Ball R H, Ade C M, Schoenborn J A, Crane J P
Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Am J Obstet Gynecol. 1996 Mar;174(3):996-1002. doi: 10.1016/s0002-9378(96)70339-3.
The null hypothesis is that there is no difference in outcome when pregnancies with ultrasonographically documented subchorionic hemorrhages are compared with those without these hemorrhages.
We performed a case-control study, utilizing our computerized ultrasonographic database. Cases were matched with two or three controls in two separate control groups. Matching criteria were maternal age, gestational age at scan, and invasive procedures (chorionic villus sampling or amniocentesis). General exclusion criteria were absence of fetal heart motion and fetal anomalies. Presence of subchorionic hemorrhage was an exclusion criterion for both control groups; however, in addition, presence of vaginal bleeding was a further criterion for one of the two. Statistical analysis was performed with chi2 analysis and Yates' correction. Odd ratios and 95% confidence intervals were calculated.
There was no difference in maternal characteristics between the cases and controls. The incidence of subchorionic hemorrhage was 1.3%. There was an increased risk of miscarriage (odds ratio 2.8, 95% confidence interval 1.7 to 7.4), stillbirth (4.5, 1.5 to 13.2), abruptio placentae (11.2, 2.7 to 46.4), and preterm labor (2.6, 1.5 to 4.6) when cases were compared with controls without subchorionic hemorrhage or bleeding. These risks were also increased in comparison with the control group with bleeding, except with respect to miscarriage. In this case the risks were similar in both cases and controls but increased with respect to the controls without bleeding. The mean birth weight was lower in the cases than in both control groups.
The presence of an ultransonographically detected subchorionic hemorrhage increases the risk of miscarriage, stillbirth, abruptio placentae, and preterm labor. The presence of bleeding alone appears to increase the risk of miscarriage. It is unclear whether the subchorionic hemorrhage is causative or whether it is simply a sign of an underlying process that produces these negative effects.
无效假设为超声检查记录有绒毛膜下出血的妊娠与无此类出血的妊娠在结局上无差异。
我们利用计算机超声数据库进行了一项病例对照研究。病例在两个独立的对照组中与两到三个对照进行匹配。匹配标准为产妇年龄、超声扫描时的孕周以及侵入性操作（绒毛取样或羊膜穿刺术）。一般排除标准为无胎儿心跳和胎儿异常。绒毛膜下出血的存在是两个对照组的排除标准；然而，此外，阴道出血的存在是其中一个对照组的进一步标准。采用卡方分析和耶茨校正进行统计分析。计算比值比和95%置信区间。
病例组和对照组的产妇特征无差异。绒毛膜下出血的发生率为1.3%。与无绒毛膜下出血或出血的对照组相比，病例组流产（比值比2.8，95%置信区间1.7至7.4）、死产（4.5，1.5至13.2）、胎盘早剥（11.2，2.7至46.4）和早产（2.6，1.5至4.6）的风险增加。与有出血的对照组相比，这些风险也增加，但流产情况除外。在这种情况下，病例组和对照组的风险相似，但与无出血的对照组相比有所增加。病例组的平均出生体重低于两个对照组。
超声检测到绒毛膜下出血会增加流产、死产、胎盘早剥和早产的风险。仅出血的存在似乎会增加流产风险。尚不清楚绒毛膜下出血是病因还是仅仅是产生这些负面影响的潜在过程的一个标志。
