Discrete placental gene expression signatures accompany diabetic disease classifications during pregnancy.

BACKGROUND: Gestational diabetes mellitus affects up to 10% of pregnancies and is classified into subtypes gestational diabetes subtype A1 (GDMA1) (managed by lifestyle modifications) and gestational diabetes subtype A2 (GDMA2) (requiring medication). However, whether these subtypes are distinct clinical entities or more reflective of an extended spectrum of normal pregnancy endocrine physiology remains unclear. OBJECTIVE: Integrated bulk RNA-sequencing (RNA-seq), single-cell RNA-sequencing (scRNA-seq), and spatial transcriptomics harbors the potential to reveal disease gene signatures in subsets of cells and tissue microenvironments. We aimed to combine these high-resolution technologies with rigorous classification of diabetes subtypes in pregnancy. We hypothesized that differences between preexisting type 2 and gestational diabetes subtypes would be associated with altered gene expression profiles in specific placental cell populations. STUDY DESIGN: In a large case-cohort design, we compared validated cases of GDMA1, GDMA2, and type 2 diabetes mellitus (T2DM) to healthy controls by bulk RNA-seq (n=54). Quantitative analyses with reverse transcription and quantitative PCR of presumptive genes of significant interest were undertaken in an independent and nonoverlapping validation cohort of similarly well-characterized cases and controls (n=122). Additional integrated analyses of term placental single-cell, single-nuclei, and spatial transcriptomics data enabled us to determine the cellular subpopulations and niches that aligned with the GDMA1, GDMA2, and T2DM gene expression signatures at higher resolution and with greater confidence. RESULTS: Dimensional reduction of the bulk RNA-seq data revealed that the most common source of placental gene expression variation was the diabetic disease subtype. Relative to controls, we found 2052 unique and significantly differentially expressed genes (-22 thresholds; q<0.05 Wald Test) among GDMA1 placental specimens, 267 among GDMA2, and 1520 among T2DM. Several candidate marker genes (chorionic somatomammotropin hormone 1 [CSH1], period circadian regulator 1 [PER1], phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit beta [PIK3CB], forkhead box O1 [FOXO1], epidermal growth factor receptor [EGFR], interleukin 2 receptor subunit beta [IL2RB], superoxide dismutase 3 [SOD3], dedicator of cytokinesis 5 [DOCK5], suppressor of glucose, and autophagy associated 1 [SOGA1]) were validated in an independent and nonoverlapping validation cohort (q<0.05 Tukey). Functional enrichment revealed the pathways and genes most impacted for each diabetes subtype, and the degree of proximal similarity to other subclassifications. Surprisingly, GDMA1 and T2DM placental signatures were more alike by virtue of increased expression of chromatin remodeling and epigenetic regulation genes, while albumin was the top marker for GDMA2 with increased expression of placental genes in the wound healing pathway. Assessment of these gene signatures in single-cell, single-nuclei, and spatial transcriptomics data revealed high specificity and variability by placental cell and microarchitecture types. For example, at the cellular and spatial (eg, microarchitectural) levels, distinguishing features were observed in extravillous trophoblasts (GDMA1) and macrophages (GDMA2). Lastly, we utilized these data to train and evaluate 4 machine learning models to estimate our confidence in predicting the control or diabetes status of placental transcriptome specimens with no available clinical metadata. CONCLUSION: Consistent with the distinct association of perinatal outcome risk, placentae from GDMA1, GDMA2, and T2DM-affected pregnancies harbor unique gene signatures that can be further distinguished by altered placental cellular subtypes and microarchitectural niches.

Maternal Metabolic Biomarkers are Associated with Obesity and Excess Gestational Weight Gain.

