Biparietal Diameter Measurements Research Articles

Scientific basis for standardization of fetal head measurements by ultrasound: a reproducibility study.

ABSTRACTObjectiveTo compare the standard methods for ultrasound measurement of fetal head circumference (HC) and biparietal diameter (BPD) (outer‐to‐outer (BPDoo) vs outer‐to‐inner (BPDoi) caliper placement), and compare acquisition of these measurements in transthalamic (TT) vs transventricular (TV) planes.MethodsThis study utilized ultrasound images acquired from women participating in the Oxford arm of the INTERGROWTH‐21st Project. In the first phase of the study, BPDoo and BPDoi were measured on stored images. In the second phase, real‐time measurements of BPD, occipitofrontal diameter (OFD) and HC in TT and TV planes were obtained by pairs of sonographers. Reproducibility of measurements made by the same (intraobserver) and by different (interobserver) sonographers, as well as the reproducibility of caliper placement and measurements obtained in different planes, was assessed using Bland–Altman plots.ResultsIn Phase I, we analyzed ultrasound images of 108 singleton fetuses. The mean intraobserver and interobserver differences were < 2% (1.34 mm) and the 95% limits of agreement were < 5% (3 mm) for both BPDoo and BPDoi. Neither method for measuring BPD showed consistently better reproducibility. In Phase II, we analyzed ultrasound images of 100 different singleton fetuses. The mean intraobserver and interobserver differences were < 1% (2.26 mm) and the 95% limits of agreement were < 8% (14.45 mm) for all fetal head measurements obtained in TV and TT planes. Neither plane for measuring fetal head showed consistently better reproducibility. Measurement of HC using the ellipse facility was as reproducible as HC calculated from BPD and OFD. OFD by itself was the least reproducible of all fetal head measurements.ConclusionsMeasurements of BPDoi and BPDoo are equally reproducible; however, we believe BPDoo should be used in clinical practice as it allows fetal HC to be measured and compared with neonatal HC. For all head measurements, TV and TT planes provide equally reproducible values at any gestational age, and HC values are similar in both planes. Fetal head measurement in the TT plane is preferable as international standards in this plane are available; however, measurements in the TV plane can be plotted on the same standards. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Role Of Sonological Fetal Cerebellar Measurement In Gestational Age Determination

Sonographic measurement of fetal biparietal diameter is a well accepted predictor of gestational age. However there is a high variability in the calculated gestational age which increases as pregnancy progresses. The estimation of gestational age from individual parameters like the HC, AC, and FL also shows a similar variability. Using all the above parameters this variability can be reduced by 25% to 30 %. There are conditions like oligohydromnios, multiple gestation, breech presentation and intrauterine growth restriction (IUGR) that can alter the shape of the fetal skull which in turn can affect the BPD and increase the variability. The present study is being undertaken to measure the transverse cerebellar diameter (TCD) to validate it as an additional morphological measurement of fetal growth with less variability. The cerebellum and posterior fossa are aligned perpendicular to the plane of maximum extrinsic compression. Hence, they are able to withstand deformation by extrinsic pressure than the parietal bones and can be a more accurate parameter for the determination of gestational age.

Association of fetal biparietal diameter with mode of delivery and perinatal outcome.

To determine the association between sonographic assessment of fetal biparietal diameter (BPD) and pregnancy outcome. This was a retrospective cohort study of pregnancies at 37-42 weeks of gestation which had antepartum sonographic measurement of BPD within 7 days before delivery. Eligibility was limited to singleton pregnancies with neither known structural or chromosomal abnormalities nor prelabor Cesarean delivery (CD). The association of BPD with outcome was analyzed using multivariate logistic regression, receiver-operating characteristics curves and stratification according to BPD quartiles. In total, 3229 women were eligible for analysis, of whom 2483 (76.9%) had a spontaneous vaginal delivery (SVD), 418 (12.9%) underwent operative vaginal delivery (OVD) and 328 (10.2%) underwent CD. The mean BPD in the obstetric intervention groups (OVD and CD) was significantly higher than that in the SVD group (P < 0.001). After adjusting for confounders, increased BPD was an independent risk factor such that higher values of BPD were associated with progressively higher risk of obstetric intervention (adjusted odds ratio, 1.05 for each 1-mm increase in BPD (95% CI, 1.02-1.09)), but no clear cut-off value for obstetric intervention was found. The fourth quartile group (BPD ≥ 97 mm) was associated with a significantly lower SVD rate (P < 0.001) and higher OVD rate (P = 0.04), relative to the first (BPD 88-90 mm) and second (BPD 91-93 mm) quartile groups, with no apparent adverse impact on immediate neonatal outcome. Increased BPD within the week prior to delivery is an independent risk factor such that higher values of BPD are associated with progressively higher risk of obstetric intervention; however, in our experience, no adverse neonatal outcome resulted from such intervention. Thus, increased BPD should not discourage a trial of vaginal delivery.

