Determinants and consequences of discrepancies in menstrual and ultrasonographic gestational age estimates

Delivery and Safety of a Two-Dose Preventive Ebola Virus Disease Vaccine in Pregnant and Non-Pregnant Participants during an Outbreak in the Democratic Republic of the Congo

During the 2018-2020 Ebola virus disease (EVD) outbreak, residents in Goma, Democratic Republic of the Congo, were offered a two-dose prophylactic EVD vaccine. This was the first study to evaluate the safety of this vaccine in pregnant women. Adults, including pregnant women, and children aged ≥1 year old were offered the Ad26.ZEBOV (day 0; dose 1), MVA-BN-Filo (day 56; dose 2) EVD vaccine through an open-label clinical trial. In total, 20,408 participants, including 6635 (32.5%) children, received dose 1. Fewer than 1% of non-pregnant participants experienced a serious adverse event (SAE) following dose 1; one SAE was possibly related to the Ad26.ZEBOV vaccine. Of the 1221 pregnant women, 371 (30.4%) experienced an SAE, with caesarean section being the most common event. No SAEs in pregnant women were considered related to vaccination. Of 1169 pregnancies with a known outcome, 55 (4.7%) ended in a miscarriage, and 30 (2.6%) in a stillbirth. Eleven (1.0%) live births ended in early neonatal death, and five (0.4%) had a congenital abnormality. Overall, 188/891 (21.1%) were preterm births and 79/1032 (7.6%) had low birth weight. The uptake of the two-dose regimen was high: 15,328/20,408 (75.1%). The vaccine regimen was well-tolerated among the study participants, including pregnant women, although further data, ideally from controlled trials, are needed in this crucial group.

Is the Biphasic Effect of Diabetes and Obesity on Fetal Growth a Risk Factor for Childhood Obesity?

In pregnancies of women with obesity or diabetes, neonates are often overgrown. Thus, the pregnancy period in these women offers a window of opportunity to reduce childhood obesity by preventing neonatal overgrowth. However, the focus has been almost exclusively on growth in late pregnancy. This perspective article addresses possible growth deviations earlier in pregnancy and their potential contribution to neonatal overgrowth. This narrative review focuses on six large-scale, longitudinal studies that included ∼14,400 pregnant women with at least three measurements of fetal growth. A biphasic pattern in growth deviation, including growth reduction in early pregnancy followed by overgrowth in late pregnancy, was found in fetuses of women with obesity, gestational diabetes mellitus (GDM), or type 1 diabetes compared with lean women and those with normal glucose tolerance. Fetuses of women with these conditions have reduced abdominal circumference (AC) and head circumference (HC) in early pregnancy (observed between 14 and 16 gestational weeks), while later in pregnancy they present the overgrown phenotype with larger AC and HC (from approximately 30 gestational weeks onwards). Fetuses with early-pregnancy growth reduction who end up overgrown presumably have undergone in utero catch-up growth. Similar to postnatal catch-up growth, this may confer a higher risk of obesity in later life. Potential long-term health consequences of early fetal growth reduction followed by in utero catch-up growth need to be explored.

Machine learning for accurate estimation of fetal gestational age based on ultrasound images

Accurate estimation of gestational age is an essential component of good obstetric care and informs clinical decision-making throughout pregnancy. As the date of the last menstrual period is often unknown or uncertain, ultrasound measurement of fetal size is currently the best method for estimating gestational age. The calculation assumes an average fetal size at each gestational age. The method is accurate in the first trimester, but less so in the second and third trimesters as growth deviates from the average and variation in fetal size increases. Consequently, fetal ultrasound late in pregnancy has a wide margin of error of at least ±2 weeks' gestation. Here, we utilise state-of-the-art machine learning methods to estimate gestational age using only image analysis of standard ultrasound planes, without any measurement information. The machine learning model is based on ultrasound images from two independent datasets: one for training and internal validation, and another for external validation. During validation, the model was blinded to the ground truth of gestational age (based on a reliable last menstrual period date and confirmatory first-trimester fetal crown rump length). We show that this approach compensates for increases in size variation and is even accurate in cases of intrauterine growth restriction. Our best machine-learning based model estimates gestational age with a mean absolute error of 3.0 (95% CI, 2.9-3.2) and 4.3 (95% CI, 4.1-4.5) days in the second and third trimesters, respectively, which outperforms current ultrasound-based clinical biometry at these gestational ages. Our method for dating the pregnancy in the second and third trimesters is, therefore, more accurate than published methods.

Machine learning prediction of gestational age from metabolic screening markers resistant to ambient temperature transportation: Facilitating use of this technology in low resource settings of South Asia and East Africa

Background

Knowledge of gestational age is critical for guiding preterm neonatal care. In the last decade, metabolic gestational dating approaches emerged in response to a global health need; because in most of the developing world, accurate antenatal gestational age estimates are not feasible. These methods initially developed in North America have now been externally validated in two studies in developing countries, however, require shipment of samples at sub-zero temperature.

Methods

A subset of 330 pairs of heel prick dried blood spot samples were shipped on dry ice and in ambient temperature from field sites in Tanzania, Bangladesh and Pakistan to laboratory in Iowa (USA). We evaluated impact on recovery of analytes of shipment temperature, developed and evaluated models for predicting gestational age using a limited set of metabolic screening analytes after excluding 17 analytes that were impacted by shipment conditions of a total of 44 analytes.

Results

With the machine learning model using all the analytes, samples shipped in dry ice yielded a Root Mean Square Error (RMSE) of 1.19 weeks compared to 1.58 weeks for samples shipped in ambient temperature. Out of the 44 screening analytes, recovery of 17 analytes was significantly different between the two shipment methods and these were excluded from further machine learning model development. The final model, restricted to stable analytes provided a RMSE of 1.24 (95% confidence interval (CI) = 1.10-1.37) weeks for samples shipped on dry ice and RMSE of 1.28 (95% CI = 1.15-1.39) for samples shipped at ambient temperature. Analysis for discriminating preterm births (gestational age <37 weeks), yielded an area under curve (AUC) of 0.76 (95% CI = 0.71-0.81) for samples shipped on dry ice and AUC of 0.73 (95% CI = 0.67-0.78) for samples shipped in ambient temperature.

Conclusions

In this study, we demonstrate that machine learning algorithms developed using a sub-set of newborn screening analytes which are not sensitive to shipment at ambient temperature, can accurately provide estimates of gestational age comparable to those from published regression models from North America using all analytes. If validated in larger samples especially with more newborns <34 weeks, this technology could substantially facilitate implementation in LMICs.

Reliability of last menstrual period recall, an early ultrasound and a Smartphone App in predicting date of delivery and classification of preterm and post-term births

Background

A reliable expected date of delivery (EDD) is important for pregnant women in planning for a safe delivery and critical for management of obstetric emergencies. We compared the accuracy of LMP recall, an early ultrasound (EUS) and a Smartphone App in predicting the EDD in South African pregnant women. We further evaluated the rates of preterm and post-term births based on using the different measures.

Methods

This is a retrospective sub-study of pregnant women enrolled in a randomized controlled trial between October 2017-December 2019. EDD and gestational age (GA) at delivery were calculated from EUS, LMP and Smartphone App. Data were analysed using SPSS version 25. A Bland–Altman plot was constructed to determine the limits of agreement between LMP and EUS.

Results

Three hundred twenty-five pregnant women who delivered at term (≥ 37 weeks by EUS) and without pregnancy complications were included in this analysis. Women had an EUS at a mean GA of 16 weeks and 3 days). The mean difference between LMP dating and EUS is 0.8 days with the limits of agreement 31.4–30.3 days (Concordance Correlation Co-efficient 0.835; 95%CI 0.802, 0.867). The mean(SD) of the marginal time distribution of the two methods differ significantly (p = 0.00187). EDDs were < 14 days of the actual date of delivery (ADD) for 287 (88.3%;95%CI 84.4–91.4), 279 (85.9%;95%CI 81.6–89.2) and 215 (66.2%;95%CI 60.9–71.1) women for EUS, Smartphone App and LMP respectively but overall agreement between EUS and LMP was only 46.5% using a five category scale for EDD-ADD with a kappa of .22. EUS 14–24 weeks and EUS < 14 weeks predicted EDDs < 14 days of ADD in 88.1% and 79.3% of women respectively. The proportion of births classified as preterm (< 37 weeks) was 9.9% (95%CI 7.1–13.6) by LMP and 0.3% (95%CI 0.1–1.7) by Smartphone App. The proportion of post-term (> 42 weeks gestation) births was 11.4% (95%CI 8.4–15.3), 1.9% (95%CI 0.9–3.9) and 3.4% (95%CI 1.9–5.9) by LMP, EUS and Smartphone respectively.

