Late Preterm Birth Rate Research Articles

The Strong Correlation Between Multiple Births and Preterm Birth Rates in Greece From 1991 to 2022.

Background This study aims to investigate the correlation between the rising preterm birth rate (PBR) in Greece from 1991 to 2022 and the incidence of multiple births. Methodology Official data on live births in Greece from 1991 to 2022 were sourced from the Hellenic Statistical Authority. The PBR, defined as the number of live births occurring at <37 gestational weeks, and the multiple birth rate (MBR), representing live births from multifetal gestations, were calculated per 100 total live births. The relationship between the PBR and the MBR was evaluated using the non-parametric Spearman's rank correlation coefficient (rho). This association was confirmed through linear regression models, with MBR as the independent variable and PBR as the dependent variable, calculating the beta coefficient (β) and the coefficient of determination (R-squared). Results A very strong direct positive correlation was identified between PBR and MBR throughout the study period, with a Spearman's rho of 0.950 (p < 0.001). This conclusion was further supported by the linear regression model, which yielded a β coefficient of 3.32 (95% confidence interval = 2.78 to 3.86, p < 0.001). The R-squared was 0.838, indicating that the change in MBR explained 83.8% of the rise in PBR. The strongest correlations were observed for moderate PBR (32-33 weeks) with a rho of 0.962 (p < 0.001) and late PBR (34-36 weeks) with a rho of 0.940 (p < 0.001). During the period of a steep increase in prematurity rates in the country (1991-2011), an almost perfect correlation between PBR and MBR (rho = 0.987, p < 0.001) was noted. However, in recent years (2011-2022), characterized by a marginal increase in PBR, this association diminished, with a rho of 0.655 (p = 0.021). Conclusions This analysis revealed a strong positive correlation between the PBR and MBR in Greece from 1991 to 2022, underscoring the significant impact of multiple pregnancies on the substantial increase in preterm births within the Greek population.

Prenatal maternal inactivated COVID-19 vaccination: the maternal and neonatal outcomes, a retrospective cohort study.

Background: Despite the widespread adoption of COVID-19 vaccination, a comprehensive understanding of potential vaccine-induced adverse effects, particularly in the context of pregnancy, remains a critical area of investigation. Elevated concerns surround the maternal and neonatal outcomes subsequent to prenatal maternal COVID-19 vaccination. While existing studies have provided insights into the safety profile of COVID-19 mRNA vaccines, the extrapolation of these conclusions to inactivated COVID-19 vaccines poses uncertainties. Notably, limited data are available regarding the maternal and neonatal effects associated with inactivated COVID-19 vaccines. Objective: To evaluate the prenatal maternal inactivated COVID-19 vaccination and the impact on maternal and neonatal outcomes. Methods: This was a retrospective cohort study of women who delivered between January and June 2022 at a single university-affiliated hospital. Those who have completed at least one dose of inactivated vaccine before or during pregnancy were included in "vaccinated group," and those who were not vaccinated were included in "unvaccinated group," the maternal, pregnancy and neonatal outcomes were evaluated. Propensity score matching (PSM) was performed to balance the baseline parameters of the two groups. Results: A total of 1926 women were enrolled in this study, 827 (42.94%) women were prenatally vaccinated, and 1099 (57.06%) unvaccinated. The gestational week of delivery were slightly lower in the vaccinated group, 38.61 ± 1.89weeks in the vaccinated group and 38.93 ± 1.49weeks in the unvaccinated group. There was a higher rate of overall preterm delivery in the vaccinated group (aOR 1.61, 95% CI 1.07-2.42; p = 0.02), however, the probability of delivery before 34 weeks and before 32weeks (early preterm delivery) were similar (p > 0.05). A total of 2009 infants were born, 851 in the vaccinated group and 1158 in the unvaccinated group. There were similar neonatal outcomes in the two groups. Conclusion: Although we found a slightly lower gestational week of delivery and a possible increased rate of late preterm birth in the vaccination group, there was no difference in mean neonatal weight, incidence of low birth weight infants and other neonatal adverse complications. Meanwhile, there was no difference in pregnancy and maternal outcomes between the two groups.

