Association between interpregnancy interval and the risk of recurrent loss after a midtrimester loss.

STUDY QUESTION: After an initial midtrimester loss, is the interval to the next conception associated with the risk of a recurrent loss? SUMMARY ANSWER: Among women who had a pregnancy loss at 14-19 weeks gestation, conception at least 3 months after this initial loss was associated with a reduced risk of a recurrent loss. WHAT IS KNOWN ALREADY: A short interpregnancy interval (IPI) has been thought to increase risk but recent studies of pregnancy after a loss have found no effect; however, these studies have been based almost entirely on an initial first trimester (<14 weeks) loss. STUDY DESIGN, SIZE, DURATION: A retrospective cohort study drawing on over 997 000 linked birth and hospital records from New South Wales, Australia for 2003-2011. Index pregnancies were those of women who had a first recorded pregnancy loss of 14-23 weeks gestation (miscarriage, termination and perinatal death). The study population was 4290 women who conceived again within 2 years. PARTICIPANTS/MATERIALS, SETTING, METHODS: The index loss was categorized by subgroups: 14-19 weeks gestation versus 20-23 weeks, and by whether spontaneous or a termination. The primary outcome was any loss or perinatal death before 24 weeks in the subsequent pregnancy. MAIN RESULTS AND THE ROLE OF CHANCE: After a 14-19 weeks index loss, an IPI of ≤3 months had an increased rate of recurrent loss compared with an IPI of >9-12 months: 21.9% versus 11.3% (adjusted relative risk (aRR) = 2.02, 95% CI 1.44-2.83). For women who had a spontaneous index loss of 20-23 weeks, there was no evidence that a short IPI increased or decreased the risk of recurrent loss. For any gestational age group of index losses, an IPI of >18-24 months increased the risk of a recurrent loss; the risk was highest after a 20-23 weeks index loss (aRR = 2.15, 95% CI 1.18-3.91). LIMITATIONS, REASONS FOR CAUTION: We do not know how many cycles were required to achieve conception. Pregnancies resulting in early first trimester losses are unlikely to have resulted in hospitalization so would not have been identified. WIDER IMPLICATIONS OF THE FINDINGS: The risk of recurrent loss after an initial midtrimester loss may differ from the risk after an initial first trimester loss. STUDY FUNDING/COMPETING INTERESTS: This work was supported by an Australian National Health and Medical Research Council (NHMRC) Centre for Research Excellence Grant (1001066). C.L.R. is supported by an NHMRC Senior Research Fellowship (#APP1021025). J.B.F. is supported by an ARC Future Fellowship (#120100069). The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Prosthetic heart valves in pregnancy, outcomes for women and their babies: a systematic review and meta-analysis.

BACKGROUND: Historically, pregnancies among women with prosthetic heart valves have been associated with an increased incidence of adverse outcomes. OBJECTIVES: Systematic review to assess risk of adverse pregnancy outcomes among women with a prosthetic heart valve(s) over the last 20 years. SEARCH STRATEGY: Electronic literature search of Medline, The Cochrane Library, Cumulative Index to Nursing and Allied Health Literature and Embase to find recent studies. SELECTION CRITERIA: Studies of pregnant women with heart valve prostheses including trials, cohort studies and unselected case series. DATA COLLECTION AND ANALYSIS: Primary analysis calculated absolute risks and 95% confidence intervals (CI) for pregnancy outcomes using a random effects model. The Freeman-Tukey transformation was utilised in secondary analysis due to the large number of individual study outcomes with zero events. MAIN RESULTS: Eleven studies capturing 499 pregnancies among women with heart valve prostheses, including 256 mechanical and 59 bioprosthetic, were eligible for inclusion. Pooled estimate of maternal mortality was 1.2/100 pregnancies (95% CI 0.5-2.2), for mechanical valves subgroup 1.8/100 (95% CI 0.5-3.7) and bioprosthetic subgroup 0.7/100 (95% CI 0.1-4.5), overall pregnancy loss 20.8/100 pregnancies (95% CI 9.5-35.1), perinatal mortality 5.0/100 births (95%CI 1.8-9.8) and thromboembolism 9.3/100 pregnancies (95% CI 4.0-16.5). CONCLUSIONS: Women with heart valve prostheses experienced higher rates of adverse outcomes than expected in a general obstetric population; however, lower than previously reported. Women with bioprostheses had significantly fewer thromboembolic events compared to women with mechanical valves. Women should be counselled pre-pregnancy about risk of maternal death and pregnancy loss. Vigilant surveillance by a multidisciplinary team throughout the perinatal period remains warranted for these women and their infants. TWEETABLE ABSTRACT: Metaanalysis suggests improvement in #pregnancy outcomes among women with #heartvalveprostheses.

