Predicting delivery date by ultrasound and last menstrual period in early gestation

The impact of obesity on first-trimester pregnancy dating using ultrasound: a retrospective cohort study

OBJECTIVES

Obese women are known to have alterations in their menstrual cycles leading to ovulatory dysfunction. The purpose of this study is to evaluate the relationship between body mass index (BMI) and early pregnancy ultrasound dating and determine the frequency of redating.

METHODS

We performed a retrospective cohort study of women who underwent a first trimester dating ultrasound at The University of Oklahoma Health Sciences Center from January 2019 to June 2020. The estimated date of delivery (EDD) calculated from the ultrasound was compared to the EDD calculated from the LMP. A discrepancy of greater than 5 days prior to 9 weeks or greater than 7 days between 9 and 13 weeks prompted redating of the pregnancy.

RESULTS

2639 women met inclusion criteria, with BMI ≥ 30 kg/m2 present in 39% of participants. Obese women had higher rates of pregnancy redating compared to non-obese women-adjusted risk ratio [aRR] 1.23 (95% confidence interval [CI] 1.07-1.41, p = 0.003). Class III obese women were more likely than any other BMI class to have their pregnancies redated by ultrasound-aRR 1.46 (95% CI 1.18-1.80, p < 0.001). Analyses adjusted for age, race, and parity showed that for each unit increase in BMI over 30 kg/m2, women had a 2% increased risk of being redated (p < 0.001). Mean EDD by ultrasound minus mean EDD by LMP was -0.98, -2.70, -2.43, and -3.35 (p < 0.001) for non-obese, class I, class II, and class III obese women, respectively. 22% of non-obese women were redated compared to 27.3% of obese women (p = 0.002) and 31.2% of class III obese women (p = 0.001).

CONCLUSIONS

Obese women have higher rates of pregnancy redating compared to normal weight women, with class III obese women having the highest rates of all groups studied. Accurate pregnancy dating is important to decrease unnecessary interventions due to false diagnoses of fetal growth restriction or macrosomia.

Different effects for different questions: An illustration using short cervix and the risk of preterm birth

OBJECTIVE

To illustrate the difference between exposure effects and population attributable effects.

METHODS

We examined the effect of mid-pregnancy short cervical length (<25 mm) on preterm birth using data from a prospective cohort of pregnant women in Lusaka, Zambia. Preterm birth was live birth or stillbirth before 37 weeks of pregnancy. For estimation, we used multivariable regression and parametric g-computation.

RESULTS

Among 1409 women included in the analysis, short cervix was rare (2.4%); 13.6% of births were preterm. Exposure effect estimates were large (marginal risk ratio 2.86, 95% confidence interval [CI] 1.80-4.54), indicating that the preterm birth risk was substantially higher among women with a short cervix compared with women without a short cervix. However, the population attributable effect estimates were close to the null (risk ratio 1.06, 95% CI 1.02-1.10), indicating that an intervention to counteract the impact of short cervix on preterm birth would have minimal effect on the population risk of preterm birth.

CONCLUSION

Although authors often refer to "the" effect, there are actually different types of effects, as we have illustrated here. In planning research, it is important to consider which effect to estimate to ensure that the estimate aligns with the research objective.

Better Estimation of Spontaneous Preterm Birth Prediction Performance through Improved Gestational Age Dating

The clinical management of pregnancy and spontaneous preterm birth (sPTB) relies on estimates of gestational age (GA). Our objective was to evaluate the effect of GA dating uncertainty on the observed performance of a validated proteomic biomarker risk predictor, and then to test the generalizability of that effect in a broader range of GA at blood draw. In a secondary analysis of a prospective clinical trial (PAPR; NCT01371019), we compared two GA dating categories: both ultrasound and dating by last menstrual period (LMP) (all subjects) and excluding dating by LMP (excluding LMP). The risk predictor's performance was observed at the validated risk predictor threshold both in weeks 191/7-206/7 and extended to weeks 180/7-206/7. Strict blinding and independent statistical analyses were employed. The validated biomarker risk predictor showed greater observed sensitivity of 88% at 75% specificity (increases of 17% and 1%) in more reliably dated (excluding-LMP) subjects, relative to all subjects. Excluding dating by LMP significantly improved the sensitivity in weeks 191/7-206/7. In the broader blood draw window, the previously validated risk predictor threshold significantly stratified higher and lower risk of sPTB, and the risk predictor again showed significantly greater observed sensitivity in excluding-LMP subjects. These findings have implications for testing the performance of models aimed at predicting PTB.

GestAltNet: aggregation and attention to improve deep learning of gestational age from placental whole-slide images

The placenta is the first organ to form and performs the functions of the lung, gut, kidney, and endocrine systems. Abnormalities in the placenta cause or reflect most abnormalities in gestation and can have life-long consequences for the mother and infant. Placental villi undergo a complex but reproducible sequence of maturation across the third-trimester. Abnormalities of villous maturation are a feature of gestational diabetes and preeclampsia, among others, but there is significant interobserver variability in their diagnosis. Machine learning has emerged as a powerful tool for research in pathology. To capture the volume of data and manage heterogeneity within the placenta, we developed GestaltNet, which emulates human attention to high-yield areas and aggregation across regions. We used this network to estimate the gestational age (GA) of scanned placental slides and compared it to a baseline model lacking the attention and aggregation functions. In the test set, GestaltNet showed a higher r2 (0.9444 vs. 0.9220) than the baseline model. The mean absolute error (MAE) between the estimated and actual GA was also better in the GestaltNet (1.0847 weeks vs. 1.4505 weeks). On whole-slide images, we found the attention sub-network discriminates areas of terminal villi from other placental structures. Using this behavior, we estimated GA for 36 whole slides not previously seen by the model. In this task, similar to that faced by human pathologists, the model showed an r2 of 0.8859 with an MAE of 1.3671 weeks. We show that villous maturation is machine-recognizable. Machine-estimated GA could be useful when GA is unknown or to study abnormalities of villous maturation, including those in gestational diabetes or preeclampsia. GestaltNet points toward a future of genuinely whole-slide digital pathology by incorporating human-like behaviors of attention and aggregation.

Reference intervals of gestational sac, yolk sac, embryonic length, embryonic heart rate at 6-10 weeks after in vitro fertilization-embryo transfer

Background

Accurately determining the normal range of early pregnancy markers can help to predict adverse pregnancy outcomes. The variance in ovulation days leads to uncertain accuracy of reference intervals for natural pregnancies. While the gestational age (GA) is accurate estimation during in vitro fertilization-embryo transfer (IVF-ET). Thus, the objective of this research is to construct reference intervals for gestational sac diameter (GSD), yolk sac diameter (YSD), embryonic length (or crown–rump length, CRL) and embryonic heart rate (HR) at 6–10 gestational weeks (GW) after IVF-ET.

Methods

From January 2010 to December 2016, 30,416 eligible singleton pregnancies were retrospectively recruited. All included participants had full records of early ultrasound measurements and phenotypically normal live neonates after 37 GW, with birth weights > the 5th percentile for gestational age. The curve-fitting method was used to screen the optimal models to predict GSD, CRL, YSD and HR based on gestational days (GD) and GW. Additionally, the percentile method was used to calculate the 5th, 50th, and 95th percentiles.

