National Institute for Medical Research, Tanga Medical Research Centre, Tanga, Tanzania.
Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
Acta Obstet Gynecol Scand. 2022 Mar;101(3):293-302. doi: 10.1111/aogs.14323. Epub 2022 Feb 13.
Identification of low birthweight and small for gestational age is pivotal in clinical management and many research studies, but in low-income countries, birthweight is often unavailable within 24 h of birth. Newborn weights measured within days after birth and knowledge of the growth patterns in the first week of life can help estimate the weight at birth retrospectively. This study aimed to generate sex-specific prediction maps and weight reference charts for the retrospective estimation of birthweight for exclusively breastfed newborns in a low-resource setting.
This was a prospective cohort study nested in a clinical trial of intermittent preventive treatment in pregnancy for malaria with either dihydroartemisinin-piperaquine with/without azithromycin or sulfadoxine-pyrimethamine in Korogwe District, north-eastern Tanzania (Clinicaltrials.gov: NCT03208179). Newborns were weighed at birth or in the immediate hours after birth and then daily for 1 week. Reference charts, nadir, time to regain weight, and prediction maps were generated using nonlinear mixed-effects models fitted to the longitudinal data, incorporating interindividual variation as random effects. Predictions and prediction standard deviations were computed using a linear approximation approach.
Between March and December 2019, 513 live newborns with birthweights measured within 24 h of delivery were weighed daily for 1 week. Complete datasets were available from 476 exclusively breastfed newborns. There was a rapid decline in weight shortly after delivery. The average weight loss, time of nadir, and time to regain weight were 4.3% (95% confidence interval [CI] 3.8-4.9) at 27 h (95% CI 24-30) and 105 h (95% CI 91-120) in boys and 4.9% (95% CI 4.2-5.6) at 28 h (95% CI 23-33) and 114 h (95% CI 93-136) in girls, respectively. The data were used to generate prediction maps with 1-h time intervals and 0.05 kg weight increments showing the predicted birthweights and weight-for-age and weight-change-for-age reference charts depicting variation in weight loss from <1 to >10%.
The prediction maps and reference charts can be used by researchers in low-resource settings to retrospectively estimate birthweights using weights collected up to 168 h after delivery, thereby maximizing data utilization. Clinical practitioners can also use the prediction maps to retrospectively classify newborns as low birthweight or small for gestational age.
在临床管理和许多研究中，识别低出生体重和小于胎龄儿至关重要，但在低收入国家，出生体重通常在出生后 24 小时内无法获得。出生后几天内测量的新生儿体重以及对生命第一周内生长模式的了解，可以帮助回顾性估计出生体重。本研究旨在为资源匮乏环境中纯母乳喂养的新生儿生成性别特异性预测图和体重参考图表，以回顾性估计出生体重。
这是一项嵌套在坦桑尼亚东北部科罗戈韦区二氢青蒿素-哌喹与/或阿奇霉素与磺胺多辛-乙胺嘧啶间歇性预防治疗妊娠疟疾的临床试验中的前瞻性队列研究（Clinicaltrials.gov：NCT03208179）。新生儿在出生时或出生后立即称重，然后每天称重 1 周。参考图表、最低点、体重恢复时间和预测图使用非线性混合效应模型生成，该模型将个体间变异作为随机效应纳入其中。使用线性近似方法计算预测值和预测标准偏差。
2019 年 3 月至 12 月期间，513 名出生后 24 小时内有出生体重测量值的活产新生儿每天称重 1 周。476 名纯母乳喂养的新生儿提供了完整的数据集。出生后体重迅速下降。男孩体重平均下降 4.3%（95%置信区间[CI]3.8-4.9），最低点出现在 27 小时（95%CI 24-30），体重恢复时间为 105 小时（95%CI 91-120），女孩体重平均下降 4.9%（95%CI 4.2-5.6），最低点出现在 28 小时（95%CI 23-33），体重恢复时间为 114 小时（95%CI 93-136）。利用这些数据生成了预测图，时间间隔为 1 小时，体重增量为 0.05kg，显示了预测的出生体重，以及体重与年龄和体重变化与年龄的参考图表，描绘了从<1 到>10%的体重减轻变化。
资源匮乏地区的研究人员可以使用预测图和参考图表，利用出生后 168 小时内收集的体重来回顾性估计出生体重，从而最大限度地利用数据。临床医生也可以使用预测图来回顾性地将新生儿分类为低出生体重或小于胎龄儿。