Amniotic fluid embolism in an Australian population-based cohort.

We utilised linked birth, hospital and death data for the entire population to determine the incidence of amniotic fluid embolism (AFE) and its mortality and morbidity. AFE diagnoses were identified from International Classification of Diseases, 10th Revision (ICD10)-coded hospital and/or death records with additional case definition criteria imposed. The AFE incidence was 3.3 per 100,000 (95% CI, 1.9-4.7), maternal fatality rate 35% (95% CI, 15-59) and perinatal mortality rate 32% (95% CI, 12-56). Newly identified risk factors included induction with vaginal prostaglandin and manual removal of the placenta, and survivors were at increased risk of cerebral infarction. Although two-thirds of women and infants survived, AFE also caused severe morbidity.

Incidence and risk factors for pulmonary embolism in the postpartum period.

SUMMARY BACKGROUND: Pregnancy and the postpartum period are times of hypercoagulability, increasing the risk of pulmonary embolism. Better quantification of risk factors can help target women who are most likely to benefit from postpartum thromboprophylaxis with heparin. OBJECTIVES: To determine the incidence rate and timing of postpartum pulmonary embolism, and assess perinatal risk factors predictive of the event. PATIENTS/METHODS: Antenatal, delivery and postpartum admission records of a cohort of 510 889 pregnancies were analysed. Pulmonary embolism was identified from ICD-10 codes at delivery, transfer or upon readmission at any time in the postpartum period. RESULTS: Pulmonary embolism occurred in 375 women and was most common postpartum. The rate of postpartum pulmonary embolism without an antecedent thrombotic event was 0.45 per 1000 births. By the end of 4 weeks postpartum, the weekly rate approached the background rate of pulmonary embolism in the population. Although the Caesarean section rate rose significantly throughout the study period, and pulmonary embolism was more common following abdominal birth, the rate of pulmonary embolism following Caesarean birth fell. Regression modelling demonstrated that stillbirth (adjusted odds ratio [aOR] =5.97), lupus (aOR = 8.83) and transfusion of a coagulation product (aOR = 8.84) were most strongly associated with pulmonary embolism postpartum. CONCLUSIONS: Pulmonary embolism most commonly occurs up to 4 weeks postpartum and following abdominal birth. Despite this the absolute event rate is low and a broadly inclusive risk factor approach to the use of pharmacological thromboprophylaxis will require many women to be exposed to heparin to prevent an embolic event.

Perinatal risk factors for early onset of Type 1 diabetes in a 2000-2005 birth cohort.

AIMS: To examine perinatal risk factors for the onset of Type 1 diabetes before 6 years of age, in a 2000-2005 Australian birth cohort. METHODS: Data from longitudinally linked delivery and hospital admission records (until June 2007) were analysed. Diabetes in mothers and children was identified from International Classification of Diseases 10 diagnosis codes in the hospital records. RESULTS: There were 272 children admitted to hospital with a first diagnosis of diabetes out of 502 040 live births. Incidence for the infants born in 2000 was 16.0 per 100 000 person-years. Maternal Type 1 diabetes was a significant risk factor [crude relative risk (RR) 6.33], but maternal Type 2 diabetes and gestational diabetes were not significantly associated with diabetes in the child. Late preterm birth (34-36 weeks) (RR 1.64) and caesarean section (RR 1.30) increased the risk of a diabetes admission. Size-for-gestational-age was significantly associated with onset of diabetes (small-for-gestational age RR 0.48), but neither birth weight categories nor birth weight as a continuous variable were associated with risk of diabetes. Increasing maternal age was associated with an increased risk of diabetes in the child (RR 1.13 for each additional 5 years of age). CONCLUSIONS: This study identified risk factors associated with onset of Type 1 diabetes before 6 years of age, in a recent birth cohort. Size-for-gestational-age had a consistent association with risk of early onset of Type 1 diabetes, small size being protective. Size-for-gestational-age measures should be preferred to birth weight thresholds when assessing risk of diabetes.

