External validation of models to estimate gestational age in the second and third trimester using ultrasound: A prospective multicentre observational study.

OBJECTIVES: Accurate assessment of gestational age (GA) is important at both individual and population levels. The most accurate way to estimate GA in women who book late in pregnancy is unknown. The aim of this study was to externally validate the accuracy of equations for GA estimation in late pregnancy and to identify the best equation for estimating GA in women who do not receive an ultrasound scan until the second or third trimester. DESIGN: This was a prospective, observational cross-sectional study. SETTING: 57 prenatal care centres, France. PARTICIPANTS: Women with a singleton pregnancy and a previous 11-14-week dating scan that gave the observed GA were recruited over an 8-week period. They underwent a standardised ultrasound examination at one time point during the pregnancy (15-43 weeks), measuring 12 foetal biometric parameters that have previously been identified as useful for GA estimation. MAIN OUTCOME MEASURES: A total of 189 equations that estimate GA based on foetal biometry were examined and compared with GA estimation based on foetal CRL. Comparisons between the observed GA and the estimated GA were made using R2, calibration slope and intercept. RMSE, mean difference and 95% range of error were also calculated. RESULTS: A total of 2741 pregnant women were examined. After exclusions, 2339 participants were included. In the 20 best performing equations, the intercept ranged from -0.22 to 0.30, the calibration slope from 0.96 to 1.03 and the RSME from 0.67 to 0.87. Overall, multiparameter models outperformed single-parameter models. Both the 95% range of error and mean difference increased with gestation. Commonly used models based on measurement of the head circumference alone were not amongst the best performing models and were associated with higher 95% error and mean difference. CONCLUSIONS: We provide strong evidence that GA-specific equations based on multiparameter models should be used to estimate GA in late pregnancy. However, as all methods of GA assessment in late pregnancy are associated with large prediction intervals, efforts to improve access to early antenatal ultrasound must remain a priority. TRIAL REGISTRATION: The proposal for this study and the corresponding methodological review was registered on PROSPERO international register of systematic reviews (registration number: CRD4201913776).

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.

[Posterm pregnancy]. / Potermínové tehotenství.

UNLABELLED: This review presents the up-to-date information from published resources on the issue of Posterm pregnancy (Medline, Cochrane Database, ACOG, RCOG, SOGC) and complements the presented guidelines. The most of resources are using the term "postterm pregnancy" for pregnancy reaching or exceeding 42+0 weeks and days of gestation, while late pregnancy is defined as a period in between 41+0 and 41+6.The exact determination of gestational age is necessary for exact diagnosis and appropriate management of late and postterm pregnancy, because these pregnancies have increased risk of perinatal morbidity and mortality. DESIGN: Review.

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.

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.