Differences In Rates Of Preterm Birth Research Articles

Socioeconomic and ethnic disparities in preterm births in an English maternity setting: a population-based study of 1.3 million births

BackgroundPreterm birth is a major cause of infant mortality and morbidity and accounts for 7–8% of births in the UK. It is more common in women from socially deprived areas and from minority ethnic groups, but the reasons for this disparity are poorly understood. To inform interventions to improve child survival and their quality of life, this study examined the socioeconomic and ethnic inequalities in preterm births (< 37 weeks of gestation at birth) within Health Trusts in England.MethodsThis study investigated socioeconomic and ethnic inequalities in preterm birth rates across the National Health Service (NHS) in England. The NHS in England can be split into different units known as Trusts. We visualised between-Trust differences in preterm birth rates. Health Trusts were classified into five groups based on their standard deviation (SD) variation from the average national preterm birth rate. We used modified Poisson regression to compute risk ratios (RR) and 95% confidence intervals (95% CI) with generalised estimating equations.ResultsThe preterm birth rate ranged from 6.8/100 births for women living in the least deprived areas to 8.8/100 births for those living in the most deprived areas. Similarly, the preterm birth rate ranged from 7.8/100 births for white women, up to 8.6/100 births for black women. Some Health Trusts had lower than average preterm birth rates in white women whilst concurrently having higher than average preterm birth rates in black and Asian women. The risk of preterm birth was higher for women living in the most deprived areas and ethnicity (Asian).ConclusionsThere was evidence of variation in rates of preterm birth by ethnic group, with some Trusts reporting below average rates in white ethnic groups whilst concurrently reporting well above average rates for women from Asian or black ethnic groups. The risk of preterm birth varied substantially at the intersectionality of maternal ethnicity and the level of socioeconomic deprivation of their residency. In the absence of other explanations, these findings suggest that even within the same Health Trust, maternity care may vary depending on the women’s ethnicity and/or whether she lives in an area of high socioeconomic deprivation. Thus, social factors are likely key determinants of inequality in preterm birth rather than provision of maternity care alone.

Obstetrical and Neonatal Outcomes of in vitro Fertilization Twins after Fresh Embryo Transfer versus Frozen-Thawed Embryo Transfer.

The limited data regarding obstetrical outcomes in multiple pregnancies following both fresh embryo transfer and frozen-thawed embryo transfer (FET), along with the association between multiple pregnancies and increased pregnancy complications compared to singleton pregnancies, highlight the need for research on this topic. Therefore, this study aimed to compare obstetrical and neonatal outcomes of twin pregnancies after fresh embryo transfer versus FET. This was a retrospective single-center study. There were in vitro fertilization (IVF) dichorionic twin pregnancies ≥23 weeks of gestation during 2010-2022. This retrospective study was based on data recorded at Galilee Medical Center, a tertiary-care university-affiliated hospital, Israel. We conducted a comparative analysis of obstetrical and neonatal outcomes between IVF dichorionic twin pregnancies after fresh embryo transfer and those after FET. This analysis included variables such as gestational age at delivery, birthweight, preterm birth rates, low birthweight rates, neonatal intensive care unit admissions, and complications related to prematurity. The study included 389 IVF twin pregnancies: 253 after fresh embryo transfer and 136 after FET. Following fresh embryo transfer compared to FET, the mean gestational age at delivery was earlier (34 + 6 vs. 35 + 5 weeks, p = 0.001) and the rate of preterm birth (&lt;37 weeks) was higher (70.4% vs. 53.7%, p = 0.001). This difference in gestational age at delivery remained significant after adjustment for maternal age, parity, and BMI (OR = 2.11, 95% CI: 2.11-3.27, p = 0.001). Similarly, the difference in preterm birth rates remained significant after adjustment of the same variables (p = 0.001). For the fresh embryo transfer compared to the FET group, the mean birthweight was lower (2,179.72 vs. 2,353.35 g, p = 0.003); and low birthweight and very low birthweight rates were higher (71.2% vs. 56.3%, p &lt; 0.001 and 13.5% vs. 6.7%, p = 0.004, respectively). For the fresh embryo transfer compared to the FET group, the proportions were higher of neonates admitted to the neonatal intensive care unit (23.3% vs. 16.0%, p = 0.019), of neonates with respiratory distress syndrome (10.5% vs. 5.9%, p = 0.045) and those needing phototherapy (23.3% vs. 16.0%, p = 0.019). Limitations of the study include its retrospective nature. Furthermore, we were unable to adjust for some confounders, such as the number of eggs retrieved, the number of embryos transferred, and methods for ovarian stimulation or preparation of the endometrium for embryo transfer. Obstetrical and neonatal outcomes of twin pregnancies were worse after fresh embryo transfer than after FET. The findings support favorable fetal outcomes after FET and support the current trend of shifting from fresh embryo transfer to FET. Prospective studies are needed to support our results.