The paradoxical influence of the COVID-19 lockdown period on different types of preterm births in Alberta: a provincial study.

The objective of this study was to determine if the COVID-19 pandemic impacted different types of preterm birth rates in Alberta, Canada. A population-based, retrospective, cohort study was conducted from March 15, 2015 to December 31, 2020 using provincial data. The primary exposure was the COVID-19 lockdown period, and the primary outcome was the incidence of preterm birth (<37 weeks gestational age). Multivariable analyses in the complete lockdown and overall lockdown (partial and complete lockdown) periods were performed to test the association between the year of birth and preterm birth status and were adjusted for various independent variables. Preterm birth status was adjusted for various confounding factors. Following the analysis of n = 41,187 mothers and their singleton infants, we found that the lockdown due to COVID-19 had no impact in reducing the overall preterm birth rate. However, a paradoxical influence was observed with an increase of extremely low preterm births in the overall lockdown period, and a decrease in moderate preterm births during the complete lockdown period. The results of this study demonstrated that there was a decrease in moderate and increase in extremely low preterm birth rates as a result of the COVID-19 lockdown. However, the COVID-19 lockdown did not impact the very preterm and late preterm birth rate in Alberta.

Early and late preterm birth rates in participants adherent to randomly assigned high dose docosahexaenoic acid (DHA) supplementation in pregnancy

Intention-to-treat analyses do not address adherence. Per protocol analyses treat nonadherence as a protocol deviation and assess if the intervention is effective if followed. To determine the rate of early preterm birth (EPTB, <34 weeks gestation) and preterm birth (PTB, <37 weeks gestation) in participants who adhered to a randomly assigned docosahexaenoic acid (DHA) dose of 1000mg/day. Eleven hundred women with a singleton pregnancy were enrolled before 20-weeks' gestation, provided a capsule with 200mg/day DHA and randomly assigned to two additional capsules containing a placebo or 800mg of DHA. In the Bayesian Adaptive Design, new randomization schedules were determined at prespecified intervals. In each randomization, the group with the most EPTB was assigned fewer participants than the other group. Adherence was defined a priori as a postpartum red blood cell phospholipid DHA (RBC-PL-DHA) ≥5.5%.and post hoc as ≥8.0% RBC-PL-DHA, the latter after examination of postpartum RBC-PL-DHA. Bayesian mixture models were fitted for gestational age and dichotomized for EPTB and PTB as a function of baseline RBC-PL-DHA and dose-adherence. Bayesian hierarchical models were also fitted for EPTB by dose adherence and quartiles of baseline RBC-PL-DHA. Adherence to the high dose using both RBC-PL-DHA cut points resulted in less EPTB compared to 200mg [Bayesian posterior probability (pp)=0.93 and 0.92, respectively]. For participants in the two lowest quartiles of baseline DHA status, adherence to the higher dose resulted in lower EPTB (≥5.5% RBC-PL-DHA, quartiles 1 and 2, pp=0.95 and 0.96; ≥8% RBC-PL-DHA, quartiles 1 and 2, pp=0.94 and 0.95). Using the Bayesian model, EPTB was reduced by 65%, from 3.45% to 1.2%, using both cut points. Adherence also reduced PTB before 35, 36 and 37 weeks using both cut points (pp≥0.95). In general, performance of the nonadherent subgroup mirrored that of participants assigned to 200mg. Adherence to high dose DHA reduced EPTB and PTB. The largest effect of adherence on reducing EPTB was observed in women with low baseline DHA levels. gov (NCT02626299).

Associations between Phthalate Exposure and Gestational Age at Delivery in a Diverse Pregnancy Cohort.

