Yasser Sabr

Maternal morbidity associated with early-onset and late-onset preeclampsia.

OBJECTIVE: To examine temporal trends in early-onset compared with late-onset preeclampsia and associated severe maternal morbidity. METHODS: The study included all singleton deliveries in Washington State between 2000 and 2008 (N=670,120). Preeclampsia onset was determined using hospital records linked to birth certificates. Severe maternal morbidity was defined as any potentially life-threatening condition. Logistic regression was used to obtain adjusted odds ratios (aOR) and 95% confidence intervals (95% CI). RESULTS: The preeclampsia rate was 3.0 per 100 singleton births, and increased slightly from 2.9 to 3.1 between 2000 and 2008. Rates of early-onset and late-onset disease were 0.3% and 2.7%, respectively. The temporal increase was significant only for early-onset disease (4.5%/year; 95% CI 2.3–5.8%) after adjustment for changes in maternal characteristics. Maternal death rates were higher among women with early-onset (42.1/100,000 deliveries) and late-onset preeclampsia (11.2/100,000) compared with women without preeclampsia (4.2/100,000). The rate of severe maternal morbidity (excluding obstetric trauma) was 12.2 per 100 deliveries in the early-onset group (aOR 3.7, 95% CI 3.2–4.3), 5.5 per 100 deliveries in the late-onset group (aOR 1.7, 95% CI 1.6–1.9), and approximately 3 per 100 in women without preeclampsia. Early-onset preeclampsia conferred a substantially higher risk of cardiovascular, respiratory, central nervous system, renal, hepatic, and other morbidity. However, rates of obstetric trauma were significantly lower among women with preeclampsia. CONCLUSION: Women with early-onset and late-onset preeclampsia have significantly higher rates of specific maternal morbidity compared with women without early-onset and late-onset disease. LEVEL OF EVIDENCE: II

Failed individual and sequential instrumental vaginal delivery: contributing risk factors and maternal-neonatal complications.

Background.  To identify the risk factors for failed instrumental vaginal delivery, and to compare maternal and neonatal morbidity associated with failed individual and sequential instruments used.

International comparisons of preterm birth: higher rates of late preterm birth are associated with lower rates of stillbirth and neonatal death.

Please cite this paper as: Lisonkova S, Sabr Y, Butler B, Joseph K. International comparisons of preterm birth: higher rates of late preterm birth are associated with lower rates of stillbirth and neonatal death. BJOG 2012;119:1630–1639.

Immortal time bias in the study of stillbirth risk factors: the example of gestational diabetes.

Background: Current understanding of the increased risk for stillbirth in gestational diabetes mellitus is often based on large cohort studies in which the risk of stillbirth in women with this disease is compared with the risk in women without. However, such studies could be susceptible to immortal time bias because, although many cohorts begin at 20 weeks’ gestation, pregnancies must “survive” until 24–28 weeks in order to be screened and diagnosed with gestational diabetes. Methods: We describe the theoretical potential for immortal time bias in studies of stillbirth and gestational diabetes and then quantify the magnitude of the bias using 2006 United States vital statistics data. Results: Although gestational diabetes was protective against stillbirth when including all births (relative risk = 0.88 [95% confidence interval = 0.79–0.99]), restricting analyses to births at >28 weeks’ gestation reversed the effect and diabetes became associated with an increased risk of stillbirth (1.25 [1.11–1.41]). Conclusion: Immortal time before diagnosis of gestational diabetes may bias our understanding of the stillbirth risk associated with this condition.