Results

There were significant associations among GSD, CRL, YSD, HR and GD and GW, the models were GSD = − 29.180 + 1.070 GD (coefficient of determination [R²] = 0.796), CRL = − 11.960 - 0.147 GD + 0.011 GD² (R² = 0.976), YSD = − 2.304 + 0.184 GD - 0.011 GD² (R² = 0.500), HR = − 350.410 + 15.398 GD - 0.112 GD² (R² = 0.911); and GSD = − 29.180 + 7.492 GW (R² = 0.796), CRL = − 11.960 - 1.028 GW + 0.535 GW² (R² = 0.976), YSD = − 2.304 + 1.288 GW - 0.054 GW² (R² = 0.500), HR = − 350.410 + 107.788 GW - 5.488 GW² (R² = 0.911), (p < 0.001).

Conclusions

Reference intervals for GSD, YSD, HR and CRL at 6–10 gestational weeks after IVF-ET were established.

Complications of Antenatal Corticosteroids in Infants Born by Early Term Scheduled Cesarean Section

OBJECTIVE

To compare neonatal hypoglycemia and respiratory morbidity rates in pregnancies complicated by diabetes following early term scheduled cesarean section (ETSCS) with and without maternal corticosteroid administration.

RESEARCH DESIGN AND METHODS

In a retrospective cohort study, women with any form of diabetes in pregnancy undergoing ETSCS were included. Primary outcomes were admission rates to the neonatal intensive care unit (NICU) for respiratory distress syndrome (RDS)/transient tachypnea of the newborn (TTN) and/or neonatal hypoglycemia.

RESULTS

NICU admission rates for neonatal hypoglycemia were significantly higher (24.2% vs. 4.4%, P = 0.003) and RDS/TTN rates were nonsignificantly higher (15.2% vs. 7.2%, P = 0.209) following corticosteroid administration.

CONCLUSIONS

Corticosteroids were not beneficial among women with any form of diabetes in pregnancy undergoing ETSCS and, indeed, may be harmful. In our hospital, we have ceased the use of corticosteroids for women under these circumstances.

Estimating onset time from longitudinal data in the presence of measurement error with application to estimating gestational age from maternal anthropometry during pregnancy

Accurate assessment of gestational age at birth is necessary for optimal pediatric care. In high resource countries, several methods using ultrasound have been proposed to assess gestational age at birth; however, these methods are not easily accessible for low-resource populations. We develop a shared random parameter model for estimating gestational age at birth from longitudinal maternal anthropometry that incorporates additional maternal information from the last menstrual period, a measure of gestational age collected with sizable measurement error. The proposed methodology is evaluated using simulation studies under a training-test set paradigm. In addition, we propose methodology to validate prediction when some measurements of the gold standard are collected with measurement error. We illustrate the proposed methodologies with data from the NICHD Fetal Growth Studies.

Cardiotocography and beyond: a review of one-dimensional Doppler ultrasound application in fetal monitoring

One-dimensional Doppler ultrasound (1D-DUS) provides a low-cost and simple method for acquiring a rich signal for use in cardiovascular screening. However, despite the use of 1D-DUS in cardiotocography (CTG) for decades, there are still challenges that limit the effectiveness of its users in reducing fetal and neonatal morbidities and mortalities. This is partly due to the noisy, transient, complex and nonstationary nature of the 1D-DUS signals. Current challenges also include lack of efficient signal quality metrics, insufficient signal processing techniques for extraction of fetal heart rate and other vital parameters with adequate temporal resolution, and lack of appropriate clinical decision support for CTG and Doppler interpretation. Moreover, the almost complete lack of open research in both hardware and software in this field, as well as commercial pressures to market the much more expensive and difficult to use Doppler imaging devices, has hampered innovation. This paper reviews the basics of fetal cardiac function, 1D-DUS signal generation and processing, its application in fetal monitoring and assessment of fetal development and wellbeing. It also provides recommendations for future development of signal processing and modeling approaches, to improve the application of 1D-DUS in fetal monitoring, as well as the need for annotated open databases.

Can support from the father of the baby buffer the adverse effects of depressive symptoms on risk of preterm birth in Black families?

BACKGROUND

While maternal depressive symptoms during pregnancy have been linked to preterm birth (PTB; birth before 37 completed weeks of gestation), little has been reported on potential buffering factors, particularly specific to Black women who are at much higher risk. We examined the association between depressive symptoms and PTB in pregnant Black women, with father of the baby (FOB) support as a potential buffering factor.

METHODS

Data were obtained from the life-course influences on fetal environments study (2009-2011), a cohort of 1,410 Black women in metropolitan Detroit, Michigan (71% response rate) using maternal interviews and medical record abstraction collected during the postpartum hospitalization. The 20-item Center for Epidemiologic Studies Depression (CES-D) scale was used to measure depressive symptoms. The 14-item social networks in adult relations questionnaire was used to assess the mother's relationship with the FOB. Logistic regression was used to explore the interaction between CES-D and FOB support with regard to PTB risk. We adjusted for maternal advanced age, income, education level, smoking status, hypertension, prenatal care and BMI.

RESULTS

The PTB rate in this cohort was 17.7%. Among women with FOB scale < 60 (less support), the odd ratio (OR) of PTB for women with CES-D scores ≥ 23 (severe depressive symptoms) as compared to CES-D scores < 23 (no severe depressive symptoms) was 2.57 [95% confidence interval (CI): 1.68, 3.94; p < 0.001]. Among women with FOB scores ≥ 60 (more support), the odds of PTB in women with CES-D scores ≥ 23 did not significantly differ from the odds of PTB in women with CES-D scores < 23 (OR = 1.34; 95% CI: 0.74, 2.44; p = 0.3). After adjustment for covariates, among women with FOB scores < 60, the OR of PTB for women with CES-D scores ≥ 23 compared to < 23 was 2.79 (95% CI: 1.75, 4.45; p < 0.001). Among women with FOB scores ≥ 60, the odds of PTB in women with CES-D scores ≥ 23 was not statistically significantly different compared to the odds of PTB in women with CES-D scores < 23 (OR = 1.21; 95% CI: 0.62, 2.35; p = 0.6). The interaction term was statistically significant (p = 0.04).

DISCUSSION/CONCLUSIONS

The adverse effect of depressive symptoms on risk of PTB may be buffered by factors such as a supportive relationship with the FOB.

Assessing the accuracy of ultrasound estimation of gestational age during routine antenatal care in in vitro fertilization (IVF) pregnancies

INTRODUCTION

In the UK an accurate gestational age is confirmed by ultrasound measured foetal crown rump length (CRL) at 11 + 2-14 + 1 weeks of gestation. The currently recommended Robinson and Fleming crown rump length reference chart was develop in 1975. Advances in ultrasound technology and standardized crown rump length measurement training could mean this is now out of date. Our study aimed to assess its accuracy in current routine antenatal care.

METHODS

Retrospective data from 178 IVF pregnancies seen for routine antenatal care at a UK Regional Maternity Unit between 1 January 2006 and 1 January 2016 was retrieved. We compared ultrasound calculated crown rump length gestational age taken at the routine First Trimester Screening Clinic (FTSC) with the 'true' gestational age calculated from the known IVF fertilization date.

