The rate of preterm birth in the United States is affected by the method of gestational age assignment

OBJECTIVE

The objective of the study was to examine the rate of preterm birth in the United States using 2 different methods of gestational age assignment and determine which method more closely correlates with the known morbidities associated with preterm birth.

STUDY DESIGN

Using National Center for Health Statistics data from 2012 United States birth certificates, we computed the rate of preterm birth defined as a birth at 36 or fewer completed weeks with gestational age assigned using the obstetric estimate as specified in the revised birth certificate. This rate was then compared with the rate when gestational age is calculated using the last menstrual period alone. The rates of neonatal morbidities associated with preterm birth were examined for each method of assigning gestational age.

RESULTS

The rate of preterm birth was 9.7% when the obstetric estimate is used to calculate gestational age, which is significantly different from the rate of 11.5% when gestational age is calculated using the last menstrual period alone. In addition, the neonates identified as preterm by obstetric estimate were more likely to qualify as low birthweight (54% vs 42%; P < .001) and suffer morbidities such as need for assisted ventilation and surfactant use than those identified with the last menstrual period alone. That is to say obstetric estimate is more sensitive and specific for preterm birth by all available markers of prematurity.

CONCLUSION

The preterm birth rate is 9.7% vs 11.5% and more closely correlates with adverse neonatal outcomes associated with preterm birth when gestational age is assigned using the obstetric estimate. This method of gestational age assignment is currently used by most industrialized nations and should be considered for future reporting of US outcomes.

Active Warming during Cesarean Delivery: Should We SCIP It?

BACKGROUND

The purpose of this open, cluster randomized controlled trial was to evaluate whether use of a fiber optic-regulated warming mattress would decrease the incidence of hypothermia in women undergoing cesarean delivery.

PATIENTS AND METHODS

A total of 484 women were randomized via the cluster method on a rotating weekly basis allocating participants to either use of the warming mattress or the standard method of warming at Parkland Hospital (heat-retaining caps, warmed intravenous and irrigation fluids, and warmed blankets). The primary outcome of interest was maternal hypothermia. Surgical site infections and neonatal outcomes were also assessed.

RESULTS

The incidence of maternal hypothermia at the conclusion of the surgery was decreased in the warming mattress group, 67 versus 80% in the standard method group (p = 0.013). There were no significant differences in maternal hypothermia at delivery or on arrival to the postanesthesia care unit. The difference in surgical site infections and neonatal outcomes were nonsignificant.

CONCLUSION

Use of a warming mattress reduced the incidence of maternal hypothermia at the conclusion of surgery; however, on admission to the postanesthesia care unit, these effects had dissipated.

Does the presence of a condition-specific obstetric protocol lead to detectable improvements in pregnancy outcomes?

OBJECTIVE

We sought to evaluate whether the presence of condition-specific obstetric protocols within a hospital was associated with better maternal and neonatal outcomes.

STUDY DESIGN

This was a cohort study of a random sample of deliveries performed at 25 hospitals over 3 years. Condition-specific protocols were collected from all hospitals and categorized independently by 2 authors. Data on maternal and neonatal outcomes, as well as data necessary for risk adjustment were collected. Risk-adjusted outcomes were compared according to whether the patient delivered in a hospital with condition-specific obstetric protocols at the time of delivery.

RESULTS

Hemorrhage-specific protocols were not associated with a lower rate of postpartum hemorrhage or with fewer cases of estimated blood loss >1000 mL. Similarly, in the presence of a shoulder dystocia protocol, there were no differences in the frequency of shoulder dystocia or number of shoulder dystocia maneuvers used. Conversely, preeclampsia-specific protocols were associated with fewer intensive care unit admissions (odds ratio, 0.28; 95% confidence interval, 0.18-0.44) and fewer cases of severe maternal hypertension (odds ratio, 0.86; 95% confidence interval, 0.77-0.96).

CONCLUSION

The presence of condition-specific obstetric protocols was not consistently shown to be associated with improved risk-adjusted outcomes. Our study would suggest that the presence or absence of a protocol does not matter and regulations to require protocols are not fruitful.

Racial and ethnic disparities in maternal morbidity and obstetric care

OBJECTIVE

To evaluate whether racial and ethnic disparities exist in obstetric care and adverse outcomes.

METHODS

We analyzed data from a cohort of women who delivered at 25 hospitals across the United States over a 3-year period. Race and ethnicity was categorized as non-Hispanic white, non-Hispanic black, Hispanic, or Asian. Associations between race and ethnicity and severe postpartum hemorrhage, peripartum infection, and severe perineal laceration at spontaneous vaginal delivery as well as between race and ethnicity and obstetric care (eg, episiotomy) relevant to the adverse outcomes were estimated by univariable analysis and multivariable logistic regression.

