Perinatal Risk for Mortality and Mental Retardation Associated with Maternal Urinary-Tract Infections

,

Original Research

Perinatal Risk for Mortality and Mental Retardation Associated with Maternal Urinary-Tract Infections

J Fam Pract. 2001 May;50(5):433-437

By

Suzanne McDermott, PhD

References

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OBJECTIVE: We analyzed the relationship between fetal exposure to maternal urinary tract infections (UTIs) and mental retardation or developmental delay and fetal death.

STUDY DESIGN: A retrospective cohort design was used to explore the risk for fetal death and mental retardation or developmental delay associated with exposure to maternal UTI during pregnancy.

POPULATION: Matched maternal-child pairs from the National Collaborative Perinatal Project (NCPP) from the decades of 1960 and 1970 were compared with a previous analysis of the South Carolina Medicaid Reimbursement System (Medicaid) for 1995-1996. Both data sets are representative of poor women and their children.

OUTCOMES MEASURED: The outcomes measured were fetal death and mental retardation or developmental delay in the live-born children.

RESULTS: There was an increased relative risk (RR) for mental retardation or developmental delay in the third trimester of pregnancy (RR=1.40; 95% confidence interval [CI], 1.01-1.95) in the NCPP, and there was a similar risk in the Medicaid data. The third trimester relative hazard for fetal death associated with maternal UTI was 2.23 (95% CI, 1.40-3.55).

CONCLUSIONS: Our findings support an association between maternal UTI and fetal death and mental retardation or developmental delay. These results confirm the importance of diligent diagnosis and treatment of maternal UTI by prenatal care providers.

Primary care providers know that the most common site of infection during pregnancy is the urinary tract.^1-6 Pregnant women at the highest risk for urinary tract infection (UTI) include those with a history of UTI, high frequency of sexual activity, high parity, functional urinary tract abnormalities, sickle cell trait, and diabetes mellitus.^1,3,5,7 The well-documented consequences of UTIs include pyelonephritis in pregnant women and preterm labor and low birth weight in the infants.^4,8-14 Fetal death has also been associated with maternal UTI. Leviton and Gilles^15-17 conducted autopsies on fetuses with clinical reports of maternal UTI and found endotoxin-damaged glial cells in the maturing forebrain. Glial cells (destined to become oligodendroglia and lay down myelin) are either destroyed (causing necrosis) or transformed (resulting in hypertrophic astrocytes and damaged glia). The end result of this process can be perinatal leukoencephalopathy and death.^17,18 The relationship between maternal UTI and deficits in child development has also been explored; there has not been a consensus, however, about this association. Researchers for the National Collaborative Perinatal Project (NCPP) reported a 2.38-point decrease in the intelligence quotient (IQ) score in white boys and no significant variation in IQ scores in girls or black boys.^19,20 There are reports of an association between UTI and delayed motor performance at the age of 8 months and an increased risk for cerebral palsy.^21,22 Others found no relationship between maternal UTI and subsequent psychomotor impairments.²³

We analyzed the relative risk for mental retardation or developmental delay following UTI, taking into account the trimester of infection and the impact of treatment. Medicaid reimbursement files were used to analyze the association for more than 41,000 mother-child pairs for the period 1994 to 1996. The proportion of women with a presumably untreated UTI who had a child with mental retardation or developmental delay was 35% higher than the unexposed group and 24% higher than the group that had a UTI and had prescriptions filled.²⁴ To further elucidate the relationships between fetal exposure to UTI and subsequent mental retardation or developmental delay, we compared the analysis of the NCPP data set with our previous analysis of the Medicaid data. We also used survival analysis to explore the potential relationship between maternal UTI and intrauterine fetal demise. This was done since the maternal UTI and death associations reported by Leviton and Gilles,^15-17 was based on autopsy studies from the NCPP, and the comparison was between dead infants whose mothers did and did not have a reported UTI. We used the retrospective cohort design to compare the risk for fetal death for infants with and without maternal UTI exposure.

Methods

The data used for these analyses were the research variables from the NCPP. Those women were recruited from 12 urban university medical centers throughout the United States between 1959 and 1974. The NCPP data for the outcome of mental retardation or developmental delay were compared with the South Carolina Medicaid data set from 1994 to 1996, using the methods previously described in the literature.²⁴

The NCPP was a longitudinal study of the outcomes of pregnancies of primarily urban poor women. A total of 53,043 pregnancies (including 7522 repeat pregnancies) were followed up, with 64% of the participants residing in the Northeast. The data were collected on the pregnancies during the prenatal visits, at admission for delivery, and during scheduled follow-up visits for 8 years. Psychologic evaluations of the children were performed at 8 months, 4 years, and 7 years. It should be noted that not all children were evaluated, since there was a 25% loss to follow-up for the 4-year examination. Of these, 9.6% died before age 4 years; 2.3% were tested for IQ, but no scores were obtained. The remaining families were either not located or refused to return for testing and examination.^19,20,25