Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA.
Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, UT Health - University of Texas Medical School at Houston, Houston, TX.
Am J Obstet Gynecol. 2017 Aug;217(2):198.e1-198.e11. doi: 10.1016/j.ajog.2017.04.020. Epub 2017 Apr 20.
The association between small-for-gestational-age (birthweight <10th percentile for gestational age) and neonatal morbidity is well established. Yet, there is a paucity of data on the relationship between suspected small for gestational age (sonographic-estimated fetal weight <10th percentile) at 2 thresholds and subsequent neonatal morbidity.
The objective of this study was to determine the relationship between sonographic-estimated fetal weight <5th percentile vs 5-9th percentile and neonatal morbidity.
This retrospective study involved 5 centers and included nonanomalous, singletons with sonographic-estimated fetal weight <10th percentile for gestational age who delivered from 2009-2012. Composite neonatal morbidity included respiratory distress syndrome, proven sepsis, intraventricular hemorrhage grade III or IV, necrotizing enterocolitis, thrombocytopenia, seizures, or death. Odd ratios were adjusted for center, maternal age, race, body mass index at first visit, smoking status, use of alcohol, use of drugs, and neonatal gender.
Of 834 women with suspected small-for-gestational-age fetuses, 513 (62%) had sonographic-estimated fetal weight <5th percentile, and 321 (38%) had sonographic-estimated fetal weight of 5-9th percentile for gestational age. At delivery, 81% of women with a suspected small-for-gestational-age fetus had a confirmed small-for-gestational-age fetus. In the group with a sonographic-estimated fetal weight <5th percentile, 59% of neonates had birthweight <5th percentile; in the group with a sonographic-estimated fetal weight 5-9th percentile, 41% had birthweight <5th percentile, and 36% had birthweight at 5-9th percentile. Neonatal intensive care unit admission differed significantly for those fetuses at <5th percentile (29%) compared with those fetuses at 5-9th percentile (15%; P<.001). The composite neonatal morbidity among the sonographic-estimated fetal weight <5th percentile group was higher than the sonographic-estimated fetal weight of 5-9th percentile group (31% vs 13%; adjusted odds ratio, 2.41; 95% confidence interval, 1.53-3.80). Similar findings were noted when the analysis was limited to sonographic-estimated fetal weight within 28 days of delivery (adjusted odds ratio, 2.22; 95% confidence interval, 1.34-3.67).
Eight of 10 suspected small-for-gestational-age fetuses had birthweight <10th percentile for gestational age; the prediction of actual birthweight was more accurate in the <5th percentile group. Neonates with sonographic-estimated fetal weight of <5th percentile were more likely to be admitted to the neonatal intensive care unit and have complications than were those neonates with sonographic-estimated fetal weight of 5-9th percentile.
小胎龄儿（出生体重低于胎龄第 10 百分位）与新生儿发病率之间的关联已得到充分证实。然而，关于超声估计胎儿体重在 2 个阈值下<10 百分位与随后的新生儿发病率之间的关系的数据很少。
本研究旨在确定超声估计胎儿体重<第 5 百分位与第 5-9 百分位与新生儿发病率之间的关系。
本回顾性研究涉及 5 个中心，纳入了超声估计胎儿体重<胎龄第 10 百分位且无畸形的单胎妊娠，且这些胎儿于 2009-2012 年分娩。复合新生儿发病率包括呼吸窘迫综合征、确诊败血症、脑室内出血 3 级或 4 级、坏死性小肠结肠炎、血小板减少症、癫痫发作或死亡。比值比根据中心、产妇年龄、种族、初诊时的体重指数、吸烟状况、饮酒、吸毒和新生儿性别进行调整。
在 834 名疑似小胎龄儿的孕妇中，513 名（62%）的超声估计胎儿体重<第 5 百分位，321 名（38%）的超声估计胎儿体重为第 5-9 百分位。分娩时，81%的疑似小胎龄儿孕妇证实胎儿为小胎龄儿。在超声估计胎儿体重<第 5 百分位的组中，59%的新生儿出生体重<第 5 百分位；在超声估计胎儿体重为第 5-9 百分位的组中，41%的新生儿出生体重<第 5 百分位，36%的新生儿出生体重在第 5-9 百分位。与超声估计胎儿体重为第 5-9 百分位的组（15%；P<.001）相比，超声估计胎儿体重<第 5 百分位的组新生儿需要入住新生儿重症监护病房的比例显著更高（29%）。超声估计胎儿体重<第 5 百分位组的复合新生儿发病率高于超声估计胎儿体重为第 5-9 百分位组（31%比 13%；调整后的比值比，2.41；95%置信区间，1.53-3.80）。当分析仅限于分娩后 28 天内的超声估计胎儿体重时，也得到了类似的结果（调整后的比值比，2.22；95%置信区间，1.34-3.67）。
10 名疑似小胎龄儿中，有 8 名的出生体重<胎龄第 10 百分位；在<第 5 百分位组，对实际出生体重的预测更准确。与超声估计胎儿体重为第 5-9 百分位的新生儿相比，超声估计胎儿体重<第 5 百分位的新生儿更有可能被收入新生儿重症监护病房并出现并发症。