Ultrasound biometry of normal human amniotic fluid index in a Nigerian population

BackgroundThe amniotic fluid index (AFI) closely represents the actual amniotic fluid volume (AFV) with measurements below and above the 5th and 95th percentiles describing oligohydramnios and polyhydramnios respectively. ObjectiveTo create a sonographic reference range nomogram of the AFI for a Nigerian population using polynomial regression, and to test for reproducibility of AFI measurements. MethodsFive hundred and sixty patients between 16 and 40 weeks fetal gestational age (FGA) were sampled for the study. The FGA was estimated sonographically by combining the fetal biparietal diameter, abdominal circumference, and femoral length measurements. The AFI was obtained by measuring and summing up the deepest pool of amniotic fluid devoid of fetal parts and umbilical cord in each quadrant of the maternal abdomen. To test for reproducibility of AFI measurements, two sonographers with more than 8 years of obstetric clinical experience independently measured the AFI of 40 patients. Polynomial regression, Pearson's correlation, and intra class correlations were used for data analysis. ResultsThe mean ± SD of the AFI obtained in the second and third trimester respectively is 15.2 ± 4.0 cm, and 16.0 ± 5.8 cm. There was a steady but insignificant decrease in the AFI at all the FGA studied. A log transformed linear model adequately fitted the relationship between the AFI and FGA, given as: AFIcm=1.1461+0.00091×FGA(R2=0.002). Our normal AFI range is from 8.6 cm to 27.0 cm. ConclusionOligohydramnios and polyhydramnios can be satisfactorily diagnosed in the study population when AFI measurement is below or above 8.6 cm and 27.0 cm respectively.

Evaluation of trainees’ ability to perform obstetrical ultrasound using simulation: challenges and opportunities

Evaluation of trainee's ability in obstetrical ultrasound is a time-consuming process, which requires involving patients as volunteers. With the use of obstetrical ultrasound simulators, virtual reality could help in assessing competency and evaluating trainees in this field. The objective of the study was to test the validity of an obstetrical ultrasound simulator as a tool for evaluating trainees following structured training by comparing scores obtained on obstetrical ultrasound simulator with those obtained on volunteers and by assessing correlations between scores of images and of dexterity given by 2 blinded examiners. Trainees, taking the 2013 French national examination for the practice of obstetrical ultrasound were asked to obtain standardized ultrasound planes both on volunteer pregnant women and on an obstetrical ultrasound simulator. These planes included measurements of biparietal diameter, abdominal circumference, and femur length as well as reference planes for cardiac 4-chamber and outflow tracts, kidneys, stomach/diaphragm, spine, and face. Images were stored and evaluated subsequently by 2 national examiners who scored each picture according to previously established quality criteria. Dexterity was also evaluated and subjectively scored between 0 and 10. The Raghunathan's modification of Pearson, Filon's z, Spearman's rank correlation, and analysis of variance tests were used to assess correlations between the scores by the 2 examiners and scores of dexterity and also to compare the final scores between the 2 different methods. We evaluated 29 trainees. The mean dexterity scores in simulation (6.5 ± 2.0) and real examination (5.9 ± 2.3) were comparable (P = .31). Scores with an obstetrical ultrasound simulator were significantly higher than those obtained on volunteers (P = .027). Nevertheless, there was a good correlation between the scores of the 2 examiners judging on simulation (R = 0.888) and on volunteers (R = 0.873) (P = .81). An obstetrical ultrasound simulator is as good a method as volunteer-based examination for evaluating practical skills in trainees following structured training in obstetrical ultrasound. The threshold for success/failure should, however, be adapted as candidates obtain higher scores on the simulator. Advantages of the obstetrical ultrasound simulator include the absence of location and time constraints without the need to involve volunteers or to interfere with the running of ultrasound clinics. However, an obstetrical ultrasound simulator still lacks the ability to evaluate the trainees' ability to interact with patients.