Conclusions

EUS and Smartphone App were the most accurate to estimate the EDD in pregnant women. LMP-based dating resulted in misclassification of a significantly greater number of preterm and post-term deliveries compared to EUS and the Smartphone App.

Luteinizing Hormone Surge More Accurately Correlates With Ultrasound Dating of Early Pregnancy Compared to the Last Menstrual Period

OBJECTIVES

To compare the use of the luteinizing hormone (LH) surge versus the last menstrual period (LMP) for the accuracy of pregnancy dating in fertile women with a diagnosis of recurrent early pregnancy loss (REPL).

METHODS

This was an observational cohort study using prospectively collected data at 2 academic REPL programs between 2005 and 2018. Women with a history of REPL and at least 1 subsequent live birth after the evaluation were included. All patients conceived by intercourse timed to the LH surge. Transvaginal ultrasound was examinations were performed 2 weeks after missed menses. The gestational age (GA) was calculated by the LH surge (GA_LH ), LMP (GA_LMP ), and first crown-rump length (CRL) that measured 5 mm or greater (GA_CRL ). A secondary analysis compared GA based on the first measurable CRL of less than 5 mm versus GA based on the first CRL of 5 mm or greater. The GA_LH and GA_LMP were compared to determine which measure showed greater concordance with the CRL. The mean absolute difference in days between the GA_CRL versus GA_LH and GA_CRL versus GA_LMP was determined.

RESULTS

A total of 115 women with 118 subsequent pregnancies resulting in live birth were included, with a mean age at delivery of 35.5 years and a mean of 3.6 prior pregnancy losses. The GA_LH showed a stronger correlation with the CRL (0.77) than the GA_LMP (0.63; P = .002). The GA_LH was more similar to the GA_CRL than the GA_LMP , with a mean absolute difference of 2.0 versus 3.1 days (P < .0001).

CONCLUSIONS

When known, the LH surge appears to be more accurate than the LMP and should be used preferentially for dating of early pregnancy.

Association of Preterm Birth With Prescription of Psychotropic Drugs in Adolescence and Young Adulthood

IMPORTANCE

Individuals born preterm have increased risk of mental health impairment compared with individuals born at term. The associations between preterm birth and attention-deficit/hyperactivity disorder and autism are well established; for depression, anxiety, psychotic and bipolar disorder, studies show divergent results.

OBJECTIVE

To compare the prescription of psychotropic drugs in adolescence and young adulthood between those born preterm and those born at term.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used registry data to identify all Norwegians born after 23 weeks of completed gestation between 1989 and 1998. Included individuals were those without registered birth defects, alive at age 10 years, and with available maternal data. Individuals were followed up from 2004 to 2016. Psychotropic drug prescriptions received from age 10 to 23 years were compared between preterm groups and peers born at term. Individuals were compared with their siblings to control for shared family confounding. Data analyses were performed from August 2018 through February 2020.

EXPOSURES

Gestational age at birth (GA) was categorized in 4 groups: extremely preterm (GA, 23 weeks and 0 days to 27 weeks and 6 days), very preterm (GA, 28 weeks and 0 days to 31 weeks and 6 days), moderately or late preterm (GA, 32 weeks and 0 days to 36 weeks and 6 days), and full term (GA, 37 weeks and 0 days to 44 weeks and 6 days).

MAIN OUTCOMES AND MEASURES

Prescriptions of psychotropic drugs (ie, prescriptions specifically of psychostimulants, antidepressants, anxiolytics, hypnotics or sedatives, or antipsychotics or prescriptions of any of these 5 drugs) among preterm groups were compared with prescriptions among peers born at term and among siblings.

RESULTS

Among 505 030 individuals (259 545 [51.4%] males; mean [SD] birth weight, 3533 [580] g), 762 individuals (0.2%) were extremely preterm, 2907 individuals (0.6%) were very preterm, 25 988 individuals (5.1%) were moderately or late preterm, and 475 373 individuals (94.1%) were full term. Individuals born preterm had increased risk of psychotropic drug prescription, with a dose-response association between GA and prescription. The extremely preterm group had higher rates of prescription for all drug types compared with peers born at term, with odds ratios from 1.7 (95% CI, 1.4-2.1) for antidepressants to 2.7 (95% CI, 2.1-3.4) for psychostimulants. The elevated odds of prescription of all types were less pronounced in the moderately to late preterm group, including odds ratios of 1.1 (95% CI, 1.0-1.1) for antidepressants and 1.2 (95% CI, 1.1-1.2) for psychostimulants. The increases in odds were smaller in the sibling comparison, and increases were not significant for several groups. For example, the OR for any prescription in the sibling analysis was 1.8 (95% CI, 1.2-2.8) in the very preterm group and 1.0 (95% CI, 0.9-1.1) in the moderately or late preterm group.

CONCLUSIONS AND RELEVANCE

This cohort study found higher rates of prescription of psychotropic drugs throughout adolescence and young adulthood among individuals with all degrees of preterm birth compared with those born at term. These results provide further evidence for an increased risk of mental health impairment among individuals born preterm and suggest that this is not restricted to the most preterm groups.

Methodological Issues in the Study of the Development of Pain Responsivity in Preterm Neonates: A Systematic Review

The study of the development of neonatal pain responses is of key importance, both for research and for clinical reasons, with particular regard to the population of preterm neonates, given the amount of painful procedures they are exposed to on a daily basis. The aim of this work was to systematize our knowledge about the development of pain responses in prematurely born neonates by focusing on some key methodological issues. Studies on the impact of age variables, namely gestational age (GA), postmenstrual age (PMA) and chronological age (CH), on pain responsivity in premature neonates were identified using Medline and Scopus. Studies (N = 42) were categorized based on terminological and methodological approaches towards age variables, and according to output variables considered (facial, nonfacial behavioral, physiological). Distinct multidimensional developmental patterns were found for each age-sampling strategy. Overall, each of the three age variables seems to affect pain responsivity, possibly differently across age windows. Targeted as well as integrated approaches, together with a renewed attention for methodological consistency, are needed to further our knowledge on this topic.

Quality of Pregnancy Dating and Obstetric Interventions During Labor: Retrospective Database Analysis

BACKGROUND

The correct dating of pregnancy is critical to support timely decisions and provide obstetric care during birth. The early obstetric ultrasound assessment before 14 weeks is considered the best reference to assist in determining gestational age (GA), with an accuracy of ±5 to 7 days. However, this information is limited in many settings worldwide.

OBJECTIVE

The aim of this study is to analyze the association between the obstetric interventions during childbirth and the quality of GA determination, according to the first antenatal ultrasound assessment, which assisted the calculation.

METHODS

This is a hospital-based cohort study using medical record data of 2113 births at a perinatal referral center. The database was separated into groups and subgroups of analyses based on the reference used by obstetricians to obtain GA at birth. Maternal and neonatal characteristics, mode of delivery, oxytocin augmentation, and forceps delivery were compared between groups of pregnancies with GA determination at different reference points: obstetric ultrasound assessment 14 weeks, 20 weeks, and ≥20 weeks or without antenatal ultrasound (suboptimal dating). Ultrasound-based GA information was associated with outcomes between the interest groups using chi-square tests, odds ratios (OR) with 95% CI, or the Mann-Whitney statistical analysis.