RESULTS

We identified a systematic overestimation of gestational age by ultrasound using the currently recommended crown rump length reference chart when compared to IVF gestational age. The mean overestimation was 3.0 days (95% CI: 2.7 to 3.4), p < 0.001. A range of alternative ultrasound reference charts also generated a systematic overestimation, ranging from 1.6 to 2.9 days (p < 0.001, for each).

CONCLUSIONS

The current crown rump length reference chart systematically overestimates gestational age by an average of three days when assessed in IVF pregnancies. A systematic overestimation was also identified in alternative crown rump length reference charts. These differences, although slight, were systematic with implications for the accuracy of gestational age estimation particularly in pregnancies at risk of pre-term delivery or growth restriction. Our findings need confirming in larger, non IVF cohorts and could lead to the need for an updated crown rump length reference chart.

Adherence to a healthy eating index for pregnant women is associated with lower neonatal adiposity in a multiethnic Asian cohort: the Growing Up in Singapore Towards healthy Outcomes (GUSTO) Study

Background

Evidence linking maternal diet quality during pregnancy with infant birth outcomes is limited in Asia.

Objective

We investigated the association of maternal diet quality with the risk of preterm birth, offspring birth size, and adiposity in a multiethnic Asian birth cohort.

Design

Dietary intakes of 1051 pregnant women were ascertained at 26-28 wk of gestation with the use of 24-h recalls and 3-d food diaries, from which diet quality (score range: 0-100) was measured by the Healthy Eating Index for pregnant women in Singapore (HEI-SGP). Gestational age was established by first-trimester ultrasound dating scan. Neonatal weight and length were measured at birth. Body composition was assessed by air displacement plethysmography in a subset of infants (n = 313) within 72 h after birth, and abdominal adiposity was assessed by MRI (n = 316) within the first 2 wk of life. Associations were assessed by multivariable linear regression for continuous outcomes and logistic regression for preterm birth.

Results

The mean ± SD maternal HEI-SGP score was 52.1 ± 13.6. Maternal diet quality during pregnancy was not associated with preterm birth or birth weight. Greater adherence to the HEI-SGP (per 10-point increment in HEI-SGP score) was associated with longer birth length [β (95% CI): 0.14 (0.03, 0.24 cm)], lower body mass index (in kg/m2) at birth [-0.07 (-0.13, -0.01)], lower sum of triceps and subscapular skinfold thickness [-0.15 (-0.26, -0.05 mm)], lower percentage body fat [-0.52% (-0.84%, -0.20%)], lower fat mass [-17.23 (-29.52, -4.94 g)], lower percentage abdominal superficial subcutaneous adipose tissue [-0.16% (-0.30%, -0.01%)], and lower percentage deep subcutaneous adipose tissue [-0.06% (-0.10%, -0.01%)].

Conclusions

Higher maternal diet quality during pregnancy was associated with longer birth length and lower neonatal adiposity but not with birth weight and preterm birth. These findings warrant further investigation in independent studies. This trial was registered at clinicaltrials.gov as NCT01174875.

Gestational age within normal range and infants' health and temperament at 3-months of age

OBJECTIVE

To examine the association between gestational age (GA) at birth across the normal GA spectrum (37-41 weeks) and the temperament and health of 3-month old infants.

METHODS

The sample comprised 242 "low-risk" mothers and infants without chronic illnesses or severe pregnancy complications. Infant temperament was defined by three constructs: Negative Affectivity (NA), Extraversion, and Regulation, assessed by parents' reports on the Infant Behavior Questionnaire. Infants' health was defined as the number of nonroutine doctors' visits attended by the infants since their release from the hospital after birth. Analyses employed a continuous measure of GA to assess outcomes across GAs and a categorical measure (37, 38, 39-41 weeks GA) to examine contrasts.

RESULTS

Extraversion was positively related to GA primarily due to the lower scores of infants born at 37 weeks compared to infants born at 39-41 weeks GA. NA showed a similar effect. The odds of infants born at 37 weeks attending a nonroutine medical visit were 2.8 times that of infants born full-term.

DISCUSSION

Infants born at 37 weeks GA express less affect and use more nonroutine medical services than do infants born at 39-41 weeks GA. The findings underscore the importance of considering the risks of pregnancy prolongation with the developmental risk associated with early-term delivery.

Assessment of Fetal Development Using Cardiac Valve Intervals

An automated method to assess the fetal physiological development is introduced which uses the component intervals between fetal cardiac valve timings and the Q-wave of fetal electrocardiogram (fECG). These intervals were estimated automatically from one-dimensional Doppler Ultrasound and noninvasive fECG. We hypothesize that the fetal growth can be estimated by the cardiac valve intervals. This hypothesis was evaluated by modeling the fetal development using the cardiac intervals and validating against the gold standard gestational age identified by Crown-Rump Length (CRL). Among the intervals, electromechanical delay time, isovolumic contraction time, ventricular filling time and their interactions were selected in a stepwise regression process that used gestational age as the target in a cohort of 57 fetuses. Compared with the gold standard age, the newly proposed regression model resulted in a mean absolute error of 3.8 weeks for all recordings and 2.7 weeks after excluding the low quality recordings. Since Fetal Heart Rate Variability (FHRV) has been proposed in the literature for assessing the fetal development, we compared the performance of gestational age estimation by our new valve-interval based method, vs. FHRV, while assuming the CRL as the gold standard. The valve interval-based method outperformed both the model based on FHRV. Results of evaluation for 30 abnormal cases showed that the new method is less affected by arrhythmias such as tachycardia and bradycardia compared to FHRV, however certain types of heart anomalies cause large errors (more than 10 weeks) with respect to the CRL-based gold standard age. Therefore, discrepancies between the regression based estimation and CRL age estimation could indicate the abnormalities. The cardiac valve intervals have been known to reflect the autonomic function. Therefore the new method potentially provides a novel approach for assessing the development of fetal autonomic nervous system, which may be growth curve independent.

The Impact of Symptoms of Depression and Walking on Gestational Age at Birth in African American Women

BACKGROUND

Symptoms of depression have been related to lower gestational age and preterm birth (<37 completed weeks gestation). Leisure time physical activity may have protective effects on preterm birth; however, less has been published with regard to other domains of physical activity such as walking for a purpose (e.g., for transportation) or the pathways by which symptoms of depression impact gestational age at birth.

METHODS

This was a secondary analysis of available data of African American women. Women were interviewed within 3 days after birth. We proposed a model in which walking for a purpose during pregnancy mediated the effects of symptoms of depression (measured by the 20-item Center for Epidemiologic Studies-Depression [CES-D] scale) on gestational age at birth in a sample of 1,382 African American women.

RESULTS

Using structural equation modeling, we found that the direct effect of CES-D scores of 23 or greater, which have been correlated with major depression diagnosis, on gestational age at birth was -4.23 (p < .001). These results indicate that symptoms of depression were associated with a decrease in gestational age at birth of 4.23 days. Walking for a purpose mediated the effect of CES-D scores of 23 or greater on gestational age at birth.

CONCLUSIONS

Compared with African American women without symptoms of depression, African American women who had symptoms of depression walked less for a purpose during their pregnancy and delivered infants with lower gestational age at birth. If not medically contraindicated, clinicians should incorporate walking as part of prenatal care recommendations and reassure women about safety of walking during pregnancy.

