Updated May 18, 2015.

Most pregnancies last approximately 40 weeks. Babies born between 37 and 42 weeks of gestation are considered full term. Babies that are born before 37 weeks gestation are defined as premature.

Currently, medically speaking the definition of viability is set at 23 weeks gestation. In many hospitals this is the cutoff point of medical intervention in the attempt to save the life a baby born prematurely.

However, this is a loose definition based on a generalization and keeping in mind the dates may be off by a few weeks in either direction. A baby born at or before 23 weeks gestation typically will require extensive medical intervention including, respiratory support, invasive treatments, and a long and sometimes tough stay in the Neonatal Intensive Care Unit.

 

PREMATURE BIRTH STATISTICS

• As many as 11.4 percent of all pregnancies end in early deliveries.
• About 450,000 babies in the United States alone are born too soon and 15 million babies are born preterm around the world - that's 1 in 10!
• 80 plus percent of preterm births are unanticipated.
• Approximately 45-50% of preterm births are idiopathic. (unknown)
• 30% are related to preterm rupture of membranes. (PROM)
• 15-20% are attributed to medically indicated (example: preeclampsia, abruption, IUGR) or elective preterm deliveries.
   

"Events leading to preterm birth are still not completely understood, although the etiology is thought to be multifactorial.

It is, however, unclear whether preterm birth results from the interaction of several pathways or the independent effect of each pathway. Causal factors linked to preterm birth include medical conditions of the mother or fetus, genetic influences, environmental exposure, infertility treatments, behavioral and socioeconomic factors, and iatrogenic (related to medical examination or treatment) prematurity." (WHO)

 

DID YOU KNOW?

• The premature birth rate in the United States has dropped for the seventh consecutive year, to 11.4 percent of all births in 2013.
• This is the lowest rate in 17 years! The federal government's goal had been to reduce preterm births from a baseline of 12.7 percent in 2007 to 11.4 percent by 2020. The new figures mean the country hit the target seven years early.
• The U.S. still has one of the highest rates of preterm birth of any high-resource country
• Medical expenses for a baby born prematurely average about $54,000, compared with $4,000 for a healthy, full-term newborn.
• Preterm birth rates remain stubbornly higher among certain racial and ethnic groups in the U.S., including black, Native American and Hispanic women. The rate of preterm birth among uninsured women also is far higher than the national average (19.8 percent in 2013.)

 

PERCENTAGE BASED ON GESTATIONAL AGE (approximate)

• More than 70 percent of premature babies are born between 34 and 36 weeks gestation.
• 12 percent of premature babies are born between 32 and 33 weeks gestation.
• 10 percent of premature babies are born between 28 and 32 weeks gestation.
• 6 percent of premature babies are born before 28 weeks gestation.

 

SURVIVAL RATES (approximately based on multiple factors)

• Babies born 23 weeks have a 17 percent chance of survival.
• Babies born at 24 weeks have a 39 percent chance of survival.
• Babies born at 25 weeks have a 50 percent chance of survival.
• Babies born at 26 weeks have an 80 percent chance of survival.
• Babies born at 27 weeks have a 90 percent chance of survival.
• Babies born between 28-31 weeks gestation have at 90-95 percent chance of survival.
• Babies born between 32-33 weeks have a 95 percent chance of survival.
• Most babies born 34 weeks or greater have the same likelihood of survival as a full term infant.

 

The odds of survival increase as the pregnancy progresses. With every week a baby remains in the womb the chance for thriving and surviving increases. However, gestational age isn’t the only determining factor for survival for babies born too early. Multiple factors play an important role in how well a baby will do including birth weight, complications of pregnancy such as placental abruption, infection, and immature lung development to name just a few. Fortunately medical research and advances have increased the chances of survival in even the tiniest of babies.

 

OUTCOME STATISTICS (approximate)

Percentage statistics based on babies born before 26 weeks gestation:

• Those who may develop a severe disability secondary to early birth- 22%
• Those who may develop a moderate disability or special needs from premature birth- 24%
• Those who may develop a mild disability- 34%
• 20% of all those born at 26 weeks gestation or earlier will have no long term effects from their prematurity.

 

Based on gestational age and birth weight, premature babies are placed loosely into defined categories of mild, moderate, and extreme prematurity:

Mild: Babies born between 33 and 36 weeks gestation and/or have a birth weight between 1500g-2000g (3lbs 5oz and 5lbs 8oz)?

Moderate: Babies born between 28 and 32 weeks gestation with a birth weight between 1000g-1500g (2lbs 3oz and 3lbs 5oz)?

Extreme:  Babies born before 28 weeks gestation or who have a birth weight of less than 1000g (2lbs 3oz)

• Late preterm baby, born between 34 and 37 weeks of pregnancy
• Preemie, born at less than 32 weeks of pregnancy
• Micro-preemie, born at less than 25 weeks of pregnancy

 

REDEFINING PREMATURITY

The American Congress of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) recently announced that they are recommending the use of the label "term" in pregnancy be replaced by new gestational age designations.

According to the new designations, full term will refer to 39 weeks through 40 weeks and 6 days of pregnancy. In the past, a pregnancy between 37 and 42 weeks was considered full term.

