Maternal Morbidity - Measuring Maternal Morbidity Resources

About one third of all pregnant women in the United States are obese. Maternal obesity at conception alters gestational metabolic adjustments and affects placental, embryonic, and fetal growth and development. Neural tube defects and other developmental anomalies are more common in infants born to obese women; these defects have been linked to poor glycemic control. Preeclampsia, a gestational disorder occurring more frequently in obese women, appears to be due to a subclinical inflammatory state that impairs early placentation and development of its blood supply. Fetal growth and development during the last half of pregnancy depends on maternal metabolic adjustments dictated by placental hormones and the subsequent oxygen and nutrient supply. Maternal obesity affects these metabolic adjustments as well. Basal metabolic rates are significantly higher in obese women, and maternal fat gain is lower, possibly in response to altered leptin function. The usual increase in insulin resistance seen in late pregnancy is enhanced in obese mothers, causing marked postprandial increases in glucose, lipids, and amino acids and excessive fetal exposure to fuel sources, which in turn increases fetal size, fat stores, and risk for disease postnatally. Impaired glucose tolerance, gestational diabetes, and hyperlipidemia are more common among obese mothers. To date, little attention has been given to the role of diet among obese women in preventing these problems. However, studies of women with impaired glucose tolerance show that replacing refined carbohydrates and saturated fat with complex, low-glycemic carbohydrates and polyunsaturated fatty acids improves metabolic homeostasis and pregnancy outcomes. Thus, current dietary guidelines regarding the amount and type of carbohydrates and fat for nonpregnant women seem appropriate for pregnant women as well.

Objective: To describe on a national basis ethnic differences in severe maternal morbidity in the United Kingdom. Design: National cohort study using the UK Obstetric Surveillance System (UKOSS). Setting: All hospitals with consultant led maternity units in the UK. Participants: 686 women with severe maternal morbidity between February 2005 and February 2006. Main outcome measures: Rates, risk ratios, and odds ratios of severe maternal morbidity in different ethnic groups. Results: 686 cases of severe maternal morbidity were reported in an estimated 775 186 maternities, representing an estimated incidence of 89 (95% confidence interval 82 to 95) cases per 100 000 maternities. 74% of women were white, and 26% were non-white. The estimated risk of severe maternal morbidity in white women was 80 cases per 100 000 maternities, and that in non-white women was 126 cases per 100 000 (risk difference 46 (27 to 66) cases per 100 000; risk ratio 1.58, 95% confidence interval 1.33 to 1.87). Black African women (risk difference 108 (18 to 197) cases per 100 000 maternities; risk ratio 2.35, 1.45 to 3.81) and black Caribbean women (risk difference 116 (59 to 172) cases per 100 000 maternities; risk ratio 2.45, 1.81 to 3.31) had the highest risk compared with white women. The risk in non-white women remained high after adjustment for differences in age, socioeconomic and smoking status, body mass index, and parity (odds ratio 1.50, 1.15 to 1.96). Conclusions: Severe maternal morbidity is significantly more common among non-white women than among white women in the UK, particularly in black African and Caribbean ethnic groups. This pattern is very similar to reported ethnic differences in maternal death rates. These differences may be due to the presence of pre-existing maternal medical factors or to factors related to care during pregnancy, labour, and birth; they are unlikely to be due to differences in age, socioeconomic or smoking status, body mass index, or parity. This highlights to clinicians and policy makers the importance of tailored maternity services and improved access to care for women from ethnic minorities. National information on the ethnicity of women giving birth in the UK is needed to enable ongoing accurate study of these inequalities.

