Born Early - A guide for Parents of Babies Born Before 32 Weeks" Dr.Wisniewski loves educating parents on various health conditions affecting their newborn babies and children.

Recent Posts