The association between prenatal phthalate exposure and late preterm birth (LPTB) is unclear. We examined singleton pregnancies (2006-2011) from a racially and socioeconomically diverse sample of women in the CANDLE cohort of the ECHO-PATHWAYS Consortium. Urine collected in the second and third trimester was analyzed for 14 phthalate metabolites. Multivariate logistic and linear regressions were performed for LPTB, defined as delivery 34-37 weeks, and gestational week, respectively. Models were controlled for socio-demographics, behavioral factors, clinical measurements, medical history, and phthalates in the other trimester. Effect modification by race and pregnancy stress, indicated by intimate partner violence (IPV), was investigated. We conducted a secondary analysis in women with spontaneous preterm labor. The rate of LPTB among 1408 women (61% Black, 32% White) was 6.7%. There was no evidence of decreased gestational age (GA) in association with any phthalate metabolite. Each two-fold increase in third trimester mono-benzyl phthalate (MBzP) was associated with 0.08 weeks longer gestational age (95% CI: 0.03, 0.12). When restricting to women with spontaneous labor, second trimester mono-n-butyl phthalate (MBP) was associated with 54% higher odds (95% CI: 2%, 132%) of LPTB. Associations were not modified by maternal race or IPV exposure. In conclusion, we observed mixed evidence concerning our hypothesis that prenatal phthalate exposure increases risk of LPTB, though secondary analyses suggest increased risk of spontaneous LPTB associated with MBP, which is consistent with a recent pooled analysis of 16 cohorts.

Point: Antenatal corticosteroid treatment in the late preterm period-Are the benefits worth the potential risks?

Point: Antenatal corticosteroid treatment in the late preterm period-Are the benefits worth the potential risks?

Is 25 mm the correct mid-trimester cut-off for cervical shortening among asymptomatic women?

To evaluate the impact of asymptomatic cervical shortening (ACS) at mid-trimester on maternal and neonatal outcomes. This was a retrospective cohort study. Women with singleton gestations and an accidental finding of cervical length of 25 mm or less at mid-trimester were compared with women with symptomatic cervical shortening (SCS) and women with normal cervical length (NCL). Primary outcome was preterm birth (PTB) rate; secondary outcomes included total hospitalization length, betamethasone treatment rate, and a composite of PTB neonatal outcomes. In all, 1483 women were diagnosed with ACS. There was no difference in early and late PTB rate between the ACS and NCL groups (4.9% versus 3.8%, P= 0.25), though there was a significantly higher rate of antenatal corticosteroids use in the ACS group (78.2% versus 7.4%, P< 0.001). A CL of 15 mm or less was significantly associated with both early and late PTB, compared with the NCL group (47.2% versus 3.6%, P< 0.001, and 35.8% versus 3.8%, P< 0.001). An ACS of 15-25 mm is not associated with an increased risk of PTB. In contrast, women with a CL of 15 mm or less are more likely to delivery prematurely compared with women with a CL greater than 15 mm.

Updates on an At-Risk Population: Late-Preterm and Early-Term Infants.

The American Academy of Pediatrics published a clinical report on late-preterm (LPT) infants in 2007 that was largely based on a summary of a 2005 workshop convened by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, at which a change in terminology from "near term" to "late preterm" was proposed. This paradigm-shifting recommendation had a remarkable impact: federal agencies (the Centers for Disease Control and Prevention), professional societies (the American Academy of Pediatrics and American College of Obstetricians and Gynecologists), and organizations (March of Dimes) initiated nationwide monitoring and educational plans that had a significant effect on decreasing the rates of iatrogenic LPT deliveries. However, there is now an evolving concern. After nearly a decade of steady decreases in the LPT birth rate that largely contributed to the decline in total US preterm birth rates, the birth rate in LPT infants has been inching upward since 2015. In addition, evidence revealed by strong population health research demonstrates that being born as an early-term infant poses a significant risk to an infant's survival, growth, and development. In this report, we summarize the initial progress and discuss the potential reasons for the current trends in LPT and early-term birth rates and propose research recommendations.

Early and Late Preterm Birth Rates Among US-Born Urban Women: The Effect of Men's Lifelong Class Status.