OBJECTIVE: To examine trends in the rates of hypertensive disorders in pregnancy and compare the rates of severe obstetric complications for delivery hospitalizations with and without hypertensive disorders. METHODS: We performed a cross-sectional study using the 1998 –2006 Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project. Logistic regressions and population-attributable fractions were used to examine the effect of hypertensive disorders on severe complications. RESULTS: The overall prevalence of hypertensive disorders among delivery hospitalizations increased significantly from 67.2 per 1,000 deliveries in 1998 to 81.4 per 1,000 deliveries in 2006. Compared with hospitalizations without any hypertensive disorders, the risk of severe obstetric complications ranged from 3.3 to 34.8 for hospitalizations with eclampsia/severe preeclampsia and from 1.4 to 2.2 for gestational hypertension. The prevalence of hospitalizations with eclampsia/severe pre-eclampsia increased moderately from 9.4 to 12.4 per 1,000 deliveries (P for linear trend <0.001) during the period of study. However, these hospitalizations were associated with 38% of hospitalizations with acute renal failure and 19% or more of hospitalizations with ventilation, disseminated intravascular coagulation syndrome, pulmonary edema, puerperal cerebrovascular disorders, and respiratory distress syndrome. Overall, hospitalizations with hypertensive disorders were associated with 57% of hospitalizations with acute renal failure, 27% of hospitalizations with disseminated intravascular coagulation syndrome, and 30% or more of hospitalizations with ventilation, pulmonary edema, puerperal cerebrovascular disorders, and respiratory distress syndrome. CONCLUSION: The number of delivery hospitalizations in the United States with hypertensive disorders in pregnancy is increasing, and these hospitalizations are associated with a substantial burden of severe obstetric morbidity. LEVEL OF EVIDENCE: III

Abstract Objectives The accuracy of maternal morbidity estimates from hospital discharge data may be influenced by incomplete identification of deliveries. In maternal/ infant health studies, obstetric deliveries are often identified only by the maternal outcome of delivery code (International Classification of Diseases code = V27). We developed an enhanced delivery identification method based on additional delivery-related codes and compared the performance of the enhanced method with the V27 method in identifying estimates of deliveries as well as estimates of maternal morbidity. Methods The enhanced and standard V27 methods for identifying deliveries were applied to data from the 1998–2004 Healthcare Cost and Utilization Project Nationwide Inpatient Sample, an annual nationwide representative survey of U.S. hospitalizations. Odds ratios (ORs) and 95% confidence intervals (CIs) from logistic regression were used to examine predictors of deliveries not identified using the V27 method. Results The enhanced method identified 958,868 (3.4%) more deliveries than the 27,128,539 identified using the V27 code alone. Severe complications including major puerperal infections (OR = 3.1, 95% CI 2.8–3.4), hysterectomy (OR = 6.0, 95% CI 5.3–6.8), sepsis (OR = 11.9, 95% CI 10.3–13.6) and respiratory distress syndrome (OR = 16.6, 95% CI 14.4–19.2) were strongly associated with deliveries not identified by the V27 method. Nationwide prevalence rates of severe maternal complications were underestimated with the V27 method compared to the enhanced method, ranging from 9% underestimation for major puerperal infections to 40% underestimation for respiratory distress syndrome. Conclusion Deliveries with severe obstetric complications may be more likely to be missed using the V27 code. Researchers should be aware that selecting deliveries from hospital stay records by V27 codes alone may affect the accuracy of their findings.

OBJECTIVE: To examine trends in the rates of severe obstetric complications and the potential contribution of changes in delivery mode and maternal characteristics to these trends. METHODS: We performed a cross-sectional study of severe obstetric complications identified from the 1998– 2005 Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project. Logistic regression was used to examine the effect of changes in delivery mode and maternal characteristics on rates of severe obstetric complications. RESULTS: The prevalence of delivery hospitalizations (per 1,000) complicated by at least one severe obstetric complication increased from 0.64% (n
48,645) in 1998– 1999 to 0.81% (n
68,433) in 2004–2005. Rates of complications that increased significantly during the study period included renal failure by 21% (from 0.23 to 0.28), pulmonary embolism by 52% (0.12 to 0.18), adult respiratory distress syndrome by 26% (0.36 to 0.45), shock by 24% (0.15 to 0.19), blood transfusion by 92% (2.38 to 4.58), and ventilation by 21 % (0.47 to 0.57). In logistic regression models, adjustment for maternal age had no effect on the increased risk for these complications in 2004–2005 relative to 1998–1999. However, after adjustment for mode of delivery, the increased risks for these complications in 2004–2005 relative to 1998–1999 were no longer significant, with the exception of pulmonary embolism (odds ratio 1.30) and blood transfusion (odds ratio 1.72). Further adjustment for payer, multiple births, and select comorbidities had little effect. CONCLUSION: Rates of severe obstetric complications increased from 1998–1999 to 2004–2005. For many of these complications, these increases were associated with the increasing rate of cesarean delivery. (Obstet Gynecol 2009;113:293–9) LEVEL OF EVIDENCE: III