OBJECTIVE: The purpose of this study was to evaluate the independent contribution of maternal obesity and gestational weight gain (GWG) in excess of the Institute of Medicine's guidelines on levels of maternal serum inflammatory and metabolic measures. STUDY DESIGN: Banked maternal serum samples from 120 subjects with documented prepregnancy or first trimester body mass index (BMI) were utilized for analyte analyses. Validated, BMI-specific formulas were utilized to categorize GWG as either insufficient, at goal or excess based on the Institute of Medicine guidelines with gestational age adjustments. Serum was analyzed for known inflammatory or metabolic pathway intermediates using the Luminex xMap system with the MILLIPLEX Human Metabolic Hormone Magnetic Bead Panel. Measured analytes included interleukin-6, monocyte chemoattractant protein-1, and tumor necrosis factor-α and metabolic markers amylin, c-peptide, ghrelin, gastric inhibitory polypeptide, glucagon-like peptide-1, glucagon, insulin, leptin, pancreatic polypeptide, and peptide YY. Kruskal-Wallis ANOVA and Pearson's correlation coefficients were calculated for each marker. RESULTS: C-peptide, insulin, and leptin all varied significantly with both obesity and GWG while glucagon-like peptide-1 varied by BMI but not GWG. These analytes covaried with other metabolic analytes, but not with inflammatory analytes. CONCLUSION: Maternal metabolic biomarkers at delivery vary significantly with both obesity and GWG. Taken together, these findings suggest that GWG (with and without comorbid obesity) is an important mediator of measurable metabolites in pregnancy but is not necessarily accompanied by inflammatory measures in serum. These findings are consistent with GWG being an independent risk factor for metabolic disturbances during pregnancy.

Visualization of microbes by 16S in situ hybridization in term and preterm placentas without intraamniotic infection.

BACKGROUND: Numerous reports have documented bacteria in the placental membranes and basal plate decidua in the absence of immunopathology using histologic techniques. Similarly, independent metagenomic characterizations have identified an altered taxonomic makeup in association with spontaneous preterm birth. Here we sought to corroborate these findings by localizing presumptive intact bacteria using molecular histology within the placental microanatomy. OBJECTIVE: Here we examined for microbes in term and preterm gestations using a signal-amplified 16S universal in situ hybridization probe set for bacterial rRNA, alongside traditional histologic methods of Warthin-Starry and Gram stains, as well as clinical culture methodologies. We further sought to differentiate accompanying 16S gene sequencing taxonomic profiles from germ-free (gnotobiotic) mouse and extraction and amplicon contamination controls. STUDY DESIGN: Placentas were collected from a total of 53 subjects, composed of term labored (n = 4) and unlabored cesarean deliveries (n = 22) and preterm vaginal (n = 18) and cesarean deliveries (n = 8); a placenta from a single subject with clinical and histologic evident choriomanionitis was employed as a positive control (n = 1). The preterm cohort included spontaneous preterm birth with (n = 6) and without (n = 10) preterm premature rupture of membranes, as well as medically indicated preterm births (n = 10). Placental microbes were visualized using an in situ hybridization probe set designed against highly conserved regions of the bacterial 16S ribosome, which produces an amplified stable signal using branched DNA probes. Extracted bacterial nucleic acids from these same samples were subjected to 16S rRNA metagenomic sequencing (Illumina, V4) for course taxonomic analysis, alongside environmental and kit contaminant controls. A subset of unlabored, cesarean-delivered term pregnancies were also assessed with clinical culture for readily cultivatable pathogenic microbes. RESULTS: Molecular in situ hybridization of bacterial rRNA enabled visualization and localization of low-abundance microbes after systematic high-power scanning. Despite the absence of clinical or histologic chorioamnionitis in 52 of 53 subjects, instances of 16S rRNA signal were confidently observed in 13 of 16 spontaneous preterm birth placentas, which was not significantly different from term unlabored cesarean specimens (18 of 22; P > .05). 16S rRNA signal was largely localized to the villous parenchyma and/or syncytiotrophoblast, and less commonly the chorion and the maternal intervillous space. In all term and unlabored cesarean deliveries, visualization of evident placental microbes by in situ hybridization occurred in the absence of clinical or histologic detection using conventional clinical cultivation, hematoxylin-eosin, and Gram staining. In 1 subject, appreciable villous bacteria localized to an infarction, where 16S microbial detection was confirmed by Warthin-Starry stain. In all instances, parallel sample principle coordinate analysis using Bray-Cutis distances of 16S rRNA gene sequencing data demonstrated consistent taxonomic distinction from all negative or potential contamination controls (P = .024, PERMANOVA). Classification from contaminant filtered data identified a distinct taxonomic makeup among term and preterm cohorts when compared with contaminant controls (false discovery rate <0.05). CONCLUSION: Presumptively intact placental microbes are visualized as low-abundance, low-biomass and sparse populations within the placenta regardless of gestational age and mode of delivery. Their taxonomic makeup is distinct from contamination controls. These findings further support several previously published findings, including our own, which have used metagenomics to characterize low-abundance and low-biomass microbial communities in the placenta.

Impact of USPSTF recommendations for aspirin for prevention of recurrent preeclampsia.