Self-assessment of eligibility for early medical abortion using m-Health to calculate gestational age in Cape Town, South Africa: a feasibility pilot study

Background

Although abortion is legally available in South Africa, barriers to access exist. Early medical abortion is available to women with a gestational age up to 63 days and timely access is essential. This study aimed to determine women’s acceptability and ability to self-assess eligibility for early medical abortion using an online gestational age calculator. Women’s acceptability, views and preferences of using mobile technology for gestational age (GA) determination were explored. No previous studies to ascertain the accuracy of online self-administered calculators in a non-clinical setting have been conducted.

Methods

A convenience sample of abortion seekers were recruited from two health care clinics in Cape Town, South Africa in 2014. Seventy-eight women were enrolled and tasked with completing an online self-assessment by entering the first day of their last menstrual period (LMP) onto a website which calculated their GA. A short survey explored the feasibility and acceptability of employing m-Health technology in abortion services. Self-calculated GA was compared with ultrasound gestational age obtained from clinical records.

Results

Participant mean age was 28 (SD 6.8), 41 % (32/78) had completed high school and 73 % (57/78) reported owning a smart/feature phone. Internet searches for abortion information prior to clinic visit were undertaken by 19/78 (24 %) women. Most participants found the online GA calculator easy to use (91 %; 71/78); thought the calculation was accurate (86 %; 67/78) and that it would be helpful when considering an abortion (94 %; 73/78). Eighty-three percent (65/78) reported regular periods and recalled their LMP (71 %; 55/78). On average women overestimated GA by 0.5 days (SD 14.5) and first sought an abortion 10 days (SD 14.3) after pregnancy confirmation.

Conclusions

Timely access to information is an essential component of effective abortion services. Advances in the availability of mobile technology represent an opportunity to provide accurate and safe abortion information and services. Our findings indicate that an online GA calculator would be accurate and helpful. GA could be calculated based on LMP recall within an error of 0.5 days, which is not considered clinically significant. An online GA calculator could potentially act as an enabler for women to access safe abortion services sooner.

Dating of Pregnancy in First versus Second Trimester in Relation to Post-Term Birth Rate: A Cohort Study

Objectives

To evaluate in a national standardised setting whether the performance of ultrasound dating during the first rather than the second trimester of pregnancy had consequences regarding the definition of pre- and post-term birth rates.

Methods

A cohort study of 8,551 singleton pregnancies with spontaneous delivery was performed from 2006 to 2012 at Copenhagen University Hospital, Holbæk, Denmark. We determined the duration of pregnancy calculated by last menstrual period, crown rump length (CRL), biparietal diameter (1^st trimester), BPD (2^nd trimester), and head circumference and compared mean and median durations, the mean differences, the systematic discrepancies, and the percentages of pre-term and post-term pregnancies in relation to each method. The primary outcomes were post-term and pre-term birth rates defined by different dating methods.

Results

The change from use of second to first trimester measurements for dating was associated with a significant increase in the rate of post-term deliveries from 2.1–2.9% and a significant decrease in the rate of pre-term deliveries from 5.4–4.6% caused by systematic discrepancies. Thereby 25.1% would pass 41 weeks when GA is defined by CRL and 17.3% when BPD (2^nd trimester) is used. Calibration for these discrepancies resulted in a lower post-term birth rate, from 3.1–1.4%, when first compared to second trimester dating was used.

Conclusions

Systematic discrepancies were identified when biometric formulas were used to determine duration of pregnancy. This should be corrected in clinical practice to avoid an overestimation of post-term birth and unnecessary inductions when first trimester formulas are used.

Risk for girls can be adversely affected post-term due to underestimation of gestational age by ultrasound in the second trimester

INTRODUCTION

Post-term pregnancies are associated with greater risks for mother and child. Accurate determination of gestational age is necessary for safe care. Female fetuses have been shown to be smaller than males at the time of second-trimester ultrasound (US) examination, leading to underestimation of their age and, potentially, greater impacts of perinatal complications in post-term girls than in post-term boys. The purpose of this study was to investigate the sex ratio of post-term births and differences in perinatal complications (stillbirth, low Apgar score, low birthweight, meconium aspiration and low umbilical artery pH) between post-term boys and girls according to dating method [second-trimester US and last menstrual period (LMP)].

MATERIAL AND METHODS

Data from gestational week ≥39 to delivery of 13 338 singleton pregnancies between 13 February 2006 and 15 January 2014, were collected from the Obstetrix(®) (Siemens Healthcare) medical records system in Dalarna County, Sweden.

RESULTS

The neonatal male:female ratio increased with gestational age after week 40, as dated by US, reaching 1.69 in gestational week 42. This ratio remained 1 throughout gestation according to dating by the LMP. Post-term pregnancy increased the risks of meconium aspiration and low Apgar score, with no sex difference observed.

CONCLUSIONS

US gestational dating indicated that more boys than girls were born post-term, whereas dating according to LMP revealed no sex difference. These results support the hypothesis that female fetuses are smaller than males, leading to underestimation of their gestational age, at the time of second-trimester US examination.

Sex bias in ultrasound measures of gestational age: assessment by sex ratio in post-term births

BACKGROUND

Estimation of fetal age by ultrasound assumes identical biometries for both sexes at identical gestational ages. However, late in the first trimester male fetuses become larger overall than female fetuses, which may introduce a sex bias with clinical consequences. A recent study showed that using due-date estimates based on biparietal diameter from the second trimester increased the post-term male-to-female ratio and the risk of stillbirth among female fetuses born at 43 gestational weeks. We aimed to evaluate whether this increased male-to-female ratio was also present when the due date was based on crown-rump length from the first trimester.

METHODS

The study population included 3987 women with a certain last menstrual period (LMP), as well as a crown-rump length measured in the first trimester and a biparietal diameter measured in the second trimester. We defined birth after 42 completed weeks estimated by LMP as post-term. Labor was not routinely induced until after 42 weeks. Male-to-female ratios were estimated using logistic regression.

RESULTS

When gestational age was estimated by biparietal diameter, the sex ratio steadily increased from 0.98 (95% confidence interval = 0.87-1.11) in week 40 to 1.54 (1.09-2.17) in week 42. A similar increase did not occur when using certain LMP or crown-rump length.

CONCLUSIONS

The use of crown-rump length for the estimation of gestational age is not associated with an increased post-term male-to-female ratio. It can therefore be used for the estimation of due date without risk of the sex bias that occurs when using biparietal diameter in second trimester of pregnancy.

Image-scoring system for crown-rump length measurement

OBJECTIVE

To develop and evaluate an objective image-scoring system for crown-rump length (CRL) measurements and to determine how this compares with subjective assessment.

METHODS

A total of 125 CRL ultrasound images were selected from the database of the International Fetal and Newborn Growth Consortium for the 21(st) Century study group. Two reviewers, who were blinded to the operators' and to each others' results, evaluated all images both subjectively and objectively. Subjective evaluation consisted of rating an image as acceptable or unacceptable, while objective evaluation was based on six criteria. Reviewer differences for both the subjective and objective evaluations were compared using percentage of agreement and adjusted kappa values.

RESULTS

The distribution of individual scores and differences between subjective and objective evaluation for the two reviewers was similar. Overall agreement between the reviewers was higher for objective evaluation (95.2%; adjusted κ, 0.904), than for subjective evaluation (77.6%; adjusted κ, 0.552). There was a high level of agreement for horizontal position (κ = 0.951), magnification (κ = 0.919), visualization of crown and rump (κ = 0.806) and caliper placement (κ = 0.756), while agreement for mid-sagittal section (κ = 0.629) and neutral position (κ = 0.565) were moderate and poor, respectively.

