Mater Research Institute, The University of Queensland, Brisbane, Australia; Mayne Medical School, The University of Queensland, Brisbane, Australia; Department of Obstetrics and Gynecology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
Mater Research Institute, The University of Queensland, Brisbane, Australia; Mayne Medical School, The University of Queensland, Brisbane, Australia; School of Public Health, The University of Queensland, Brisbane, Australia.
Am J Obstet Gynecol. 2023 Oct;229(4):451.e1-451.e15. doi: 10.1016/j.ajog.2023.04.044. Epub 2023 May 5.
Determining the optimal time of birth at term is challenging given the ongoing risks of stillbirth with increasing gestation vs the risks of significant neonatal morbidity at early-term gestations. These risks are more pronounced in small infants.
This study aimed to evaluate the risks of stillbirth, neonatal mortality, and severe neonatal morbidity by comparing expectant management with delivery from 37 weeks of gestation.
This was a retrospective cohort study evaluating women with singleton, nonanomalous pregnancies at 37 to 40 weeks' gestation in Queensland, Australia, delivered from 2000 to 2018. Rates of stillbirth, neonatal death, and severe neonatal morbidity were calculated for <3rd, 3rd to <10th, 10th to <25th, 25th to <90th, and ≥90th birthweight centiles. The composite risk of mortality with expectant management for an additional week in utero was compared with rates of neonatal mortality and severe neonatal morbidity.
Of 948,895 singleton, term nonanomalous births, 813,077 occurred at 37 to 40 weeks' gestation. Rates of stillbirth increased with gestational age, with the highest rate observed in infants with birthweight below the third centile: 10.0 per 10,000 (95% confidence interval, 6.2-15.3) at 37 to 37 weeks, rising to 106.4 per 10,000 (95% confidence interval, 74.6-146.9) at 40 to 40 weeks' gestation. The rate of neonatal mortality was highest at 37 to 37 weeks for all birthweight centiles. The composite risk of expectant management rose sharply after 39 to 39 weeks, and was highest in infants with birthweight below the third centile (125.2/10,000; 95% confidence interval, 118.4-132.3) at 40 to 40 weeks' gestation. Balancing the risk of expectant management and delivery (neonatal mortality), the optimal timing of delivery for each birthweight centile was evaluated on the basis of relative risk differences. The rate of severe neonatal morbidity sharply decreased in the period between 37 to 37 and 38 to 38 weeks, particularly for infants with birthweight below the third centile.
Our data suggest that the optimal time of birth is 37 to 37 weeks for infants with birthweight <3rd centile and 38 to 38 weeks' gestation for those with birthweight between the 3rd and 10th centile and >90th centile. For all other birthweight centiles, birth from 39 weeks is associated with the best outcomes. However, large numbers of planned births are required to prevent a single excess death. The healthcare costs and acceptability to women of potential universal policies of planned birth need to be carefully considered.
由于在延长妊娠期间胎儿仍有死亡风险，而在早期妊娠时新生儿的发病率较高，因此很难确定足月分娩的最佳时间。这些风险在小婴儿中更为明显。
本研究旨在通过比较从 37 孕周开始期待治疗与分娩的方式，评估胎儿仍有死亡、新生儿死亡和严重新生儿发病率的风险。
这是一项回顾性队列研究，评估了澳大利亚昆士兰州 37 至 40 孕周、单胎、非畸形妊娠的女性，这些女性在 2000 年至 2018 年期间分娩。计算了<第 3 百分位数、第 3 百分位数至<第 10 百分位数、第 10 百分位数至<第 25 百分位数、第 25 百分位数至<第 90 百分位数和≥第 90 百分位数的出生体重的胎儿仍有死亡、新生儿死亡和严重新生儿发病率的发生率。将期待治疗时每周胎儿在宫内的额外死亡风险与新生儿死亡率和严重新生儿发病率进行比较。
在 948895 例单胎、足月非畸形出生中，813077 例发生在 37 至 40 孕周。随着胎龄的增加，胎儿仍有死亡的发生率增加，在出生体重低于第 3 百分位数的婴儿中发生率最高：37 至 37 孕周时为每 10000 例 10.0（95%置信区间，6.2-15.3），而在 40 至 40 孕周时上升至 106.4/10000（95%置信区间，74.6-146.9）。所有出生体重百分位数中，新生儿死亡率在 37 至 37 孕周时最高。在 39 至 39 孕周之后，期待治疗的风险急剧上升，在出生体重低于第 3 百分位数的婴儿中最高（125.2/10000；95%置信区间，118.4-132.3）在 40 至 40 孕周。根据相对风险差异，评估了每个出生体重百分位数时分娩的最佳时间，平衡了期待治疗和分娩（新生儿死亡）的风险。严重新生儿发病率在 37 至 37 周和 38 至 38 周之间的期间急剧下降，尤其是出生体重低于第 3 百分位数的婴儿。
我们的数据表明，对于出生体重<第 3 百分位数的婴儿，最佳分娩时间为 37 至 37 周，对于出生体重在第 3 至 10 百分位数和>第 90 百分位数的婴儿，最佳分娩时间为 38 至 38 周。对于所有其他出生体重百分位数，从 39 孕周开始分娩与最佳结局相关。然而，需要进行大量的计划分娩，以防止单个死亡人数的增加。需要仔细考虑潜在的普遍计划分娩政策的医疗保健成本和对妇女的可接受性。
