Giulia M. Muraca

Factors Underlying the Temporal Increase in Maternal Mortality in the United States.

OBJECTIVE To identify the factors underlying the recent increase in maternal mortality ratios (maternal deaths per 100,000 live births) in the United States. METHODS We carried out a retrospective study with data on maternal deaths and live births in the United States from 1993 to 2014 obtained from the birth and death files of the Centers for Disease Control and Prevention. Underlying causes of death were examined between 1999 and 2014 using International Classification of Diseases, 10th Revision (ICD-10) codes. Poisson regression was used to estimate maternal mortality rate ratios (RRs) and 95% confidence intervals (CIs) after adjusting for the introduction of a separate pregnancy question and the standard pregnancy checkbox on death certificates and adoption of ICD-10. RESULTS Maternal mortality ratios increased from 7.55 in 1993, to 9.88 in 1999, and to 21.5 per 100,000 live births in 2014 (RR 2014 compared with 1993 2.84, 95% CI 2.49-3.24; RR 2014 compared with 1999 2.17, 95% CI 1.93-2.45). The increase in maternal deaths from 1999 to 2014 was mainly the result of increases in maternal deaths associated with two new ICD-10 codes (O26.8, ie, primarily renal disease; and O99, ie, other maternal diseases classifiable elsewhere); exclusion of such deaths abolished the increase in mortality (RR 1.09, 95% CI 0.94-1.27). Regression adjustment for improvements in surveillance also abolished the temporal increase in maternal mortality ratios (adjusted maternal mortality ratios 7.55 in 1993, 8.00 per 100,000 live births in 2013; adjusted RR 2013 compared with 1993 1.06, 95% CI 0.90-1.25). CONCLUSION Recent increases in maternal mortality ratios in the United States are likely an artifact of improvements in surveillance and highlight past underestimation of maternal death. Complete ascertainment of maternal death in populations remains a challenge even in countries with good systems for civil registration and vital statistics.

Perinatal and maternal morbidity and mortality among term singletons following midcavity operative vaginal delivery versus caesarean delivery

To quantify severe perinatal and maternal morbidity/mortality associated with midcavity operative vaginal delivery compared with caesarean delivery.

Association Between Prepregnancy Body Mass Index and Severe Maternal Morbidity

Importance Although high body mass index (BMI) is associated with adverse birth outcomes, the association with severe maternal morbidity is unclear. Objective To examine the association between prepregnancy BMI and severe maternal morbidity. Design, Setting, and Participants Retrospective population-based cohort study including all singleton hospital births in Washington State, 2004-2013. Demographic data and morbidity diagnoses were obtained from linked birth certificates and hospitalization files. Exposures Prepregnancy BMI (weight in kilograms divided by height in meters squared) categories included underweight (<18.5), normal BMI (18.5-24.9), overweight (25.0-29.9), obesity class 1 (30.0-34.9), obesity class 2 (35.0-39.9), and obesity class 3 (≥40). Main Outcomes and Measures Composite severe maternal morbidity or mortality included life-threatening conditions and conditions leading to serious sequelae (eg, amniotic fluid embolism, hysterectomy), complications requiring intensive care unit admission, and maternal death. Logistic regression was used to obtain adjusted odds ratios (ORs) and adjusted rate differences with 95% confidence intervals, adjusted for confounders (eg, maternal age and parity). Results Overall, 743 630 women were included in the study (mean age, 28.1 [SD, 6.0] years; 41.4% nulliparous). Prepregnancy BMI was distributed as follows: underweight, 3.2%; normal weight, 47.5%; overweight, 25.8%; obesity class 1, 13.1%; obesity class 2, 6.2%; and obesity class 3, 4.2%. Rates of severe maternal morbidity or mortality were 171.5, 143.2, 160.4, 167.9, 178.3 and 202.9 per 10 000 women, respectively. Adjusted ORs were 1.2 (95% CI, 1.0-1.3) for underweight women; 1.1 (95% CI, 1.1-1.2) for overweight women; 1.1 (95% CI, 1.1-1.2) for women with class 1 obesity; 1.2 (95% CI, 1.1-1.3) for women with class 2 obesity; and 1.4 (95% CI, 1.3-1.5) for women with class 3 obesity compared with women with normal BMI. Absolute risk increases (adjusted rate differences per 10 000 women, compared with women with normal BMI) were 28.8 (95% CI, 12.2-47.2) for underweight women, 17.6 (95% CI, 10.5-25.1) for overweight women, 24.9 (95% CI, 15.7-34.6) for women with class 1 obesity, 35.8 (95% CI, 23.1-49.5) for women with class 2 obesity, and 61.1 (95% CI, 44.8-78.9) for women with class 3 obesity. Conclusions and Relevance Among pregnant women in Washington State, low and high prepregnancy BMI, compared with normal BMI, were associated with a statistically significant but small absolute increase in severe maternal morbidity or mortality.

