ArticleThe Journal of nutrition2026
Modeling the Association between Repeated Measures of Hemoglobin during Pregnancy and Adverse Birth Outcomes.
Article in The Journal of nutrition, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundMaternal hemoglobin (Hb) concentrations and their trajectories throughout pregnancy are important determinants of birth outcomes. However, longitudinal studies on pregnancy frequently rely on cross-sectional analyses at specific time points or utilize summary measures, overlooking valuable information contained in repeated Hb measurements.
objectivesThis study aimed to illustrate various statistical approaches for modeling longitudinal Hb data and their associations with birth outcomes, highlighting the strengths and limitations of each method.
methodsWe analyzed 8 pregnancy datasets (6452 women, 13,580 Hb measurements) from the Biomarker Reflecting Inflammation and Nutritional Determinants of Anemia project using: 1) logistic regression incorporating residual Hb, 2) 2-stage mixed effect model, 3) distributed lag nonlinear model (DLNM), 4) generalized additive mixed model (GAMM), and 5) group-based trajectory modeling (GBTM). Outcomes were low birth weight (<2.5 kg), preterm birth (PTB, <37 wk), and small for gestational age (birthweight <10th percentile).
resultsLogistic regression using residual Hb, 2-stage mixed-effects model, and DLNM did not reveal any significant associations between Hb concentrations and adverse birth outcomes. GAMM showed that women with PTB had lower Hb concentrations before 20 wk of gestation compared with those without PTB. GBTM identified 4 distinct Hb trajectory clusters, but no significant associations were found between trajectory groups and adverse birth outcomes.
conclusionsThese analytic approaches provide complementary insights into the relationship between maternal Hb and birth outcomes, while illustrating how inference can vary depending on the method used. DLNMs can help pinpoint critical gestational periods of vulnerability, whereas models such as GAMM and GBTM capture nonlinear trends and heterogeneous trajectories. Researchers should be aware that conclusions about Hb and birth outcomes may be highly sensitive to modeling decisions. Overall, these methods can guide researchers in selecting statistical strategies best suited to their study aims and data structure.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.