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Adequacy of Prenatal-Care Utilization -- California, 1989-1994

A national health objective for the year 2000 is to increase to at least 90% the proportion of pregnant women who receive prenatal care during the first trimester of pregnancy (objective 14.11) (1). Adequate prenatal care is believed to result in better pregnancy outcomes, including reduced maternal and infant morbidity and mortality and reduced risk for preterm delivery and for low birthweight (less than 2500 g {less than 5 lb 8 oz}) (2). However, measures of prenatal-care utilization based on first-trimester initiation of prenatal care address only the timing of prenatal-care initiation and do not include the frequency of visits thereafter, which can provide a more comprehensive measure of prenatal-care utilization. To calculate rates of prenatal-care utilization for California during 1989-1994, the California Department of Health Services (CDHS) analyzed data from birth certificates using a more comprehensive measure of prenatal-care utilization. This report presents annual rates of adequate prenatal-care utilization (APNCU) for California during 1989-1994 (the most recent year for which complete data were available), compares these data with the year 2000 objective for prenatal-care utilization, and examines rates of APNCU in California by payment source (for prenatal care) for 1989, 1992, and 1994.

CDHS defines APNCU as care initiated during the first 4 months of pregnancy, followed by greater than or equal to 80% of the expected total number of visits recommended by the American College of Obstetricians and Gynecologists (ACOG), adjusted for the length of gestation (3). For a full-term (40-week) pregnancy with no complications, ACOG recommends prenatal-care visits "...every 4 weeks for the first 28 weeks of pregnancy, every 2-3 weeks until 36 weeks of gestation, and weekly, thereafter, although flexibility is desirable" (4). Birth certificate data for live-born infants in California were used to calculate annual APNCU rates by accounting for both the time of prenatal-care initiation and the number of visits relative to gestational age (3). Information obtained from the birth certificate included prenatal-care utilization as self-reported by the mother and gestational age. Infants of women who had no prenatal care or for whom the source of payment for prenatal care was unknown were excluded from this analysis, accounting for approximately 1.8% of live-born infants in 1989, 1.3% in 1992, and 1.6% in 1994. In addition, gestational age was missing for 3.1% of birth certificates in 1989, 2.8% in 1992, and 3.1% in 1994; however, the algorithm used to calculate APNCU estimated gestational age from sex and birthweight data.

During 1989-1994, the overall annual rate of prenatal-care initiation during the first trimester increased 6.9%, from 72.1 per 100 live-born infants to 77.1 per 100. In comparison, the rate of APNCU increased 18.2%, from 56.2 per 100 to 66.4 per 100, an annual rate of increase of 2.2 per 100 per year. In 1994, 16% of women in California who initiated prenatal care during the first trimester had less than 80% of the ACOG-recommended visits.

While the total number of live-born infants in California remained stable during 1989-1994, the distribution of live-born infants within payment source categories changed disproportionately (Table_1). From 1989 to 1994, there were decreases in the number of live-born infants whose care was uninsured (70.8% {from 85,407 to 24,909}) or covered by fee-for-service arrangements (31.1% {from 161,937 to 111,632}) or other sources of payment (35.1% {from 22,852 to 14,831}). In comparison, the numbers covered by California's Medicaid program (Medi-Cal) and health-maintenance organizations (HMOs) increased 67.9% (from 154,660 to 259,643) and 9.2% (from 134,473 to 146,854), respectively. In 1994, the cost of prenatal-care services for nearly half (46.5%) of all live-born infants was paid through Medi-Cal.

During 1989-1994, rates of APNCU increased within all payment source categories. The largest percentage increases in APNCU rates were among Medi-Cal recipients (34.9%) and the uninsured (29.7%). Despite these large increases, in 1994 the APNCU rates were lowest among Medi-Cal (56.7 per 100 live-born infants) and uninsured (42.2 per 100) groups. Rates of APNCU were highest among privately insured groups (81.7 per 100 for fee-for-service providers and 75.0 per 100 for HMOs).

Reported by: S Kessler, MBA, Primary Care and Family Health, R Shah, MD, Maternal and Child Health Br, T Smith, MD, Perinatal Care Section, D Taylor, MA, California Dept of Health Svcs. Div of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion; Div of Applied Public Health Training (proposed), Epidemiology Program Office, CDC.

Editorial Note

Editorial Note: The findings in this report indicate that in California during 1989-1994, the rate of first-trimester initiation of prenatal care increased 6.9%; in contrast, the overall rate of APNCU increased 18.2%. The primary reason for the difference in rates is that first-trimester initiation addresses only the timing of prenatal-care initiation and, therefore, presents an incomplete assessment of prenatal-care utilization. If the trends in both rates continue until the year 2000, the rates of first-trimester initiation and APNCU should converge at 80 per 100 live-born infants. Although the rate of first-trimester initiation was higher than the rate of APNCU in 1994, the trend toward decreasing differences in the rates indicates that, in 1994, among women who initiated prenatal care, a greater proportion had the appropriate number of prenatal-care visits recommended by ACOG than in 1989. The findings for California can not be generalized to the entire population of live-born infants in the United States; however, other states can use similar analyses to calculate more comprehensive measures of APNCU.