RESULTS

Of 115,502 studied women, 95% were classified by one of the race and ethnicity categories. Non-Hispanic white women were significantly less likely to experience severe postpartum hemorrhage (1.6% non-Hispanic white compared with 3.0% non-Hispanic black compared with 3.1% Hispanic compared with 2.2% Asian) and peripartum infection (4.1% non-Hispanic white compared with 4.9% non-Hispanic black compared with 6.4% Hispanic compared with 6.2% Asian) than others (P<.001 for both). Severe perineal laceration at spontaneous vaginal delivery was significantly more likely in Asian women (2.5% non-Hispanic white compared with 1.2% non-Hispanic black compared with 1.5% Hispanic compared with 5.5% Asian; P<.001). These disparities persisted in multivariable analysis. Many types of obstetric care examined also were significantly different according to race and ethnicity in both univariable and multivariable analysis. There were no significant interactions between race and ethnicity and hospital of delivery.

CONCLUSION

Racial and ethnic disparities exist for multiple adverse obstetric outcomes and types of obstetric care and do not appear to be explained by differences in patient characteristics or by delivery hospital.

LEVEL OF EVIDENCE

II.

Relation between birth weight and weight and height at the age of 2 in children born preterm

OBJECTIVE

The aim of the study was to evaluate associations between fetal growth and weight at 2 years in infants born preterm using a customized approach for birth weight.

STUDY DESIGN

This is a secondary analysis of a multicenter trial that included a 2-year follow-up of children born prematurely. Customized birth weight percentiles were calculated using the Gardosi model for a U.S. population, and the relation between customized percentile and weight and height at 2 years (adjusted for gender using z-score) was determined using regression analysis and by comparing z-scores for children with birth weight <10th versus ≥10th percentile.

RESULTS

Weight z-score at 2 years was significantly lower in the <10th than in the ≥10th percentile group (median [interquartile range, IQR]: -0.66 [-1.58, -0.01] vs. -0.23 [-1.05, 0.55]; p < 0.001), and remained after adjusting for maternal education (p < 0.001). A similar relationship was noted for height z-score between groups (median [IQR]: -0.56 [-1.29, 0.19] vs. -0.24 [-0.99, 0.37]; p < 0.001). Positive relationships between customized birth weight percentile and weight and height at 2 years were noted (p < 0.001 for both), but were not strong (R (2) = 0.04 and 0.02, respectively).

CONCLUSION

Customized birth weight percentile is a minor determinant of weight at 2 years among children born preterm.

Effect of magnesium sulfate administration for neuroprotection on latency in women with preterm premature rupture of membranes

OBJECTIVE

This study aims to evaluate whether magnesium sulfate administration for neuroprotection prolongs latency in women with preterm premature rupture of membranes (PPROM) between 24 and 31(6/7) weeks' gestation.

STUDY DESIGN

This is a secondary analysis of a randomized controlled trial of magnesium sulfate for prevention of cerebral palsy. Gravid women with a singleton pregnancy between 24 and 31(6/7) weeks' gestation with PPROM without evidence of labor were randomized to receive magnesium sulfate, administered intravenously as a 6-g bolus followed by a constant infusion of 2 g per hour up to 12 hours, or placebo. Maternal outcomes for this analysis were delivery in less than 48 hours and in less than 7 days from randomization. Neonatal outcomes included a composite of respiratory distress syndrome, interventricular hemorrhage grades 3 or 4, periventricular leukomalacia, sepsis, necrotizing enterocolitis, retinopathy of prematurity, or death.

RESULTS

A total of 1,259 women were included. The rate of delivery < 48 hours was not different in the magnesium sulfate and the placebo groups (22.2 and 20.7%, p = 0.51). Delivery < 7 days was similar between groups (55.4 and 51.4%, p = 0.16). Median latency was also similar between groups (median [interquartile range], 6.0 days [range, 2.4-13.8 days] and 6.6 days [range, 2.4-15.1 days], p = 0.29). Composite neonatal outcomes did not differ between groups.

CONCLUSION

Magnesium sulfate administration given for neuroprotection in women with a singleton gestation with PPROM and without labor before 32 weeks does not impact latency.

Morbidly adherent placenta treatments and outcomes

OBJECTIVE

To describe recent maternal and neonatal delivery outcomes among women with a morbidly adherent placenta in major centers across the United States.