RESULTS

The chance of nonspontaneous delivery was higher in pregnancies with 14 weeks ultrasound-based GA (OR 1.64, 95% CI 1.35-1.98) and 20 weeks ultrasound-based GA (OR 1.58, 95% CI 1.31-1.90) when compared to the pregnancies with ≥20 weeks ultrasound-based GA or without any antenatal ultrasound. The use of oxytocin for labor augmentation was higher for 14 weeks and 20 weeks ultrasound-based GA, OR 1.41 (95% CI 1.09-1.82) and OR 1.34 (95% CI 1.04-1.72), respectively, when compared to those suboptimally dated. Moreover, maternal blood transfusion after birth was more frequent in births with suboptimal ultrasound-based GA determination (20/657, 3.04%) than in the other groups (14 weeks ultrasound-based GA: 17/1163, 1.46%, P=.02; 20 weeks ultrasound-based GA: 25/1456, 1.71%, P=.048). Cesarean section rates between the suboptimal dating group (244/657, 37.13%) and the other groups (14 weeks: 475/1163, 40.84%, P=.12; 20 weeks: 584/1456, 40.10%, P=.20) were similar. In addition, forceps delivery rates between the suboptimal dating group (17/657, 2.6%) and the other groups (14 weeks: 42/1163, 3.61%, P=.24; 20 weeks: 46/1456, 3.16%, P=.47) were similar. Neonatal intensive care unit admission was more frequent in newborns with suboptimal dating (103/570, 18.07%) when compared with the other groups (14 weeks: 133/1004, 13.25%, P=.01; 20 weeks: 168/1263, 13.30%, P=.01), excluding stillbirths and major fetal malformations.

CONCLUSIONS

The present analysis highlighted relevant points of health care to improve obstetric assistance, confirming the importance of early access to technologies for pregnancy dating as an essential component of quality antenatal care.

Second-trimester fetal head circumference in more than 350 000 pregnancies: Outcome and suggestion for sex-dependent cutoffs for small heads

OBJECTIVE

To explore the relationship between small fetal second-trimester head circumference (HC) and pregnancy outcome and identify a cutoff point for offering genetic testing.

METHOD

Data from second-trimester scans in Denmark were linked to national registers. Fetuses with anomalies diagnosed before this scan were excluded. Fetuses were grouped according to HC z-score.

RESULTS

We included 352 515 singleton fetuses. The mean HC was significantly larger among males than among females with z-scores averaging 0.52 more in males. Small HC was associated with chromosomal anomaly, malformations of the CNS and heart, miscarriage/perinatal death, termination, preterm delivery, and intrauterine growth restriction (test for trend: P < .001 for all outcomes). Fetuses in the group with z-score less than -3 had the highest incidence of adverse outcome, irrespective of fetal sex. In the groups with z-scores between -3 and -2.5, and between -2.5 and -2, risk of adverse outcome was lower for females than males for all outcome categories.

CONCLUSION

Small HC in second trimester is a prognostic marker for adverse outcome. The smaller the HC, the higher the risk of adverse outcome. We suggest an HC cutoff point of -2 SD for males and -2.5 SD for females for offering genetic testing.

Adherence to Swedish national pregnancy dating guidelines and management of discrepancies between pregnancy dating methods: a survey study

Background

Swedish national guidelines for pregnancy dating were published in 2010. Follow-up is needed to assess adherence and to identify whether any clinical topics are not covered in the guidelines.

Methods

All units in Sweden that performed ultrasound-based pregnancy dating were asked to complete a web-based questionnaire comprising multiple-response questions and commentary fields. Information was collected regarding baseline information, current and previous clinical practice, and management of discrepancies between last-menstrual-period- and ultrasound-based methods for pregnancy dating.

Results

The response rate was 79%. Half of the units offered first-trimester ultrasound to all pregnant women. However, contrary to the guidelines, the crown–rump length was not used for ultrasound-based pregnancy dating in most units. Instead, ultrasound-based pregnancy dating was performed only if the biparietal diameter was between 21 and 55 mm. Management of discrepancies between methods for pregnancy dating varied widely.

Conclusions

The units reported high adherence to national guidelines, except for early pregnancy dating, for which many units followed unwritten or informal guidelines. The management of discrepancies between last-menstrual-period-based and ultrasound-based estimated day of delivery varied widely. These findings emphasize the need for regular updating of national written guidelines and efforts to improve their implementation in all units.

Placental epigenetic clocks: estimating gestational age using placental DNA methylation levels

The human pan-tissue epigenetic clock is widely used for estimating age across the entire lifespan, but it does not lend itself well to estimating gestational age (GA) based on placental DNAm methylation (DNAm) data. We replicate previous findings demonstrating a strong correlation between GA and genome-wide DNAm changes. Using substantially more DNAm arrays (n=1,102 in the training set) than a previous study, we present three new placental epigenetic clocks: 1) a robust placental clock (RPC) which is unaffected by common pregnancy complications (e.g., gestational diabetes, preeclampsia), and 2) a control placental clock (CPC) constructed using placental samples from pregnancies without known placental pathology, and 3) a refined RPC for uncomplicated term pregnancies. These placental clocks are highly accurate estimators of GA based on placental tissue; e.g., predicted GA based on RPC is highly correlated with actual GA (r>0.95 in test data, median error less than one week). We show that epigenetic clocks derived from cord blood or other tissues do not accurately estimate GA in placental samples. While fundamentally different from Horvath's pan-tissue epigenetic clock, placental clocks closely track fetal age during development and may have interesting applications.

Quantifying bias between reported last menstrual period and ultrasonography estimates of gestational age in Lusaka, Zambia

OBJECTIVE

To quantify differences in assessing preterm delivery when calculating gestational age from last menstrual period (LMP) versus ultrasonography biometry.

METHODS

The Zambian Preterm Birth Prevention Study is an ongoing prospective cohort study that commenced enrolment in August 2015 at Women and Newborn Hospital of University Teaching Hospital in Lusaka, Zambia. Women at less than 20 weeks of pregnancy who were enrolled between August 17, 2015, and August 31, 2017, and underwent ultrasonography examination were included in the present analysis. The primary outcome was the difference between ultrasonography- and LMP-based estimated gestational age. Associations between baseline predictors and outcomes were assessed using simple regression. The proportion of preterm deliveries using LMP- and ultrasonography-derived gestational dating was calculated using Kaplan-Meier analysis.

RESULTS

The analysis included 942 women. The discrepancy between estimating gestational age using ultrasonography and LMP increased with greater gestational age at presentation and among patients with no history of preterm delivery. In a Kaplan-Meier analysis of 692 deliveries, 140 (20.2%, 95% confidence interval [CI] 17.7-23.0) and 79 (11.4%, 95% CI 9.6-13.6) deliveries were classified as preterm by LMP and ultrasonography estimates, respectively.

CONCLUSION

Taking ultrasonography as a standard, a bias was observed in LMP-based gestational age estimates, which increased with advancing gestation at presentation. This resulted in misclassification of term deliveries as preterm.

The human yolk sac size reflects involvement in embryonic and fetal growth regulation

INTRODUCTION

The human yolk sac provides the embryo with stem cells, nutrients, and gas exchange. We hypothesized that more maternal resources, reflected in body size and body composition, would condition a a larger yolk sac, ensuring resources for the growing embryo. Thus, we aimed to determine the relation between maternal size in early pregnancy and yolk sac size.

MATERIAL AND METHODS

This subsidiary study was embedded in the multinational World Health Organization fetal growth project that included healthy women with a body mass index of 18-30, reliable information of their regular last menstrual period and singleton pregnancies. Yolk sac diameter, crown-rump length, and maternal height, weight, body mass index, and body composition were assessed before 13 weeks of gestation, and the fetal biometry was repeated during the pregnancy.

RESULTS

Of 140 participants, 122 with a successful yolk sac measurement were entered in the present analysis. Maternal weight was negatively associated with the yolk sac diameter (P = 0.007) and so was maternal height (P = 0.011), fat mass (P = 0.037), and lean body mass (P = 0.018), but not body mass index (P = 0.121). Significant effects were predominantly due to the female embryos and could be traced at 24 weeks of gestation. That is, a small yolk sac : crown-rump length ratio in early pregnancy was associated with a high fetal abdominal circumference (P < 0.001) and estimated fetal weight (P = 0.001).