Perinatal and maternal morbidity and mortality after attempted operative vaginal delivery at midpelvic station

BACKGROUND: Increased use of operative vaginal delivery (i.e., forceps or vacuum application), of which 20% occurs at midpelvic station, has been advocated to reduce the rate of cesarean delivery. We aimed to quantify severe perinatal and maternal morbidity and mortality associated with attempted midpelvic operative vaginal delivery. METHODS: We studied all term singleton deliveries in Canada between 2003 and 2013, by attempted midpelvic operative vaginal or cesarean delivery with labour (with and without prolonged second stage). The primary outcomes were composite severe perinatal morbidity and mortality (e.g., convulsions, assisted ventilation, severe birth trauma and perinatal death), and composite severe maternal morbidity and mortality (e.g., severe postpartum hemorrhage, shock, sepsis, cardiac complications, acute renal failure and death). RESULTS: The study population included 187 234 deliveries. Among women with dystocia and prolonged second stage of labour, midpelvic operative vaginal delivery was associated with higher rates of severe perinatal morbidity and mortality compared with cesarean delivery (forceps, adjusted odds ratio [AOR] 1.81, 95% confidence interval [CI] 1.24 to 2.64; vacuum, AOR 1.81, 95% CI 1.17 to 2.80; sequential instruments, AOR 3.19, 95% CI 1.73 to 5.88), especially with higher rates of severe birth trauma. Rates of severe maternal morbidity and mortality were not significantly different after operative vaginal delivery, although rates of obstetric trauma were higher (forceps, AOR 4.51, 95% CI 4.04 to 5.02; vacuum, AOR 2.70, 95% CI 2.35 to 3.09; sequential instruments, AOR 4.24, 95% CI 3.46 to 5.19). Among women with fetal distress, similar associations were seen for severe birth trauma and obstetric trauma, although vacuum was associated with lower rates of severe maternal morbidity and mortality (AOR 0.52, 95% CI 0.33 to 0.80). Associations tended to be stronger among women without a prolonged second stage. INTERPRETATION: Midpelvic operative vaginal delivery is associated with higher rates of severe birth trauma and obstetric trauma, whereas overall rates of severe perinatal and maternal morbidity and mortality vary by indication and operative instrument.

The Association Between Maternal Age and Depression

OBJECTIVE Postpartum depression is a relatively common and potentially debilitating condition but its relationship with advanced maternal age has not been adequately studied. We evaluated the relationship between age and depression in a population-based sample of Canadian women. METHODS Data on women aged 20 to 44 years were obtained from the Canadian Community Health Survey, 2007 to 2008. Depression was defined using the Short-Form score from the Composite International Diagnostic Interview (depression defined as a score of ≥ 5). Women were stratified according to whether they had a live birth within five years preceding the interview. Logistic regression was used to compare the prevalence of depression among women of advanced maternal age versus younger women after adjusting for education, marital status, and chronic disease. RESULTS Among women who had delivered recently, 8.0% (207 of 2326) were depressed compared with 10% (597 of 5610) of women who had not recently delivered. The prevalence of depression in women who had recently delivered was significantly higher in women aged 40 to 44 years than in women aged 30 to 35 years (adjusted OR 3.72; 95% CI 2.15 to 6.41). Depression rates were not higher among older women who had not had a recent delivery (adjusted OR among women 40 to 44 years 0.75; 95% CI 0.56 to 1.01). CONCLUSION Women of advanced maternal age have significantly higher rates of depression than younger women. Research is required to determine if a program of targeted depression screening and prevention will help reduce the burden of illness among older mothers.