METHODS

This study reviewed a cohort of 115,502 women and their neonates born in 25 hospitals in the United States between March 2008 and February 2011 from the Assessment of Perinatal EXcellence data set. All cases of morbidly adherent placenta were identified. Maternal demographics, procedures undertaken, and maternal and neonatal outcomes were analyzed.

RESULTS

There were 158 women with a morbidly adherent placenta (1/731 births, 95% confidence interval 1/632-866). Eighteen percent of women with a morbidly adherent placenta were nulliparous and 37% had no prior cesarean delivery. Only 53% (84/158) were suspected to have a morbidly adherent placenta before delivery. Women with a prenatally suspected morbidly adherent placenta experienced large blood loss (33%), hysterectomy (92%), and intensive care unit admission (39%) compared with 19%, 45%, and 22%, respectively, in those not suspected prenatally to have a morbidly adherent placenta (P<.05 for all).

CONCLUSION

Eighteen percent of women with a morbidly adherent placenta were nulliparous. Half of the morbidly adherent placenta cases were suspected before delivery and outcomes were poorer in this group, probably because the more clinically significant morbidly adherent placentas are more likely to be suspected before delivery.

LEVEL OF EVIDENCE

: II.

The association of cord serum cytokines with neurodevelopmental outcomes

OBJECTIVE

To test whether elevated umbilical cord serum inflammatory cytokine levels predicted subsequent cerebral palsy (CP) or neurodevelopmental delay (NDD).

STUDY DESIGN

Nested case-control analysis within a clinical trial of antenatal magnesium sulfate (MgSO4) before anticipated preterm birth (PTB) for prevention of CP, with evaluation of surviving children at the age of 2. NDD was defined as a Bayley psychomotor developmental index (PDI) and/or mental developmental index (MDI) < 70. Controls, defined as surviving children without CP and with Bayley PDI and MDI ≥ 85, were matched by race and gestational age. Cord serum was analyzed for interleukin-8 (IL-8) interleukin-1 beta (IL-1β), and tumor necrosis factor-α (TNF-α) levels. Elevated cytokine levels were defined as ≥ 75th percentile in placebo-exposed controls. Analyses compared case/control cytokine levels, adjusting for MgSO4 exposure, gestational age, race/ethnicity, and sociodemographic differences.

RESULTS

Logistic regression analysis with 339 cases and 276 controls showed that elevated IL-8 and IL-1β were more common in cord blood serum from infants with subsequent low MDI as compared with controls. After adjusting for additional confounders, the significant differences were no longer evident. Cytokine levels (IL-8, IL-1β, and TNF-α) were not elevated with CP or low PDI.

CONCLUSION

Cord serum IL-8, IL-1β, and TNF-α levels in preterm infants are not associated with subsequent CP or NDD.

Nonmedically indicated induction vs expectant treatment in term nulliparous women

OBJECTIVE

The purpose of this study was to compare maternal and neonatal outcomes in nulliparous women with nonmedically indicated inductions at term vs those expectantly treated.

STUDY DESIGN

Data were obtained from maternal and neonatal charts for all deliveries on randomly selected days across 25 US hospitals over a 3-year period. A low-risk subset of nulliparous women with vertex nonanomalous singleton gestations who delivered 38 0/7 to 41 6/7 weeks were selected. Maternal and neonatal outcomes for nonmedically indicated induction within each week were compared with women who did not undergo nonmedically indicated induction during that week. Multivariable analysis was used to adjust for hospital, maternal age, race/ethnicity, body mass index, cigarette use, and insurance status.

RESULTS

We found 31,169 women who met our criteria. Neonatal complications were either less frequent with nonmedically indicated induction or no different between groups. Nonmedically indicated induction was associated with less frequent peripartum infections (odds ratio [OR], 0.39; 95% confidence interval [CI], 0.16-0.98) at 38 weeks of gestation and less frequent third- and fourth-degree lacerations (OR, 0.60; 95% CI, 0.42-0.86) and less frequent peripartum infections (OR, 0.66; 95% CI, 0.49-0.90) at 39 weeks of gestation. Nonmedically indicated induction was associated with a longer admission-to-delivery time by approximately 3-4 hours and increased odds of cesarean delivery at 38 (OR, 1.50; 95% CI, 1.08-2.08) and 40 weeks (OR, 1.30; 95% CI, 1.15-1.46) of gestation.

CONCLUSION

At 39 weeks of gestation, nonmedically indicated induction is associated with lower maternal and neonatal morbidity than women who are expectantly treated.