CONCLUSION

The proposed six-point scoring system for CRL image rating is more reproducible than is subjective evaluation and should be considered as a method of quality assessment and audit.

Longer gestation among children born full term influences cognitive and motor development

Children born preterm show persisting impairments in cognitive functioning, school achievement, and brain development. Most research has focused on implications of birth prior to 37 gestational weeks; however, the fetal central nervous system continues to make fundamental changes throughout gestation. Longer gestation is associated with reduced morbidity and mortality even among infants born during the period clinically defined as full term (37-41 gestational weeks). The implications of shortened gestation among term infants for neurodevelopment are poorly understood. The present study prospectively evaluates 232 mothers and their full term infants (50.4% male infants) at three time points across the first postnatal year. We evaluate the association between gestational length and cognitive and motor development. Infants included in the study were full term (born between 37 and 41 weeks gestation). The present study uses the combination of Last Menstrual Period (LMP) and early ultrasound for accurate gestational dating. Hierarchical Linear Regression analyses revealed that longer gestational length is associated with higher scores on the Bayley scales of mental and motor development at 3, 6 and 12 months of age after considering socio-demographic, pregnancy, and infant-level covariates. Findings were identical using revised categories of early, term, and late term proposed by the Working Group for Defining Term Pregnancy. Our findings indicate that longer gestation, even among term infants, benefits both cognitive and motor development.

[Pregnancy dating in common practice in Cameroon: reliability of the date of last menstrual period]

Introduction

La détermination précise de l’âge gestationnel (AG) est essentielle pour un suivi adapté de la grossesse. La date de dernières règles (DDR) et l’échographie de datation du premier trimestre sont les moyens habituels de datation de la grossesse. La DDR est souvent imprécise du fait des erreurs de rappel ou d'un trouble du cycle menstruel. Cette étude transversale et descriptive avait pour objectif d’évaluer la fiabilité de la DDR dans la datation de la grossesse en pratique courante à Yaoundé.

Méthodes

Etude transversale et descriptive réalisée dans deux hôpitaux universitaires de Yaoundé du 15 décembre 2012 au 15 avril 2013. La collecte des données était effectuée par un interrogatoire des femmes enceintes au cours de la consultation prénatale et l'examen de leur dossier médical. Les femmes enceintes présentant une complication du premier trimestre (menace d'avortement, grossesse arrêtée ou extra-utérine, grossesse molaire) et celles ne se rappelant pas de leur DDR ont été exclues de l’étude. Les données étaient saisies dans Epi-Data 3.1 et analysées dans le logiciel SPSS. 21.

Résultats

Cinq cent huit femmes enceintes ont été enrôlées dans cette étude, 267(52,56%) d'entre elles avaient noté leur DDR sur un support tandis que 241(47,44%) utilisaient leur mémoire pour se rappeler leur DDR. Cent dix-sept (23,03%) femmes enceintes avait réalisé une échographie de datation du premier trimestre et parmi elles, 50 (42,70%) avaient une discordance des âges gestationnels théorique et échographique. Le rappel de la DDR par la mémoire (OR. 3,46; IC: 1,59-7,53), le cycle irrégulier (OR. 6,15; IC: 1,24-30,4) et le doute sur la DDR communiquée (OR. 31,06; IC: 3.95-244) étaient les facteurs significativement associés à la discordance des AG théorique et échographique.

Conclusion

La DDR utilisée pour la datation de la grossesse en pratique courante à Yaoundé est fréquemment imprécise.

Determinants of number-specific recall error of last menstrual period: a retrospective cohort study

OBJECTIVE

To assess the digit preference for last menstrual period (LMP) dates, associated determinants and impact on obstetric outcome.

DESIGN

Retrospective cohort study.

SETTING

University medical centre (the Netherlands).

POPULATION

Cohort of 24 665 LMP records and a subgroup of 4630 cases with known crown-rump length (CRL) measurement, and obstetric outcome.

METHODS

Digit preference was determined by comparing the observed to expected counts of each day. Associated determinants were identified by multivariate regression analysis. Differences in obstetric outcome between LMP and CRL dating were analysed.

MAIN OUTCOME MEASURES

(Non)deprived neighbourhood, cycle irregularity, certainty of LMP date, maternal age, smoking, body mass index, parity and ultrasound investigator. Preterm and post-term delivery.

RESULTS

LMP digit preference for the first [odds ratio (OR), 1.28; 95% confidence interval (95% CI), 1.20-1.36], fifth (OR, 1.10; 95% CI, 1.03-1.17), 10th (OR, 1.17; 95% CI, 1.09-1.25), 15th (OR, 1.31; 95% CI, 1.23-1.40), 20th (OR, 1.22; 95% CI, 1.15-1.30) and 25th (OR, 1.08; 95% CI, 1.01-1.15) days of the month occurred more often than expected. Digit preference occurred more frequently in women living in a deprived neighbourhood (OR, 1.21; 95% CI, 1.06-1.39), with uncertain LMP (OR, 2.03; 95% CI, 1.63-2.52) or irregular cycle (OR, 1.24; 95% CI, 1.06-1.44). More post-term (≥42 weeks) deliveries (OR, 1.27; 95% CI, 1.05-1.54) were observed in LMP dating. This effect was larger in women with a digit preference (OR, 1.56; 95% CI, 1.03-2.37).

CONCLUSIONS

LMP digit preference occurs more often in women living in deprived neighbourhoods, with uncertain LMP or an irregular cycle. LMP-dated pregnancies are associated with more post-term pregnancies.

Fetal imaging: Executive summary of a Joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging Workshop

Given that practice variation exists in the frequency and performance of ultrasound and magnetic resonance imaging in pregnancy, the Eunice Kennedy Shriver National Institute of Child Health and Human Development hosted a workshop to address indications for ultrasound and magnetic resonance imaging in pregnancy, to discuss when and how often these studies should be performed, to consider recommendations for optimizing yield and cost-effectiveness and to identify research opportunities. This article is the executive summary of the workshop.

Women's perception of accuracy of ultrasound dating in late pregnancy: a challenge to prevention of prolonged pregnancy in a resource-poor Nigerian setting

Background

Expected date of delivery (EDD) is estimated from the last menstrual period (LMP) or ultrasound scan. Conflicts between these estimates especially on the part of the physician and his/her patient could pose a challenge to prevention of prolonged pregnancy. The objective of this study was to determine the perception and acceptability of menstrual dating (EDD derived from LMP) with regard to timing of labor induction for postdatism by pregnant women who have a late pregnancy (≥23 weeks’ gestation) ultrasound scan.

Methods

This cross-sectional study included 443 consecutive pregnant women receiving antenatal care at two tertiary health institutions in Enugu, Nigeria, from January 1, 2013 to March 31, 2013.

Results

The mean age of the women was 27.9±2.41 (range 17–45) years. Most ultrasound scans (90.8%, 357/389) were carried out in late pregnancy, and 41.9% (167/389) were self-referred. The majority of the respondents (51.7%, 229/443) did not accept induction of labor for postdatism at a certain menstrual dating-derived gestational age of 40 weeks plus 10 days if the late pregnancy ultrasound scan dating was less. Predictors of this poor attitude to timing of induction of labor for postdatism included low educational level, low social class, and poor knowledge of the limitations of ultrasound scan dating in late pregnancy (P<0.05).