Can the date of last menstrual period be trusted in the first trimester? Comparisons of gestational age measures from a prospective cohort study in six low-income to middle-income countries

ObjectivesWe examined gestational age (GA) estimates for live and still births, and prematurity rates based on last menstrual period (LMP) compared with ultrasonography (USG) among pregnant women at seven sites...

Association of Prepregnancy Risk Factors With Racial Differences in Preterm Birth Rates

Association of Prepregnancy Risk Factors With Racial Differences in Preterm Birth Rates

Reduction in preterm birth among COVID-19–vaccinated pregnant individuals in the United States

Most studies investigating preterm birth and COVID-19 vaccination have suggested no difference in preterm birth rates between vaccinated and unvaccinated pregnant individuals; however, 1 recent study suggested a protective effect of COVID-19 vaccination on preterm birth rates in Australia. This study aimed to determine whether a similar association and protective effect of COVID-19 vaccination on preterm birth would be found in our multistate, US cohort. A cohort study was conducted using the Vizient Clinical Database, which included data from 192 hospitals in 38 states. Pregnant individuals who delivered between January 2021 and April 2022 were included. Propensity score matching was used to match a "treated" group of pregnant individuals with any COVID-19 vaccination (incomplete or complete vaccination) to a group that had not received any COVID-19 vaccination (the "untreated" group). A complete vaccination series of ≥2 doses of the Moderna or Pfizer vaccines or at least 1 dose of the Johnson & Johnson vaccine was considered. An incomplete series was receipt of 1 dose of the Pfizer or Moderna vaccine. We examined the association between COVID-19 vaccination status and preterm birth at <28, <34, and <37 weeks of gestation. Multivariable logistic regression models were used to adjust for potential confounders, with adjusted odds ratios as the measure of treatment effect. Matching with replacement was performed for 5749 treated participants. After propensity score matching, there was no difference in maternal demographics of age, race, insurance status, parity, or comorbid conditions. Vaccinated individuals were 26% less likely to deliver at <37 weeks of gestation (adjusted odds ratio, 0.74; 95% confidence interval, 0.73-0.75; P<.001), 37% less likely to deliver at <34 weeks of gestation (adjusted odds ratio, 0.63; 95% confidence interval, 0.61-0.64; P<.001), and 43% less likely to deliver at <28 weeks of gestation (adjusted odds ratio, 0.57; 95% confidence interval, 0.55-0.60; P<0.001) than unvaccinated individuals. Vaccination against COVID-19 may be protective against preterm birth.

Effects of female body mass index on pregnancy during in vitro fertilization-embryo transfer.

To investigate the effect of different body mass index (BMI) on transplantation and pregnancy outcomes during assisted reproductive therapy (ART). This study assessed the data on embryo transplantation from April 1, 2016, to March 31, 2021, at the Hangzhou Women's Hospital. According to the women's BMI, they were divided into three groups: the overweight, normal weight, and overweight groups. The differences in general clinical data, embryo transfer, pregnancy outcome and newborn birth weight were analyzed. There was no difference in clinical pregnancy rate between the three groups, but a positive correlation between multiple pregnancy rates and BMI in the fresh cycle was observed. Although there was no significant difference in live birth rates among the three groups (p = 0.291), the average birth weight of newborns among the three groups was different (p < 0.05). Furthermore, the mean birth weight of a single fetus was positively correlated with maternal BMI, and the mean birth weight of twins was lower than that of single twins (p < 0.001). The BMI of women treated with ART did not affect clinical pregnancy outcomes and live birth rates after embryo transfer, but differences in preterm birth rates and newborn birth weight were observed.

Fewer Preterm Births in the First COVID-19 Pandemic Year? An Evaluation of the Berlin Perinatal Data for the Years 2017 to 2020.