Mode of delivery after a previous cesarean birth, and associated maternal and neonatal morbidity

BACKGROUND: The mode of delivery for women with a previous cesarean delivery remains contentious. We conducted a study comparing maternal and infant outcomes after attempted vaginal birth after cesarean delivery versus elective repeat cesarean delivery. METHODS: We used data from the Discharge Abstract Database that includes all hospital deliveries in Canada (excluding Quebec). In our analysis, we included singleton deliveries to women between 37 and 43 weeks gestation who had a single prior cesarean delivery between April 2003 and March 2015. The primary outcomes were severe maternal morbidity and mortality, and serious neonatal morbidity and mortality. We used logistic regression to estimate adjusted rate ratios (RRs) and 95% confidence intervals (CIs). RESULTS: Absolute rates of severe maternal morbidity and mortality were low but significantly higher after attempted vaginal birth after cesarean delivery compared with elective repeat cesarean delivery (10.7 v. 5.65 per 1000 deliveries, respectively; adjusted RR 1.96, 95% CI 1.76 to 2.19). Adjusted rate differences in severe maternal morbidity and mortality, and serious neonatal morbidity and mortality were small (5.42 and 7.09 per 1000 deliveries, respectively; number needed to treat 184 and 141, respectively). The association between vaginal birth after cesarean delivery, and serious neonatal morbidity and mortality showed a temporal worsening (adjusted RR 0.94, 95% CI 0.77 to 1.15 in 2003–2005; adjusted RR 2.07, 95% CI 1.83 to 2.35 in 2012–2014). INTERPRETATION: Although absolute rates of adverse outcomes are low, attempted vaginal birth after cesarean delivery continues to be associated with higher relative rates of severe morbidity and mortality in mothers and infants. Temporal worsening of infant outcomes after attempted vaginal birth after cesarean delivery highlights the need for greater care in selecting candidates, and more careful monitoring of labour and delivery.

Ecological association between operative vaginal delivery and obstetric and birth trauma

BACKGROUND: Increased use of operative vaginal delivery (use of forceps, vacuum or other device) has been recommended to address high rates of cesarean delivery. We sought to determine the association between rates of operative vaginal delivery and obstetric trauma and severe birth trauma. METHODS: We carried out an ecological analysis of term, singleton deliveries in 4 Canadian provinces (2004–2014) using data from the Canadian Institute for Health Information. The primary exposure was mode of delivery. The primary outcomes were obstetric trauma and severe birth trauma. RESULTS: Data on 1 938 913 deliveries were analyzed. The rate of obstetric trauma was 7.2% in nulliparous women, and 2.2% and 2.7% among parous women without and with a previous cesarean delivery, respectively, and rates of severe birth trauma were 2.1, 1.7 and 0.7 per 1000, respectively. Each 1% absolute increase in rates of operative vaginal delivery was associated with a higher frequency of obstetric trauma among nulliparous women (adjusted rate ratio [ARR] 1.06, 95% confidence interval [CI] 1.05–1.06), parous women without a previous cesarean delivery (ARR 1.10, 95% CI 1.08–1.13) and parous women with a previous cesarean delivery (ARR 1.11, 95% CI 1.07–1.16). Operative vaginal delivery was associated with more frequent severe birth trauma, but only in nulliparous women (ARR 1.05, 95% CI 1.03–1.07). In nulliparous women, sequential vacuum and forceps instrumentation was associated with the largest increase in obstetric trauma (ARR 1.44, 95% CI 1.35–1.55) and birth trauma (ARR 1.53, 95% CI 1.03–2.27). INTERPRETATION: Increases in population rates of operative vaginal delivery are associated with higher population rates of obstetric trauma, and in nulliparous women with severe birth trauma.

Maternal age and severe maternal morbidity: A population-based retrospective cohort study