To ascertain the relation of men's lifelong class status (as measured by neighborhood income) to the rates of early (< 34weeks) and late (34-36weeks) preterm birth (PTB). Stratified and multilevel, multivariable binomial regression analyses were computed on the Illinois transgenerational birth-file of infants (born 1989-1991) and their parents (born 1956-1976) with appended U.S. census income information. The median family income of men's census tract residence at two-time periods were utilized to assess lifelong class status (defined by residence in either the lower or upper half of neighborhood income distribution). In Cook County Illinois, the preterm rate for births (n = 8115) to men with a lifelong lower class status was twice that of births (n = 10,330) to men with a lifelong upper class status: 13% versus 6.0%, RR = 2.2 (2.0, 2.4). This differential was greatest in early PTB rates: 3.9% versus 1.4%, RR = 3.0 (2.5, 3.7). The relation of men's lifelong class status to both PTB components persisted among non-teens, married, college-educated, and non-Latina White women, respectively. The adjusted (controlling for maternal demographic characteristics) RR of early and late PTB for men with a lifelong lower (versus upper) class status were 1.4 (1.1, 1.9) and 1.2 (1.0, 1.4), respectively. The population attributable risk of early PTB for men's lifelong lower class status equaled 16%. Men's lifelong lower (versus upper) class status is a novel risk factor for early preterm birth regardless of maternal demographic characteristics. This intriguing finding has public health relevance.

QuickStats: Changes* in Late Preterm Birth Rates,† by State - National Vital Statistics System, United States, 2014 and 2016.

QuickStats: Changes* in Late Preterm Birth Rates,† by State - National Vital Statistics System, United States, 2014 and 2016.

741: Bidet toilet use; the association with abnormal vaginal colonization and preterm birth in high risk pregnant women, a prospective study

Habitual bidet toilets are widely used these days for cleaning the anal or urogenital area in many women. Although there might be some concerns that the use of bidet toilets may alter vaginal flora and cause abnormal vaginal colonization, the actual association between habitual bidet toilet use and the change of vaginal normal flora and the risk of subsequent preterm birth is rarely investigated. Here, we aimed to evaluate the effect of bidet toilets on abnormal vaginal colonization and preterm birth in patients with preterm labor (PTL) and preterm premature rupture of membrane (PPROM). This is a prospective cohort study of 212 women who admitted to high-risk pregnancy unit due to PTL or PPROM in two tertiary hospitals between 2015 and 2017. Response to a questionnaire containing the use, mode, or the time of bidet toilet usage and vaginal culture were obtained. The bidet toilet user was defined as those who have used bidet toilet since at least one year before pregnancy and during pregnancy. Maternal baseline characteristics, vaginal culture results, obstetrical outcome and neonatal outcome were collected and compared between the user and non-users of bidet toilet. Abnormal vaginal colonization included aerobe, anaerobe, and Ureaplasma species. Among 212 subjects, 67 (32.0 %) women responded that they used bidet toilet. The incidence of preterm birth before 37 weeks of gestation was significantly higher in the users compared to the non-users (86.8% vs. 72.8%, P=0.047). Interestingly, the rate of late preterm birth (GA 34+0-36+6 weeks) in the users was more than twice than the non-users (43.4% vs. 20.6%, P=0.003). Abnormal vaginal colonization rate was significantly higher in the users than the non-users (60.3% vs. 42.7%, P=0.027). Notably, the Escherichia coli colonization rate was higher in users than non-users (11.9% vs. 3.2%, P=0.039). The colonization rates of other bacterial types or genital Ureaplasma were not associated with use of bidet. Our study results implicate that the use of bidet toilet is associated with a higher rate of preterm birth and abnormal vaginal colonization in women with PTL and PPROM. Interestingly, E. coli colonization rate was significantly higher in bidet users.

Provider-initiated delivery, late preterm birth and perinatal mortality: a secondary analysis of the WHO multicountry survey on maternal and newborn health

IntroductionIn high-income countries, a reduced clinical threshold for obstetric interventions such as labour induction (LI) and prelabour caesarean delivery (PLCD) has played a substantial role in increasing rates of late...

Temporal Trends in Late Preterm and Early Term Birth Rates in 6 High-Income Countries in North America and Europe and Association With Clinician-Initiated Obstetric Interventions.