Conclusion

The worrisome confidence in ultrasound scan dating is a challenge to the prevention of prolonged pregnancy and its complications in our environment. Antenatal health education should discourage self-referral for ultrasound scan dating and emphasize its limitations in late pregnancy as well as the perinatal effects of prolonged pregnancy.

Estimation of gestational age in early pregnancy from crown-rump length when gestational age range is truncated: the case study of the INTERGROWTH-21st Project

BACKGROUND

Fetal ultrasound scanning is considered vital for routine antenatal care with first trimester scans recommended for accurate estimation of gestational age (GA). A reliable estimate of gestational age is key information underpinning clinical care and allows estimation of expected date of delivery. Fetal crown-rump length (CRL) is recommended over last menstrual period for estimating GA when measured in early pregnancy i.e. 9+0-13+6 weeks.

METHODS

The INTERGROWTH-21st Project is the largest prospective study to collect data on CRL in geographically diverse populations and with a high level of quality control measures in place. We aim to develop a new gestational age estimation equation based on the crown-rump length (CRL) from women recruited between 9+0-13+6 weeks. The main statistical challenge is modelling data when the outcome variable (GA) is truncated at both ends, i.e. at 9 and 14 weeks.We explored three alternative statistical approaches to overcome the truncation of GA. To evaluate these strategies we generated a data set with no truncation of GA that was similar to the INTERGROWTH-21st Project CRL data, which we used to explore the performance of different methods of analysis of these data when we imposed truncation at 9 and 14 weeks of gestation. These 3 methods were first tested in a simulation based study using a previously published dating equation by Verburg et al. and evaluated how well each of them performed in relation to the model from which the data were generated. After evaluating the 3 approaches using simulated data based on the Verburg equations, the best approach will be applied to the INTERGROWTH-21st Project data to estimate GA from CRL.

RESULTS

Results of these rather "ad hoc" statistical methods correspond very closely to the "real data" for Verburg, a data set that is similar to the INTERGROWTH-21st project CRL data set.

CONCLUSIONS

We are confident that we can use these approaches to get reliable estimates based on INTERGROWTH-21st Project CRL data. These approaches may be a solution to other truncation problems involving similar data though their application to other settings would need to be evaluated.

Should a first trimester dating scan be routine for all pregnancies?

Accurate pregnancy dating is important for diagnostic and management decisions during pregnancy. Dating by last menstrual period is less reliable than dating by ultrasound, since the former has memory-related and other sources of inaccuracy. Dating by first trimester ultrasound, via the crown-rump length, has a 95% confidence range of ±5 days, slightly better than the ±8 days for dating by second trimester ultrasound at 14-20 weeks. This small difference appears to be too small to justify a routine first trimester scan for the purpose of dating the pregnancy.

Validation of the global reference for fetal weight and birth weight percentiles

The objective of this study was to evaluate whether the global reference curves adapted on the basis of WHO data for India and the Hadlock reference curves fit the population in India and to validate the reference curves. The data were retrieved retrospectively from the records of women registration for antenatal care at a charitable maternity hospital in Mumbai, India. All pregnancies were dated on CRL obtained before 14 weeks. Births before 34(th) week were excluded. The expected frequencies of birth weights below the 1(st), 5(th), 10(th), 50(th), 90(th), 95(th) and 99(th) centiles from three reference ranges were compared with observed frequencies. It was found that the WHO generic reference adapted to India significantly underpredicted the birth weights and that the Hadlock reference ranges significantly overpredicted the birth weights. The use of generic reference adapted to Sri Lanka showed a better fit to the observed data. We concluded that global reference curves adapted on the basis of WHO data for India and the Hadlock reference ranges do not fit all the population in India and the charts need validation. Reference charts modified on the basis of data for Sri Lankan population show a better fit to the observed data, and therefore are more appropriate for use in clinical practice in South India.

Determining gestational age for public health care users in Brazil: comparison of methods and algorithm creation

BACKGROUND

A valid, accurate method for determining gestational age (GA) is crucial in classifying early and late prematurity, and it is a relevant issue in perinatology. This study aimed at assessing the validity of different measures for approximating GA, and it provides an insight into the development of algorithms that can be adopted in places with similar characteristics to Brazil. A follow-up study was carried out in two cities in southeast Brazil. Participants were interviewed in the first trimester of pregnancy and in the postpartum period, with a final sample of 1483 participants after exclusions. The distribution of GA estimates at birth using ultrasound (US) at 21-28 weeks, US at 29+ weeks, last menstrual period (LMP), and the Capurro method were compared with GA estimates at birth using the reference US (at 7-20 weeks of gestation). Kappa, sensitivity, and specificity tests were calculated for preterm (<37 weeks of gestation) and post-term (>=42 weeks) birth rates. The difference in days in the GA estimates between the reference US and the LMP and between the reference US and the Capurro method were evaluated in terms of maternal and infant characteristics, respectively.

RESULTS

For prematurity, US at 21-28 weeks had the highest sensitivity (0.84) and the Capurro method the highest specificity (0.97). For postmaturity, US at 21-28 weeks and the Capurro method had a very high sensitivity (0.98). All methods of GA estimation had a very low specificity (≤0.50) for postmaturity. GA estimates at birth with the algorithm and the reference US produced very similar results, with a preterm birth rate of 12.5%.

CONCLUSIONS

In countries such as Brazil, where there is less accurate information about the LMP and lower coverage of early obstetric US examinations, we recommend the development of algorithms that enable the use of available information using methodological strategies to reduce the chance of errors with GA. Thus, this study calls into attention the care needed when comparing preterm birth rates of different localities if they are calculated using different methods.

First trimester growth restriction and uterine artery blood flow in the second trimester as predictors of adverse pregnancy outcome

OBJECTIVES

To investigate if fetuses with first trimester growth restriction have poorer perfusion of the placenta compared to a control group, and to investigate whether first trimester growth restriction in combination with poor flow in the uterine arteries in the second trimester can be used to predict poor outcome.

STUDY DESIGN

Women with singleton pregnancies, where the gestational age estimated by crown-rump length (CRL) at the first trimester scan was 7 days or more smaller than the gestational age estimated by last menstrual period, and a control group of women, where the gestational age was either equal to or 1 day larger than the gestational age estimated by last menstrual period, were invited to join the study. The study entailed the routine scans; Down syndrome screening in gestational week 11-14 and an anomaly scan in gestational week 18-21. In addition to the routine scans the participants were offered a growth scan in gestational week 23-24. At the anomaly scan and growth scan, umbilical and uterine artery Doppler flows were measured.

RESULTS

182 cases and 230 controls were included in the study. The case and control groups showed no significant differences in placental blood flow characteristics at 18-21 weeks or 23-24 weeks. In our logistic regression models the only outcome that showed a significant association to the case group was birth weight below 2500 g. Having a CRL 7 days or more smaller than expected increased the risk of having a child with a birth weight below 2500 g with an odds ratio of 3.29.

CONCLUSIONS

We were unable to demonstrate a link between first trimester growth restriction and poor placental perfusion. The case group had increased risk of birth weight below 2500 g, but only with an odds ratio of 3. Therefore we do not recommend implementation of uterine or umbilical artery flow measurements specifically for fetuses with first trimester growth restriction.