Prenatal vitamin C and E supplementation in smokers is associated with reduced placental abruption and preterm birth: a secondary analysis

OBJECTIVE

Smoking and pre-eclampsia (PE) are associated with increases in preterm birth, placental abruption and low birthweight. We evaluated the relationship between prenatal vitamin C and E (C/E) supplementation and perinatal outcomes by maternal self-reported smoking status focusing on outcomes known to be impacted by maternal smoking.

DESIGN/SETTING/POPULATION

A secondary analysis of a multi-centre trial of vitamin C/E supplementation starting at 9-16 weeks in low-risk nulliparous women with singleton gestations.

METHODS

We examined the effect of vitamin C/E by smoking status at randomisation using the Breslow-Day test for interaction.

MAIN OUTCOME MEASURES

The trial's primary outcomes were PE and a composite outcome of pregnancy-associated hypertension (PAH) with serious adverse outcomes. Perinatal outcomes included preterm birth and abruption.

RESULTS

There were no differences in baseline characteristics within subgroups (smokers versus nonsmokers) by vitamin supplementation status. The effect of prenatal vitamin C/E on the risk of PE (P = 0.66) or PAH composite outcome (P = 0.86) did not differ by smoking status. Vitamin C/E was protective for placental abruption in smokers (relative risk [RR] 0.09; 95% CI 0.00-0.87], but not in nonsmokers (RR 0.92; 95% CI 0.52-1.62) (P = 0.01), and for preterm birth in smokers (RR 0.76; 95% CI 0.58-0.99) but not in nonsmokers (RR 1.03; 95% CI 0.90-1.17) (P = 0.046).

CONCLUSION

In this cohort of women, smoking was not associated with a reduction in PE or the composite outcome of PAH. Vitamin C/E supplementation appears to be associated with a reduction in placental abruption and preterm birth among smokers.

Is preeclampsia associated with fetal malformation? A review and report of original research

OBJECTIVE

To examine fetal malformations in mother-infant pairs with and without pregnancy-related hypertension.

METHODS

This was an observational, population-based study of women delivering a singleton at our hospital. Specific fetal malformations identified in women with gestational hypertension or preeclampsia were compared to those without pregnancy-related hypertension. Women with chronic hypertension, superimposed preeclampsia on chronic hypertension and pregestational diabetes were excluded.

RESULTS

Between March 2002 and December 2012, a total of 151 997 women delivered, and 10 492 (7%) had preeclampsia, 4282 (3%) had gestational hypertension and 137,223 (90%) were referent normotensive controls. Women with preeclampsia were significantly more likely to deliver infants with malformations when compared to normotensive controls (2.5% versus 1.6%, p < 0.001), whereas women with gestational hypertension were not (1.9% versus 1.6%, p = 0.16). The overall risk for fetal malformation associated with preeclampsia remained significant following logistic regression for age, race, parity and maternal body-habitus (adjusted OR 1.5; 95% CI: 1.3-1.7). Only single-organ system malformations - microcephaly and hypospadias - remained associated with preeclampsia (p < 0.001), and fetal growth restriction was a co-factor for both.

CONCLUSIONS

Preeclampsia was associated with increased rates of fetal malformations when compared to normotensive women - specifically microcephaly and hypospadias. These associations appear predominantly as a consequence of impaired fetal growth.

Laboratory abnormalities in pregnancy-associated hypertension: frequency and association with pregnancy outcomes

OBJECTIVE

To estimate the frequency of abnormal laboratory test results in pregnancy-associated hypertension and the relationship with pregnancy outcomes.

METHODS

This was a secondary analysis of a multicenter trial of vitamin C and E for prevention of pregnancy-associated hypertension in low-risk nulliparous women. Laboratory abnormalities included: platelets less than 100,000/mm, aspartate aminotransferase 100 units/L or greater, creatinine 1.5 mg/dL or greater, lactate dehydrogenase 600 units/L or greater, total bilirubin 1.2 mg/dL or greater, or evidence of hemolysis on peripheral smear. Mild pregnancy-associated hypertension was defined as blood pressure 140-159/90-109 mm Hg. Severe pregnancy-associated hypertension was defined as persistent blood pressure 160/110 mm Hg or greater, acute antihypertensive treatment, or any blood pressure elevation associated with clinical signs of end-organ dysfunction (one or more of headache, epigastric pain, blurred vision, pulmonary edema, eclampsia, or oliguria). Pregnancy outcomes were compared across four groups: I, mild hypertension alone; II, mild hypertension+abnormal laboratory values; III, severe pregnancy-associated hypertension alone; and IV, severe pregnancy-associated hypertension+abnormal laboratory values.