Clinicians have been urged to delay the use of obstetric interventions (eg, labor induction, cesarean delivery) until 39 weeks or later in the absence of maternal or fetal indications for intervention. To describe recent trends in late preterm and early term birth rates in 6 high-income countries and assess association with use of clinician-initiated obstetric interventions. Retrospective analysis of singleton live births from 2006 to the latest available year (ranging from 2010 to 2015) in Canada, Denmark, Finland, Norway, Sweden, and the United States. Use of clinician-initiated obstetric intervention (either labor induction or prelabor cesarean delivery) during delivery. Annual country-specific late preterm (34-36 weeks) and early term (37-38 weeks) birth rates. The study population included 2,415,432 Canadian births in 2006-2014 (4.8% late preterm; 25.3% early term); 305,947 Danish births in 2006-2010 (3.6% late preterm; 18.8% early term); 571,937 Finnish births in 2006-2015 (3.3% late preterm; 16.8% early term); 468,954 Norwegian births in 2006-2013 (3.8% late preterm; 17.2% early term); 737,754 Swedish births in 2006-2012 (3.6% late preterm; 18.7% early term); and 25,788,558 US births in 2006-2014 (6.0% late preterm; 26.9% early term). Late preterm birth rates decreased in Norway (3.9% to 3.5%) and the United States (6.8% to 5.7%). Early term birth rates decreased in Norway (17.6% to 16.8%), Sweden (19.4% to 18.5%), and the United States (30.2% to 24.4%). In the United States, early term birth rates decreased from 33.0% in 2006 to 21.1% in 2014 among births with clinician-initiated obstetric intervention, and from 29.7% in 2006 to 27.1% in 2014 among births without clinician-initiated obstetric intervention. Rates of clinician-initiated obstetric intervention increased among late preterm births in Canada (28.0% to 37.9%), Denmark (22.2% to 25.0%), and Finland (25.1% to 38.5%), and among early term births in Denmark (38.4% to 43.8%) and Finland (29.8% to 40.1%). Between 2006 and 2014, late preterm and early term birth rates decreased in the United States, and an association was observed between early term birth rates and decreasing clinician-initiated obstetric interventions. Late preterm births also decreased in Norway, and early term births decreased in Norway and Sweden. Clinician-initiated obstetric interventions increased in some countries but no association was found with rates of late preterm or early term birth.

Provider-Initiated Late Preterm Births in Brazil: Differences between Public and Private Health Services.

BackgroundA large proportion of the rise in prematurity worldwide is owing to late preterm births, which may be due to the expansion of obstetric interventions, especially pre-labour caesarean section. Late preterm births pose similar risks to overall prematurity, making this trend a concern. In this study, we describe factors associated with provider-initiated late preterm birth and verify differences in provider-initiated late preterm birth rates between public and private health services according to obstetric risk.MethodsThis is a sub-analysis of a national population-based survey of postpartum women entitled “Birth in Brazil”, performed between 2011 and 2012. We included 23,472 singleton live births. We performed non-conditional multiple logistic regressions assessing associated factors and analysing differences between public and private health services.ResultsProvider-initiated births accounted for 38% of late preterm births; 32% in public health services and 61% in private health services. They were associated with previous preterm birth(s) and maternal pathologies for women receiving both public and private services and with maternal age ≥35 years for women receiving public services. Women receiving private health services had higher rates of provider-initiated late preterm birth (rate of 4.8%) when compared to the ones receiving public services (rate of 2.4%), regardless of obstetric risk–adjusted OR of 2.3 (CI 1.5–3.6) for women of low obstetric risk and adjusted OR of 1.6 (CI 1.1–2.3) for women of high obstetric risk.ConclusionThe high rates of provider-initiated late preterm birth suggests a considerable potential for reduction, as such prematurity can be avoided, especially in women of low obstetric risk. To promote healthy births, we advise introducing policies with incentives for the adoption of new models of birth care.

