Results
During the study period, 41 uterine rupture cases were identified among
a total of 209,112 deliveries. The incidence of UR was 1.96/10 000
births. There were no maternal
deaths, hysterectomy and obstetric
injury secondary to uterine rupture in our study. Among all cases, there
were 16(39.0%) cases with complication and 25(61.0%) cases without. 15
(36.6%) were complete rupture cases, and 26 (63.4%) incomplete rupture
cases. 38(92.7%) were scarred uterus and 3 (7.3%) unscarred uterus.
The total number of deliveries, scarred uterus and VBAC rate have
increased over the eight years period. However, the proportion of
uterine rupture remained consistent (Figure. 1.Due to the large number
difference, a logarithmic axis is applied). UR rate was not associate
with VBAC rate (Correlation coefficient: -0.095, p =0.826)
Demographic data and clinical characteristics of mothers and fetuses
between uterine rupture and non-uterine rupture were presented in Table
1. Patients in UR group were significantly older and more than half
(58.5%) of them were over 35 years old, compared with 18.8% of the
non-UR. The mean gravidity of the case women of the UR group was
2.95±1.41, significantly higher than that of the non-UR group
(1.85±1.09). The proportion of primiparity in non-UR group (72.7%) were
much higher than UR group (24.4%). There was a statistically
significant difference in the gestational age at delivery, birth weight
and maternal hospital stay between the groups (39.0±1.6 vs 37.04±3.52,
3296.9±470.1 vs 3016.59±755.1, 4.3±4.1vs 7.71±5.28; p<0.05).
The incidences of gestational hypertension, artificial reproductive
technology, cesarean delivery, postpartum hemorrhage, preterm birth and
5-minute Apgar score<7 in the uterine rupture group were
higher than those in non-UR group (7.3% vs 1.1%, 12.2% vs 4.0%,
100% vs 39.9%, 31.7% vs1.5%, 39.0% vs 6.6%, 19.5% vs 1.0%; p
<0.05).
Table 2 displayed the occurrence of obstetrical risk factors in
complicated and not complicated uterine rupture groups. Among all
patients with uterine rupture, 16 (39.0%) had maternal and fetal
complications. Compared with not complicated uterine rupture, women in
complicated uterine rupture group had more primiparity, a higher
prevalence of uterine myomectomy history, artificial reproductive
technology use, blood transfusion, Intensive Care Unit (ICU) admission
and complete UR. Complicated UR group also presented a larger amount of
bleeding, a longer hospital stay, a higher probability of preterm birth,
multiple pregnancy, a smaller rupture gestational weeks, a lower birth
weight and prevalence of previous cesarean history.
Patients’ rate with abnormal fetal heart rate and vaginal bleeding
(68.8%vs 24.0%,43.8%vs 24.0%) were significantly higher in the
uterine rupture group with maternal and fetal complications. In
complicated group, the earliest and the latest ruptured gestational week
were 23 weeks and 40 weeks. In not complicated group, the earliest and
the latest ruptured gestational week were 35 weeks and 40 weeks. There
was no maternal death. The perinatal mortality attributable to uterine
rupture was 7.3%. 21 (51.2%) mothers were diagnosed with uterine
rupture preoperatively, 20 (48.8%) were diagnosed intraoperatively. The
diagnosed time and the proportion of TOLAC were similar in the 2 groups
(p=0.16; 0.156).
Multiple logistic regression analysis was employed to examine whether
signs and symptoms were associated with the presence of UR with
complication (Table 3). The model, which included all signs and symptoms
as independent variables, showed that abnormal fetal heart rate emerged
as a significant and independent factor associated with the complicated
uterine rupture compared with other signs. (p<0.05 and OR
12.45, 95% CI 1.16-133.54). Other clinical signs, however, were not
different.
Figure 2 shows the rupture sites involved.
24 (59%) cases were anterior
lower uterine segment; 3(7%) cases had posterior segment rupture; 9
(22%) cases were ruptured at the lateral segment; 4 (10%) cases were
fundal segment rupture and one ruptured more than one place (2%).
Detailed clinical information on all uterine rupture cases following
laparoscopic myomectomy is shown in Table 4