Introduction The study analyzes and interprets possible effects of the COVID-19 pandemic on the preterm birth rate. Research questions included: were there fewer preterm births in Berlin in 2020, the first year of the pandemic, compared to the three years before the pandemic? Were there differences in preterm birth rates grouped according to weeks of gestation? Method The perinatal data of all singleton pregnancies were evaluated with regard to birth rates in Berlin, and the numbers of preterm neonates born in the three pre-pandemic years from 2017 to 2019 were compared to the rate for 2020, the first year of the pandemic. Results The overall number of singleton pregnancies born in maternity hospitals and labor wards in Berlin decreased in the first year of the pandemic. The percentage of preterm neonates born before 37+0 weeks of gestation (GW) was significantly lower in 2020 compared to the three previous years, with significantly more preterm neonates born before 28+0 GW and significantly fewer preterm neonates born between 28+0 to 35+0 GW. In 2020, significantly fewer neonates born before 37+0 weeks of gestation were delivered by primary caesarean section. The incidence of induced births was approximately the same. Conclusions In the first year of the pandemic, a range of social, iatrogenic, and biological factors may have had an impact on preterm birth rates. A Germany-wide evaluation of perinatal data across different German federal states for the period 2020 to 2022 would offer the opportunity to identify the causes of this lower rate of preterm births and determine whether conclusions can be drawn from this which would affect future strategies to reduce preterm birth rates.

"Is This Mic On?" Improving NICU Quality of Care by Amplifying Black Mothers' Voices.

"Is This Mic On?" Improving NICU Quality of Care by Amplifying Black Mothers' Voices.

Ethnic differences in preterm birth in Southwest China, 2014-2018: A population-based observational study.

ObjectivePreterm birth is a major healthcare problem and has been rising gradually in the past three decades in China. Yet the ethnic differences in the rates and distributions of preterm birth remain largely unknown in China. This study used data from Yunnan, a multiethnic province, to explore the differences in preterm birth across ethnicities.MethodsA population-based observational study was conducted based on data from the National Free Preconception Health Examination Project in rural Yunnan from Jan 1, 2014 to Dec 31, 2018. Pregnancies with at least one livebirth were included in this study. We estimated the rates and 95% confidence intervals (CIs) of overall preterm birth (born < 37 weeks’ gestation), moderate to late preterm birth (born between 32 and <37 weeks’ gestation), very preterm birth (born between 28 and 31 weeks’ gestation), and extremely preterm birth (born < 28 weeks’ gestation) across maternal ethnicity and compared them using log-binomial regressions. Multivariable log-binomial regressions were used to assess the association between maternal ethnicity and preterm birth with adjustment for potential confounders, including year of delivery, maternal age at delivery, education, occupation, pre-pregnancy body mass index, history of chronic disease, history of preterm birth, smoking and drinking alcohol during early pregnancy, and parity and multiple pregnancy of current pregnancy.ResultsAmong 195,325 women who delivered at least one live baby, 7.90% (95% CI, 7.78–8.02%) were born preterm. The rates of moderate to late preterm birth, very preterm birth, and extremely preterm birth were 6.20% (95% CI, 6.09–6.30%), 1.18% (95% CI, 1.13–1.23%), and 0.52% (95% CI, 0.49–0.56%), respectively. The rates of overall preterm birth, moderate to late preterm birth, very preterm birth, and extremely preterm birth differed across maternal ethnicity. The preterm birth rates in Dai (10.73%), Miao (13.23%), Lisu (12.64%), Zhuang (11.77%), Wa (10.52%), and Lagu (12.34%) women were significantly higher than that in Han women, and the adjusted relative risks were 1.45 [95% CI, 1.36, 1.54], 1.74 (95% CI, 1.62, 1.86), 1.60 (95% CI, 1.47, 1.75), 1.60 (95% CI, 1.46, 1.75), 1.40 (95% CI, 1.22, 1.60), and 1.67 (95% CI, 1.50, 1.87) respectively. There was no difference in preterm birth rate between Han women and Hani, Bai, or Hui women.ConclusionThis study found notable differences in the rates of preterm birth and its sub-categories across maternal ethnicities, which were especially higher in ethnic minority women. The findings suggest that greater efforts to reduce ethnic inequalities in preterm birth. Future studies are warranted to understand the drivers of ethnic inequalities in preterm birth in China.

Why did preterm birth rates fall during the COVID-19 pandemic?

Why did preterm birth rates fall during the COVID-19 pandemic?

Preterm birth during the COVID-19 pandemic: more, less, or just the same?