Considerations on the late-preterm newborn with cardiac problems

Focus on the late preterm birth (LPB) and critical congenital heart defects (CCHD) Data on outcomes of CCHD specifically in late preterm infants are exceedingly scarce. The preterm newborn with associated complex CHD presents many intricate problems to clinicians who take care (neonatologist, cardiologist, cardiothoracic surgeon). Therapies used for the preterm neonate without heart disease frequently need to be altered in the presence of heart disease and those needed for management of heart disease may need to be altered because of prematurity. The population of newborn born preterm is at higher risk for postoperative death and short and long term complications than term newborn with the same CHD and the causes of this are multifactorial. Technical issue related to small cardiac structure, immaturity of other organ systems, decreased nutritional and cardiac reserve, increased risks of bleeding, abnormal chest wall mechanics after sternotomy can all together account for this epidemiologic data. In past years these findings were related in particular to low-birth weight infants and conventional management was oriented to await a threshold weight in order to reduce bypass-related morbidities. From 1990 rates of LPB have risen and now account for 75% of all preterm births. Whether late preterm infants with CHD, who may be only marginally more immature than their term counterparts, remain at risk for adverse outcome in unclear. Some recent papers do demonstrate the independent effect of LPB on mortality and morbidity if a CHD is present and this issue emerge as an important factor for a correct counseling. Natarajan have observed that the weight at surgical intervention was significantly lower and age higher in the late preterm infants compared to those delivered at term. Late preterm infants had significantly higher rates of NEC and seizures, with a greater risk of supplemental oxygen and tube feeding at discharge. Costello have examined mortality and morbidity stratified by gestational age, reporting for LPB group with CHD an hospital mortality rate of 16.4% compared to 2.6-8% in the term group. The exact mechanism of this vulnerability remains unclear although functional immaturity of the lung and the brain are plausible aetiologies. Altered intrinsic cardiac mechanism could play a role in adverse outcome of late preterm with CHD. Gestational age at delivery can be a risk factor over which clinicians might have some control. Before birth the challenge is planning the time and the place for the delivery of a foetus with CHD. After birth the challenge is not waiting for obtain an arbitrary correct weight for surgery but working in a complex team to discuss each case in order to maximize outcome. Domande inerenti la relazione del Dott. Stefano Fiocchi

Short-Term Neonatal Outcomes in Diamniotic Twin Pregnancies Delivered after 32 Weeks and Indications of Late Preterm Deliveries

We sought to compare neonatal outcomes in twin pregnancies following moderately preterm birth (MPTB), late preterm birth (LPTB), and term birth and determine the indications of LPTB. We performed a retrospective cohort study. MPTB was defined as delivery between 32(0/7) and 33(6/7) weeks and LPTB between 34(0/7) and 36(6/7) weeks. The composite neonatal adverse respiratory outcome was defined as respiratory distress syndrome and/or bronchopulmonary dysplasia. The composite neonatal adverse nonrespiratory outcome included early onset culture-proven sepsis, necrotizing enterocolitis, retinopathy of prematurity, intraventricular hemorrhage, or periventricular leukomalacia. LPTB cases were categorized as spontaneous (noniatrogenic), evidence-based iatrogenic, and non-evidence-based (NEB) iatrogenic. Of the 747 twin deliveries during the study period, 453 sets met the inclusion criteria with 22.7% (n = 145) MPTB, 32.1% (n = 206) LPTB, and 15.9% (n = 102) term births. Compared with term neonates, the composite neonatal adverse respiratory outcome was increased following MPTB (relative risk [RR] 24; 95% confidence interval [CI] 3.0 to 193.6) and LPTB (RR 13.7; 95% CI 1.8 to 101.8). Compared with term neonates, the composite neonatal adverse nonrespiratory outcome was increased following MPTB (RR 22.3; 95% CI 3.9 to 127.8) and LPTB (RR 5.5; 95% CI 1.1 to 27.6). Spontaneous delivery of LPTB was 63.6% (n = 131/206) and the rate of iatrogenic delivery was 36.4% (n = 75/206). The majority, 66.6% (n = 50/75), of these iatrogenic deliveries were deemed NEB, giving a total of 24.2% (50/206) NEB deliveries in LPTB group. Our data demonstrate a high rate of late preterm birth among twin pregnancies, with over half of nonspontaneous early deliveries due to NEB indications. Although our morbidity data will be helpful to providers in counseling patients, our finding of high NEB indications underscores the need for systematic evaluation of indications for delivery in LPTB twin deliveries. Furthermore, this may lead to more effective LPTB rate reduction efforts.

