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The Relationship between Pre-Natal Care and Immunization
Rates of Inner-City Medicaid Newborns


Maryellen Guinan
University of Pennsylvania School of Nursing
Children’s Hospital of Philadelphia, Philadelphia, Pa


Objective:     The objective of this study was to determine the relationship between patterns of pre-natal care (PNC) in Medicaid enrolled women and subsequent preventive immunization rates among the infants of their current pregnancy.

Methods:      A prospective cohort study of 608 newborns delivered at the Hospital of  University of Pennsylvania.  Data was collected through medical chart review, and  primary care physician chart review.  Outcomes measure included adequate immunization at 6 months and adequate PNC. 

Results:      Mothers with adequate PNC were 1.47 times as likely to have  their child’s immunization up to date (C.I 0.98,2.3) p=0.06.

Conclusion:  Our findings strongly suggest that adequate PNC affects the immunization rates of children and was influenced by whether or not a women completed high school and if she was employed prior to the pregnancy.


Immunizations are effective in preventing many highly contagious and potentially deadly childhood infectious diseases (Peter,1992).  Immunization rates among pre-school children remain below the goals identified for the year 2000 Health Objectives for the nation (CDC, 1993).  Low immunization rates have been associated with inner-city populations and with lack of PNC care (Cutts et al., 1992).  The objective of this study was to determine the relationship between patterns of PNC in Medicaid enrolled women and subsequent preventive-immunization rates among the infants of their current pregnancy.

Literature Summary

Immunization against childhood infectious diseases is one of the most important and cost-effective public health interventions (Gergen et al., 1995; Peter, 1992).  Although 95% of school age children are immunized, immunization rates for pre-school students are much lower (CDC,1993; Hinman, 1991). 


It has been shown that mothers with minimum PNC are less likely to obtain up-to-date immunizations for their newborns (Cutts et al., 1992).  Numerous attempts to improve access to PNC for women on Medicaid (e.g. Medicaid or community health clinics) have been only partially successful (Butz et al., 1993; Krieger, Connell and LoGerfo, 1992).  Our present healthcare system has not addressed the maternal factors that contribute to lack of immunization and this may explain the lower compliance (NVAC,1991; Roghmann & Haggerty, 1972).  Understanding the necessity of childhood immunizations has taken on even more importance since September 11th , 2001 because of the threat of biological warfare (e.g., diphtheria) in the U.S.  This study was conducted to identify those maternal variables associated with higher immunization rates for newborns.


Women enrolled in Medicaid who obtain adequate PNC will subsequently have up-to-date immunizations for their newborns.  Adequate pre-natal care is defined as 8 or more pre-natal visits with the first pre-natal visit in the first trimester.


Institute Review Board approval was obtained along with patient consent.  A prospective cohort study was conducted of 608 newborns delivered at the Hospital of the University of Pennsylvania in 2000.  Inclusion criteria were: (a) enrollment in Medicaid, (b) greater than 34 week gestation, (c) greater than 2 Kg birth weight, and (d) less than 10 day nursery stay.  Information on the independent variables of PNC (Table I) was determined by mother’s post partum information and medical record review.  Data collection included medical record review and primary care chart review.  STATA was used for statistical analysis of data.  Outcome information for up to date immunizations (Table I) at 6 months of age included: 1 HepB, 2 Hib, 2 DTAP, and 2 IPV and was obtained through primary care physician chart review.