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.

Ultrasound Reference Chart Based on IVF Dates to Estimate Gestational Age at 6-9 weeks' Gestation

Accurate determination of gestational age underpins good obstetric care. We assessed the performance of six existing ultrasound reference charts to determine gestational age in 1268 singleton IVF pregnancies, where “true” gestational age could be precisely calculated from date of fertilisation. All charts generated dates significantly different to IVF dates (P < 0.0001 all comparisons). Thus we generated a new reference chart, The Monash Chart, based on a line of best fit describing crown-rump length across 6 + 1 to 9 + 0 weeks of gestation (true gestational age) in the IVF singleton cohort. The Monash Chart, but none of the existing charts, accurately determined gestational age among an independent IVF twin cohort (185 twin pairs). When applied to 3052 naturally-conceived singletons scans, The Monash Chart generated estimated due dates that were different to all existing charts (P ≤ 0.004 all comparisons). We conclude that commonly used ultrasound reference charts have inaccuracies. We have generated a CRL reference chart based on true gestational age in an IVF cohort that can accurately determine gestational age at 6–9 weeks of gestation.

Preterm birth in the Inuit and First Nations populations of Québec, Canada, 1981-2008

OBJECTIVES

To evaluate preterm birth (PTB) for Inuit and First Nations vs. non-Indigenous populations in the province of Québec, Canada.

STUDY DESIGN

Retrospective cohort study.

METHODS

We evaluated singleton live births for Québec residents, 1981-2008 (n = 2,310,466). Municipality of residence (Inuit-inhabited, First Nations-inhabited, rest of Québec) and language (Inuit, First Nations, French/English) were used to identify Inuit and First Nations births. The outcome was PTB (<37 completed weeks). Cox proportional hazards regression was employed to estimate hazard ratios (HR) and 95% confidence intervals (CI) of PTB, adjusting for maternal age, education, marital status, parity and birth year.

RESULTS

PTB rates were higher for Inuit language speakers in Inuit-inhabited areas and the rest of Québec compared with French/English speakers in the rest of Québec, and disparities persisted over time. Relative to French/English speakers in the rest of Québec, Inuit language speakers in the rest of Québec had the highest risk of PTB (HR 1.98, 95% CI: 1.62-2.41). The risk was also elevated for Inuit language speakers in Inuit-inhabited areas, though to a lesser extent (HR 1.29, 95% CI: 1.18-1.41). In contrast, First Nations language speakers in First Nations-inhabited areas and the rest of Québec had similar or lower risks of PTB relative to French/English speakers in the rest of Québec.

CONCLUSIONS

Inuit populations, especially those outside Inuit-inhabited areas, have persistently elevated risks of PTB, indicating a need for strategies to prevent PTB in this population.

Use of health services by remote dwelling Aboriginal infants in tropical northern Australia: a retrospective cohort study

BACKGROUND

Australia is a wealthy developed country. However, there are significant disparities in health outcomes for Aboriginal infants compared with other Australian infants. Health outcomes tend to be worse for those living in remote areas. Little is known about the health service utilisation patterns of remote dwelling Aboriginal infants. This study describes health service utilisation patterns at the primary and referral level by remote dwelling Aboriginal infants from northern Australia.

RESULTS

Data on 413 infants were analysed. Following birth, one third of infants were admitted to the regional hospital neonatal nursery, primarily for preterm birth. Once home, most (98%) health service utilisation occurred at the remote primary health centre, infants presented to the centre about once a fortnight (mean 28 presentations per year, 95%CI 26.4-30.0). Half of the presentations were for new problems, most commonly for respiratory, skin and gastrointestinal symptoms. Remaining presentations were for reviews or routine health service provision. By one year of age 59% of infants were admitted to hospital at least once, the rate of hospitalisation per infant year was 1.1 (95%CI 0.9-1.2).

CONCLUSIONS

The hospitalisation rate is high and admissions commence early in life, visits to the remote primary health centre are frequent. Half of all presentations are for new problems. These findings have important implications for health service planning and delivery to remote dwelling Aboriginal families.

Preterm birth during an extreme weather event in Québec, Canada: a "natural experiment"

To clarify the relationship between preterm birth (PTB) and extreme weather events, we evaluated PTB during a January 1998 ice storm that had led to a provincial emergency in the middle of winter in the province of Québec, Canada. Singleton live births for three periods (1993-1997, 1998, 1999-2003) were obtained (N = 855,320). PTB was defined as gestational age <37 completed weeks. Births in the Triangle of Darkness, the area most strongly affect by the storm, were geocoded. Multivariate logistic regression was used to calculate the likelihood of PTB for the Triangle relative to metropolitan Montréal, adjusting for maternal age, education, civil status, maternal birthplace, and previous deliveries. Associations for 1998 relative to other periods were evaluated. Short-term (January-February) and long-term (March-October) exposure periods were examined. The proportion PTB for 1998 January-February births in the Triangle (8.7%) was high compared with 1998 March-October births (6.0%) and with the corresponding proportions for 1993-1997 (6.2%) and 1999-2003 (6.9%). Covariate-adjusted odds of PTB for January-February 1998 were 27% higher for the Triangle relative to metropolitan Montréal, though precision was low. Furthermore, adjusted odds were 28% higher for 1998 relative to 1999-2003, despite increasing rates of PTB over time. Odds were not elevated over a long-term exposure period. This study suggests a weak association between PTB and exposure to extreme weather for the two months following an ice storm, but not for later periods after the storm.

Individually customised fetal weight charts derived from ultrasound measurements: the Generation R Study

Maternal and fetal characteristics are important determinants of fetal growth potential, and should ideally be taken into consideration when evaluating fetal growth variation. We developed a model for individually customised growth charts for estimated fetal weight, which takes into account physiological maternal and fetal characteristics known at the start of pregnancy. We used fetal ultrasound data of 8,162 pregnant women participating in the Generation R Study, a prospective, population-based cohort study from early pregnancy onwards. A repeated measurements regression model was constructed, using backward selection procedures for identifying relevant maternal and fetal characteristics. The final model for estimating expected fetal weight included gestational age, fetal sex, parity, ethnicity, maternal age, height and weight. Using this model, we developed individually customised growth charts, and their corresponding standard deviations, for fetal weight from 18 weeks onwards. Of the total of 495 fetuses who were classified as small size for gestational age (<10th percentile) when fetal weight was evaluated using the normal population growth chart, 80 (16%) were in the normal range when individually customised growth charts were used. 550 fetuses were classified as small size for gestational age using individually customised growth charts, and 135 of them (25%) were classified as normal if the unadjusted reference chart was used. In conclusion, this is the first study using ultrasound measurements in a large population-based study to fit a model to construct individually customised growth charts, taking into account physiological maternal and fetal characteristics. These charts might be useful for use in epidemiological studies and in clinical practice.

Rate of postdates induction using first-trimester ultrasound to determine estimated due date: Wellington Regional Hospital audit

AIM

The aim of this audit was to examine the effect of using first-trimester (<14 weeks) ultrasound scan to determine EDD (US EDD) on the rate of induction for postdates pregnancies at Wellington Regional Hospital.

