Uterine rupture: trends over 40 years.

OBJECTIVE: To follow trends of uterine rupture over a period of 40 years in Norway.

DESIGN: Population-based study using data from the Medical Birth Registry, the Patient Administration System, and medical records.

SETTING: Norway.

SAMPLE: Women giving birth in 21 maternity units in Norway during the period 1967-2008 (n = 1 441 712 maternities).

METHODS: The incidence and outcomes of uterine rupture were compared across four decades: 1967-1977; 1978-1988; 1989-1999; and 2000-2008. Multivariable logistic regression was used to determine the odds ratio (OR) for uterine rupture in each decade compared with the second decade.

MAIN OUTCOME MEASURE: Trends in uterine rupture.

RESULTS: We identified 359 uterine ruptures. The incidence rates per 10 000 maternities in the first, second, third, and fourth decade were 1.2, 0.9, 1.7, and 6.1, respectively. The ORs for complete and partial ruptures in the fourth versus the second decade were 6.4 (95% confidence interval, 95% CI 3.8-10.8) and 7.2 (95% CI 4.2-12.3), respectively. Significant contributing factors to this increase were the higher rates of labour augmentation with oxytocin, scarred uteri from a previous caesarean section, and labour induction with prostaglandins or prostaglandins combined with oxytocin. After adjusting for risk factors, the ORs for complete and partial ruptures were 2.2 (95% CI 1.3-3.8) and 2.8 (95% CI 1.6-4.8), respectively. Severe postpartum haemorrhage, hysterectomy, intrapartum death and infant death after complete uterine ruptures decreased significantly over time.

CONCLUSIONS: A sharply increasing trend of uterine rupture was found. Obstetric interventions contributed to this increase, but could not explain it entirely.

TWEETABLE ABSTRACT: A sharply increasing trend of uterine ruptures has been found in Norway in recent years.