ABSTRACT Objectives Coronavirus disease (COVID-19) and its mitigation measures have been associated with changes in preterm birth (PTB) incidences. The objective of this paper is to summarize and comment on the literature on COVID-19 and PTB and to compare PTB incidence between 2019 (pre-COVID-19) and 2020 (COVID-19) in three Belgian tertiary care hospitals. Methods A non-systematic review on COVID-19 and PTB was performed, and literature was summarized in a table. Preterm birth rates at Ghent University Hospital, Ziekenhuis Oost-Limburg, and University Hospital Leuven in 2019 and 2020 were compared. Chi-square and Fisher’s exact tests were used to compare PTB rates between 2019 and 2020, and Kaplan Meier survival analysis was used to compare pregnancy duration. The mean outcome measure was PTB incidence in 2020 (COVID-19) compared with PTB incidence in 2019 (pre-COVID-19). Results Some (parts of) countries report decreases in PTB rates, others report no differences in incidence, and a minority of countries report an increased incidence of PTB. Almost all studies only consider live-births. In three tertiary care hospitals in Flanders, there were no differences in PTB rates before and during the COVID-19 pandemic. Conclusion The impact of the (mitigation measures during the) COVID-19 pandemic on PTB incidence is unclear and difficult to explore. To enable a correct interpretation, all conceptions before and during the pandemic should be taken into consideration, as well as all births, still or alive.

Analysis of Differences in Preterm Birth Rates According to Household Occupation in Japan From 2007 to 2019.

ObjectivesNo studies have examined the association between preterm birth rates and socioeconomic factors in Japan using nationwide statistical data. We analyzed the association between preterm birth rates and household occupation using Vital Statistics data.MethodsAggregated Vital Statistics data from Japan from 2007 to 2019 were obtained from the Ministry of Health, Labour and Welfare. From the data, the number of births according to year, age group, gestational period, number of pregnancies, and household occupation were used in this study. Crude preterm birth rates and preterm birth rates adjusted by maternal age according to household occupation were calculated for each year. Poisson regression analysis was conducted to evaluate the association between household occupation and preterm births.ResultsUnemployed households had the highest preterm birth rate, and households with an occupation classification of “full-time worker 2” (an employee at a large company, civil servant, or board member) had the lowest preterm birth rate throughout each period. Poisson regression analysis revealed that unemployed households were statistically significantly associated with a high preterm birth risk. In contrast, the preterm birth rate adjusted by maternal age remained stable throughout each period regardless of household occupation, and preterm birth rates were found not to have increased in recent years in Japan.ConclusionsUnemployed households had higher preterm birth rates than other household occupations. Further studies investigating the characteristics of unemployed households are needed to identify the reasons for this disparity.

Perinatal Outcomes of Using Ursodeoxycholic Acid to Treat Monochorionic and Dichorionic Twin Pregnancy Complicated by Intrahepatic Cholestasis of Pregnancy

To study the effect of using ursodeoxycholic acid (UDCA) to treat monochorionic and dichorionic twin pregnancies complicated by intrahepatic cholestasis of pregnancy (ICP) and to examine the differences in perinatal outcomes. A total of 406 twin-carrying pregnant women who had ICP and received care at West China Second Hospital, Sichuan University between January 1, 2015 and November 1, 2018 were included in the study. The clinical data of monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA) twins with ICP were analyzed. Analysis was done to compare the treatment effect for lowering serum total bile acid (TBA) and the perinatal outcomes with simple UDCA medication or combination medication. There were no statistically significant differences in TBA levels, early-onset ICP, simple UDCA medication or combination medication, neonatal Apgar score, birth weight, length of hospital stay, C-section rate, and perinatal mortality between the MCDA and the DCDA twin groups with ICP. However, maternal age, BMI, scarred uterus, in vitro fertilization-embryo transfer, preeclampsia, twin comorbidity rate of the two groups showed statistical differences. Further comparison between twin pregnancies with mildly-elevated TBA and those with severely-elevated TBA showed significant difference in preterm birth rate ( P<0.05). Simple UDCA medication or combination medication may have the same therapeutic effect on MCDA and DCDA twin pregnancies with ICP. Monochorionic twin pregnancy, twin comorbidities and pregnancy complications were still important factors affecting pregnancy outcomes of twin pregnancies with ICP. Twin pregnancies with slightly elevated TBA have been managed as severe ICP, which may be associated with increased iatrogenic preterm births.

