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Premature Baby Survival Rate By Week During Pregnancy

premature baby survival ratesWhen I was pregnant with my first child, I involuntarily got to learn about premature survival rates in different weeks of pregnancy.

You have probably read in the newspapers about babies miraculously born and saved as early as after 22 weeks of pregnancy. A few years ago, a baby in Germany actually survived being born before the end of week 22, which is a new record.

When I came in with ambulance to the hospital, having contractions three minutes apart and dilating (and in complete panic) in week 26 of my pregnany, the doctors and midwives were wonderful (and smart):

“Oh, week 26, they said, that’s a big baby, no worries. (But try keeping her inside for as long as you can.)”

They wanted to calm me down, since stress is a known factor involved in preterm labor. And it worked. I did feel slightly less panicked. And my baby, predicted by all involved doctors to be born within hours, actually stayed in my womb until week 37. A small miracle. (And a lot of lying down on my part.)

In this article, I have gathered statistics from available research on baby survival rates per week during pregnancy from week 22 completed to week 33. During these weeks, the chance of survival increases on average from 21% to 100%. Of course, statistics are just numbers and each case of preterm labour is special. Nevertheless, these percentages do say something about our little babies’ chances of survival if pregnancy ends much too soon.

If you are reading this, you might be in the very stressful situations of either being at risk for preterm labour or having already given birth to a preemie. In such case, me heart goes out to you! Feel free to leave a comment to share your thoughts and experiences are the bottom of this article.

Survival Possibilities For Extremely Premature Babies

When can a pregnant mom breathe out in relief? In what week is her baby big enough to survive a preterm labor and hopefully develop normally in the future?

The answer isn’t all that simple. It turns out that it isn’t only the week of pregnancy, but also the weight of the baby that determines the chance of survival (if assuming that the child is healthy). In addition, researchers have recently also been able to pinpoint two additional factors that contribute to the chances of survival for a particular child: the gender and whether or not the mother received ante-natal steroids before the baby was born. The latter is a medicine that promotes lung development in the baby.

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But disregarding the effect of all these different factors, you’ll find the average survival rates week by week below, for extremely premature babies that received mechanical breathing help, which is necessary for survival for extremely premature babies. (Statistics for older babies follow below)

Survival Rates For Extremely Premature Babies

  • 22 weeks completed: 21% survival
  • 23 weeks completed: 37% survival
  • 24 weeks completed: 60% survival
  • 25 weeks completed: 77% survival

Source:NICHD Neonatal Research Network (NRN): Extremely Preterm Birth Outcome Data
Note: 22 pregnancy weeks completed, means that you have entered the 23 week of pregnancy and so on.

The factors influencing the survival rates

Babies that are heavier than the average, are girls, singleton (i.e. not twins or more), and/or where mom receives ante-natal steroids in time have tend to have higher chances of survival than the above figures, generally speaking.

The National Institute of Child Health and Human Development (NICHD) has developed a tool, where doctors and parents can get a rough guide to potential premature survival rates in their particular situation. You can try the tool here. But please remember that it is NOT intended to project the outcome for individual infants!

Survival Possibilities For All Premature Babies

Survival rates for extremely early preterm babies have improved dramatically over the past 15 years. In 1995, practically no children survived when born as early as 22 weeks gestation age, while in 2008 21% survived, as seen above. The most dramatic improvement has been noted among infants born in week 24 and week 25. In 1995 24% of the infants born in week 24 survived, while the rate in 2005 was 41%. In 2008, the share had risen to 60% according to the above study.

The earliest born babies, at pregnancy week 22 and 23, however, are apparently still complicated to save. Even though survival rates have improved also for these children, survival rate almost doubles between gestation week 23 and week 24.

After these very critical, earliest weeks of survival for extremely premature babies, premature survival rates rise rapidly. Putting together the statistics above with data from Pediatrix Medical Group, in 2005, you’ll find survival rates for premature babies week by week as follows:

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Premature Baby Survival Rate By Week

  • 22 weeks completed: 21% survival
  • 23 weeks completed: 37% survival
  • 24 weeks completed: 60% survival
  • 25 weeks completed: 77% survival
  • 26 weeks completed: 85% survival
  • 27 weeks completed: 91% survival
  • 28 weeks completed: 95% survival
  • 29 weeks completed: 97% survival
  • 30 weeks completed: 98% survival
  • 31 weeks completed: 99% survival
  • 32 weeks completed: 100% survival
  • 33 weeks completed (and on): 100% survival

Source:NICHD Neonatal Research Network (NRN): Extremely Preterm Birth Outcome Data
Statistics from Pediatrix Medical Group, 2005, reprinted by Merck Manuals
Note: 22 pregnancy weeks completed, means that you have entered the 23 week of pregnancy and so on.


Going back to my own situation, the doctors gave me a few landmarks to strive for. The first one was to keep my baby in for 12 hours. If I managed that, the ante-natal steroids injection would have helped mature my baby’s lungs to facilitate breathing.

The second milestone, when things started to calm down, (I was still in hospital medicated through intravenous drip and ordered complete bedrest) was to get as close as possible to full week 28. Babies born after 28 full weeks tend to almost always survive and the risk of serious brain and lung damage falls sharply.

Next goal was 32 weeks completed. By then a (healthy) baby most likely will be born with no permanent injuries at all.

Finally, 35 weeks. After that most babies are more or less ready to be born. They may be a bit skinny and need help to suckle, but with a little assistance, they are just fine.

SO when to take that deep sigh of relief? I’d say when you enter week 28 of pregnancy chances are huge that you will bring home a perfectly healthy baby regardless of when labor sets in. But compared to some 10 years ago, giving birth to a baby already in pregnancy week 24 or 25, your baby stands a very good chance of surviving with the right neonatal care.


I hope you found this information on premature survival rates and factors useful. You’ll find videos about fetal development as well as one with premature babies here.

Please share your own thoughts and experiences by leaving a comment below. 🙂

  • Barry

    Big Thanks for this article ,help a lot …..my wife gave birth through c-section to our first baby @ 29 weeks … It makes me feel terrible , now she is 17 days old . Although she is still in the NICU Room , i can see she is getting well …. Cant wait to bring her Home …

  • Heather Lopez

    Great article!!!! I had my identical twin girls at 22 weeks and 5 days. My youngest twin passed away at 2 weeks old. But my oldest is doing great!!!! She is delayed physically as far as size and weight. But other then that she is perfectly healthy.

    • How both fantastic and sad at the same time! Twins being born that early is really early. How much did she weigh when newborn? Wonderful to hear that your daughter is doing great! 🙂