CONCLUSIONS

The human yolk sac is involved in the regulation of embryonic growth, but contrary to our hypothesis, the yolk sac has a compensatory capacity, being larger when the mothers are smaller; and the effect can be traced on fetal size at 24 weeks of gestation.

Discrepancy between pregnancy dating methods affects obstetric and neonatal outcomes: a population-based register cohort study

To assess associations between discrepancy of pregnancy dating methods and adverse pregnancy, delivery, and neonatal outcomes, odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for discrepancy categories among all singleton births from the Medical Birth Register (1995-2010) with estimated date of delivery (EDD) by last menstrual period (LMP) minus EDD by ultrasound (US) -20 to +20 days. Negative/positive discrepancy was a fetus smaller/larger than expected when dated by US (EDD postponed/changed to an earlier date). Large discrepancy was <10^th or >90^th percentile. Reference was median discrepancy ±2 days. Odds for diabetes and preeclampsia were higher in pregnancies with negative discrepancy, and for most delivery outcomes in case of large positive discrepancy (+9 to +20 days): shoulder dystocia [OR 1.16 (95% CI 1.01-1.33)] and sphincter injuries [OR 1.13 (95% CI 1.09-1.17)]. Odds for adverse neonatal outcomes were higher in large negative discrepancy (-4 to -20 days): low Apgar score [OR 1.18 (95% CI 1.09-1.27)], asphyxia [OR 1.18 (95% CI 1.11-1.25)], fetal death [OR 1.47 (95% CI 1.32-1.64)], and neonatal death [OR 2.19 (95% CI 1.91-2.50)]. In conclusion, especially, large negative discrepancy was associated with increased risks of adverse perinatal outcomes.

Postnatal gestational age estimation using newborn screening blood spots: a proposed validation protocol

Background

Knowledge of gestational age (GA) is critical for guiding neonatal care and quantifying regional burdens of preterm birth. In settings where access to ultrasound dating is limited, postnatal estimates are frequently used despite the issues of accuracy associated with postnatal approaches. Newborn metabolic profiles are known to vary by severity of preterm birth. Recent work by our group and others has highlighted the accuracy of postnatal GA estimation algorithms derived from routinely collected newborn screening profiles. This protocol outlines the validation of a GA model originally developed in a North American cohort among international newborn cohorts.

Methods

Our primary objective is to use blood spot samples collected from infants born in Zambia and Bangladesh to evaluate our algorithm’s capacity to correctly classify GA within 1, 2, 3 and 4 weeks. Secondary objectives are to 1) determine the algorithm's accuracy in small-for-gestational-age and large-for-gestational-age infants, 2) determine its ability to correctly discriminate GA of newborns across dichotomous thresholds of preterm birth (≤34 weeks, <37 weeks GA) and 3) compare the relative performance of algorithms derived from newborn screening panels including all available analytes and those restricted to analyte subsets. The study population will consist of infants born to mothers already enrolled in one of two preterm birth cohorts in Lusaka, Zambia, and Matlab, Bangladesh. Dried blood spot samples will be collected and sent for analysis in Ontario, Canada, for model validation.

Discussion

This study will determine the validity of a GA estimation algorithm across ethnically diverse infant populations and assess population specific variations in newborn metabolic profiles.

Utilizing Infant Cry Acoustics to Determine Gestational Age

OBJECTIVES/HYPOTHESIS

The date of last menstruation period and ultrasonography are the most commonly used methods to determine gestational age (GA). However, if these data are not clear, some scoring systems performed after birth can be used. New Ballard Score (NBS) is a commonly used method in estimation of GA. Cry sound may reflect the developmental integrity of the infant. The aim of this study was to evaluate the connection between the infants' GA and some acoustic parameters of the infant cry.

STUDY DESIGN

A prospective single-blind study was carried out.

METHODS

In this prospective study, medically stable infants without any congenital craniofacial anomalies were evaluated. During routine blood sampling, cry sounds were recorded and acoustic analysis was performed. Step-by-step multiple linear regression analysis was performed.

RESULTS

The data of 116 infants (57 female, 59 male) with the known GA (34.6 ± 3.8 weeks) were evaluated and with Apgar score of higher than 5. The real GA was significantly and well correlated with the estimated GA according to the NBS, F0, Int, Jitt, and latency parameters. The obtained stepwise linear regression analysis model was formulized as GA=(31.169) - (0.020 × F0)+(0.286 × GA according to NBS) - (0.003 × Latency)+(0.108 × Int) - (0.367 × Jitt). The real GA could be determined with a ratio of 91.7% using this model.

CONCLUSIONS

We have determined that after addition of F0, Int, Jitt, and latency to NBS, the power of GA estimation would be increased. This simple formula can be used to determine GA in clinical practice but validity of such prediction formulas needs to be further tested.

Maternal and fetal characteristics affect discrepancies between pregnancy-dating methods: a population-based cross-sectional register study

INTRODUCTION

Gestational age is estimated by ultrasound using fetal size as a proxy for age, although variance in early growth affects reliability. The aim of this study was to identify characteristics associated with discrepancies between last menstrual period-based (EDD-LMP) and ultrasound-based (EDD-US) estimated delivery dates.

MATERIAL AND METHODS

We identified all singleton births (n = 1 201 679) recorded in the Swedish Medical Birth Register in 1995-2010, to assess the association between maternal/fetal characteristics and large negative and large positive discrepancies (EDD-LMP earlier than EDD-US and 10th percentile in the discrepancy distribution vs. EDD-LMP later than EDD-US and 90th percentile). Analyses were adjusted for age, parity, height, body mass index, smoking, and employment status.

RESULTS

Women with a body mass index >40 kg/m² had the highest odds for large negative discrepancies (-9 to -20 days) [odds ratio (OR) 2.16, 95% CI 2.01-2.33]. Other factors associated with large negative discrepancies were: diabetes, young maternal age, multiparity, body mass index between 30 and 39.9 kg/m² or <18.5 kg/m² , a history of gestational diabetes, female fetus, shorter stature (<-1 SD), a history of preeclampsia, smoking or snuff use, and unemployment. Large positive discrepancies (+4 to +20 days) were associated with male fetus (OR 1.80, 95% CI 1.77-1.83), age ≥30 years, multiparity, not living with a partner, taller stature (>+1 SD), and unemployment.

CONCLUSIONS

Several maternal and fetal characteristics were associated with discrepancies between dating methods. Systematic associations of discrepancies with maternal height, fetal sex, and partly obesity, may reflect an influence on the precision of the ultrasound estimate due to variance in early growth.

Gestational age and birthweight for risk assessment of neurodevelopmental impairment or death in extremely preterm infants

BACKGROUND

The risk of poor outcomes in preterm infants is primarily determined by birthweight (BW) and gestational age (GA). It is not known whether BW is a better outcome predictor than GA.

OBJECTIVE

To test whether BW is better than GA (measured in days, rather than completed weeks) for prediction of neurodevelopmental impairment (NDI) and death.

DESIGN/METHODS

Extremely preterm infants born at the National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centres between 1998 and 2009 were studied. For the unadjusted analysis, the associations of GA (in days based on best obstetrical estimate) and BW (in grams) with NDI or death were compared using area under the curve (AUC). Adjusted analyses were performed using birth year, sex, race, antenatal steroids, singleton birth, pre-eclampsia, Apgar score at 5 min and small for GA as covariates.

RESULTS

10 652 preterm infants (89%) had outcome data at 18-22 months' corrected age. The mean BW was 678 g (SD: 155) and the mean GA was 173 days (SD: 10) or 24^5/7 weeks (SD: 1^3/7). The AUC for NDI or death was 80% with BW and 79% with GA (p=0.82). Unadjusted and adjusted analyses did not differ. NDI or death rates decreased with increasing GA through 26 weeks (estimated risk reduction with each additional day of gestation: 2.2%).

