小于胎龄儿产科危险因素的病例对照研究

目的探讨产科因素及孕母文化程度与小于胎龄儿（SGA）之间的关系。方法采用病例对照方法,选取于2000年1月至2004年10月在第三医院出生的单胎活产SGA,全部病例共834例（男443例,女391例）作为病例组。以胎儿性别及出生胎龄进行频数匹配,按1：3的比例,采用完全随机抽样方法选取性别及胎龄别出生体重在10％～90％分位的适于胎龄儿2502名（男1329名,女1173名）为对照组,比较了病例组及对照组新生儿母亲年龄、文化程度及主要产科危险因素的比例。结果多因素logistic回归分析显示,SGA病例组母亲妊娠合并妊娠高血压综合征（妊高征）、羊水过少、有既往异常妊娠史和病毒性肝炎与对照组比较,OR值（95％Cj）分别为4．00（2．81～5．71）、2．95（2．27～3-83）、5．95（3．05～10．64）和0．50（0．30～0．84）;SGA母亲为初中及以下文化程度者与大专或以上文化程度者比较OR=3．46（95％CI：2．75～4．24）。其他因素与SGA无统计学意义的关联。结论孕母文化程度低、孕期合并妊高征、羊水过少、不良妊娠史可显著增加SGA发生的危险性。

A case-control study on small-for-gestational-age in relation to obstetrical risk factors

OBJECTIVE: Previous studies suggested that a number of obstetrical factors were associated with small-for-gestational-age (SGA) infant. However, it remained uncertain which obstetrical factors might increase the risk of SGA due to limitations of small sample size and poor study designs in the previous studies in China. We assessed the association of a few maternal factors, such as pregnancy-induced hypertension (PIH), oligohydramnios, infectious diseases of reproductive system, abnormal conditions of placenta or umbilical cord, previous adverse pregnancy outcomes, hysteromyoma and maternal education level, and the risk of SGA. METHODS: We examined the association in a case-control study, in which the SGA group included all of 834 (443 males and 391 females) singleton alive SGA deliveries in our hospital during January 2000 to October 2004. 2502 (1329 males and 1173 females) appropriate-for-gestational-age (AGA) infants (1:3, SGA/AGA) matched by gender- and gestational-age-stratified frequencies of SGA were randomly selected for controls from infants with sex-specific birthweight for gestational age ranged between 10th-90th percentiles. Odds ratios (95% confidence interval, 95% CI) of these factors for SGA were calculated in univariate and multivariate analyses. The maternal risk factors were diagnosed by the relevant criteria used in China. SGA was defined as sex-specific birthweight for gestational age that was less than 10th percentile cut-off of fetal growth reference of singleton alive infants delivered in our hospital during that period. RESULTS: Results from univariate analysis showed that PIH, oligohydramnios, history of adverse pregnancy outcome, poor maternal education and viral hepatitis were significantly associated with SGA. The odds ratios (95% CI) of these five factors for SGA were 3.95(2.79-5.60), 2.94(2.27-3.80), 7.01(3.87-12.70), 3.62(2.92-4.49) and 0.52(0.32-0.87), respectively. In the multivariate logistic analysis, a similar result was shown. The ratios of maternal PIH, oligohydramnios, history of adverse pregnancy outcome and viral hepatitis in the SGA group were 4.00(2.81-5.71), 2.95 (2.27-3.83), 5.95 (3.05-10.64), 0.50(0.30-0.84) folds of those in the AGA group; the ratio of maternal low formal education (< or = 9 years) in the SGA group was 3.46(2.75-4.24) times of the AGA group. CONCLUSION: PIH, oligohydramnios, poor maternal education and a history of adverse pregnancy outcome were significantly associated with an increased risk of SGA while viral hepatitis might be associated with a decreased risk of SGA.