RESULTS

Of 9,969 women, 2,752 (27.9%) developed pregnancy-associated hypertension and of these, laboratory abnormalities occurred in 7.3%. Laboratory abnormalities increased with severity of hypertension: mild hypertension alone (4.9%), severe hypertension alone (8.9%), and mild or severe hypertension with clinical signs of end-organ dysfunction (12.2%) (P for trend<.001). Compared with women with mild hypertension alone, the adjusted odds for the perinatal composite (2-fold to 4.8-fold in Category III-IV), preterm birth (2.1-fold to 7.8-fold in Category II-IV), and other adverse perinatal outcomes increase with disease severity, particularly with laboratory abnormalities and severe clinical signs.

CONCLUSION

The frequency of abnormal laboratory values in women with pregnancy-associated hypertension increases with disease severity. Adverse perinatal outcomes increase in the presence of abnormal laboratory values, particularly in those with clinical signs, likely atttributable in part to the decision to deliver early.

Adverse pregnancy outcomes among women with prior spontaneous or induced abortions

OBJECTIVE

The aim of the article is to determine whether prior spontaneous abortion (SAB) or induced abortion (IAB), or the interpregnancy interval are associated with subsequent adverse pregnancy outcomes in nulliparous women.

METHODS

We performed a secondary analysis of data collected from nulliparous women enrolled in a completed trial of vitamins C and E or placebo for preeclampsia prevention. Adjusted odds ratios (ORs) for maternal and fetal outcomes were determined for nulliparous women with prior SABs and IABs as compared with primigravid participants.

RESULTS

Compared with primigravidas, women with one prior SAB were at increased risk for perinatal death (adj. OR, 1.5; 95% CI, 1.1-2.3) in subsequent pregnancies. Two or more SABs were associated with an increased risk for spontaneous preterm birth (PTB) (adj. OR, 2.6, 95% CI, 1.7-4.0), preterm premature rupture of membranes (PROM) (adj. OR, 2.9; 95% CI, 1.6-5.3), and perinatal death (adj. OR, 2.8; 95% CI, 1.5-5.3). Women with one previous IAB had higher rates of spontaneous PTB (adj. OR, 1.4; 95% CI, 1.0-1.9) and preterm PROM (OR, 2.0; 95% CI, 1.4-3.0). An interpregnancy interval less than 6 months after SAB was not associated with adverse outcomes.

CONCLUSION

Nulliparous women with a history of SAB or IAB, especially multiple SABs, are at increased risk for adverse pregnancy outcomes.

Umbilical cord serum interleukin-6, C-reactive protein, and myeloperoxidase concentrations at birth and association with neonatal morbidities and long-term neurodevelopmental outcomes

OBJECTIVE

The aim of the study is to determine if umbilical cord serum concentrations of interleukin-6 (IL-6), C-reactive protein (CRP), and myeloperoxidase (MPO), in pregnancies at risk for preterm birth (PTB), are associated with neonatal morbidities and/or altered neurodevelopmental outcomes in the children.

STUDY DESIGN

Umbilical cord serum samples were collected at birth from 400 newborns delivered within a multicenter randomized controlled trial of repeated versus single course of antenatal corticosteroids (ACs), in women at increased risk for PTB. Newborns were followed through discharge and were evaluated between 36 and 42 months corrected age with neurological examination and Bayley Scales of Infant Development. Umbilical cord serum concentrations of IL-6, CRP, and MPO were determined using enzyme-linked immunoassays. Multivariate logistic regression analyses explored the relationship between umbilical cord serum IL-6, CRP, and MPO levels, adverse newborn outcomes, and PTB < 32 weeks of gestational age (GA).

RESULTS

Univariate analysis revealed that umbilical cord IL-6 above the 75th percentile was associated with increased respiratory distress syndrome (RDS) and chronic lung disease (CLD), but not with necrotizing enterocolitis (NEC), intraventricular hemorrhage (IVH), or neonatal sepsis; however, this association was not significant after adjusting for GA at delivery and treatment group. No significant associations between CRP or MPO and RDS, CLD, NEC, sepsis, or IVH were evident. Regression analysis revealed that CRP above the 75th percentile was associated with a decreased risk of CLD (odds ratio, 0.10; 95% confidence interval, 0.02-0.41). No associations between umbilical cord IL-6, CRP, or MPO and MDI < 70 or PDI < 70 were evident. Umbilical cord serum concentrations of IL-6, CRP, and MPO, above the 75th percentile, were associated with more frequent PTB < 32 weeks of GA.