CONCLUSION

Both BW in grams and GA in days are good predictors of NDI and death in a preterm population selected on the basis of reliable GA.

TRIAL REGISTRATION NUMBER

NCT00009633.

Adverse Infant Outcomes Associated with Discordant Gestational Age Estimates

BACKGROUND

Gestational age estimation by last menstrual period (LMP) vs. ultrasound (or best obstetric estimate in the US) may result in discrepant classification of preterm vs. term birth. We investigated whether such discrepancies are associated with adverse infant outcomes.

METHODS

We studied singleton livebirths in the Medical Birth Registries of Norway, Sweden and Finland and US live birth certificates from 1999 to the most recent year available. Risk ratios (RR) with 95% confidence intervals (CI) by discordant and concordant gestational age estimation for infant, neonatal and post-neonatal mortality, Apgar score <4 and <7 at 5 min, and neonatal intensive care unit (NICU) admission were estimated using generalised linear models, adjusting for maternal age, education, parity, year of birth, and infant sex. Results were presented stratified by country.

RESULTS

Compared to infants born at term by both methods, infants born preterm by ultrasound/best obstetric estimate but term by LMP had higher infant mortality risks (range of adjusted RRs 3.9 to 7.2) and modestly higher risks were obtained among infants born preterm by LMP but term by ultrasound/best obstetric estimate (range of adjusted RRs 1.6 to 1.9). Risk estimates for the other outcomes showed the same pattern. These findings were consistent across all four countries.

CONCLUSIONS

Infants classified as preterm by ultrasound/best estimate, but term by LMP have consistently higher risks of adverse outcomes than those classified as preterm by LMP but term by ultrasound/best estimate. Compared with ultrasound/best estimate, use of LMP overestimates the proportion of births that are preterm.

Circulating Influenza Virus and Adverse Pregnancy Outcomes: A Time-Series Study

Individual-level epidemiologic studies of pregnancy outcomes after maternal influenza are limited in number and quality and have produced inconsistent results. We used a time-series design to investigate whether fluctuation in influenza virus circulation was associated with short-term variation in population-level rates of preterm birth, stillbirth, and perinatal death in Ontario between 2003 and 2012. Using Poisson regression, we assessed the association between weekly levels of circulating influenza virus and counts of outcomes offset by the number of at-risk gestations during 3 gestational exposure windows. The rate of preterm birth was not associated with circulating influenza level in the week preceding birth (adjusted rate ratio = 1.01, 95% confidence interval: 1.00, 1.02) or in any other exposure window. These findings were robust to alternate specifications of the model and adjustment for potential confounding. Stillbirth and perinatal death rates were similarly not associated with gestational exposure to influenza circulation during late pregnancy. We could not assess mortality outcomes relative to early gestational exposure because of missing dates of conception for many stillbirths. In this time-series study, population-level influenza circulation was not associated with short-term variation in rates of preterm birth, stillbirth, or perinatal death.

Determining gestational age based on information from the Birth in Brazil study

This study aimed at assessing the validity of different measures for estimating gestational age and to propose the creation of an algorithm for gestational age at birth estimates for the Birth in Brazil survey--a study conducted in 2011-2012 with 23,940 postpartum women. We used early ultrasound imaging, performed between 7-20 weeks of gestation, as the reference method. All analyses were performed stratifying by payment of maternity care (public or private). When compared to early ultrasound imaging, we found a substantial intraclass correlation coefficient of ultrasound-based gestational age at admission measure (0.95 and 0.94) and of gestational age reported by postpartum women at interview measure (0.90 and 0.88) for the public and private payment of maternity care, respectively. Last menstrual period-based measures had lower intraclass correlation coefficients than the first two measures evaluated. This study suggests caution when using the last menstrual period as the first measure for estimating gestational age in Brazil, strengthening the use of information obtained from early ultrasound imaging results.

Discrepancy in term calculation from second trimester ultrasound scan versus last menstrual period in women with type 1 diabetes

OBJECTIVE

To study differences in ultrasound-based compared to menstrual-based term estimation in women with type 1 diabetes.

DESIGN

Nationwide register study.

SETTING

Norway.

POPULATION

Deliveries in Norway 1999-2004 by women registered in the Norwegian Childhood Diabetes Registry (n = 342) and the background population (n = 307 248), with data on both ultrasound-based and menstrual-based gestational age notified in the Birth Registry of Norway. Births with major malformations were excluded.

METHODS

Linkage of two nationwide registries, the Medical Birth Registry of Norway and the Norwegian Childhood Diabetes Registry.

MAIN OUTCOME MEASURES

Estimated gestational age at delivery based on routine second trimester ultrasound measurements and last menstrual period.

RESULTS

In women with type 1 diabetes, the distribution of gestational age at delivery was shifted considerably towards a lower gestational age when using second trimester ultrasound data for estimation, compared with last menstrual period data. The difference between the two estimation methods was larger among women with type 1 diabetes, although also evident in the general population. One in four women with diabetes and a certain last menstrual period date had their ultrasound-calculated term postponed 1 week or more, while one in 10 had it postponed 2 weeks or more. Corresponding numbers in the background population were one in five and one in 20.

CONCLUSIONS

We found a systematic postponement of ultrasound-based compared with menstrual-based term estimation in women with type 1 diabetes. Relying solely on routine ultrasound-based term calculation for delivery decision may imply a risk of going beyond an optimal pregnancy length.

Trends in the distribution of gestational age and contribution of planned births in New South Wales, Australia

BACKGROUND

There is concern that the rate of planned births (by pre-labour caesarean section or induction of labour) is increasing and that the gestation at which they are being conducted is decreasing. The aim of this study was to describe trends in the distribution of gestational age, and assess the contribution of planned birth to any such changes.

METHODS

We utilised the New South Wales (NSW) Perinatal Data Collection to undertake a population-based study of all births in NSW, Australia 1994-2009. Trends in gestational age were determined by year, labour onset and plurality of birth.

RESULTS

From 1994-2009, there was a gradual and steady left-shift in overall distribution of gestational age at birth, with a decline in the modal gestational age from 40 to 39 weeks. For singletons, there was a steady but significant reduction in the proportion of spontaneous births. Labour inductions increased in the proportion performed, with a gradual and changing shift in the distribution from a majority at 40 weeks to an increase at both 37-39 weeks and 41 weeks gestation. The proportion of pre-labour caesareans also increased steadily at each gestational age and doubled since 1994, with most performed at 39 weeks in 2009 compared with 38 weeks up to 2001.

CONCLUSIONS

Findings suggest a changing pattern towards births at earlier gestations, fewer births commencing spontaneously and increasing planned births. Factors associated with changing clinical practice and long-term implications on the health and well-being of mothers and babies should be assessed.

Low birth weight: causes and consequences

During our phylogenetic evolution we have selected genes, the so called thrifty genes, that can help to maximize the amount of energy stored from every consumed calorie. An imbalance in the amount of stored calories can lead to many diseases. In the early 80's the distinguished English epidemiologist David Barker, formulated a hypothesis suggesting that many events that occur during the intrauterine life and early in infancy can influence the occurrence of many diseases that will develop in adulthood. This theory proposes that under-nutrition and other insult or adverse stimulus in utero and during infancy can permanently change the body's structure, physiology and metabolism. The lasting or lifelong effects of under-nutrition will depend on the period in the development at which it occurs. The clues that led Barker to his conclusions started to be discovered when he was studying the temporal trends in the incidence of ischemic heart disease in England and Wales. Examining data found in The Hertfordshire records, collected in the beginning of the last century, he found that the rates of mortality by ischemic heart disease was much higher in children born in less affluent counties and mostly in those with low birth weight. After his initial findings a myriad of diseases have been found to be linked to low birth weight and under-nutrition in utero and in the neonatal period. These diseases were then nominated adult diseases with fetal origin. Epidemiological studies that led to these findings suggest that in utero and early postnatal life have critical importance for long-term programming of health and disease, opening unique chances for primary prevention of chronic diseases.