Uterine myomas: effect of prior myomectomy on pregnancy outcomes

Objective Reproductive aged women with fibroids must weigh the risks and benefits of preconception myomectomy. Women with fibroids may have higher rates of fetal growth restriction (FGR) and stillbirth; however, there is a paucity of data on the impact of myomectomy on pregnancy outcomes. We compared perinatal outcomes in women with prior myomectomy versus those with no prior myomectomy and at least one fibroid ≥ 5 cm. Methods Retrospective cohort study of women at a single center who delivered between 2008 and 2017 with a viable intrauterine pregnancy at initial ultrasound scan and either prior myomectomy, or, in the no-myomectomy cohort, at least one fibroid ≥ 5 cm on a prenatal scan performed at < 21 weeks’ gestation (wga). Pregnancies complicated by major congenital anomalies were excluded. Primary outcome was preterm birth (PTB) < 37wga. Secondary outcomes included rates of spontaneous loss, cesarean delivery (CD), abnormal placentation, malpresentation, FGR, birthweight, birthweight percentile, estimated blood loss (EBL), blood transfusion, and neonatal survival to discharge. Results A total of 290 women met inclusion criteria: 70 had a prior myomectomy, 220 women had ≥1 fibroid ≥5cm. Women with prior myomectomy were older, more likely to have private insurance, and more likely used artificial reproductive technology to conceive; 20% with prior myomectomy still had at least one ≥ 5 cm myoma on their obstetric scan. Rates of spontaneous loss were lower in the prior myomectomy group (1.4% vs 7.3%; p = .08). Of the 273 pregnancies continuing beyond 20 weeks, women with prior myomectomy had significantly more PTBs (35% vs. 21%, p = .02) and significantly different primary birth indications (p < .0001). However, after controlling for late preterm, prelabor cesareans recommended by providers in the myomectomy cohort, the difference in PTB rates was not significant (p = .13). The myomectomy group had more CDs (88% vs. 53%, p < .0001), higher EBL (1250 mL vs. 811 mL, p = .04), and a trend toward more blood transfusions (16% vs 8%, p = .05). Other selected outcomes were similar, including rates of FGR. Conclusions Women with prior myomectomy had significantly more PTBs, due in part to more preterm, prelabor cesareans in the late preterm period. Otherwise, prior myomectomy did not confer appreciable obstetric or perinatal benefits, as patients had more CDs, and higher EBL. Recommendations to perform preterm prelabor cesareans in this population may explain some of the PTB disparity. The effect of prior myomectomy on early pregnancy loss and infertility requires further study.

Cervical pessary plus vaginal progesterone in a singleton pregnancy with a short cervix: an experience-based analysis of cervical pessary’s efficacy

Background Several studies were published about cervical pessary, with controversial results. These studies demonstrated that the patient follow-up after pessary insertion is very different between the study centers and the number of pessary insertions per center was often <30 cases. This study aims to determine cervical pessary performance in singleton pregnancies with a short cervix based on a single center learning curve. Methods Between 2011 and 2018, 128 singleton pregnancies between 18 and 24 gestational weeks with a short cervix (<25 mm) were referred to our clinic. All cases were treated with progesterone, and when available in our supplies (due to low resources) cervical pessary was also offered. Three groups were created for statistical analysis: Group 1 (n = 33), treated with progesterone-only; Groups 2 and 3, treated with cervical pessary plus progesterone. Group 2 included the first cases (n = 30) of pessary, defined by a learning curve and cumulative sum analysis, while Group 3 included the subsequent 65 cases. The primary outcome was preterm birth (PTB) < 34 gestational weeks. Results The learning curve was performed with all cases of pessary plus progesterone, and 30 patients were obtained as the number needed for learning, in our study with two operators. The PTB rate < 34 weeks was 27.3, 20, and 4.6% in groups 1, 2, and 3, respectively. There was no significant difference between Group 1 and 2 (OR 1.1; 95% CI 0.066 − 18.45; p = .945). When comparing Groups 1 and 3 there was a significant difference in PTB rates (OR 0.08; CI95% 0.01–0.42; p = .003). Considering Kaplan-Meyer Survival analysis, we can observe that the performance of progesterone alone (Group 1) was similar to Group 2 (progesterone + first 30 cases of pessary) (p = .432), but the performance of Group 3 (progesterone + subsequent 65 cases of pessary) and Group 1 shows a statistically significant difference (p = .011). Conclusion Learning curve and cumulative sum analysis determined that the application and surveillance of at least 30 patients is required to see significant improvements in the primary outcome of PTB < 34 weeks.