CONCLUSION

Elevated umbilical cord serum concentration of CRP is associated with reduced risk for CLD even after adjusting for GA at delivery. Occurrence of levels > 75th percentile of IL-6, CRP, and MPO in umbilical cord serum was associated with PTB < 32 weeks of GA. Elevated umbilical cord serum concentrations of IL-6, CRP, and MPO at birth were not associated with poor neurodevelopmental outcomes.

Obstetric antecedents to body-cooling treatment of the newborn infant

OBJECTIVE

Obstetric antecedents were analyzed in births in which the infant received whole-body cooling for neonatal encephalopathy.

STUDY DESIGN

This retrospective cohort study included all live-born singleton infants delivered at or beyond 36 weeks' gestation from October 2005 through December 2011. Infants who had received whole-body cooling identified by review of a prospective neonatal registry were compared with a control group comprising the remaining obstetric population delivered at greater than 36 weeks but not cooled. Univariable analysis was followed up by a staged, stepwise selection of variables with the intent to rank significant risk factors for cooling.

RESULTS

A total of 86,371 women delivered during the study period and 98 infants received whole-body cooling (1.1 per 1000 live births). Of these 98 infants, 80 newborns (88%) had moderate encephalopathy and 10 (12%) had severe encephalopathy prior to cooling. Maternal age of 15 years or younger, low parity, maternal body habitus (body mass index of ≥40 kg/m(2)), diabetes, preeclampsia, induction, epidural analgesia, chorioamnionitis, length of labor, and mode of delivery were associated with significantly increased risk of infant cooling during a univariable analysis. Catastrophic events to include umbilical cord prolapse (odds ratio [OR], 14; 95% confidence interval [CI], 3-72), placental abruption (OR, 17; 95% CI, 7-44), uterine rupture (OR, 130; 95% CI, 11-1477) were the strongest factors associated with infant cooling after staged-stepwise logistic analysis.

CONCLUSION

A variety of intrapartum characteristics were associated with infant cooling for neonatal encephalopathy, with the most powerful antecedents being umbilical cord prolapse, placental abruption, and uterine rupture.

Can differences in obstetric outcomes be explained by differences in the care provided? The MFMU Network APEX study

OBJECTIVE

The purpose of this study was to determine whether hospital differences in the frequency of adverse obstetric outcomes are related to differences in care.

STUDY DESIGN

The Assessment of Perinatal EXcellence cohort comprises 115,502 women and their neonates who were born in 25 hospitals in the United States between March 2008 and February 2011. Hierarchical logistic regression was used to quantify the amount of variation in postpartum hemorrhage, peripartum infection, severe perineal laceration, and a composite adverse neonatal outcome among hospitals that is explained by differences in patient characteristics, hospital characteristics, and obstetric care provided.

RESULTS

The study included 115,502 women. For most outcomes, 20-40% of hospital differences in outcomes were related to differences in patient populations. After adjusting for patient-, provider-, and hospital-level factors, multiple care processes were associated with the predefined adverse outcomes; however, these care processes did not explain significant variation in the frequency of adverse outcomes among hospitals. Ultimately, 50-100% of the interhospital variation in outcomes was unexplained.

CONCLUSION

Hospital differences in the frequency of adverse obstetric outcomes could not be explained by differences in frequency of types of care provided.

Association of cord blood digitalis-like factor and necrotizing enterocolitis

OBJECTIVE

Endogenous digoxin-like factor (EDLF) has been linked to vasoconstriction, altered membrane transport, and apoptosis. Our objective was to determine whether increased EDLF in the cord sera of preterm infants was associated with an increased incidence of necrotizing enterocolitis (NEC).

STUDY DESIGN

Cord sera from pregnant women enrolled in a randomized trial of MgSO4 for fetal neuroprotection were analyzed for EDLF using a red cell Rb(+) uptake assay in which the inhibition of sodium pump-mediated Rb(+) transport was used as a functional assay of EDLF. Specimens were assayed blinded to neonatal outcome. Cases (NEC, n = 25) and controls (neonates not developing stage 2 or 3 NEC, n = 24) were matched by study center and gestational age. None of the women had preeclampsia. Cases and controls were compared using the Wilcoxon test for continuous and the Fisher exact test for categorical variables. A conditional logistic regression analysis was used to assess the odds of case vs control by EDLF level.

RESULTS

Cases and controls were not significantly different for gestational age, race, maternal steroid use, premature rupture of membranes, or MgSO4 treatment. In logistic models adjusted for treatment group, race, premature rupture of membranes, and gestational age, cord sera EDLF was significantly associated with development of NEC (P = .023).