Trends in gestational age and birth weight in Chile, 1991-2008. A descriptive epidemiological study

Background

Gestational age and birth weight are the principal determinants of newborn’s health status. Chile, a middle income country traditionally has public policies that promote maternal and child health. The availability of an exhaustive database of live births has allows us to monitor over time indicators of newborns health.

Methods

This descriptive epidemiological study included all live births in Chile, both singleton and multiple, from 1991 through 2008. Trends in gestational age affected the rate of prevalence (%) of preterm births (<37 weeks, including the categories < 32 and 32–36 weeks), term births (37–41) and postterm births (42 weeks or more). Trends in birth weight affected the prevalence of births < 1500 g, 1500–2499 g, 2500–3999 g, and 4000 g or more.

Results

Data from an exhaustive register of live births showed that the number of term and postterm births decreased and the number of multiple births increased significantly. Birth weights exceeding 4000 g did not vary.

Total preterm births rose from 5.0% to 6.6%, with increases of 28% for the singletons and 31% for multiple births (p for trend < 0.0001). Some categories increased even more: specifically preterm birth < 32 weeks increased 32.3% for singletons and 50.6% for multiple births (p for trend 0.0001).

The overall rate of low birth weight infants (<2500 g) increased from 4.6% to 5.3%. This variation was not statistically significant for singletons (p for trend = 0.06), but specific analyses exhibited an important increase in the category weighing <1500 g (42%) similar to that observed in multiple births (43%).

Conclusions

The gestational age and birth weight of live born child have significantly changed over the past two decades in Chile. Monitoring only overall rates of preterm births and low-birth-weight could provide restricted information of this important problem to public health. Monitoring them by specific categories provides a solid basis for planning interventions to reduce adverse perinatal outcomes.

This epidemiological information also showed the need to assess several factors that could contribute to explain these trends, as the demographics changes, medical interventions and the increasing probability of survival of extremely and very preterm child.

Correction of systematic bias in ultrasound dating in studies of small-for-gestational-age birth: an example from the Iowa Health in Pregnancy Study

The authors examined whether early ultrasound dating (≤20 weeks) of gestational age (GA) in small-for-gestational-age (SGA) fetuses may underestimate gestational duration and therefore the incidence of SGA birth. Within a population-based case-control study (May 2002-June 2005) of Iowa SGA births and preterm deliveries identified from birth records (n = 2,709), the authors illustrate a novel methodological approach with which to assess and correct for systematic underestimation of GA by early ultrasound in women with suspected SGA fetuses. After restricting the analysis to subjects with first-trimester prenatal care, a nonmissing date of the last menstrual period (LMP), and early ultrasound (n = 1,135), SGA subjects' ultrasound GA was 5.5 days less than their LMP GA, on average. Multivariable linear regression was conducted to determine the extent to which ultrasound GA predicted LMP dating and to correct for systematic misclassification that results after applying standard guidelines to adjudicate differences in these measures. In the unadjusted model, SGA subjects required a correction of +1.5 weeks to the ultrasound estimate. With adjustment for maternal age, smoking, and first-trimester vaginal bleeding, standard guidelines for adjudicating differences in ultrasound and LMP dating underestimated SGA birth by 12.9% and overestimated preterm delivery by 8.7%. This methodological approach can be applied by researchers using different study populations in similar research contexts.

Early childhood development when second-trimester ultrasound dating disagrees with last menstrual period: a prospective cohort study

BACKGROUND

When an ultrasound-based estimate of gestational age (GA) is less (greater) than an estimate based on a definite last menstrual period, the fetus may grow slower (faster) than average. While the association between these discrepancies in GA estimates and adverse perinatal outcomes has been examined extensively, there is scant evidence about long-term effects, such as child neurodevelopment.

METHODS

Using data from a prospective cohort study titled, NICHD Study of Successive Small-for-Gestational Age Births, we examined if GA discrepancies in early second trimester of pregnancy (17 weeks' gestation) are associated with: (1) impaired motor and mental function at 13 months (measured using Bayley Scales of Infant Development (Bayley)), and (2) impaired cognitive development at five years (assessed by Wechsler Preschool and Primary Scale of Intelligence - Revised Intelligence Quotient (WPPSI-R)) in the infant. The study population consisted of 572 (30% of the overall sample of 1,945) women who presented for prenatal care in Norway and Sweden between 1986 and 1988.

RESULTS

Our results showed that GA discrepancies in early second trimester are significantly associated with birthweight. We found no significant relationship, however, with the Bayley development scores at 13 months and with the WPPSI-R IQ measures at five years.

CONCLUSIONS

GA discrepancies at 17 weeks' gestation are not associated child neurodevelopment. These discrepancies do, however, relate to birthweights, providing a basis for detecting fetal growth patterns early in the second trimester of pregnancy. Our study, however, was unable to evaluate the impact of first-trimester discrepancies on impaired neurodevelopment in the infant.

Challenges in defining and classifying the preterm birth syndrome

In 2009, the Global Alliance to Prevent Prematurity and Stillbirth Conference charged the authors to propose a new comprehensive, consistent, and uniform classification system for preterm birth. This first article reviews issues related to measurement of gestational age, clinical vs etiologic phenotypes, inclusion vs exclusion of multifetal and stillborn infants, and separation vs combination of pathways to preterm birth. The second article proposes answers to the questions raised here, and the third demonstrates how the proposed system might work in practice.

Association between maternal comorbidity and preterm birth by severity and clinical subtype: retrospective cohort study

Background

Preterm birth (PTB) is a major cause of infant morbidity and mortality, but the relationship between comorbidity and PTB by clinical subtype and severity of gestational age remains poorly understood. We evaluated associations between maternal comorbidities and PTB by clinical subtype and gestational age.

Methods

We conducted a retrospective cohort study of 1,329,737 singleton births delivered in hospitals in the province of Québec, Canada, 1989-2006. PTB was classified by clinical subtype (medically indicated, preterm premature rupture of membranes (PPROM), spontaneous preterm labour) and gestational age (< 28, 28-31, 32-36 completed weeks). Odds ratios (OR) of PTB by clinical subtype for systemic and localized maternal comorbidities were estimated using polytomous logistic regression, adjusting for maternal age, grand multiparity, and period. Attributable fractions were calculated.

Results

PTB rates were higher among mothers with comorbidity (10.9%) compared to those without comorbidity (4.7%). Several comorbidities were associated with greater odds of medically indicated PTB compared with no comorbidity, but only comorbidities localized to the reproductive system were associated with spontaneous PTB. Drug dependence and mental disorders were strongly associated with PPROM and spontaneous PTBs across all gestational ages (OR > 2.0). At the population level, several major comorbidities (placental abruption, chorioamnionitis, oliogohydramnios, structural abnormality, cervical incompetence) were key contributors to all clinical subtypes of PTB, especially at < 32 weeks. Major systemic comorbidities (preeclampsia, anemia) were key contributors to PPROM and medically indicated PTBs.

Conclusions

The relationship between comorbidity and clinical subtypes of PTB depends on gestational age. Prevention of PPROM and spontaneous PTB may benefit from greater attention to preeclampsia, anemia and comorbidities localized to the reproductive system.

Home pregnancy test compared to standard-of-care ultrasound dating in the assessment of pregnancy duration

OBJECTIVE

To determine the level of agreement between the Clearblue Digital Pregnancy Test with Conception Indicator home pregnancy test and standard-of-care ultrasound in assessing pregnancy duration in a real-life, observational setting encompassing routine, clinical care.

RESEARCH DESIGN AND METHODS

This was a prospective observational study of non-pregnant women seeking conception. Women collected daily urine samples from day 1 of their next menstrual cycle. If any volunteer became pregnant, daily urine samples continued to be collected for 43 days after the LH surge. Samples from day -7 to day +28 relative to the expected period (LH surge + 15 days) were tested using the home pregnancy test. This categorised any resulting pregnancies into one of three groups: 1-2 weeks, 2-3 weeks, and 3+ weeks since conception. Information from the standard UK ultrasound dating scan was also recorded by the midwife, including the expected delivery date according to ultrasound and the expected delivery date according to LMP.