Temporal trends in ankyloglossia and frenotomy in British Columbia, Canada, 2004-2013: a population-based study

BACKGROUND Routine surveillance of congenital anomalies has shown recent increases in ankyloglossia (tongue-tie) in British Columbia, Canada. We examined the temporal trends in ankyloglossia and its surgical treatment (frenotomy). METHODS We conducted a population-based cohort study involving all live births in British Columbia from Apr. 1, 2004, to Mar. 31, 2014, with data obtained from the provinces Perinatal Data Registry. Spatiotemporal trends in ankyloglossia and frenotomy, and associations with maternal and infant characteristics, were quantified using logistic regression analysis. RESULTS There were 459 445 live births and 3022 cases of ankyloglossia between 2004 and 2013. The population incidence of ankyloglossia increased by 70% (rate ratio 1.70, 95% confidence interval [CI] 1.44-2.01), from 5.0 per 1000 live births in 2004 to 8.4 per 1000 in 2013. During the same period, the population rate of frenotomy increased by 89% (95% CI 52%-134%), from 2.8 per 1000 live births in 2004 to 5.3 per 1000 in 2013. The 2 regional health authorities with the lowest population rates of frenotomy (1.5 and 1.8 per 1000 live births) had the lowest rates of ankyloglossia and the lowest rates of frenotomy among cases with ankyloglossia, whereas the 2 regional health authorities with the highest population rates of frenotomy (5.2 and 5.3 per 1000 live births) had high rates of ankyloglossia and the highest rates of frenotomy among cases of ankyloglossia. Nulliparity, multiple birth, male infant sex, birth weight and year were independently associated with ankyloglossia. INTERPRETATION Large temporal increases and substantial spatial variations in ankyloglossia and frenotomy rates were observed that may indicate a diagnostic suspicion bias and increasing use of a potentially unnecessary surgical procedure among infants.

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.

Diagnosis of subclinical amniotic fluid infection prior to rescue cerclage using gram stain and glucose tests: an individual patient meta-analysis.

OBJECTIVES Microbial invasion of the amniotic cavity (MIAC) can affect outcomes following rescue cerclage. We carried out a study to compare the diagnostic performance of the Gram stain and glucose tests for detecting subclinical MIAC. METHODS We used individual-level data from published studies on Gram stain, glucose, and amniotic fluid culture among women with preterm labour. We calculated the sensitivity, specificity, area under the curve (AUC) and other indices, with amniotic fluid culture results used as the gold standard. The probability of infection using both tests as predictors was also estimated using logistic regression. RESULTS The rate of culture-confirmed MIAC was 11.8% (34 of 288 women). The Gram stain test yielded a sensitivity of 65% (95% CI 46% to 78%) and a specificity of 99% (95% CI 98% to 100%). A positive Gram stain or glucose test had a sensitivity of 88% (95% CI 72% to 96%) and a specificity of 87% (95% CI 82% to 90%), while a positive Gram stain and a positive glucose test had a sensitivity of 62% (95% CI 44% to 77%) and a specificity of 100% (95% CI 98% to 100%). The AUC for the tests were Gram stain 0.82 (95% CI 0.74 to 0.90), glucose 0.86 (95% CI 0.80 to 0.93), and combined Gram stain and glucose 0.92 (95% CI 0.86 to 0.98). Using the tests, singly or in combination, provided greater clinically important calibration, risk-stratification, and classification accuracy than using no tests. CONCLUSION Amniotic fluid Gram stain and/or glucose testing provides substantially improved performance for the diagnosis of subclinical MIAC compared with no testing.

Random urine albumin:creatinine ratio in high-risk pregnancy - Is it clinically useful?

We evaluated the frequency of measurable albuminuria (⩾6.00mg/L) for albumin:creatinine ratios (ACr) among 160 consecutive women attending high-risk clinics. Of last urine samples before delivery, 76 had measurable albuminuria and 41/76 (53.9%) had ACr ⩾2mg/mmol of which 7.3% had normal pregnancy outcome. 84 samples had albuminuria <6.00mg/L and 43/84 (51.2%) had ACr ⩾2mg/mmol of which 25.6% had normal pregnancy outcome (p=0.025). Excluding 48/160 (30.0%) dilute samples (urinary creatinine <3mM), no samples with unmeasurable albuminuria had ACr ⩾2mg/mmol. In pregnancy, urine is often dilute and without measurable albuminuria, leading to a clinically relevant proportion of false positive results by ACr.

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.