A185 THE IMPACT OF PRIOR SURGERY ON ADVERSE PREGNANCY OUTCOMES IN PREGNANT PATIENTS WITH INFLAMMATORY BOWEL DISEASE

Abstract Background During the course of inflammatory bowel disease (IBD), approximately 20% of patients with ulcerative colitis (UC) and 80% of Crohn’s disease (CD) patients will require surgery. The most common operation is total proctocolectomy and ileoanal pouch anastomosis (IPAA) for UC patients and ileocecal (IC) resection for CD. In pregnant IBD patients, guidelines name the presence of IPAA as a relative indication for Cesarean section (C-section). The effect of prior IBD-related surgery on mode of delivery and pregnancy-related outcomes remains unknown. Aims To describe pregnancy-related outcomes in pregnant women with IBD who have undergone prior IBD-related surgery. Methods We performed a retrospective cohort study of pregnant women with IBD including those with prior IBD-related surgeries including IPAA, IC resection, total or partial colectomy and ileostomy formation who delivered an infant at our medical center from 2016 to 2020. We assessed the mode of delivery, delivery characteristics (emergency vs. planned C-section) and maternal and neonatal outcomes Results Fifty-six UC patients and 64 CD patients were included in the analysis, of which 10 and 24 had undergone prior IBD-related surgery, respectively. The mean age at conception was 34.10 years in the surgical UC group and 30.30 years in the surgical CD group. Mode of delivery: C-section rates were higher in post-surgical compared to non-surgical UC patients (70% vs. 30.4%, p = 0.02). Similar numbers of C-sections were performed emergently in the surgical compared to non-surgical UC group (10% vs. 18%, p = 0.53). Comparatively, there was no significant difference in C-section rates in post -surgical compared to non-surgical CD mothers (50% vs. 40%, p = 0.44), with 13% performed emergently in both groups. Maternal outcomes: Gestational diabetes developed in 10% of surgical UC and 4.5% of surgical CD patients. Premature rupture of membranes developed in 10% of surgical UC and 9.1% of surgical CD patients. There was no difference in pre-eclampsia rates in the surgical and non-surgical CD groups (9.1% vs 13.2%, p = 0.64). Neonatal outcomes: There was no significant difference in pre-term birth rates in post-surgical compared to non-surgical UC mothers (10% vs. 15.2%, p = 0.67) or in surgical compared to non-surgical CD mothers (13.6% vs. 5.1%, p = 0.29). Neonatal Intensive Care Unit (NICU) requirements were higher in infants born to post-surgical CD compared to non-surgical CD mothers (18.2% vs. 2.7%, p = 0.04). More low birth weight (LBW) infants were born to post-surgical CD vs non-surgical CD mothers (13.6% vs. 0%, p = 0.02). Conclusions Women with IBD who have had prior IBD-related surgery may be at increased risk of developing adverse gestational and neonatal outcomes. Women with surgical UC have an increased incidence of Cesarean delivery. Funding Agencies None

Racial Disparities in the Risk for Preterm Birth as a Function of Maternal Age [25C

INTRODUCTION: We sought to investigate the impact of maternal age on the risk for preterm birth (PTB) and whether it is affected by maternal race. METHODS: This retrospective cohort study utilized the US Live Birth database from the CDC for the years 2016–2017. Nulliparous women with in-hospital, singleton PTBs between 22–37 weeks of gestation were eligible for analysis. Exclusion criteria included fetal anomalies and maternal hypertension and/or diabetes complicating pregnancy. Maternal race was characterized as non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic and Asian. The rate of PTB was calculated among each racial group across all maternal ages. Chi-squared analysis was used to compare the prevalence of PTB per maternal age across the different racial groups. RESULTS: The cohort included 199,643 PTBs. Of those, 102,815 (51.5%) were NHW, 37,844 (19%) were NHB, 44,472 (22.3%) were Hispanic and 14,512 (7.2%) were Asian. Across all racial groups, the rate of PTB is higher at the extremes of maternal age, with the highest risk occurring in women &gt;35 years old (P&lt;.05). The difference in PTB rates between NHB and all other racial groups increased as a function of age (P&lt;.05). CONCLUSION: The rate of PTB is higher in the extremes of maternal age for all races. At each maternal age interval, a racial disparity in PTB rates exists and increases as maternal age increases. Clinicians should be aware of this disparity in the risk of PTB and the impact of extremes of the maternal age when counseling patients during pregnancy.