BACKGROUND: The US Preventive Services Task Force recommends low-dose aspirin for the prevention of preeclampsia among women at high risk for primary occurrence or recurrence of disease. Recommendations for the use of aspirin for preeclampsia prevention were issued by the US Preventive Services Task Force in September 2014. OBJECTIVES: The objective of the study was to evaluate the incidence of recurrent preeclampsia in our cohort before and after the US Preventive Services Task Force recommendation for aspirin for preeclampsia prevention. STUDY DESIGN: This was a retrospective cohort study designed to evaluate the rates of recurrent preeclampsia among women with a history of preeclampsia. We utilized a 2-hospital, single academic institution database from August 2011 through June 2016. We excluded multiple gestations and included only the first delivery for women with multiple deliveries during the study period. The cohort of women with a history of preeclampsia were divided into 2 groups, before and after the release of the US Preventive Services Task Force 2014 recommendations. Potential confounders were accounted for in multivariate analyses, and relative risk and adjusted relative risk were calculated. RESULTS: A total of 17,256 deliveries occurred during the study period. A total of 417 women had a documented history of prior preeclampsia: 284 women before and 133 women after the US Preventive Services Task Force recommendation. Comparing the before and after groups, the proportion of Hispanic women in the after group was lower and the method of payment differed between the groups (P <.0001). The prevalence of type 1 diabetes was increased in the after period, but overall rates of pregestational diabetes were similar (6.3% before vs 5.3% after [P > .05]). Risk factors for recurrent preeclampsia included maternal age >35 years (relative risk, 1.83; 95% confidence interval, 1.34-2.48), Medicaid insurance (relative risk, 2.08; 95% confidence interval, 1.15-3.78), type 2 diabetes (relative risk, 2.13; 95% confidence interval, 1.37-3.33), and chronic hypertension (relative risk, 1.96; 95% confidence interval, 1.44-2.66). The risk of recurrent preeclampsia was decreased by 30% in the after group (adjusted relative risk, 0.70; 95% confidence interval, 0.52-0.95). CONCLUSION: Rates of recurrent preeclampsia among women with a history of preeclampsia decreased by 30% after release of the US Preventive Services Task Force recommendation for aspirin for preeclampsia prevention. Future prospective studies should include direct measures of aspirin compliance, gestational age at initiation, and explore the influence of race and ethnicity on the efficacy of this primary prevention.

Marijuana use and its effects in pregnancy.

BACKGROUND: It is generally assumed that marijuana is one of the more widely used controlled substances during pregnancy. However, there remains a general paucity of population-based data regarding its use and subsequent perinatal morbidity. We hypothesized that direct patient query during pregnancy regarding marijuana, tobacco, and nicotine use would provide crucial initial population-based data on perinatal risk. OBJECTIVE: Our study sought to examine maternal and neonatal outcomes in pregnancies with reported marijuana exposure, in isolation or in combination with maternal cigarette smoking. STUDY DESIGN: We applied a retrospective cohort study design to subjects (n = 12,069) with available information on marijuana use and pregnancy outcomes. Since 2011, we have routinely and directly questioned all gravidae regarding use of marijuana, tobacco, and nicotine-containing products. We examined perinatal outcomes in marijuana smokers vs nonsmokers, as well as patients reporting both marijuana and cigarette smoking. Multivariate analysis enabled determination of adjusted odds ratios for maternal and fetal outcomes, adjusting for confounders. Significance was determined with Mann-Whitney U, χ(2), and Fischer exact tests (as appropriate). RESULTS: In all, 106/12,069 reported marijuana use (0.88%), with 48/12,069 (0.4%; or 48/106, 45%) concurrently using cigarettes and marijuana. After controlling for potential confounding variables, while marijuana use alone was not associated with significant adverse outcomes, use in combination with cigarette smoking was significantly associated with increased risk of multiple adverse perinatal outcomes (increased occurrence of maternal asthma [adjusted odds ratio, 2.4; 95% confidence interval, 1.0-5.9]; preterm birth [adjusted odds ratio, 2.6; 95% confidence interval, 1.3-4.9]; decreased [<25th percentile] head circumference [adjusted odds ratio, 2.8; 95% confidence interval, 1.3-4.3]; and decreased [<25th percentile] birthweight [adjusted odds ratio, 2.8; 95% confidence interval, 1.6-5.0]). Maternal pregnancy-related hypertension was not increased in marijuana smokers (adjusted odds ratio, 1.30; 95% confidence interval, 0.681-2.498), or in cigarette smokers (adjusted odds ratio, 1.4; 95%, confidence interval, 0.9-1.9). However, co-users had elevated rates of preeclampsia compared to nonusers (adjusted odds ratio, 2.5; 95% confidence interval, 1.4-5.0). CONCLUSION: In our initial cohort analysis, after controlling for potential confounders, while marijuana exposure alone was not associated with significant perinatal adverse outcomes, co-use with cigarette smoking rendered increased risk over either alone. Due to observed prevalence of concurrent cigarette and marijuana use, it is of likely importance to counsel patients regarding use in pregnancy.