METHODS

Women with singleton live pregnancies who had postdates (≥41 weeks) induction at Wellington Hospital during January 2009 to November 2009 were identified using a computerised database [Perinatal Information Management System (PIMS)]. The first-trimester ultrasound images and reports for these women were retrieved and reviewed by a specialist in obstetric ultrasound. Only ultrasound studies that had technically satisfactory images at <14 weeks were included.

RESULTS

A total of 329 women with a singleton live pregnancy were induced for postdates during the study period. Of these women, 50 (15.2%) were not ≥41 weeks on PIMS EDD and therefore on the best available evidence should not have been induced for being postdates. Of the remaining 279 women, 158 had first-trimester scans available for review. Forty-three of 158 (27%) were <41 weeks when US EDD was used.

CONCLUSIONS

The rate of postdates inductions at Wellington NRH could be decreased by 38% if induction was limited to women over 41-week gestation and by using US EDD as opposed to last menstrual period EDD. The use of early gestational scans (<14 weeks) to estimate EDD lowers the rate of postdates induction. This is very similar to the observed findings in literature.

Malaria in pregnancy: the difficulties in measuring birthweight

Recommendations for interventions to control malaria in pregnancy are often based on studies using birthweight as the primary endpoint. Differences in birthweight may be attributable partly to methodological difficulties. We performed a structured search of the literature using ‘malaria’, ‘pregnancy’ and ‘birth weight’ as search terms. Of the clinical trials reporting birthweight, only 33% (14/43) gave information about the timing of the measurement and details on the scales used. Seventy seven per cent explained how gestational age was estimated. We propose a standardised method for the measurement and reporting of birthweight in future studies.

A new population-based term prediction model vs. two traditional sample-based models: validation on 9046 ultrasound examinations

OBJECTIVES

To compare results of predictions of date of delivery from a new population-based model with those from two traditional regression models.

METHODS

We included 9046 fetal biparietal diameter (BPD) measurements and 8776 femur length (FL) measurements from the routine ultrasound examinations at Stavanger University Hospital between 2001 and 2007. The prediction models to be validated were applied to the data, and the resulting predictions were compared with the actual time of the subsequent deliveries. The primary measure was the median bias (the difference between the true and the predicted date of delivery), calculated for each method, for the study population as a whole and for three subgroups of BPD/FL measurements. We also assessed the proportion of births within ± 14 days of the predicted day, and rates of preterm and post-term deliveries, which were regarded as secondary measures.

RESULTS

For the population-based model, the median bias was -0.15 days (95% confidence interval (CI), -0.43 to 0.12) for the BPD-based, and -0.48 days (95% CI, -0.86 to -0.46) for the FL-based predictions, and both biases were stable over the inclusion ranges. The biases of the traditional regression models varied, depending on the fetal size at the time of the examination; the extremes were -3.2 and + 4.5 days for the BPD-based, and -1.0 and + 5.0 days for the FL-based predictions.

CONCLUSIONS

The overall biases, as well as the biases for the subgroups, were all smaller with the population-based model than with the traditional regression models, which exhibited substantial biases in some BPD and FL subcategories. For the population-based model, the FL-based predictions were in accordance with the BPD-based predictions.

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.

Birth weight in children with birth defects

BACKGROUND

Birth defects (BDs) are a serious public health problem in Mexico. The objective of this paper was to identify the frequency of newborns (NBs) that are born small for gestational age with a birth defect.

MATERIALS AND METHODS

A cross-sectional study of NBs from hospitals part of the Mexican Institute of Social Security in Chihuahua, Mexico, was conducted. NBs were classified according to the presence or absence of a BD and according to their weight percentile using regional standards of birth weight.

RESULTS

NBs diagnosed with (n = 263) or without BDs (n = 64,626) were included in this study. A greater proportion of NBs small for gestational age were identified in cases involving BDs (20%), compared with NBs without BDs (9%). Moreover, the average decrease in birth weights of NBs with BDs associated with their digestive system was 210 grams (95% confidence interval [CI], -436/-12), with their genital organs 440 grams (95% CI, -730/-151), involving chromosomal abnormalities 230 grams (95% CI, -435/-26), or with their musculoskeletal system 289 grams (95% CI, -43/-147) according to the gestational age, sex, and condition of the NB (p < 0.05).

CONCLUSIONS

A greater proportion of NBs with BDs were associated with a low birth rate for their gestational age. In addition, some BDs were found to be associated with an impaired birth weight more often than others This suggests that clinical decisions regarding NBs with congenital defects and a lower birth weight for their gestational age should be diagnosed and treated for additional nutritional considerations as needed. Birth Defects Research (Part A), 2011. © 2011 Wiley-Liss, Inc.

Guidelines for the management of postterm pregnancy

A pregnancy reaching 42 completed weeks (294 days) is defined as postterm (PT). The use of ultrasound in early pregnancy for precise dating significantly reduces the number of PT pregnancies compared to dating based on the last menstrual period. Although the fetal, maternal and neonatal risks increase beyond 41 weeks, there is no conclusive evidence that prolongation of pregnancy, per se, is the major risk factor. Other specific risk factors for adverse outcomes have been identified, the most important of which are restricted fetal growth and fetal malformations. In order to prevent PT and associated complications routine induction before 42 weeks has been proposed. There is no conclusive evidence that this policy improves fetal, maternal and neonatal outcomes as compared to expectant management. It is also unclear if the rate of cesarean sections is different between the two management strategies. After careful identification and exclusion of specific risks, it would seem appropriate to let women make an informed decision about which management they wish to undertake. There is consensus that the number of inductions necessary to possibly avoid one stillbirth is very high. If induction is preferred, procedures for cervical ripening should be used, especially in nulliparous women. Close intrapartum fetal surveillance should be offered, irrespective of whether labor was induced or not.

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.

First- vs second-trimester ultrasound: the effect on pregnancy dating and perinatal outcomes

OBJECTIVE

The objective of the study was to examine the effect of first-trimester obstetric ultrasound (OBUS) on the measurement of the effect of complications ascribed to postterm pregnancies.

STUDY DESIGN

We conducted a retrospective cohort study of all term, singleton pregnancies delivered at our institution who had an OBUS at a gestation of 24 weeks or less. Those women who underwent an OBUS at a gestation of 12 weeks or less (OBUS12) were compared with those who had an OBUS at 13-24 weeks of gestation (OBUS13-24). The primary outcome measures were the rates of postterm pregnancies greater than 41 or 42 weeks' gestation. Secondary outcomes were the differences between the postterm and term gestations in maternal and neonatal outcomes.

RESULTS

In the OBUS12 group, the rate of postterm pregnancy 42 weeks or longer was lower (2.7%) as compared with the OBUS13-24 group (3.7%, P = .022). With regard to reaching 41 weeks of gestation, the OBUS12 group was again lower (18.2%) as compared with the OBUS13-24 group (22.1%, P < .001). There were also fewer postterm inductions at 42 weeks or longer in the OBUS12 group (1.8%) as compared with the OBUS13-24 group (2.6%, P = .017). When comparing perinatal outcomes between those women who reached 41 weeks of gestation and those prior to 41 weeks of gestation, the OBUS12 group demonstrated greater differences between these 2 groups.

CONCLUSION

Our findings suggest that earlier obstetric ultrasound, which leads to better pregnancy dating, reduces the rate of estimated postterm pregnancies. This may, in turn, reduce unnecessary intervention and lead to better identification of postterm pregnancies at greater risk of complications.