CONCLUSION

These data demonstrated an association between cord sera EDLF and NEC.

Frequency of and factors associated with severe maternal morbidity

OBJECTIVE

To estimate the frequency of severe maternal morbidity, assess its underlying etiologies, and develop a scoring system to predict its occurrence.Supplemental Digital Content is Available in the Text.

METHODS

This was a secondary analysis of a Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network cohort of 115,502 women and their neonates born in 25 hospitals across the United States over a 3-year period. Women were classified as having severe maternal morbidity according to a scoring system that takes into account the occurrence of red blood cell transfusion (more than three units), intubation, unanticipated surgical intervention, organ failure, and intensive care unit admission. The frequency of severe maternal morbidity was calculated and the underlying etiologies determined. Multivariable analysis identified patient factors present on admission that were independently associated with severe maternal morbidity; these were used to develop a prediction model for severe maternal morbidity.

RESULTS

Among 115,502 women who delivered during the study period, 332 (2.9/1,000 births, 95% confidence interval 2.6-3.2) experienced severe maternal morbidity. Postpartum hemorrhage was responsible for approximately half of severe maternal morbidity. Multiple patient factors were found to be independently associated with severe maternal morbidity and were used to develop a predictive model with an area under the receiver operating characteristic curve of 0.80.

CONCLUSION

Severe maternal morbidity occurs in approximately 2.9 per 1,000 births, is most commonly the result of postpartum hemorrhage, and occurs more commonly in association with several identifiable patient characteristics.

LEVEL OF EVIDENCE

: II.

Placental pathology suggesting that preeclampsia is more than one disease

OBJECTIVE

Our purpose was to evaluate the placental pathology in women with preeclampsia occurring at varying gestational ages.

STUDY DESIGN

This was a secondary analysis of a prospective observational study of placentas from prespecified complicated pregnancies routinely submitted for standardized examination. For this study, a database of placental diagnoses from liveborn singleton gestations without major malformations was linked to a computerized obstetric database. The rates of standardized placental findings including vascular (atherosis, infarction) and nonvascular (hyperplasia) changes were evaluated according to gestational age at diagnosis of preeclampsia.

RESULTS

Between Jan. 1, 2001, and Sept. 30, 2007, a total of 7122 women with pregnancies complicated by preeclampsia were delivered at our hospital. Of these, 1210 (17%) had placental examinations. Within this cohort, 209, 355, and 646 women were diagnosed with preeclampsia at gestations of 24(0/67) to 33(6/7), 34(0/7) to 36(6/7), and 37(0/7) weeks or longer, respectively. Placental findings revealed hypoplasia was significantly associated with preeclampsia early in the third trimester, and histological evidence of placental vascular lesions was significantly increased at gestations of 24(0/67) to 33(6/7) weeks (53%) compared with 34% and 26% at 34(0/7) to 36(6/7) and 37 weeks or longer, respectively (P < .001).

CONCLUSION

The placentas of women with preeclampsia onset before 34 weeks' gestation were significantly different from those with preeclampsia at term. The former group demonstrated placental findings predominantly consistent with insufficiency because of vascular abnormalities. Such differing placental findings support the hypothesis that preeclampsia is a different disease, depending on the gestational age at diagnosis.

Risk-adjusted models for adverse obstetric outcomes and variation in risk-adjusted outcomes across hospitals

OBJECTIVE

Regulatory bodies and insurers evaluate hospital quality using obstetrical outcomes, however meaningful comparisons should take preexisting patient characteristics into account. Furthermore, if risk-adjusted outcomes are consistent within a hospital, fewer measures and resources would be needed to assess obstetrical quality. Our objective was to establish risk-adjusted models for 5 obstetric outcomes and assess hospital performance across these outcomes.

STUDY DESIGN

We studied a cohort of 115,502 women and their neonates born in 25 hospitals in the United States from March 2008 through February 2011. Hospitals were ranked according to their unadjusted and risk-adjusted frequency of venous thromboembolism, postpartum hemorrhage, peripartum infection, severe perineal laceration, and a composite neonatal adverse outcome. Correlations between hospital risk-adjusted outcome frequencies were assessed.