The accuracy of reporting of general anaesthesia for childbirth: a validation study.

Administrative population health data, such as hospital discharge data, are a potentially valuable resource for determining anaesthesia and analgesia use in childbirth at a population level. However the reliability of general anaesthesia reporting is unknown. This study aimed to determine the accuracy of the reporting of peripartum general anaesthesia in single and linked population health data. Data from a statewide validation study of 1200 women provided the gold standard for delivery and postpartum general anaesthesia use. The validation data were merged with both the hospital discharge and birth databases. As both of these datasets collect information on general anaesthesia, it could be reported in one, both or neither database. Among the 1184 records available for review, 7.7% of women had a general anaesthetic during the birth admission, of which 6.2% were for delivery and 1.5% were for a postpartum procedure. Reporting sensitivities ranged from 26% to 97% and specificities 94% to 100%. Identifying general anaesthesia from either the birth or hospital data improved general anaesthesia ascertainment. Limiting analysis to caesarean sections resulted in very accurate identification of general anaesthesia for delivery (sensitivity 97.0%, specificity 99.8%) while limiting to vaginal births was moderately accurate for identifying postpartum general anaesthesia (sensitivity 73.2%, specificity 99.8%). General anaesthesia for delivery is reported with a high level of accuracy in birth and linked birth-hospital data, but not in hospital discharge data alone. Population health data are a reliable source for examining general anaesthesia for delivery.

Effects of different regimens to lower blood pressure on major cardiovascular events in older and younger adults: meta-analysis of randomised trials.

OBJECTIVE: To quantify the relative risk reductions achieved with different regimens to lower blood pressure in younger and older adults. DESIGN: Meta-analyses and meta-regression analyses used to compare the effects on the primary outcome between two age groups (<65 v > or =65 years). Evidence for an interaction between age and the effects of treatment sought by fitting age as a continuous variable and estimating overall effects across trials. PRIMARY OUTCOME: total major cardiovascular events. RESULTS: 31 trials, with 190 606 participants, were included. The meta-analyses showed no clear difference between age groups in the effects of lowering blood pressure or any difference between the effects of the drug classes on major cardiovascular events (all P> or =0.24). Neither was there any significant interaction between age and treatment when age was fitted as a continuous variable (all P>0.09). The meta-regressions also showed no difference in effects between the two age groups for the outcome of major cardiovascular events (<65 v > or =65; P=0.38). CONCLUSIONS: Reduction of blood pressure produces benefits in younger (<65 years) and older (> or =65 years) adults, with no strong evidence that protection against major vascular events afforded by different drug classes varies substantially with age.

Prospective observational study of acute coronary syndromes in China: practice patterns and outcomes.

OBJECTIVE: To describe the investigation and management of patients admitted to hospitals in China with suspected acute coronary syndromes (ACS) and to identify potential areas for improvement in practice. DESIGN: A multicentre prospective survey of sociodemographic characteristics, medical history, clinical features, in-hospital investigations, treatment practices and major events among patients with suspected ACS. SETTING: Large urban public hospitals. PATIENTS: Consecutive patients admitted to in-patient facilities with a diagnosis of suspected acute myocardial infarction (MI) or unstable angina pectoris. MAIN OUTCOME MEASURES: Myocardial infarction/re-infarction, heart failure, death. RESULTS: Between September 2004 and May 2005, data were collected prospectively from 2973 patients admitted to 51 hospitals in 18 provinces of China. An initial diagnosis of ST elevation MI, non-ST elevation MI and unstable angina was made in 43%, 11% and 46% of patients, respectively. Diagnosis was inconsistent with objective measures in up to 20% of cases. At both tertiary and non-tertiary centres, there was little evidence that clinical risk stratification was used to determine the intensity of investigation and management. The mortality rate during hospitalisation was 5% overall and similar in tertiary and non-tertiary centres, but reported in-hospital re-infarction rates (8%) and heart failure rates (16%) were substantially higher at non-tertiary centres. CONCLUSION: This study has identified a number of areas in the management of ACS patients, including diagnosis and risk stratification, which deviate from current guidelines. These findings will help inform the introduction of widely used quality improvement initiatives such as clinical pathways.