This change reflects findings from the National Institute of Child Health and Development NICHD, research about poorer health outcomes of babies born at 37 and 38 weeks of pregnancy, (previously considered full-term) compared to those born after 39 weeks.

For example, research shows that compared to babies born at or after 39 weeks of pregnancy, babies born before 39 weeks are:

• At greater risk of being admitted into the Neonatal Intensive Care Unit (NICU)
• At a 20% greater risk of complications, including: breathing, feeding, and temperature problems; sepsis (severe blood infection); and cerebral palsy
• 5% more likely to have an intellectual or developmental disability
• At a 50% greater risk for death within the first year of life

Mothers who deliver at or after 39 weeks of pregnancy typically have better outcomes than do mothers who deliver before 39 weeks.

New categories as defined by NICHD:

• Early term: 37 weeks through 38 weeks and 6 days
• Full term: 39 weeks through 40 weeks and 6 days
• Late term: 41 weeks through 41 weeks and 6 days
• Post-term: 42 weeks and beyond

 

FAMOUS PREEMIES OF YESTERDAY AND TODAY

Napoleon Bonaparte: born in 1769 was one of the greatest military leaders in history. His small statue is noted to be the result of his premature birth.

Victor Hugo: a great French novelist, most famous for creating Les Miserable, was a preemie born in 1802

Mark Twain: An accomplished American writer born in 1835, born 2 months premature.

Sidney Poitier: Award winning actor, film director and activist.

Winston Churchill: A British politician and statesman, born 2 months premature in 1874.

Albert Einstein: Born premature in Germany in March of 1879. Einstein experienced small beginnings in a time where neonatology was virtually nonexistent, and went on to make outstanding achievements in math and science.

Anna Pavlova: Born 2 months premature in 1881 and grew up to become one of the world’s most famous ballerinas.

Patrick Bouvier Kennedy: The 3rd child of Jacqueline and John F. Kennedy was born at 34 weeks and died at 2 days of age due to Hyaline Membrane Disease, also known as Respiratory Distress Syndrome or RDS. RDS is one of the most common complications of prematurity. The loss of the first family’s baby deeply moved the nation and led to an outpouring of public and private resources for medical research leading to use of surfactant therapy in babies born with immature lungs.

Stevie Wonder: Famous American singer born in 1950 and was one of many premature infants born in the 40’s and 50’s affected by a condition called Retinopathy of Prematurity (ROP) that caused him to lose his eyesight as a baby. Medically advances today have dramatically reduced the risk of ROP in babies born too soon.

Isaac Newton: Scientist and inventor who described the laws of gravity. Born in 1643, small enough to fit into a quart mug, according to his mother.

Charles Darwin: An English naturalist and scientist- the originator of the biological theory of evolution.

Pablo Picasso: Artist and Spanish painter- famous sculptor, print-maker, ceramicist.

Michael J. Fox: Canadian born actor, author, producer, and activist.

Wayne Brady: American actor, singer, comedian and television personality; born 3 months premature.

Phillip Phillips: Musician and winner of American Idol 2012. Born premature in 1990 and almost didn’t make it. He has struggled with digestive issues and is said to be a NEC survivor.

 

CURRENT RECORDS

Some famous preemies are only known to the world due to their early birth:

• Rumaisa Rahman, born at 25 weeks gestation in September of 2004 in a Chicago area hospital is thought to hold the current record as the World’s smallest surviving baby, weighing 244 grams or 8.6 ounces.
• James Elgin Gill, born in May 1987 in Ottawa Canada was the earliest premature baby in the world. He was 128 days premature at 21 weeks and 5 days gestation. James weighed 644g or 1lb 6oz. He survived and is reported to be healthy in his mid-20’s.
• ?Amillia Taylor has also been cited as the most premature baby. Born in October 2006 in Miami Florida at 21 weeks and 6 days gestation. At birth she was 9 inches long and weighed 233g or 10 ounces.

 

There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.”? Albert Einstein

 

References

The impact of premature birth on society | March of Dimes. (n.d.). Retrieved from http://www.marchofdimes.org/mission/the-economic-and-societal-costs.aspx

March of Dimes. (n.d.). Retrieved from http://www.marchofdimes.org/materials/premature-birth-report-card-united-states.pdf

PeriStats | March of Dimes. (n.d.). Retrieved from http://www.marchofdimes.org/peristats/Peristats.aspx

Premature Birth Statistics | Statistic Brain. (n.d.). Retrieved from http://www.statisticbrain.com/premature-birth-statistics/

Prematurity at Birth: Determinants, Consequences, and Geographic Variation - Preterm Birth - NCBI Bookshelf. (n.d.). Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK11386/

PRETERM BIRTH AS A PUBLIC HEALTH INITIATIVE. (n.d.). Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2496946/

Products - Data Briefs - Number 39 - May 2010. (n.d.). Retrieved from http://www.cdc.gov/nchs/data/databriefs/db39.htm

Statistics about Premature Birth - RightDiagnosis.com. (n.d.). Retrieved from http://www.rightdiagnosis.com/p/premature_birth/stats.htm

WHO | Preterm birth. (n.d.). Retrieved from http://www.who.int/mediacentre/factsheets/fs363/en/