Preterm birth outcomes among Asian women by maternal place of birth.

To investigate overall, spontaneous, and medically indicated preterm birth (PTB) rates between US-born and non-US-born Asian women living in California. Nulliparous women with a singleton livebirth and Asian race in California between 2007 and 2011 were investigated. The prevalence of overall (<37 weeks), spontaneous, and medically indicated PTB was examined by self-reported race and place of birth among ten Asian subgroups. There were marked differences in PTB rates between the individual Asian subgroups. After adjustments, non-US-born Chinese, Japanese, Vietnamese, and Indian women had lower odds of overall PTB and Chinese, Vietnamese, Cambodian, and Indian women had lower odds of spontaneous PTB compared with their US-born counterparts. Further investigation of biological and social factors contributing to these lower odds of spontaneous PTB among the non-US-born Asian population could potentially offer clues for reducing the burden of PTB among the US born.

MAVRIC: a multicenter randomized controlled trial of transabdominal vs transvaginal cervical cerclage

Vaginal cerclage (a suture around the cervix) commonly is placed in women with recurrent pregnancy loss. These women may experience late miscarriage or extreme preterm delivery, despite being treated with cerclage. Transabdominal cerclage has been advocated after failed cerclage, although its efficacy is unproved by randomized controlled trial. The objective of this study was to compare transabdominal cerclage or high vaginal cerclage with low vaginal cerclage in women with a history of failed cerclage. Our primary outcome was delivery at <32 completed weeks of pregnancy. This was a multicenter randomized controlled trial. Women were assigned randomly (1:1:1) to receive transabdominal cerclage, high vaginal cerclage, or low vaginal cerclage either before conception or at <14 weeks of gestation. The data for 111 of 139 women who were recruited and who conceived were analyzed: 39 had transabdominal cerclage; 39 had high vaginal cerclage, and 33 had low vaginal cerclage. Rates of preterm birth at <32 weeks of gestation were significantly lower in women who received transabdominal cerclage compared with low vaginal cerclage (8% [3/39] vs 33% [11/33]; relative risk, 0.23; 95% confidence interval, 0.07-0.76; P=.0157). The number needed to treat to prevent 1 preterm birth was 3.9 (95% confidence interval, 2.32-12.1). There was no difference in preterm birth rates between high and low vaginal cerclage (38% [15/39] vs 33% [11/33]; relative risk, 1.15; 95% confidence interval, 0.62-2.16; P=.81). No neonatal deaths occurred. In an exploratory analysis, women with transabdominal cerclage had fewer fetal losses compared with low vaginal cerclage (3% [1/39] vs 21% [7/33]; relative risk, 0.12; 95% confidence interval, 0.016-0.93; P=.02). The number needed to treat to prevent 1 fetal loss was 5.3 (95% confidence interval, 2.9-26). Transabdominal cerclage is the treatment of choice for women with failed vaginal cerclage. It is superior to low vaginal cerclage in the reduction of risk of early preterm birth and fetal loss in women with previous failed vaginal cerclage. High vaginal cerclage does not confer this benefit. The numbers needed to treat are sufficiently low to justify transabdominal surgery and cesarean delivery required in this select cohort.

The promise and pitfalls of precision medicine to resolve black-white racial disparities in preterm birth.

Differences in preterm birth rates between black and white women are the largest contributor to racial disparities in infant mortality. In today's age of precision medicine, analysis of the genome, epigenome, metabolome, and microbiome has generated interest in determining whether these biomarkers can help explain racial disparities. We propose that there are pitfalls as well as opportunities when using precision medicine analyses to interrogate disparities in health. To conclude that racial disparities in complex conditions are genetic in origin ignores robust evidence that social and environmental factors that track with race are major contributors to disparities. Biomarkers measured in omic assays that may be more environmentally responsive than genomics, such as the epigenome or metabolome, may be on the causal pathway of race and preterm birth, but omic observational studies suffer from the same limitations as traditional cohort studies. Confounding can lead to false conclusions about the causal relationship between omics and preterm birth. Methodological strategies (including stratification and causal mediation analyses) may help to ensure that associations between biomarkers and exposures, as well as between biomarkers and outcomes, are valid signals. These epidemiologic strategies present opportunities to assess whether precision medicine biomarkers can uncover biology underlying perinatal health disparities.