Birth Order and Injury-Related Infant Mortality in the U.S

Identifying infants at risk of sudden unexpected death with an automated predictive risk model

BACKGROUND/OBJECTIVE

Sudden unexpected infant death (SUID) is a common cause of infant death. We evaluated whether a predictive risk model (PRM) - Hello Baby - which was developed to stratify children by risk of entry into foster care could also identify infants at highest risk of SUID and non-fatal unsafe sleep events.

PARTICIPANTS AND SETTING

Cases: Infants with SUID or an unsafe sleep event over 5½ years in a single county.

CONTROLS

All births in the same county.

METHODS

Retrospective case-control study. Demographic and clinical data were collected and a Hello Baby PRM score was assigned. Descriptive statistics and the predictive value of a PRM score of 20 were calculated.

RESULTS

Infants with SUID (n = 62) or an unsafe sleep event (n = 37) (cases) were compared with 23,366 births (controls). Cases and controls were similar for all demographic and clinical data except that infants with unsafe sleep events were older. Median PRM score for cases was higher than controls (17.5 vs. 10, p < 0.001); 50 % of cases had a PRM score 17-20 vs. 16 % of controls (p < 0.001).

CONCLUSIONS

The Hello Baby PRM can identify newborns at high risk of SUID and non-fatal unsafe sleep events. The ability to identify high-risk newborns prior to a negative outcome allows for individualized evaluation of high-risk families for modifiable risk factors which are potentially amenable to intervention. This approach is limited by the fact that not all counties can calculate a PRM or similar score automatically.

Determination of risk factors associated with unintentional injury in children: Case-control study

OBJECTIVE

This study aimed to determine the risk factors associated with unintentional injury in children aged 0-6 years.

DESIGN

This is a case-control study.

SAMPLE

A total of 150 participants (n: 75 case group, n: 75 control group) were included in the study. The case group consisted of mothers of children who had unintentional injuries and the control group was composed of the mothers of children who did not have unintentional injuries.

MEASUREMENTS

Data were collected using the Participant Information Form and the Identification of Safety Precautions of Mothers with 0-6 year-old Children for the Prevention of Unintentional Injuries Scale.

RESULTS

The mean attitude score of the mothers in the case group toward preventing unintentional injury (177.72 ± 15.53) was found to be higher than the mean score of the mothers in the control group (171.64 ± 17.93). An increase in mothers' scores on preventing unintentional injury reduces the risk of children having unintentional injuries 0.98 times.

CONCLUSION

The findings of the study revealed that mothers' attitudes toward preventing injury, the birth order of the child, and the child having a disability increase risk for unintentional injury.

Folate Levels by Time Since Last Live Birth Among U.S. Women, 2007-2016

Background: Folate depletion in the postpartum period may increase the risk of adverse pregnancy outcomes for women with a short interpregnancy interval following a live birth. We sought to examine folate levels by time since last live birth among U.S. women. Materials and Methods: Data were from 4,809 U.S. women, 20-44 years of age, participating in the National Health and Nutrition Examination Survey, 2007-2016. Red blood cell (RBC) folate was measured using microbiological assay on whole blood samples. Dietary folate intake and folic acid supplementation were measured during a 24-hour dietary recall. Prevalence of supplementation by time since last live birth was estimated from logistic regression models; mean levels of RBC folate and mean intake of dietary folate equivalent were estimated from linear regression models. Models were adjusted for maternal sociodemographic characteristics. Results: In adjusted models, supplementation (±standard error) was highest among women in the first year postpartum (31.7% ± 3.2) compared with nulliparous women (23.7% ± 1.9) and those 2-3 years (15.6% ± 1.9) and ≥3 years (18.4% ± 1.6) after last live birth. Mean RBC folate was highest among women in the first year postpartum, regardless of supplementation, with overall mean levels of 606 ± 15 ng/mL, compared with 484 ± 9, 477 ± 11, and 474 ± 7 among women in the aforementioned groups, respectively. Mean dietary folate intake was also highest among postpartum women: 542 ± 23 mcg/day, compared with 474 ± 12, 486 ± 21, and 467 ± 12. Conclusions: Folate levels are highest in the first year postpartum compared with other time periods within a woman's reproductive lifespan. These findings do not support the idea that postpartum U.S. women are depleted in folate, on average.

Beyond birth outcomes: Interpregnancy interval and injury-related infant mortality

BACKGROUND

Several studies have examined the association between IPI and birth outcomes, but few have explored the association between interpregnancy interval (IPI) and postnatal outcomes.