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

To examine international rates of preterm birth and potential associations with stillbirths and neonatal deaths at late preterm and term gestation. Ecological study. Canada, USA and 26 countries in Europe. All deliveries in 2004. Information on preterm birth (<37, 32-36, 28-31 and 24-27 weeks of gestation) and perinatal deaths was obtained for 28 countries. Data sources included files and publications from Statistics Canada, the EURO-PERISTAT project and the National Center for Health Statistics. Pearson correlation coefficients and random-intercept Poisson regression were used to examine the association between preterm birth rates and gestational age-specific stillbirth and neonatal death rates. Rate ratios with 95% confidence intervals were estimated after adjustment for maternal age, parity and multiple births. Stillbirths and neonatal deaths ≥ 32 and ≥ 37 weeks of gestation. International rates of preterm birth (<37 weeks) ranged between 5.3 and 11.4 per 100 live births. Preterm birth rates at 32-36 weeks were inversely associated with stillbirths at ≥ 32 weeks (adjusted rate ratio 0.94, 95% CI 0.92-0.96) and ≥ 37 weeks (adjusted rate ratio 0.88, 95% CI 0.85-0.91) of gestation and inversely associated with neonatal deaths at ≥ 32 weeks (adjusted rate ratio 0.88, 95% CI 0.85-0.91) and ≥ 37 weeks (adjusted rate ratio 0.82, 95% CI 0.78-0.86) of gestation. Countries with high rates of preterm birth at 32-36 weeks of gestation have lower stillbirth and neonatal death rates at and beyond 32 weeks of gestation. Contemporary rates of preterm birth are indicators of both perinatal health and obstetric care services.

820 Late Preterm Deliveries and Neonatal Outcomes in Multicentre French Regional Perinatal Network

ObjectiveThe objective of the study was to present the neonatal outcomes for late preterm birth by gestational age at 33.34 and 35 weeks in a multicentric neonatal network.Study DesignThis was...

The Late Preterm Birth Rate and Its Association with Comorbidities in a Population-Based Study

We sought to identify rates, associated morbidities, and preventable causes of late preterm birth (LPB) in a defined population. We conducted a retrospective cross-sectional analysis using deidentified delivery data for all who delivered in San Antonio/Bexar County, Texas between 2000 and 2008 (N = 259,576). LPB was defined as a live birth from 34(0/7) to 36(6/7) weeks. Variables analyzed included age, race/ethnicity, weight gain, hypertensive disease, diabetes, and preterm labor including premature rupture of membranes. From 2000 to 2006, the LPB rate in San Antonio/Bexar County, Texas, was slightly higher than the national average, 9% versus 8.7% (P < 0.01). From 2000 to 2008, 23,312 LPBs occurred in San Antonio/Bexar County and 53% experienced at least one studied comorbidity. Using logistic regression comparing LPB to term, variables associated with an increased risk of LPB were black race, age < 17, age ≥ 35, gestational hypertension, eclampsia, chronic hypertension, and diabetes. LPB was higher than the national average in our population, and preventable causes of LPB (extremes of age, hypertensive disease, and diabetes) were commonly associated with LPB. We speculate that teenage pregnancy prevention, counseling regarding risks associated with advanced maternal age, and improved management and prevention of hypertensive disease and diabetes should prove beneficial in decreasing the LPB rate.

Late preterm births: irreducible because E = mc2

Defined as delivery at 34(0/7)-36(6/7) weeks, late preterm births have increased by 15% between 1992 and 2002 and currently they occur in about 8% of singletons and 35% of multiple gestations. Compared with newborns at 39 weeks, late preterm births undeniably have a significantly higher rate of morbidity (respiratory distress syndrome, pneumonia, need for ventilation), as well as neonatal and infant mortality. Thus, to lower the rate of late preterm birth seems to be self-evident necessity, but there is a need for judicious caution because there is insufficient evidence that prolonging these pregnancies improves maternal-fetal outcomes.