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Preterm Births

The fetus is developing along with critical organ systems during pregnancy. There are critical windows during the development when environmental exposures could damage the fetus growth and function. We know some risk factors and others need more research, such as how family history, genetics, lifestyle, and environment may interact to put some women at greater risk for a premature delivery. In New Mexico, we will track premature (preterm) birth, which is the annual percentage of live singleton births that are preterm or born at less than 37 completed weeks of gestation. This and other measures, such as low birth weight, have specifically been created to track environmentally related birth/reproductive outcome and as such are more relevant for linkage to environmental exposure data than the routinely collected data and measures in New Mexico. Preterm birth is a multifactorial and heterogeneous birth outcome. The focus of this measure is restricted to singleton births because preterm birth rates differ dramatically between singleton and multiple births.
Preterm birth (at less than 37 completed weeks of gestation and among all births regardless of plurality) affects more than 500,000 or 12.5% of live births in the US and is a leading cause of infant mortality and morbidity. All infants born preterm are at risk for serious health problems; however, those born earliest are at greater risk of medical complications, long-term disabilities, and death.

Studies have shown that children born prematurely, especially those with very low birth weight (VLBW) have an increased risk of neurological problems ranging from attention deficit hyperactivity disorder to cerebral palsy or mental retardation in comparison with those born at term gestation (1, 6, 9, 15). Preterm birth is associated with nearly half of all congenital neurological defects, such as cerebral palsy (10); it is also associated with congenital gastrointestinal defects, such as gastroschisis.
A Premature Birth is a birth that is at least three weeks before a baby's due date. It is also known as preterm birth or less than 37 weeks (full term is about 40 weeks). Of the premature births, the majority (about 84%) of premature babies are born moderately preterm (between 32 and 36 completed weeks of gestation). About 16% are born very preterm (at less than 32 weeks of gestation); of those, about 10% are born between 28 and 31 weeks of gestation and about 6% are born at less than 28 weeks of gestation.

Prematurity is the leading cause of death among newborn babies. Being born prematurely is also a risk for serious health problems; however, those babies born earliest are at greatest risk for medical complication or death. Some babies will require special care and spend weeks or months hospitalized in a neonatal intensive care unit (NICU). Those who survive may face lifelong problems such as:
  • intellectual disabilities,
  • cerebral palsy (external Web site),
  • breathing and other respiratory problems,
  • vision and hearing loss, and
  • feeding and digestive problems.
Although the more preterm a baby is born, the more severe his or her health problems are likely to be, even babies born just a few weeks early can have more health problems than full-term babies. For example, a baby born at 35 weeks is more likely to have:
  • jaundice (external Web site),
  • breathing problems, and
  • longer hospital stays.
Not only is premature birth an emotional roller coaster for families, there is a tremendous financial toll as well. Preterm births account for health care expenditure of over $3 billion per year. The average first-year medical costs are about 10 times greater for preterm than for full-term babies.

Very preterm infants have the greatest risk of death and lasting disabilities, including mental retardation, cerebral palsy, respiratory (premature lung) and gastrointestinal problems (including birth defects such as gastroschisis), and vision and hearing loss.

Preterm infants are at greater risk for serious health problems for several reasons: the earlier a baby is born, the less it will weigh, the less developed its organs will be, and the more medical complications it will likely face later in life.
There are some known risk factors for premature singleton birth. But even if a woman does everything "right" during pregnancy, she still can have a premature baby.
The known risk factors are:
  • Having a previous preterm birth.
  • Problems with the uterus or cervix.
  • Chronic health problems in the mother, such as high blood pressure, diabetes (external Web site), and clotting disorders.
  • Certain infections during pregnancy.
  • Cigarette smoking (external Web site), alcohol use, or illicit drug use during pregnancy.
  • Other potential risk factors include:
    • Mother's age, race, poverty (for example, African-American women, women younger than 17 and older than 35, and poor women are at greater risk than other women).
    • Male babies (associated with singleton preterm birth).
    • Certain lifestyles and environmental factors, including:
      • Late or no prenatal care,
      • exposure to the medication diethylstilbestrol (DES),
      • domestic violence,
      • lack of social support,
      • stress,
      • long working hours with long periods of standing,
      • being underweight before pregnancy,
      • obesity,
      • marital status,
      • spacing of births (less than 6-9 months between birth and the beginning of the next pregnancy),
      • neighborhood-level characteristics, and
      • environmental contaminants (e.g., exposure to air pollution and drinking water contaminated with chemical disinfection by-products or lead).
    Preterm birth can happen to anyone and many women who have a premature birth have no known risk factors. There are things you can do to help your own health and lower your risk of having a premature baby, such as:
  • Quit smoking and avoid substances such as alcohol or drugs.
  • See your health care provider for a medical checkup before pregnancy.
  • Work with your health care provider to control diseases such as high blood pressure or diabetes.
  • Get prenatal care early, as soon as you think you may be pregnant and throughout the pregnancy.
  • Discuss concerns during pregnancy with your health care provider, and seek medical attention for any warning signs or symptoms of preterm labor.
  • The NM EPHT website is supported by Cooperative Agreement Number, 6 NUE1EH001354 (previously, 5 U38EH000949), funded by the Centers for Disease Control and Prevention (CDC). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of CDC or do not necessarily reflect the official policies of the Department of Health and Human Services, nor does the mention of trade names, commercial practices, or organizations imply endorsement by the U.S. Government. The information published on this website may be reproduced without permission. Please use the following citation: " Retrieved Tue, 25 January 2022 0:22:36 from New Mexico EPHT Tracking Public Web site: ".

    Content updated: Thu, 4 Jun 2020 16:26:03 MDT