RESULTS

Venous thromboembolism occurred too infrequently (0.03%; 95% confidence interval [CI], 0.02-0.04%) for meaningful assessment. Other outcomes occurred frequently enough for assessment (postpartum hemorrhage, 2.29%; 95% CI, 2.20-2.38, peripartum infection, 5.06%; 95% CI, 4.93-5.19, severe perineal laceration at spontaneous vaginal delivery, 2.16%; 95% CI, 2.06-2.27, neonatal composite, 2.73%; 95% CI, 2.63-2.84). Although there was high concordance between unadjusted and adjusted hospital rankings, several individual hospitals had an adjusted rank that was substantially different (as much as 12 rank tiers) than their unadjusted rank. None of the correlations between hospital-adjusted outcome frequencies was significant. For example, the hospital with the lowest adjusted frequency of peripartum infection had the highest adjusted frequency of severe perineal laceration.

CONCLUSION

Evaluations based on a single risk-adjusted outcome cannot be generalized to overall hospital obstetric performance.

The association of cerebral palsy and death with small-for-gestational-age birthweight in preterm neonates by individualized and population-based percentiles

OBJECTIVE

The objective of the study was to determine whether an individualized growth standard (IS) improves the identification of preterm small-for-gestational-age (SGA) neonates at risk of developing moderate/severe cerebral palsy (CP) or death.

STUDY DESIGN

This study was a secondary analysis of data from a randomized trial of MgSO4 for the prevention of CP or death among anticipated preterm births. Singleton nonanomalous liveborns delivered before 34 weeks' were classified as SGA (less than the 10th percentile for their gestational age) by a population standard (PS) or an IS (incorporating maternal age, height, weight, parity, race/ethnicity, and neonatal sex). The primary outcome was the prediction of moderate or severe CP or death by age 2 years.

RESULTS

Of 1588 eligible newborns, 143 (9.4%) experienced CP (n = 33) or death (n = 110). Forty-four (2.8%) were SGA by the PS and 364 (22.9%) by the IS. All PS-SGA newborns also were identified as IS-SGA. SGA newborns by either standard had a similarly increased risk of CP or death (PS: relative risk [RR], 2.4, 95% confidence interval [CI], 1.3-4.3 vs IS: RR, 1.8, 95% CI, 1.3-2.5, respectively). The similarity of RRs remained after stratification by the MgSO4 treatment group. The IS was more sensitive (36% vs 6%, P < .001) but less specific (78% vs 98%, P < .001) for CP or death. The receiver operating characteristic curve analysis revealed a statistically lower area under the curve for the PS, although the ability of either method to predict which neonates would subsequently develop CP or death was poor (PS: 0.55, 95% CI, 0.49-0.60 vs IS: 0.59, 95% CI, 0.54-0.64, P < .001).

CONCLUSION

An individualized SGA growth standard does not improve the association with, or prediction of, CP or death by age 2 years.

Adherence to criteria for transvaginal ultrasound imaging and measurement of cervical length

OBJECTIVE

Adherence to published criteria for transvaginal imaging and measurement of cervical length is uncertain. We sought to assess adherence by evaluating images submitted to certify research sonographers for participation in a clinical trial.

STUDY DESIGN

We reviewed qualifying test results of sonographers seeking certification to image and measure cervical length in a clinical trial. Participating sonographers were required to access training materials and submit 15 images, 3 each from 5 pregnant women not enrolled in the trial. One of 2 sonologists reviewed all qualifying images. We recorded the proportion of images that did not meet standard criteria (excess compression, landmarks not seen, improper image size, or full maternal bladder) and the proportion in which the cervical length was measured incorrectly. Failure for a given patient was defined as >1 unacceptable image, or >2 acceptable images with incorrect caliper placement or erroneous choice of the "shortest best" cervical length. Certification required satisfactory images and cervical length measurement from ≥4 patients.

RESULTS

A total of 327 sonographers submitted 4905 images. A total of 271 sonographers (83%) were certified on the first, 41 (13%) on the second, and 2 (0.6%) on the third submission. Thirteen never achieved certification. Of 314 who passed, 196 submitted 15 acceptable images that were appropriately measured for all 5 women. There were 1277 deficient images: 493 were acceptable but incorrectly measured images from sonographers who passed certification because mismeasurement occurred no more than twice. Of 784 deficient images submitted by sonographers who failed the certification, 471 were rejected because of improper measurement (caliper placement and/or failure to identify the shortest best image), and 313 because of failure to obtain a satisfactory image (excessive compression, required landmarks not visible, incorrect image size, brief examination, and/or full maternal bladder).

CONCLUSION

Although 83% of sonographers were certified on their first submission, >1 in 4 ultrasound images submitted did not meet published quality criteria. Increased attention to standardized education and credentials is warranted for persons who perform ultrasound examinations of the cervix in pregnancy.