Birth Rates Among Hispanics and Non-Hispanics and their Representation in Contemporary Obstetric Clinical Trials.

Objective Our study aims were to establish whether subjects enrolled in current obstetric clinical trials proportionately reflects the contemporary representation of Hispanic ethnicities and their birth rates in the United States. Methods Using comprehensive source data over a defined interval (January 2011-September 2015) on birth rates by ethnicity from the Centers for Disease Control and Prevention (CDC), we evaluated the proportional rate by ethnicity, then analyzed the observed to expected relative ratio of enrolled subjects. Results Hispanic women comprise a significant contribution to births in the United States (23% of all births). Systematic analysis of 90 published obstetric clinical trials showed a correlation between inclusion of Hispanic gravidae and the corresponding state's birth rates (r = 0.501, p < 0.001). While the mean was strongly correlated, individual clinical trials may have relatively over-enrolled (n = 31, or 34%) or under-enrolled (n = 33, or 37%) relative to their regional population. In 48% of obstetric clinical trials the Hispanic proportion of the study population was not reported. Conclusion Hispanic gravidae represent a significant number of contemporary U.S. births, and are generally adequately represented as obstetric subjects in clinical trials. However, this is trial-dependent, with significant trial-specific under- and over-enrollment of Hispanic subjects relative to the regional birth population.

Candy twists as an alternative to the glucola beverage in gestational diabetes mellitus screening.

OBJECTIVE: Screening for gestational diabetes mellitus commonly uses an oral glucose challenge test with a 50-g glucola beverage and subsequent venous puncture. However, up to 30% of pregnant women report significant side-effects, and the beverage is costly. We hypothesized that equivalent glucose loads could be achieved from a popular candy twist (Twizzlers; The Hershey Company, Hershey, PA) and tested it as cost-effective, tolerable alternative with a test of equivalency. STUDY DESIGN: The glucose equivalent of the 50-g glucola was calculated as 10 candy twists. We initially used a triple crossover design in nonpregnant patients whereby each subject served as her own control; this ensured the safety and equivalency of this load before using it among pregnant subjects. We then recruited pregnant women with an abnormal screening at 1 hour (glucose challenge test) in a double crossover design study. Subjects consumed 10 candy twists with a 1-hour venous blood glucose assessment. All subjects subsequently completed the confirmatory 3-hour glucose tolerance test. Sensitivity, specificity, positive predictive values, negative predictive values, false-referral rates, and detection rates were calculated. RESULTS: At ≥130 mg/dL, the sensitivity (100%) was the same for candy twists and glucola. However, the false-referral rate (82% vs 90%), positive predictive value (18% vs 10%), and detection rate (18% vs 10%) were improved for candy twists when compared with the 50-g glucola beverage. CONCLUSION: Our results indicate that strawberry-flavored candy twists are potentially an equally effective screening test, compared with the gold standard glucola beverage but lead to fewer false-positive screens and therefore could be a cost-effective alternative.

The preterm placental microbiome varies in association with excess maternal gestational weight gain.

OBJECTIVE: Although a higher maternal body mass index is associated with preterm birth, it is unclear whether excess gestational weight gain (GWG) or obesity drives increased risk. We and others have shown that the placenta harbors microbiota, which is significantly different among preterm births. Our aim in this study was to investigate whether the preterm placental microbiome varies by virtue of obesity or alternately by excess GWG. STUDY DESIGN: Placentas (n=320) were collected from term and preterm pregnancies. Genomic DNA was extracted and subjected to metagenomic sequencing. Data were analyzed by clinical covariates that included the 2009 Institute of Medicine's GWG guideline and obesity. RESULTS: Analysis of 16S recombinant RNA-based metagenomics revealed no clustering of the microbiome by virtue of obesity (P=.161). Among women who spontaneously delivered preterm, there was again no clustering by obesity (P=.480), but there was significant clustering by excess GWG (P=.022). Moreover, among preterm births, detailed analysis identified microbial genera (family and genus level) and bacterial metabolic gene pathways that varied among pregnancies with excess GWG. Notably, excess GWG was associated with decreased microbial folate biosynthesis pathways and decreased butanoate metabolism (linear discriminate analysis, >3.0-fold). CONCLUSION: Although there were no significant alterations in the microbiome by virtue of obesity per se, excess GWG was associated with an altered microbiome and its metabolic profile among those women who experienced a preterm birth.