Blood pressure-dependent and independent effects of agents that inhibit the renin-angiotensin system.

OBJECTIVES: To evaluate the blood pressure-dependent and independent effects of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) on major cardiovascular events. METHODS: Using data from 26 large-scale trials comparing an ACEI or an ARB with placebo or another drug class, meta-regression analyses were conducted in which treatment-specific relative risks for major cause-specific outcomes [stroke, major coronary heart disease (CHD) events and heart failure] were regressed against follow-up blood pressure differences. RESULTS: From a total of 146 838 individuals with high blood pressure or an elevated risk of cardiovascular disease, 22 666 major cardiovascular events were documented during follow-up. The analyses showed comparable blood pressure-dependent reductions in risk with ACEI and ARB (P >or= 0.3 for all three outcomes). The analyses also showed that ACEI produced a blood pressure-independent reduction in the relative risk of CHD of approximately 9% (95% confidence interval 3-14%). No similar effect was detected for ARB, and there was some evidence of a difference between ACEI and ARB in this regard (P = 0.002). For both stroke and heart failure there was no evidence of any blood pressure-independent effects of either ACEI or ARB. CONCLUSION: There are similar blood pressure-dependent effects of ACEI and ARB for the risks of stroke, CHD and heart failure. For ACEI, but not ARB, there is evidence of blood pressure-independent effects on the risk of major coronary disease events.

Test characteristics of placental location screening by transabdominal ultrasound at 18-20 weeks.

OBJECTIVES: To determine the test characteristics of a second-trimester transabdominal fetal anomaly scan in screening for placenta previa. PATIENTS AND METHODS: This was a case-control study carried out at a tertiary obstetric hospital involving 54 women (0.5% of the total number booked for antenatal care and delivery at the center) with clinically significant placenta previa at the time of delivery, and 168 randomly selected controls who attended for antenatal care and delivery in 2000-2003. Sensitivity, specificity and false positive rate of the placenta-os measurement in the second-trimester transabdominal fetal anomaly scan for identification of clinically significant placenta previa were assessed. RESULTS: Women with placenta previa at delivery had significantly different second-trimester placenta-os measurements from those of controls (P < 0.0001). For women with placenta previa, the mean (standard deviation) placenta-os measurement was -0.96 cm (1.95) vs. 4.15 cm (1.77) for controls (P < 0.0001). Using the anomaly scan as a screening test for placenta previa with a placenta-os measurement cut-off point of < or = 2 cm, all cases of placenta previa should be identified, but 11.1% (95% CI, 7.1-14.8) of women without placenta previa would have false positive results. At cut-off points of 3 cm and 1.5 cm the false positive rates were 25.7% (95% CI, 18.8-30.2%) and 6.6% (95% CI, 3.8-9.6%), respectively, but at 1.5 cm 3.8% of cases would be missed. CONCLUSIONS: The second-trimester transabdominal fetal anomaly scan is a useful screening test for placenta previa. However, because of false positives among the much larger population of women without placenta previa, we estimate that with a cut-off point of < or =2 cm, 23 women would have to be followed up to confirm one true placenta previa.

Trends in place of birth for preterm infants in New South Wales, 1992-2001.

OBJECTIVE: To examine trends in preterm births, especially those less than 33 weeks gestation, occurring in perinatal centres in New South Wales (NSW) from 1992 to 2001. METHODS: Population data were obtained from the NSW Midwives' Data Collection. Trends in the proportion of births in perinatal centres by gestation and by type of preterm birth (spontaneous or elective), and in Apgar scores and neonatal mortality were determined. RESULTS: The preterm birth rate increased from 6.1% in 1992 to 6.7% in 2001. Factors contributing to the increase in preterm births were multiple births and elective preterm deliveries. Births less than 33 weeks gestation in perinatal centres increased from 76% to 83% and for multiple births from 77% to 87%. This coincided with a decrease in 1-minute Apgar scores less than 4 but no significant change in 5-minute Apgar scores or neonatal mortality. CONCLUSIONS: Progress has been made towards the National Health and Medical Research Council guideline that births less than 33 weeks gestation occur in perinatal centres. Preterm births are increasing, creating greater demands for neonatal intensive care unit care and ventilation services.

Trends in twin births in New South Wales, Australia, 1990-1999.