In California, efforts to improve the availability and financial accessibility of prenatal care have included use of federal Medicaid options and state-based funding to nearly double Medi-Cal eligibility levels for health-care coverage for pregnant women since 1989 and to promote early, continuous, and comprehensive prenatal care. For example, eligibility requirements for coverage of pregnancy-related services under Medi-Cal were increased from 185% of the poverty level in 1989 to 200% in 1990. During the same period, implementation of several Medi-Cal obstetric initiatives improved provider participation and improved and expanded prenatal-care services to women in California. These initiatives include the BabyCal campaign, a statewide media effort promoting the importance of prenatal care and assistance in obtaining Medi-Cal; the Comprehensive Perinatal Services Program, a program that provides support services during prenatal care; and improved access to Medi-Cal through presumptive and continuous eligibility, waived asset tests, and reduced application paperwork. In addition, most (86%) women and children who are Medi-Cal beneficiaries in California are expected to be enrolled in some form of managed care by 1997.

The year 2000 objective reflects only initiation of prenatal care during the first trimester; however, additional important factors include a minimum of 14 subsequent prenatal-care visits (for a full-term pregnancy), adjusted for the length of gestation (3). Although the definition of APNCU used in this report neither addresses the quality or content of the prenatal-care visit nor adjusts for maternal risk conditions (3), it does provide a readily available measure of APNCU. The findings of this report will be used in California for assessing the impact of changes in the health-care system on prenatal-care utilization.


  1. Public Health Service. Healthy people 2000: national health promotion and disease prevention objectives -- full report, with commentary. Washington, DC: US Department of Health and Human Services, Public Health Service, 1991; DHHS publication no. (PHS)91-50212.

  2. Office of Technology Assessment, US Congress. Healthy children: investing in the future. Washington, DC: US Congress, Office of Technology Assessment, 1988.

  3. Kotelchuck M. An evaluation of the Kessner adequacy of prenatal care index and a proposed adequacy of prenatal care utilization index. Am J Public Health 1994;84:1414-20.

  4. American Academy of Pediatrics/American College of Obstetricians and Gynecologists. Guidelines for perinatal care. 3rd ed. Washington, DC: American Academy of Pediatrics/American College of Obstetricians and Gynecologists, 1992:53.

Note: To print large tables and graphs users may have to change their printer settings to landscape and use a small font size.

TABLE 1. Prevalence rate of adequate prenatal-care utilization, by payment
source and selected years -- California, 1989-1994
                           Total births            Births with adequate
                       within payment source     prenatal-care utilization *
Source                 ---------------------     ---------------------------
  of payment/Year          No.       (%)               No.      (%)
Uninsured +
 1989                    85,407      15.3            27,789    32.5
 1992                    38,027       6.4            15,742    41.4
 1994                    24,909       4.5            10,520    42.2

 1989                   134,473      24.0            89,773    66.8
 1992                   146,825      24.8           107,230    73.0
 1994                   146,854      26.3           110,187    75.0

Fee-for-service &
 1989                   161,937      29.0           117,372    72.5
 1992                   130,042      21.9           101,683    78.2
 1994                   111,632      20.0            91,238    81.7

Medi-Cal @
 1989                   154,660      27.7            64,929    42.0
 1992                   257,683      43.5           127,424    49.5
 1994                   259,643      46.5           147,078    56.7

Other **
 1989                    22,852       4.1            14,423    63.1
 1992                    20,456       3.5            14,998    73.3
 1994                    14,831       2.7            11,575    78.1

Total ++
 1989                   559,329     100.0           314,286    56.2
 1992                   593,033     100.0           367,077    61.9
 1994                   557,869     100.0           370,598    66.4
*  Care initiated during the first 4 months of pregnancy, followed by >=80% of
   the total number of visits recommended by the American College of
   Obstetricians and Gynecologists, adjusted for the length of gestation.
+  Includes persons who self-paid, those not charged, and those who were
&  Non-health-maintenance organization private insurance.
@  The state Medicaid program for California residents.
** Includes Medicare, Workmens' Compensation, other governmental and
   nongovernmental programs.
++ Infants of women who had no prenatal care or for whom the source of
   payment for prenatal care was unknown were excluded from this analysis,
   accounting for approximately 1.8% of live-born infants in 1989, 1.3% in
   1992, and 1.6% in 1994.

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