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Preterm births, 32-33 weeks of gestation
Maryland - Somerset

Measurement Period: 2007-2013
HP2020 Baseline: 1.6 (1.60000002384186)
HP2020 Baseline Year: 2007
HP2020 Target: 1.4






HP 2020

  • 1.1
  • 2.1
  • 2.2
Percent of live births at 32 to 33 weeks of gestation


Number of infants born between 32 and 33 completed weeks of gestation


Number of live births

2007-2013 - Dimensions

  • Total

    Comparison of 25 Counties
      Low: 1.1             High: 2.2

Historical Data

  • Dimension2007-20132006-20122005-20112004-20102003-2009
    0.7% / 1.7%
    0.8% / 1.9%
    0.9% / 2.0%
    1.1% / 2.3%
    1.2% / 2.4%
    Not Hispanic or Latino (Of mother)DSU1.3%
    0.7% / 1.8%
    0.8% / 1.9%
    1.0% / 2.3%
    1.1% / 2.4%
  • DSU - Data statistically unreliable.


  • Estimates of preterm birth are calculated based on gestational age information reported on the birth certificate. The primary measure used to determine the gestational age of the newborn is the interval between the first day of the mother’s last normal menstrual period (LMP) and the date of birth, and presented as number of weeks. It is subject to error for several reasons, including imperfect maternal recall or misidentification of the LMP because of postconception bleeding, delayed ovulation, or intervening early miscarriage. These data are edited for LMP-based gestational ages that are clearly inconsistent with the infant’s plurality and birthweight, but reporting problems for this item persist and may occur more frequently among some subpopulations and among births with shorter gestations.


    The 1989 revision of the U.S. Standard Certificate of Live Birth includes an item, “clinical estimate of gestation” and the 2003 revision of the birth certificate includes a comparable item “Obstetric estimate of gestation”. The clinical or obstetric estimate was compared with length of gestation computed using the LMP when the latter appears to be inconsistent with birth weight. This was done for normal weight births of apparently short gestations and very low birth weight births reported to be full term. For those births, the clinical or obstetric estimate was used if it was compatible with the reported birth weight. The clinical or gestation estimate was also used if the LMP date was not reported.


    A description of the primary measurement used to determine the infant’s gestational age, the interval between the first day of LMP and the birth has been published by NCHS.


  • National Center for Health Statistics. User guide to the 2010 natality public use file. Hyattsville, MD.

Data Source(s)

  • National Vital Statistics System-Natality (NVSS-N)

    Description Vital statistics natality data are a fundamental source of demographic, geographic, and medical and health information on all births occurring in the United States. This is one of the few sources of comparable health-related data for small geographic areas over an extended period of time. The data are used to present the characteristics of babies and their mothers, track trends such as birth rates for teenagers, and compare natality trends with those in other countries.

    MethodologyThe National Vital Statistics System Natality component (NVSS-N) obtains information on deaths from the registration offices of each of the 50 states, New York City, the District of Columbia, Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and Northern Mariana Islands. By law, registration of deaths is the responsibility of the professional attendant at birth, generally a physician or midwife. The birth certificate must be filed with the local registrar in the district in which the birth occurred, within a time period prescribed by law (generally 1 to 10 days). State birth certificates are modeled on a U.S. Standard Certificate that is revised periodically. States provide the National Center for Health Statistics (NCHS) with birth records in electronic format.


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