Interpretation
The rate of repeat complete uterine rupture in our study was similar to the rate of 4.8% in the review by Lim from 1971-2005.11 They included five earlier studies from Ireland, the United States, Saudi Arabia, Qatar, and Nigeria, as well as five women from their unit in the Netherlands, for a total of 85 pregnancies. Half of these women were recruited from Nigeria, where all of the repeat ruptures occurred. This gives a rate of 9% for this country.
On the other hand, a 2018 review by Zoe6 found an overall rate of 12.3% after including 11 studies from different countries with low and high resources in 1981-2015. The review found a wide range in the rate between different studies (0 to 37.5%); a study from Israel12 in 2015 showed a recurrent rupture rate of 15.2% among 46 pregnancies. Moreover, 8.7% of pregnancies developed partial ruptures (dehiscence), similar to our rate.
These outcomes from the Israeli study occurred despite 71.7% of deliveries occurring before 37 weeks. We had a lower rupture rate despite only 36.1% of infants being delivered before 37 weeks. Moreover, we showed that timing the delivery at an earlier gestational age was not necessarily associated with a reduced risk of rupture, as all repeat complete ruptures occurred preterm. A similar finding was reported by Usta et al.5 in a study from Beirut that included 24 pregnancies. They showed no significant difference in the mean or median gestational age between pregnancies in which rupture occurred and those in which it did not. However, Ritchi et al.13 found that 85% of repeat ruptures occurred after 36 weeks.
The absence of maternal deaths and the low perinatal death rate in our study reflect the importance of immediate access to emergency obstetric care, regardless of the timing of delivery.
All three repeat complete ruptures occurred in those who had a previous rupture outside the LS. This indicates that women with previous rupture in the LS have a better prognosis. However, the majority of those with previous ruptures outside the LS did not have a repeat rupture. This is in contrast to the findings of Usta et al.,5 who found 100% repeated rupture among those with previous rupture outside the LS. Our finding of zero complete ruptures when the inter-delivery interval was 2-3 years is in agreement with previous studies.2, 14 Furthermore, we found an increased repeat rupture rate when the inter-delivery interval was either 1 year or ≥ 4 years. This is not in agreement with Usta et al.,5 who found that the median inter-delivery interval in those who had repeat ruptures was significantly shorter, 2 vs. 5 years. One should take into consideration that the sample in Usta et al. was smaller than our sample. Similar to the results reported by Usta, we found a tendency toward increased repeat rupture when previous rupture was at gestational age < 37 weeks. Our findings suggest that women with previous ruptures at an earlier gestational age, with too short an inter-delivery interval, or previous rupture outside the LS should not be excluded from trying a new pregnancy. However, as there is an increased tendency toward rupture, even though it was not statistically significant, careful counseling and monitoring is important.