OBJECTIVE: To examine trends in gestational age and the mode of delivery of twins. METHOD: All twin births in New South Wales, Australia from 1990 through 1999 were analyzed. RESULTS: Twin births increased from 1922 (2.2%) in 1990 to 2522 (2.9%) in 1999. Twins born preterm (<37 weeks) increased from 40.8 to 48.8%. The increase in preterm twin births was associated with increases in induction of labor and cesareans before labor at 32-36 weeks. The rate of fetal deaths decreased by 49% and Apgar scores <4 at 5 min by 28%. CONCLUSIONS: A greater than expected increase in preterm twins was largely explained by an increase in elective deliveries at 35-36 weeks' gestation. Increasing maternal age does not appear to have contributed to the increase in preterm twin births. Lower rates of fetal death and low Apgar scores were achieved seemingly at the price of delivering more infants before term.

Differences and trends in obstetric interventions at term among urban and rural women in New South Wales: 1990-1997.

The aim of this study was to compare the management of term births among rural and urban women, including the effect of indigenous status and out-of-area-birth for rural women. Data were obtained from the NSW Midwives Data Collection (MDC), on 619,298 women who gave birth to a live, singleton infant at term (37-45 weeks gestation) from 1 January 1990 to 31 December 1997. Compared with urban non-indigenous women, rural women and indigenous women had lower rates of obstetric interventions both before birth (induction of labour, planned Caesarean section and epidural) and at the time of birth (Caesarean after labour, instrumental delivery and episiotomy). This was especially true for rural women giving birth in the their local area. The differing pregnancy risk profile of rural women did not explain the differences in intervention rates but differences were partly explained by higher rates of epidural anaesthesia in urban areas.

The urban and rural divide for women giving birth in NSW, 1990-1997.

OBJECTIVE: To examine trends in the pregnancy profile and outcomes of urban and rural women. METHODS: Data were obtained from the NSW Midwives Data Collection on births in NSW, 1990-1997. Associations between place of residence (urban/rural) and maternal factors and pregnancy outcomes were examined, including changes over time. RESULTS: From 1990 to 1997 there were 685,631 confinements in NSW and these mothers resided as follows: 76% metropolitan, 5% large rural centres, 8% small rural centres, 11% other rural areas and 1% remote areas. Rural mothers were more likely to be teenagers, multiparous, without a married or de facto partner, public patients and smokers. Births in rural areas declined, particularly among women aged 20-34 years. Infants born to mothers in remote communities were at increased odds of stillbirth and low Apgar scores (all women) and small-for-gestational- age (SGA) (Indigenous women only). CONCLUSIONS: The profile of pregnant women in rural NSW is different from their urban counterparts and is consistent with relative socioeconomic disadvantage and possibly suboptimal maternity services in some areas. While increased risk of SGA is associated with environmental factors such as smoking and nutrition, the reasons the increased risk of stillbirth are unclear. Although there does not appear to be an increase d risk of preterm birth for rural women this may be masked by transfer of high risk pregnancies interstate. IMPLICATIONS: Maternity services need to be available and accessible to all rural women with targeting of interventions known to reduce low birthweight and perinatal death.

Term breech birth in New South Wales, 1990-1997.

Data on 636,708 women delivering a singleton infant of gestational age > or =37 weeks in NSW from 1 January 1990 to 31 December 1997 were used to examine trends in breech births at term and the mode of delivery. From 1990 to 1997, although the crude rate of breech births at term remained stable at 3.4%, the adjusted odds ratio for breech birth compared with cephalic birth decreased over time. Among live breech births, the crude rate of vaginal breech birth declined from 29.4% to 19.7%, with an attendant increase in elective Caesarean sections from 49.1% to 58.4%. Most of this increase was at 38 and 39 weeks gestation. There was no change in the perinatal mortality rate among breech births during the study period. Despite increasing maternal age, the adjusted odds of a breech birth at term decreased over time. This could be due to offsetting factors, such as increased use of external cephalic version. If the decrease in vaginal breech birth continues, it may lead to the skills for this procedure being lost.

Antenatal transfer of rural women: how does the NSW Inpatient Statistics Collection compare with an audit of hospital records?