Table I.  Outcome Measures for Adequate Pre-Natal Care and Up to Date Immunizations

Pre-Natal Care

Immunizations (6 months)

  • 34-36 weeks gestation

  • 1 HepB

  • 8 or more pre-natal visits

  • 2 Hib

  • First pre-natal visit in first trimester

  • 2 DTAP


  • 2 IPV


423 of 608 infants born during 2000 were followed for this study.  The reasons for 185 infants not being followed included: (a) patient relocation, (b) incorrect phone numbers, and (c) refusal to comply with requests.  Table 2 shows that the mean age and education of the mothers was 22 years old and 11 years respectively and 63% were employed before pregnancy. Figure 1 shows that adequate PNC was found in 52% of the population and up-to-date 6-month immunizations, as defined by American Committee of Immunization Practices, was 63%.  Mothers with adequate PNC were 1.47 times more likely to have their child’s immunization up-to-date than were those without adequate PNC (C.I. 0.98,2.3) p=0.06.  Significant variables for adequate PNC were completing high school education and pre-pregnancy employment. (p<0.0001) (Table 3)

Table 2:  Maternal Characteristics (N=423)

Maternal Characteristics


Mean Age

22 years old

Mean Educational Level

11th grade

Number employed pre pregnancy

266 (63%)

Mean timing of first pre-natal visit

13.5  weeks



Figure 1.  Relationship of Pre-natal Care to Immunization.


60    52%            
    Adequate Pre-natal Care   Up-to-date Immunizations   Adequate Pre-natal Care and up-to-date immunization



Table 3.  Maternal Characteristics and Adequate Pre-natal Care



Significant (S)/

Not significant (NS)





Timing of first pre-natal visit


High School Completion


Pre-pregnancy Employment






The results of this study strongly suggest that adequate PNC affects the immunization rates of children.  Adequate PNC was influenced by high school completion and pre-pregnancy employment.  The mother’s age, race, and time of first pre-natal visit were not significant variables for immunization. 

These findings suggest that identification of newborns at risk for non-immunization can be determined by identifying mothers without a high school degree and mothers who were unemployed prior to becoming pregnant.  The limitations of study are:   a) homogenous populations – 96.9% African American, and (b) convenient sample size due to chart and physician availability and transient residence of mothers. Future research should include the identification of other variables such as transportation and the number of children in the family which might be used to further predict newborns at risk for non-immunization.


Butz, A.M., Funkhouser, A., Calkeb, L., & Rosenstein, B.L.  (1993).  Infant health care utilization predicted by pattern of prenatal care. Pediatrics. 92, 50-54.


Centers for Disease Control and Prevention.  (1994).  Reported vaccine-preventable disease United States, 1993, and the Childhood Immunization Initiative. Morbidity & Mortality Weekly Report, 43, 57-60.


Cutts, F.T,, Zell, E. R,, Mason, D., Venier, R. M., Dini,  E. F., & Orenstein,  W. A. (1992)  Monitoring progress toward US preschool immunization goals.  Journal of the American Medical Association, 267, 1952-1955.


Gergen, P, McQuillan, G, Kiely, M. Ezzati-Rice, T., Sutter, R., & Virella, G. A. (1995).  Population-based serologic survey of immunity to tetanus in the United States. New England Journal of Medicine, 332, 761-765.


Hinman, A. R.  (1991).  What will it take to fully protect all American children with vaccines? American Journal of Disease in Children, 145, 559-562.  


Krieger, J. W., Connell, F. A., & LoGerfo, J. P. (1992).  Medicaid prenatal care: A comparison of use and outcomes in fee-for-service and managed care.  American Journal of Public Health, 82(2), 185-190.


National Vaccine Advisory Committee.  (1991). The measles epidemic:  the problems, barriers and recommendations. Journal of the American Medical Association, 266, 1547-1552.


Peter, G. (1992).  Childhood immunizations. New England Journal of Medicine, 327-1, 1794-1800.  


Roghmann, K. J., & Haggerty,  R. J. (1972).   Family stress and the use of health services.  International Journal of Epidemiology, 1, 279-282.


I wish to acknowledge the assistance of Dr. E. Alessandrin, Emergency Department, Children’s Hospital of Philadelphia, for allowing me to conduct this study and giving me access to the database and to Dr. Maryanne McGuckin, University of Pennsylvania School of Medicine for her assistance with this manuscript.


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