Objective: To assess the prevalence and causes of severe maternal morbidity in Dublin over a two year period from 2004 to 2005. Study design: A prospective cohort study from January 2004 to December 2005 was undertaken in the three large maternity hospitals in Dublin, which serve a population of 1.5 million people. All are tertiary referral centres for obstetrics and neonatology and have an annual combined delivery rate of circa 23,000 births. Cases of severe maternal morbidity were identified. A systems based classification was used. The primary cause of maternal morbidity and the number of events experienced per patient was recorded. Results: We identified 158 women who fulfilled the definition for severe maternal morbidity, giving a rate of 3.2 per 1000maternities. There were two maternal deaths during the time period givingmortality to morbidity ratio of 1:79. The commonest cause of severe morbidity was vascular dysfunction related to obstetric haemorrhage. Eclampsia comprised 15.4% of cases. Intensive care or coronary care admission occurred in 12% of cases. Conclusion: The prevalence of severe maternal morbidity in this population is 3.2/1000 maternities. Obstetric haemorrhage was the main cause of severe maternal morbidity.

Objective. To define the rate of severe maternal morbidity in different modes of delivery and to find out if the rate of severe morbidity has changed over a 5-year time span. Design. Retrospective register-based study. Setting. Finnish Medical Birth Registry and Hospital Discharge Registry. Population. All singleton deliveries in Finland in 1997 and 2002 (n
110,717). Methods. Diagnoses and operative interventions recorded in the Hospital Discharge Registry indicating a severe maternal complication were linked with Birth Register data and compared by mode of delivery: spontaneous vaginal delivery (VD), instrumental VD, elective cesarean section and non-elective cesarean section. Main outcome measures were severe maternal morbidity: deep venous thromboembolism and amniotic fluid embolism, major puerperal infection, severe hemorrhage, events requiring operative intervention after delivery, uterine rupture and inversion, and intestinal obstruction. Results. Severe maternal morbidity was more frequent in cesarean than vaginal deliveries (pB0.001), and more frequent in nonelective than in elective operations (pB0.001). The rate of severe maternal morbidity increased considerably from 1997 to 2002; from 5.9 to 7.6 per 1,000 in all deliveries (pB0.001), from 4.0 per 1,000 to 5.2 per 1,000 in spontaneous vaginal deliveries (p
0.005), from 9.9 per 1,000 to 12.1 per 1,000 in elective cesarean sections (CSs) (p
0.164), and from 19.6 per 1,000 to 27.2 per 1,000 in non-elective CSs (p
0.090), respectively. Conclusions. Severe maternal morbidity has increased both in cesarean and vaginal deliveries from 1997 to 2002. Cesarean delivery, even an elective one, carries a significantly higher risk of life-threatening maternal complications than VD.

Objective: To assess incidence, case fatality rate, risk factors and substandard care in severe maternal morbidity in the Netherlands. Design Prospective population-based cohort study. Setting: All 98 maternity units in the Netherlands. Population: All pregnant women in the Netherlands. Methods: Cases of severe maternal morbidity were collected during a 2-year period. All pregnant women in the Netherlands in the same period acted as reference cohort (n = 371 021). As immigrant women are disproportionately represented in Dutch maternal mortality statistics, special attention was paid to the ethnic background. In a subset of 2.5% of women, substandard care was assessed through clinical audit. Main outcome measures: Incidence, case fatality rates, possible risk factors and substandard care. Results: Severe maternal morbidity was reported in 2552 women, giving an overall incidence of 7.1 per 1000 deliveries. Intensive care unit admission was reported in 847 women (incidence 2.4 per 1000), uterine rupture in 218 women (incidence 6.1/10 000), eclampsia in 222 women (incidence 6.2/10 000) and major obstetric haemorrhage in 1606 women (incidence 4.5 per 1000). Non-Western immigrant women had a 1.3-fold increased risk of severe maternal morbidity (95% CI 1.2–1.5) when compared with Western women. Overall case fatality rate was 1 in 53. Substandard care was found in 39 of a subset of 63 women (62%) through clinical audit. Conclusions: Severe maternal morbidity complicates at least 0.71% of all pregnancies in the Netherlands, immigrant women experiencing an increased risk. Since substandard care was found in the majority of assessed cases, reduction of severe maternal morbidity seems a mandatory challenge.