The aim of this study was to determine whether the NSW Inpatient Statistics Collection (ISC), a census of hospital admissions, could be used to estimate the magnitude of, and reasons for, antenatal transfer of rural women. Data from the ISC were compared with results of a clinical audit of all antenatal admissions of rural women to perinatal centres in NSW during 1997-1998. While the overall number of perinatal centre admissions identified by the ISC and the audit were similar, the ISC identified only about 70% of antenatal transfers. Rural hospitals identified 12% of women as indigenous compared with 9% at perinatal centres. The ISC showed 28% of rural women admissions and 42% of transfers were for threatened preterm labour compared with 21% and 30% respectively from the audit.

Small fetal size: a risk factor for breech birth at term.

OBJECTIVE: To examine fetal size as a risk factor for breech birth at term. METHODS: Singleton breech or cephalic births of gestational age > or = 37 weeks in New South Wales (NSW), Australia from 1990 to 1996 were analyzed. Birthweight percentile was used as a measure of fetal size at the time of birth. Factors associated with breech birth at term were analyzed using logistic regression. RESULTS: There were 18914 singleton breech and 540164 cephalic births in the study period. The important independent predictors of breech birth at term were advancing maternal age, primiparity, female sex and small size for gestational age. Infants < 10th percentile had an adjusted odds ratio of 1.33 (95% CI 1.28-1.38) for breech birth at term compared with 25th-75th percentile infants. CONCLUSIONS: Breech birth at term was associated with smaller fetal size for gestational age. This was shown directly through an association with birthweight-for-gestational-age percentiles and indirectly through association with female sex, primiparous birth and congenital anomalies.

Trends in infant mortality in Connecticut, 1981-1992.

Assessing infant mortality rates (IMRs) is important in public health planning. However, single year fluctuations in IMRs often receive attention without consideration of long-term trends. Trends in IMR over 12 years in Connecticut were examined using linked birth and death files. Overall, there was an exponential decline in IMR from 12.2/1,000 live births in 1981 to 7.3/1,000 live births in 1992. However, differential declines in IMRs resulted in an increased relative risk of infant death over time for infants of Black women compared with infants of White women. IMRs were also higher for infants of Black, teenaged, and less educated mothers. Targeted local maternal and child health programs are needed if IMRs are to continue to decline for all sections of the population in Connecticut.

Racial aspects of comorbidity in systemic lupus erythematosus.

OBJECTIVE: To investigate racial differences in the expression of systemic lupus erythematosus (SLE) by comparing comorbidity at death among individuals with SLE. METHODS: Proportional mortality rates were estimated for common contributing causes of death among white and black females in the United States, 1989-1991, whose death certificates listed SLE as an underlying or contributing cause. Logistic regression analysis was used to assess the effects of SLE and race on variation in proportional mortality using rates from non-SLE deaths as a comparison baseline. RESULTS: Common contributing causes of death listed with SLE included conditions that are known sequelae of the disease. Proportional mortality rates for these conditions varied with race and age. However, among black deaths that listed SLE, the rates of renal disease surpassed those of all other conditions regardless of age. When rates of renal disease among black SLE deaths or among white SLE deaths in any age group were compared to those among white non-SLE deaths, proportional mortality ratios were significantly greater than 1. This also held when rates of renal disease among black non-SLE deaths were compared to rates among white non-SLE deaths. However, across all ages, the proportional mortality ratios for renal disease in black SLE deaths significantly exceeded corresponding ratios for white SLE deaths and for black non-SLE deaths. CONCLUSION: Black females who die with SLE appear to experience a combination of the excess renal disease reported for persons with SLE and for all blacks. This combination may be a source of the elevated SLE mortality rates observed among US blacks.

A meningococcal vaccination campaign on a university campus: vaccination rates and factors in nonparticipation.

OBJECTIVES: This study was undertaken to determine an accurate vaccination rate and identify factors influencing nonvaccination in a meningococcal vaccination campaign on a Connecticut university campus in May 1993. METHODS: Vaccination and student data were merged to determine demographic factors associated with nonvaccination. A case-control study examined reasons for nonvaccination. RESULTS: The estimated vaccination rate for students returning to the campus was 93%. Lower rates occurred among older students, students living off campus, graduate and nondegree students, and married students. Perceived poor access to the vaccination center was the strongest predictor of nonvaccination. CONCLUSIONS: Higher vaccination rates may be achieved by specifically targeting students who live off campus and by providing multiple vaccination sites with extended hours.