MAIN OUTCOME MEASURES

Full data were available from 52 pregnant women who had conceived naturally. During the study analysis, 4786 urine samples were cross-compared with 52 routine 12-week NHS ultrasound assessments and the level of agreement between home pregnancy testing and standard-of-care ultrasound in determining pregnancy duration was calculated.

RESULTS

The agreement between the gestational age as calculated by the home pregnancy test result and the exact midwife-recorded gestational age using ultrasound was 82.3%. However, when a ± 5-day range was applied to the ultrasound reading (as per routine UK clinical practice), the level of agreement was 98%.

CONCLUSIONS

The home pregnancy test provides a significantly high (98%) level of agreement with standard-of-care ultrasound when assessing pregnancy duration in a real-life, observational setting which closely mirrors daily clinical practice.

The influence of overweight and obesity on longitudinal trends in maternal serum leptin levels during pregnancy

Maternal obesity influences a number of metabolic factors that can affect the course of pregnancy. Among these factors, leptin plays an important role in energy metabolism and fetal development during pregnancy. Our objective was to estimate the influence of maternal overweight/obesity on variation in the maternal serum leptin profile during pregnancy. In a prospective cohort of 143 adult gravidas with singleton pregnancies presenting for general prenatal care, we measured serum leptin levels at 6-10, 10-14, 16-20, 22-26, and 32-36 weeks' gestation. The longitudinal effects of maternal prepregnancy BMI, categorized as nonoverweight (≤ 26.0 kg/m(2)) and overweight/obese (>26.0 kg/m(2)), on serum leptin concentration were analyzed using linear mixed models. Overweight/obese women had significantly higher serum leptin concentrations than their nonoverweight counterparts throughout pregnancy (P < 0.01). Although these concentrations increased significantly across gestation for both groups, the rate of increase was significantly smaller for overweight/obese women (P < 0.05). To investigate whether these differences merely reflected differences in weight-gain patterns between the two groups, we examined an index of leptin concentration per unit body weight (leptin (ng/ml)/weight (kg)). Overweight/obese women had a significantly higher index throughout pregnancy (P < 0.01). However, although this index increased significantly across pregnancy for nonoverweight women, it actually decreased significantly for overweight/obese women (P < 0.01). Our results suggest that factors other than fat mass alone influence leptin concentrations in overweight/obese women compared to normal-weight women during pregnancy. Such factors may contribute to differences in the intrauterine environment and its influence on pregnancy outcomes in the two groups.

Assisted reproduction for the validation of gestational age assessment methods

Despite major achievements in medicine, preterm birth (PTB) remains a leading cause of infant morbidity and mortality, worldwide. Research efforts have been devoted towards a better understanding of the multifactorial aetiology of PTB and its subtypes, with the purpose of prevention and control. The availability of valid and reliable gestational age data is a prerequisite for PTB classification. Pregnancies conceived through assisted reproduction treatments provide an opportunity for the exact determination of gestational age using date of delivery and dates of fertilization or implantation. The purpose of this review article is to evaluate the current evidence for or against the various methods that can be applied to measure gestational age, namely the first day of the last menstrual period, ultrasound before 20 weeks of gestation and post-natal assessments, and to propose the use of assisted reproduction treatments populations for further validation of these methods.

Maternal and paternal height and BMI and patterns of fetal growth: the Pune Maternal Nutrition Study

We examined the differential associations of each parent's height and BMI with fetal growth, and examined the pattern of the associations through gestation. Data are from 557 term pregnancies in the Pune Maternal Nutrition Study. Size and conditional growth outcomes from 17 to 29 weeks to birth were derived from ultrasound and birth measures of head circumference, abdominal circumference, femur length and placental volume (at 17 weeks only). Parental height was positively associated with fetal head circumference and femur length. The associations with paternal height were detectible earlier in gestation (17-29 weeks) compared to the associations with maternal height. Fetuses of mothers with a higher BMI had a smaller mean head circumference at 17 weeks, but caught up to have larger head circumference at birth. Maternal but not paternal BMI, and paternal but not maternal height, were positively associated with placental volume. The opposing associations of placenta and fetal head growth with maternal BMI at 17 weeks could indicate prioritisation of early placental development, possibly as a strategy to facilitate growth in late gestation. This study has highlighted how the pattern of parental-fetal associations varies over gestation. Further follow-up will determine whether and how these variations in fetal/placental development relate to health in later life.

Calculation of gestational age in late second and third trimesters by ex vivo magnetic resonance spectroscopy of amniotic fluid

OBJECTIVE

The purpose of this study was to develop a reliable model for the calculation of gestational age (GA) in second and third trimesters with the use of amniotic fluid (AF) metabolite profiles that were determined by magnetic resonance spectroscopy.

STUDY DESIGN

High-resolution (11.7 T) ex vivo magnetic resonance spectroscopy was performed on 95 AF samples (mean, 31.7 weeks; range, 15.6-39.9 weeks). GA was determined by last menstrual period or first-trimester ultrasound scanning. Concentrations of 21 AF metabolites were measured with automated techniques. Metabolite concentrations, inverses, natural logs, and squares were entered as predictive variables in a stepwise linear regression model.

RESULTS

The following formula was derived: GA = 64.922 - (14.456 x alanine) + (4.965 x natural log [creatinine]) - (0.931 x glucose) - (5.202 x valine). This model fit the data with an R(2) value of 0.926. Average error among all samples was +/-1.75 weeks (SD, +/-1.43 weeks), for the second trimester was +/-2.21 weeks (SD, +/-1.78 weeks), and for the third trimester was +/-1.59 weeks (SD, +/-1.26 weeks).

CONCLUSION

Statistical modeling accurately predicted GA with amniotic fluid metabolite profiles that were obtained by magnetic resonance spectroscopy, which may represent a significant improvement over conventional ultrasound dating in the third trimester. Future studies should compare these techniques directly.

Estimating the effect of gestational age on test performance of combined first-trimester screening for Down syndrome: a preliminary study

OBJECTIVE

To establish how different methods of estimating gestational age (GA) affect reliability of first-trimester screening for Down syndrome.

METHODS

Retrospective single-center study of 100 women with a viable singleton pregnancy, who had first-trimester screening. We calculated multiples of the median (MoM) for maternal-serum free beta human chorionic gonadotropin (free beta-hCG) and pregnancy associated plasma protein-A (PAPP-A), derived from either last menstrual period (LMP) or ultrasound-dating scans.

RESULTS

In women with a regular cycle, LMP-derived estimates of GA were two days longer (range -11 to 18), than crown-rump length (CRL)-derived estimates of GA whereas this discrepancy was more pronounced in women who reported to have an irregular cycle, i.e., six days (range -7 to 32). Except for PAPP-A in the regular-cycle group, all differences were significant. Consequently, risk estimates are affected by the mode of estimating GA. In fact, LMP-based estimates revealed ten "screen-positive" cases compared to five "screen-positive" cases where GA was derived from dating-scans.

CONCLUSION

Provided fixed values for nuchal translucency are applied, dating-scans reduce the number of screen-positive findings on the basis of biochemical screening. We recommend implementation of guidelines for Down syndrome screening based on CRL-dependent rather than LMP-dependent parameters of GA.