Role of Maternal Serum Alpha-Fetoprotein and Ultrasonography in Contemporary Detection of Spina Bifida.

OBJECTIVE: Midtrimester maternal serum alpha-fetoprotein (MSAFP) and sonographic evaluation have been used to screen for spina bifida. With the increased uptake of cell-free DNA (cfDNA) and first trimester screening, MSAFP levels may no longer be obtained routinely. Our aim was to evaluate a pediatric neurosurgical referral center database of spina bifida cases to determine the antenatal detection rate and means of diagnosis. STUDY DESIGN: Nested case series of all spina bifida cases referred postnatally from 2007 to 2013. Data were abstracted from the maternal record and rates of antenatal detection with MSAFP and sonographic screening were determined. RESULTS: Of the 105 postnatally referred cases, 11.4% (12/105) were not identified until delivery. Overall, 39% of the cases had MSAFP screening. The odds ratio for sonogram-based detection of spina bifida was 4.9 (95% confidence interval, 2-11.9). Of the neonatally detected cases, 100% had prenatal care and 91.6% (11 of the 12 cases) had documented sonography. CONCLUSION: We have found that 11.4% of the spina bifida cases were not detected before delivery. Nine out of the 12 cases of antenatally missed spina bifida were not screened using MSAFP. Our findings support the approach of midtrimester MSAFP screening combined with sonographic evaluation. We speculate that prenatal screening with MSAFP is underutilized.

Chorioamnionitis and adverse outcomes in low-risk pregnancies: a population-based study.

OBJECTIVE: To compare the composite neonatal and maternal adverse outcomes among low-risk pregnancies with versus without chorioamnionitis. METHODS: We conducted a retrospective cohort study using U.S. Vital Statistics Data. The study population was restricted to full term, low-risk, singleton pregnancies. Pregnancies were categorized into those affected and unaffected by chorioamnionitis. The primary outcome was composite neonatal adverse outcome and the secondary outcome was composite maternal adverse outcome. Multivariable Poisson regression models with robust error variance were used to examine the factors associated with chorioamnionitis and to evaluate the association between chorioamnionitis and adverse outcomes [using adjusted relative risk (aRR) and 95% confidence interval (CI)]. RESULTS: Of 19.7 million live births, 59.4% met inclusion criteria; among them, 1.7% were complicated by chorioamnionitis. The risk of composite neonatal adverse outcome was higher in newborns delivered by women with chorioamnionitis (aRR = 3.40; 95% CI = 3.30-3.49). Compared to women without chorioamnionitis, those with chorioamnionitis had a higher risk of composite maternal adverse outcome (aRR = 2.42; 95% CI = 2.31-2.55). Infant mortality was also higher in affected pregnancies (aRR = 1.23; 95% CI = 1.09-1.38). CONCLUSION: Among low-risk pregnancies, chorioamnionitis is associated with a higher risk of composite neonatal and maternal adverse outcomes. Infant death is also increased.

Inpatient Biophysical Profiles and the Effect on Clinical Decision Making.

Objective Our primary objective was to determine whether biophysical profiles (BPP) performed on the antepartum unit result in changes in clinical decision making. Study Design A retrospective cohort chart review was performed among women who had a BPP during hospital admission. BPP status was categorized as normal (8/8 points) and abnormal (6/8 or less points). The primary outcome, clinical decision making, was the need for prolonged external fetal monitoring (defined as > 2 hours) or decision to proceed with delivery. Secondary outcomes included mode of delivery, indicated preterm delivery, birth weight, 5-minute Apgar's score <7, and neonatal intensive care unit (NICU) admission. Results Among our cohort ( n = 186), 85.5% ( n = 159) had a normal BPP. Delivery management was altered in one case (0.54%) by the BPP findings, and there were no BPPs that resulted in need for prolonged monitoring. Compared with women with normal BPP, women with abnormal BPPs were more likely to deliver at <37 weeks, to be admitted to the NICU, or have a 5-minute Apgar's score <7. Conclusion In-hospital BPPs alter clinical decision making in less than 1% of cases.