OBJECTIVE

We examined the association between IPI and injury-related infant mortality, a leading cause of postneonatal mortality.

METHODS

We used 2011-2015 US period-linked birth-infant death vital statistics data to generate a multiyear birth cohort of non-first-born singleton births (N = 9 782 029). IPI was defined as the number of months between a live birth and the start of the pregnancy leading to the next live birth. Causes of death in the first year of life were identified using ICD-10 codes. Hazard ratios (HR) for IPI categories were estimated using Cox proportional hazards models adjusted for birth order, county poverty level, and maternal characteristics (marital status, race/ethnicity, education, age at previous birth).

RESULTS

After adjustment, overall infant mortality (48.1 per 10 000 births) was higher for short and long IPIs compared with IPI 18-23 months (reference): <6, aHR 1.61, 95% CI 1.54, 1.68; 6-11, aHR 1.22, 95% CI 1.17, 1.26; and 60+ months, aHR 1.12, 95% CI 1.08, 1.16. In comparison, the risk of injury-related infant mortality (4.4 per 10 000 births) decreased with longer IPIs: <6, aHR 1.77, 95% CI 1.55, 2.01; 6-11, aHR 1.41, 95% CI 1.25, 1.59; 12-17, aHR 1.25, 95% CI 1.10, 1.41; 24-59, aHR 0.78, 95% CI 0.69, 0.87; and 60+ months, aHR 0.55, 95% CI 0.48, 0.62.

CONCLUSION

Unlike overall infant mortality, injury-related infant mortality decreased with IPI length. While injury-related deaths are rare, these patterns suggest that the timing between births may be a marker of risk for fatal infant injuries. The first year postpartum may be an ideal time for the delivery of evidence-based injury prevention programmes as well as family planning services.

Maternal characteristics associated with injury-related infant death in West Virginia, 2010-2014

Although injury-related deaths have been documented among children and adult populations, insufficient attention has been directed towards injury-related infant deaths. The objective of this retrospective study was to investigate maternal and infant characteristics associated with injury-related infant deaths in West Virginia. Birth and infant mortality data for 2010-2014 were sourced from the West Virginia Bureau for Public Health, Charleston. Relative risk was calculated using log-binomial regression utilizing generalized estimating equations. Maternal characteristics associated with injury-related infant mortality in West Virginia were race/ethnicity ([Formula: see text] = 7.48, p = .03), and smoking during pregnancy ([Formula: see text], p < .00). Risk of a Black Non-Hispanic infant suffering an injury-related death was 4.0 (95% CL 1.7, 9.3) times that of infants of other races/ethnicities. Risk of an infant dying from an injury-related cause, if the mother smoked during pregnancy, was 2.9 (95% CL 1.6, 5.0) times the risk of such a death if maternal smoking status during pregnancy is unknown or no smoking, controlling for race/ethnicity. This study provides important information to public health stakeholders at both the state and local levels in designing interventions for partial reduction or prevention of injury-related infant mortality in West Virginia.

Good practices for the design, analysis, and interpretation of observational studies on birth spacing and perinatal health outcomes

BACKGROUND

Meta-analyses of observational studies have shown that women with a shorter interpregnancy interval (the time from delivery to start of a subsequent pregnancy) are more likely to experience adverse pregnancy outcomes, such as preterm delivery or small for gestational age birth, than women who space their births further apart. However, the studies used to inform these estimates have methodological shortcomings.

METHODS

In this commentary, we summarise the discussions of an expert workgroup describing good practices for the design, analysis, and interpretation of observational studies of interpregnancy interval and adverse perinatal health outcomes.

RESULTS

We argue that inferences drawn from research in this field will be improved by careful attention to elements such as: (a) refining the research question to clarify whether the goal is to estimate a causal effect vs describe patterns of association; (b) using directed acyclic graphs to represent potential causal networks and guide the analytic plan of studies seeking to estimate causal effects; (c) assessing how miscarriages and pregnancy terminations may have influenced interpregnancy interval classifications; (d) specifying how key factors such as previous pregnancy loss, pregnancy intention, and maternal socio-economic position will be considered; and (e) examining if the association between interpregnancy interval and perinatal outcome differs by factors such as maternal age.

CONCLUSION

This commentary outlines the discussions of this recent expert workgroup, and describes several suggested principles for study design and analysis that could mitigate many potential sources of bias.