Background One of the United Nations’ Millennium Development Goals of 2000 was to reduce maternal mortality by 75% in 15 y; however, this challenge was not met by many industrialized countries. As average maternal age continues to rise in these countries, associated potentially life-threatening severe maternal morbidity has been understudied. Our primary objective was to examine the associations between maternal age and severe maternal morbidities. The secondary objective was to compare these associations with those for adverse fetal/infant outcomes. Methods and findings This was a population-based retrospective cohort study, including all singleton births to women residing in Washington State, US, 1 January 2003–31 December 2013 (n = 828,269). We compared age-specific rates of maternal mortality/severe morbidity (e.g., obstetric shock) and adverse fetal/infant outcomes (e.g., perinatal death). Logistic regression was used to adjust for parity, body mass index, assisted conception, and other potential confounders. We compared crude odds ratios (ORs) and adjusted ORs (AORs) and risk differences and their 95% CIs. Severe maternal morbidity was significantly higher among teenage mothers than among those 25–29 y (crude OR = 1.5, 95% CI 1.5–1.6) and increased exponentially with maternal age over 39 y, from OR = 1.2 (95% CI 1.2–1.3) among women aged 35–39 y to OR = 5.4 (95% CI 2.4–12.5) among women aged ≥50 y. The elevated risk of severe morbidity among teen mothers disappeared after adjustment for confounders, except for maternal sepsis (AOR = 1.2, 95% CI 1.1–1.4). Adjusted rates of severe morbidity remained increased among mothers ≥35 y, namely, the rates of amniotic fluid embolism (AOR = 8.0, 95% CI 2.7–23.7) and obstetric shock (AOR = 2.9, 95% CI 1.3–6.6) among mothers ≥40 y, and renal failure (AOR = 15.9, 95% CI 4.8–52.0), complications of obstetric interventions (AOR = 4.7, 95% CI 2.3–9.5), and intensive care unit (ICU) admission (AOR = 4.8, 95% CI 2.0–11.9) among those 45–49 y. The adjusted risk difference in severe maternal morbidity compared to mothers 25–29 y was 0.9% (95% CI 0.7%–1.2%) for mothers 40–44 y, 1.6% (95% CI 0.7%–2.8%) for mothers 45–49 y, and 6.4% for mothers ≥50 y (95% CI 1.7%–18.2%). Similar associations were observed for fetal and infant outcomes; neonatal mortality was elevated in teen mothers (AOR = 1.5, 95% CI 1.2–1.7), while mothers over 29 y had higher risk of stillbirth. The rate of severe maternal morbidity among women over 49 y was higher than the rate of mortality/serious morbidity of their offspring. Despite the large sample size, statistical power was insufficient to examine the association between maternal age and maternal death or very rare severe morbidities. Conclusions Maternal age-specific incidence of severe morbidity varied by outcome. Older women (≥40 y) had significantly elevated rates of some of the most severe, potentially life-threatening morbidities, including renal failure, shock, acute cardiac morbidity, serious complications of obstetric interventions, and ICU admission. These results should improve counselling to women who contemplate delaying childbirth until their forties and provide useful information to their health care providers. This information is also useful for preventive strategies to lower maternal mortality and severe maternal morbidity in developed countries.

Methodological Challenges in International Comparisons of Perinatal Mortality

Purpose of ReviewSeveral prestigious agencies routinely rank countries based on crude perinatal and infant mortality rates, while more recently, international neonatal networks have begun comparing neonatal mortality and morbidity rates among very preterm and very low-birth-weight infants. We discuss the methodologic challenges that compromise such comparisons and potential remedies.Recent FindingsCrude perinatal mortality rates are biased by international variations in birth registration, especially at the borderline of viability. Such bias is demonstrated by significant differences in crude versus birth weight- and gestational age-specific comparisons of perinatal mortality. Comparisons of neonatal mortality among very preterm and very low-birth-weight infants are plagued by incorrect denominators, and this leads to paradoxical findings.SummaryA lack of standardization with regard to birth registration and inadequate appreciation of the methods for calculating gestational age-specific mortality rates are responsible for biasing international comparisons of perinatal mortality.

Morbidity and Mortality Associated With Forceps and Vacuum Delivery at Outlet, Low, and Midpelvic Station

OBJECTIVE This study sought to quantify perinatal and maternal morbidity and mortality associated with forceps and vacuum delivery compared with Caesarean delivery in the second stage of labour and to estimate whether these associations differed by pelvic station. METHODS The investigators conducted a population-based, retrospective cohort study of term singleton deliveries by operative delivery with prolonged second stage of labour in Canada (2003-2013) using national hospitalization data. The primary study outcomes were severe perinatal morbidity and mortality (i.e., seizures, assisted ventilation, severe birth trauma, and perinatal death) and severe maternal morbidity and mortality (i.e., severe postpartum hemorrhage, cardiac complication, and maternal death). Logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) after stratifying by indication (dystocia or fetal distress). The Breslow-Day chi-square test for heterogeneity in ORs was used to test effect modification by pelvic station (outlet, low, or midpelvic). RESULTS There were 61 106 deliveries included in the study. Among women with dystocia, forceps and vacuum deliveries were associated with higher rates of perinatal morbidity and mortality compared with Caesarean delivery (forceps: aOR 1.56; 95% CI 1.13-2.17; vacuum: aOR 1.44; 95% CI 1.06-1.97). Vacuum delivery was associated with lower rates of maternal morbidity and mortality compared with Caesarean delivery (dystocia: aOR 0.64; 95% CI 0.51-0.81; fetal distress: aOR 0.43; 95% CI 0.32-0.57). Pelvic station did not significantly modify the associations between forceps or vacuum and perinatal or maternal morbidity and mortality. CONCLUSION Forceps and vacuum delivery is associated with increased rates of severe perinatal morbidity and mortality compared with Caesarean delivery among women with dystocia, whereas vacuum delivery is associated with decreased rates of severe maternal morbidity and mortality.