Reproductive and birth outcomes information


What are reproductive and birth outcomes?

Reproductive and birth outcomes refer to the health of infants and mothers. Poor reproductive and birth outcomes include infertility, preterm birth (prematurity), low birth weight, birth defects, and maternal, fetal and infant death.

Why are reproductive and birth outcomes a concern?

In Colorado, approximately 69,000 births occur each year. In 2010, 8.8 percent of infants born in Colorado were born at a low birth weight and 9.1 percent of babies were born before 37 weeks (preterm). While most women have a normal 38-40 week term pregnancy and deliver a healthy baby, a safe and healthy pregnancy is not experienced by all women. Preterm birth is the leading cause of death among newborn babies. Premature birth is one of the main reasons why a baby may be born with low birth weight.

Low birth weight infants (those weighing 5.5 pounds or less):

  • have a higher death rate than normal-weight infants

  • may require neonatal intensive care and repeated hospitalizations.

  • may experience increased illnesses through life and are at increased risk of obesity in childhood and adulthood.,

​Unintended pregnancies, defined as pregnancies occurring sooner than desired or occurring when no pregnancy is desired, can also contribute to poor birth outcomes. Unintended pregnancies are linked to late entry into prenatal care, birth defects, and low birth weight. Nearly half of all pregnancies in Colorado are unintended.

What is known about reproductive and birth outcomes and the environment?

Research on reproductive and birth outcomes has improved the understanding of the risks of several substances found in the environment. According to the CDC, the following risk factors reflect the limited knowledge of the environment's role:

  • Secondhand smoke exposure to nonsmoking pregnant women is a risk factor for some poor birth outcomes

  • A limited body of evidence points to a link between components of air pollution and poor birth outcomes

  • Certain pesticides have been associated with fetal death

  • Lead exposure has measurable adverse effects on maternal and infant health, such as fertility, hypertension, and infant neurodevelopment

  • Abnormal and decreased sperm have been seen in males with occupational lead exposure

  • Exposure to endocrine disruptors may affect the sex of the child

Who is at risk?

The factors that cause low birth weight and preterm births are not well understood despite research efforts. The reasons for differences in the rate of poor birth outcomes among different racial and ethnic groups are complex. We know that nutrition and the mother’s health are important, as are early and high-quality prenatal care. Women at increased risk of having poor birth outcomes include:

  • Women who do not gain enough weight during pregnancy, which is associated with low birth weight babies.

  • Women who smoke. Cigarette smoking during pregnancy is associated with spontaneous abortion, preterm birth, low birth weight, and stillbirth.

  • Women who drink alcohol while pregnant. Drinking alcohol during pregnancy has been linked with low birth weight, increased spontaneous abortions and fetal alcohol spectrum disorder.

  • Women with uncontrolled chronic diseases, such as diabetes.

  • Women with untreated infections, such as bacterial vaginosis and trichomoniasis.

  • Women who do not get enough vitamins, such as folic acid.

How can risk be reduced?

Women who are pregnant or may become pregnant should take these steps to reduce the likelihood of a poor birth outcome:

  • Seek preconception health care

  • Stop smoking and avoid secondhand smoke

  • Do not use alcohol or illegal drugs

  • Obtain medical treatment for infections and other illnesses, especially for vaginitis

  • Seek prenatal care as soon as possible and follow provider advice carefully

  • Gain an appropriate amount of weight - not too little or too much

  • Reduce heavy or prolonged exertion when air quality is poor, particularly with unhealthy levels of particulate matter

  • Reduce the use of indoor sources of air pollution, like wood-burning stoves and fireplaces, and make efforts to reduce the amount of time spent outdoors near areas with heavy traffic

  • Avoid exposure to lead, mercury and pesticides

  • Take a multivitamin every day

  • Be up to date on adult vaccinations

How are reproductive and birth outcomes tracked?

By law, a ‘Certificate of Live Birth’ (birth certificate) is submitted to the Colorado Department of Public Health and Environment for every baby born in Colorado. The birth certificate contains information about the mother and the baby such as age of mother, birth weight of baby, and number of weeks of gestation. Each year, new birth data are analyzed, summarized and made available for study.