新生儿窒息的产前危险因素：危险几何

Prenatal risk factors for neonatal asphyxia: how risk for each?

摘要:

目的：新生儿窒息是全球新生儿的第三位死因和主要致残原因，防重于治。此前文献多限于回顾性调查某些产前危险因素与低Apgar评分的关系。该课题前瞻性研究46项产前危险因素与新生儿窒息之间的关联，单个和多个危险因素对新生儿窒息发生率的影响，筛查对新生儿窒息有意义的危险因素，以便制订预防对策。方法：连续纳入该院分娩的活产婴10 376例，将产前46种危险因素印成表格，由产、儿两科密切配合，逐一查询、记录。拟诊窒息的标准：兼备①1分钟Apgar评分≤7分；②脐动脉血pH<7.20；③至少一个脏器受损；④排除引起低Apgar评分的其他情况和疾病。统计单种和多种危险因素在整个样本中出现的例数、出现率、构成比及其对窒息发生率的影响，依次采用单因素逻辑回归和多重logistic回归前向性逐步纳入法（forward stepwise conditional），以选入界值α≤0.05、剔除界值α≥0.10为标准，以P<0.05为差异有显著性意义，筛查对发生窒息有意义的危险因素，并计算其相对风险比（OR）和95%的可信区间（CI）。 结果：10 376例活产婴中8 530例（82.2%）有危险因素1～9 种不等，共发生新生儿窒息117例（1.13%）；无危险因素的1 846者中无1例发生新生儿窒息（χ2＝25.6，P<0.01)。窒息发生率随具有危险因素种数的增加而升高,由具有1种危险因素时的0.23%逐渐升至具有9种危险因素时的14.3%（r=0.96，P<0.01）；有意义的12项危险因素为胎心监护图型异常(OR=17.1, 95%CI: 11.2~25.9)、胎盘早剥(OR=15.2, 95%CI:4.5~51.8)、母肺脏病(OR=11.5, 95%CI:1.4~91.3)、胎儿酸中毒(OR=6.1, 95%CI:1.5~24.1)、前置胎盘(OR=5.0,95%CI:1.5~16.9)、臀位分娩(OR=4.5, 95%CI:2.1~9.9)、羊水粪染(OR=3.2, 95%CI:2.2~4.8)、产钳助娩(OR=3.2,95%CI:1.1~9.9)、产程延长(OR=2.94,95%CI:1.5~5.8)、宫缩异常(OR=2.8，95%CI:1.7~4.6)、早产(OR=2.5,95%CI:1.4~4.8)、剖宫产(OR=0.6,95%CI:0.4~0.9), 均P<0.05。结论：产前全面筛查危险因素，对有危险因素尤其是前述有意义的危险因素或有多种危险因素者加强监护和必要时给予干预对预防围生儿窒息具有重要意义，而合理的符合指征的剖宫产似可降低窒息的发生率。［中国当代儿科杂志，2009，11（3）：161-165］

Abstract:

OBJECTIVE: Neonatal asphyxia is the third leading cause of neonatal death and main cause of long-term neurodevelopmental handicap throughout the world. Prevention is more important than treatment. Most previous reports are limited to retrospective investigations of the relationships between some prenatal risk factors and low Apgar scores. This study was designed to prospectively investigate the relationship between prenatal risk factors and neonatal asphyxia and the influence of single or multiple risk factors on the incidence of neonatal asphyxia, and examine significant risk factors for neonatal asphyxia. METHODS: From April 2002 through October 2004, a total of 10 376 live-born newborns were enrolled. Forty-six prenatal risk factors were investigated. Neonatal asphyxia was diagnosed based on the following four items: ① 1-min Apgar score ≤7; ② Umbilical artery blood pH<7.20; ③ At least one organ had evidence of asphyxial injury; ④ Other causes of low Apgar score were excluded. The number, the constituent ratio and the exposure frequency of newborns with single or multiple risk factors were counted. The influence of risk factors on the incidence of asphyxia was analyzed. The significant risk factors were screened by single logistic regression analysis and forward stepwise conditional multiple logistic regression analysis, with enrolled threshold α≤0.05, excluded threshold α≥0.10 and P<0.05 as significant. The OR and 95%CI were calculated for each significant risk factor. RESULTS: Of the 10 376 newborns, 8 530 cases (82.21%) had 1-9 risk factors, and asphyxia occurred in 117 cases (1.13%) out of the 8 530 cases. In the 1 846 cases without risk factors, none had asphyxia (χ2＝25.6, P<0.01). The incidence of asphyxia increased with increasing numbers of risk factors, from 0.23% in newborns with one risk factor to 14.29% in newborns who had nine risk factors (r=0.96, P<0.01). Twelve significant risk factors identified were as follows: ominous fetal heart rate patterns (OR=17.1,95%CI:11.2-25.9), placenta abruption (OR=15.2, 95% CI: 4.5-51.8), maternal lung diseases (OR=11.5, 95% CI:1.4-91.3), fetal acidosis (OR=6.1, 95% CI:1.5-24.1), placenta previa (OR=5.0,95% CI:1.5-16.9), breech delivery (OR=4.5, 95% CI: 2.1-9.9), meconium stained amniotic fluid (OR=3.2, 95% CI:2.2-4.8), forceps-assisted delivery (OR=3.2, 95%CI: 1.1-9.9), prolonged labor (OR=2.94, 95%CI:1.5-5.8), abnormal utero contraction (OR=2.8, 95% CI:1.7-4.6), and premature delivery (OR=2.5,95%CI:1.4-4.8). Cesarean section had a protective effect (OR=0.6, 95% CI:0.4-0.9) (all P<0.05). CONCLUSIONS: It is very important to prevent perinatal asphyxia by systematically examining prenatal risk factors and giving interventions for the newborns with risk factors, especially those with the above significant risk factors or with multiple risk factors. Proper cesareon section according to indications might be helpful to decrease the incidence of birth asphyxia.［Chin J Contemp Pediatr, 2009, 11 (3):161-165］