Maternal hemoglobin level and fetal outcome at low and high altitudes

Both, low (<7 g/dl) and high (>14.5 g/dl), maternal hemoglobin (Hb) levels have been related to poor fetal outcome. Most studies have been done at low altitude (LA). Here, we have sought to determine whether this relationship exists at both high and low altitude, and also whether there is an adverse effect of high altitude (HA) on fetal outcome independent of level of maternal hemoglobin. The study is based on a retrospective multicenter analysis of 35,449 pregnancies at LA and six other cities above 3000 meters. In analyses of all women at both LA and HA, those with Hb <9 g/dl had odds ratios (ORs) and 95% confidence intervals (CI) of 4.4 (CI: 2.8-6.7), 2.5 (CI: 1.9-3.2), and 1.4 (CI: 1.1-1.9) for stillbirths, preterm, and small for gestational age (SGA) births, respectively, compared with women with 11-12.9 g/dl of Hb, after adjustment for confounders. These risks by hemoglobin level differed little between women at LA and HA, suggesting that no correction of the definition of anemia is necessary for women at HA. Women living at high altitude with hemoglobin >15.5 g/dl had higher risks for stillbirths (OR: 1.3; CI: 1.05-1.3), preterm (OR: 1.5; CI 1.3-1.8), and SGA births (OR: 2.1, CI 1.8-2.3). There was also a significant adverse effect of living at HA, independent of hemoglobin level for all three outcomes (OR: 3.9, 1.7, and 2.3; CI: 2.8-5.2, 1.5-1.9, and 2.1-2.5) for stillbirths, preterms, and SGA respectively, after adjusting for hemoglobin level. Both, high and low maternal hemoglobin levels were related to poor pregnancy outcome, with similar effect of low hemoglobin in both LA and HA. Our data suggest, that maternal hemoglobin above 11 g/dl but below 13 g/dl is the area of minimal risk of poor adverse outcomes. Living at HA had an adverse effect independent of hemoglobin level.

Dating and growth in the first trimester

Measurement of embryonic or foetal size using the greatest length of the embryo or foetal crown rump length can be used to accurately determine the gestational age of a normal first trimester pregnancy to within three to five days. Transvaginal ultrasound scan can be used to measure the size of an embryo and gestation sac earlier than transabdominal ultrasound. The original Robinson curve used for dating pregnancies is still valid in most cases. Ultrasound dating in the first trimester is now recommended for all women with spontaneous pregnancies, even those with certain menstrual dates. First trimester growth in normal pregnancy is not uniform and is influenced by both maternal and foetal factors. Early foetal growth restriction is demonstrated in many pregnancies that subsequently end in first trimester miscarriage and is also demonstrated in fetuses with triploidy, trisomy 18 and possibly trisomy 13. Pregnancies which are small at the 11-14 week ultrasound scan appear to be at risk of later intrauterine growth restriction, preeclampsia and preterm delivery. Cross-sectional and serial measurement of foetal growth in the first trimester may be helpful in predicting both miscarriage and adverse late pregnancy outcomes.

Birth weight charts for gestational age in 63,620 healthy infants born in Peruvian public hospitals at low and at high altitude

AIM

To construct distribution curves for birth weight, length and head circumference using a large sample of infants born at low (150 m) and high (3000-4400 m) altitude.

METHODS

Cross-sectional analysis of a perinatal database. All live singleton deliveries from public hospitals during 2001-2006 (gestational age from 26 to 42 weeks) with no history of perinatal deaths or smoking and no current obstetric complications (n = 63 620) were included. Fractional polynomial regression models were used to smooth curves for each gestational age.

RESULTS

Mean and median birth weight differences between those born at low and high altitudes reached statistical significance after 35 and 33 weeks, respectively. Values of the 10th percentile were higher at low altitude from 36 weeks, whereas values at the 90th percentile were different from 34 weeks. In the Peruvian growth curves, birth weight was greater at each gestational age than in the curves derived by Lubchenco.

CONCLUSION

Altitude affects growth patterns; these growth standards will provide useful references for the care of the newborn in highland populations. In addition, the data have implications for the antepartum management of pregnant patients undergoing sonographic evaluation of fetal weight in whom new definitions of what represents small or large for gestational age in utero can result in differences in time or mode of delivery.

Comparison of gestational age at birth based on last menstrual period and ultrasound during the first trimester

Reported last menstrual period (LMP) is commonly used to estimate gestational age (GA) but may be unreliable. Ultrasound in the first trimester is generally considered a highly accurate method of pregnancy dating. The authors compared first trimester report of LMP and first trimester ultrasound for estimating GA at birth and examined whether disagreement between estimates varied by maternal and infant characteristics. Analyses included 1867 singleton livebirths to women enrolled in a prospective pregnancy cohort. The authors computed the difference between LMP and ultrasound GA estimates (GA difference) and examined the proportion of births within categories of GA difference stratified by maternal and infant characteristics. The proportion of births classified as preterm, term and post-term by pregnancy dating methods was also examined. LMP-based estimates were 0.8 days (standard deviation = 8.0, median = 0) longer on average than ultrasound estimates. LMP classified more births as post-term than ultrasound (4.0% vs. 0.7%). GA difference was greater among young women, non-Hispanic Black and Hispanic women, women of non-optimal body weight and mothers of low-birthweight infants. Results indicate first trimester report of LMP reasonably approximates gestational age obtained from first trimester ultrasound, but the degree of discrepancy between estimates varies by important maternal characteristics.

Temporal changes in key maternal and fetal factors affecting birth outcomes: a 32-year population-based study in an industrial city

Background

The link between maternal factors and birth outcomes is well established. Substantial changes in society and medical care over time have influenced women's reproductive choices and health, subsequently affecting birth outcomes. The objective of this study was to describe temporal changes in key maternal and fetal factors affecting birth outcomes in Newcastle upon Tyne over three decades, 1961–1992.

Methods

For these descriptive analyses we used data from a population-based birth record database constructed for the historical cohort Particulate Matter and Perinatal Events Research (PAMPER) study. The PAMPER database was created using details from paper-based hospital delivery and neonatal records for all births during 1961–1992 to mothers resident in Newcastle (out of a total of 109,086 singleton births, 97,809 hospital births with relevant information). In addition to hospital records, we used other sources for data collection on births not included in the delivery and neonatal records, for death and stillbirth registrations and for validation.

Results

The average family size decreased mainly due to a decline in the proportion of families with 3 or more children. The distribution of mean maternal ages in all and in primiparous women was lowest in the mid 1970s, corresponding to a peak in the proportion of teenage mothers. The proportion of older mothers declined until the late 1970s (from 16.5% to 3.4%) followed by a steady increase. Mean birthweight in all and term babies gradually increased from the mid 1970s. The increase in the percentage of preterm birth paralleled a two-fold increase in the percentage of caesarean section among preterm births during the last two decades. The gap between the most affluent and the most deprived groups of the population widened over the three decades.

Conclusion

Key maternal and fetal factors affecting birth outcomes, such as maternal age, parity, socioeconomic status, birthweight and gestational age, changed substantially during the 32-year period, from 1961 to 1992. The availability of accurate gestational age is extremely important for correct interpretation of trends in birthweight.

Intensive care for extreme prematurity--moving beyond gestational age

BACKGROUND

Decisions regarding whether to administer intensive care to extremely premature infants are often based on gestational age alone. However, other factors also affect the prognosis for these patients.

METHODS

We prospectively studied a cohort of 4446 infants born at 22 to 25 weeks' gestation (determined on the basis of the best obstetrical estimate) in the Neonatal Research Network of the National Institute of Child Health and Human Development to relate risk factors assessable at or before birth to the likelihood of survival, survival without profound neurodevelopmental impairment, and survival without neurodevelopmental impairment at a corrected age of 18 to 22 months.

RESULTS

Among study infants, 3702 (83%) received intensive care in the form of mechanical ventilation. Among the 4192 study infants (94%) for whom outcomes were determined at 18 to 22 months, 49% died, 61% died or had profound impairment, and 73% died or had impairment. In multivariable analyses of infants who received intensive care, exposure to antenatal corticosteroids, female sex, singleton birth, and higher birth weight (per each 100-g increment) were each associated with reductions in the risk of death and the risk of death or profound or any neurodevelopmental impairment; these reductions were similar to those associated with a 1-week increase in gestational age. At the same estimated likelihood of a favorable outcome, girls were less likely than boys to receive intensive care. The outcomes for infants who underwent ventilation were better predicted with the use of the above factors than with use of gestational age alone.

CONCLUSIONS

The likelihood of a favorable outcome with intensive care can be better estimated by consideration of four factors in addition to gestational age: sex, exposure or nonexposure to antenatal corticosteroids, whether single or multiple birth, and birth weight. (ClinicalTrials.gov numbers, NCT00063063 [ClinicalTrials.gov] and NCT00009633 [ClinicalTrials.gov].).