Under Pressure: Intraluminal Filling Pressures of Postpartum Hemorrhage Tamponade Balloons.

Objective Uterine tamponade by fluid-filled balloons is now an accepted method of controlling postpartum hemorrhage. Available tamponade balloons vary in design and material, which affects the filling attributes and volume at which they rupture. We aimed to characterize the filling capacity and pressure-volume relationship of various tamponade balloons. Study Design Balloons were filled with water ex vivo. Intraluminal pressure was measured incrementally (every 10 mL for the Foley balloons and every 50 mL for all other balloons). Balloons were filled until they ruptured or until 5,000 mL was reached. Results The Foley balloons had higher intraluminal pressures than the larger-volume balloons. The intraluminal pressure of the Sengstaken-Blakemore tube (gastric balloon) was initially high, but it decreased until shortly before rupture occurred. The Bakri intraluminal pressure steadily increased until rupture occurred at 2,850 mL. The condom catheter, BT-Cath, and ebb all had low intraluminal pressures. Both the BT-Cath and the ebb remained unruptured at 5,000 mL. Conclusion In the setting of acute hemorrhage, expeditious management is critical. Balloons that have a low intraluminal pressure-volume ratio may fill more rapidly, more easily, and to greater volumes. We found that the BT-Cath, the ebb, and the condom catheter all had low intraluminal pressures throughout filling.

Mode of Delivery in Premature Neonates: Does It Matter?

OBJECTIVE: Despite the current prevalence of preterm births, no clear guidelines exist on the optimal mode of delivery. Our objective was to investigate the effects of mode of delivery on neonatal outcomes among premature infants in a large cohort. STUDY DESIGN: We applied a retrospective cohort study design to a database of 6,408 births. Neonates were stratified by birth weight and a composite score was calculated to assess neonatal outcomes. The results were then further stratified by fetal exposure to antenatal steroids, birth weight, and mode of delivery. RESULTS: No improvement in neonatal outcome with cesarean delivery (CD) was noted when subjects were stratified by mode of delivery, both in the presence or absence of antenatal corticosteroid administration. In the 1,500 to 1,999 g subgroup, there appears to be an increased risk of respiratory distress syndromes in neonates born by CD. CONCLUSION: In our all-comers cohort, replicative of everyday obstetric practice, CD did not improve neonatal outcomes in preterm infants.

Trends in the delivery route of twin pregnancies in the United States, 2006-2013.

OBJECTIVES: To determine the trends of cesarean delivery rate among twin pregnancies from 2006 to 2013. STUDY DESIGN: This is a population-based, cross-sectional analysis of twin live births from United State birth data files of the National Center for Health Statistics for calendar years 2006 through 2013. We stratified the population based on the gestational age groups, maternal race/ethnicity, advanced maternal age (AMA) which was defined by age more than 35 years and within the standard birth weight groups (group 1: birth weight 500-1499g, group 2: birth weight 1500-2499g and group 3: birth weight >2500g). We also analyzed the effect of different risk factors for cesarean delivery in twins. RESULTS: There were 1,079,102 infants born of twin gestations in the U.S. from 2006 to 2013, representing a small but significant increase in the proportion of twin births among all births (3.2% in 2006 versus 3.4% in 2013). The rate of cesarean delivery in twin live births peaked at 75.3% in 2009, and was significantly lower (74.8%) in 2013. The rate of the twin live birth with the breech presentation increased steadily from 26.3% in 2006 to 29.1% in 2013. For the fetus of the twin pregnancy presented as breech, the cesarean delivery rate peaked at 92.2% in 2010, falling slightly but significantly in the ensuing 3 years. The results demonstrated that the decrease in cesarean delivery rate was due to fewer cesareans in non-Hispanic white patients; all other ethnic subgroups showed increasing rates of cesarean delivery throughout the study. Gestational diabetes, gestational hypertension, previous cesarean delivery and breech presentation were all significant risk factors for cesarean delivery during the entire study period. Induction of labor and premature rupture of the membranes were associated with lower rates of cesarean delivery in twins. CONCLUSION: The recent decrease in the cesarean delivery rate in twin gestation appears to be largely attributable to a decline in cesarean among pregnancies complicated by breech presentation in non-Hispanic white women, and may reflect a health care disparity that deserves further research.