Ultrasonographic fetometry formulas of inner chorionic cavity diameter and biparietal diameter for medium-sized dogs can be used in giant breeds

The aim of this study was to evaluate the suitability of the ultrasonographic fetometry method, involving inner chorionic cavity diameter (ICC) and biparietal diameter (BP) measurements, to predict the parturition date in giant breed dogs. Overall, 30 ICC and 24 BP measurements were taken on 24 giant breed bitches. The measured values were substituted into Luvoni and Grioni (2000) formulas for medium-sized bitches because formulas with ICC and BP to dogs with a body mass greater than 40 kg have not been defined. The accuracy of the parturition date predictions proved the method to be highly useful in the observed group of dogs. Prediction accuracy in the giants ranged between 54.16% (±1 day, using BP) and 90% (±2 days, using ICC), depending on the parameter measured and precision levels used. Numerically, the results obtained using ICC were better; however, no statistically significant differences between ICC and BP accuracy were found when comparing the effectiveness of the parturition date predictions. Regression lines based on the own fetometric measurements were highly convergent with the lines defined by Luvoni and Grioni (2000) formulas for medium-sized bitches. This outcome suggests a similar gestational development of fetuses in giant dogs and the possible use of Luvoni and Grioni (2000) formulas for medium-sized dogs with breeds weighing greater than 40 kg.

Biparietal/transverse abdominal diameter ratio ≤ 1: potential marker for open spina bifida at 11-13-week scan.

In the first trimester of pregnancy, a biparietal diameter (BPD) below the 5(th) percentile is a simple marker that enables the prenatal detection of half of all cases of open spina bifida. We hypothesized that relating the BPD measurement to the transverse abdominal diameter (TAD) might be another simple and effective screening method. In this study we assessed the performance of using the BPD/TAD ratio during the first trimester of pregnancy in screening for open spina bifida. A total of 20,551 first-trimester ultrasound scans (11-13 weeks' gestation), performed between 2000 and 2013, were analyzed retrospectively; there were 26 cases of open spina bifida and 17,665 unaffected pregnancies with a crown-rump length of 45-84 mm and a record of both BPD and TAD measurements. The mean (± SD) BPD/TAD ratio was 1.00 ± 0.06 for fetuses with spina bifida and 1.13 ± 0.06 for those without (P < 0.0001). A BPD ≤ 5(th) percentile enabled the prenatal detection of 46.2% of spina bifida cases, while a BPD/TAD ratio of ≤ 1.00 detected 69.2%. If we considered cases in which either BPD was ≤ 5(th) percentile or BPD/TAD ratio was ≤ 1, we identified 76.9% of cases. In the latter case, the false-positive rate was 5.1%, while that for using a combination of both BPD ≤ 5th percentile and BPD/TAD ratio ≤ 1 was 0.6%, with a sensitivity of 38.5%. The positive predictive value of using a combination of BPD ≤ 5th percentile and BPD/TAD ratio ≤ 1 for detecting spina bifida was 8.5%. Between 11 and 13 weeks' gestation, relating BPD to TAD improves considerably the diagnostic performance of using BPD measurement alone in screening for open spina bifida. Screening using this marker is simple and applicable to a large population.

Assessment of fetal gestational age by ultrasonic measurement of bi-parietal diameter in the southern part of Rajasthan

<b>Introduction:</b> Assessment of gestational age (GA) in pregnancy can be carried out by measuring several fetal parameters in ultrasound scans and serial ultrasounds can monitor fetal growth. This study was carried out to assess GA in second and third trimesters with the help of ultrasonography measurements of one of the important fetal parameter that is, the bi-parietal diameter (BPD) in the local population (southern zone) of Rajasthan. <b>Aim:</b> The aim was to provide data for GA estimation by ultrasonic measurement of fetal BPD. <b>Materials</b> <b>and</b> <b>Methods:</b> A total of 200 normal pregnant females were studied with the known last menstrual period in the southern part of Rajasthan. GA determined by measurement of fetal BPD with real time ultrasonography machine. Statistics was applied to correlate GA and BPD. <b>Observation</b> <b>and</b> <b>Results:</b> In this study, fetal mean BPD showed a linear increase from 13 to 36 weeks. Statistically significant correlation was found between GA and BPD (<i>r</i> = 0.38). Mean BPD showed an increase of 2.38 cm in 13-20 weeks, 2.18 cm between 20 and 27 weeks and only 1.72 cm from 27 to 34 weeks. Average growth rate of BPD was found to be 0.31 cm/week from 13 to 28 week, which then later reduced to 0.23 cm/week from 28 to 36 weeks of gestation. <b>Conclusion:</b> Bi-parietal diameter is one of the useful criteria to measure GA and to predict expected date of delivery. Mean measurements of BPD in this study was found to be lower than that of western studies except Hadlock series, which compares well with this study. The mean BPD values of this study compares well with some Indian studies and other found higher results. Variation in predicted values is attributed to anthropometric differences between the two populations due to racial, genetic, nutritional, and socioeconomic factor. Therefore, large scale studies should be done and population-specific tables should be derived to correlate BPD and GA.

Ultrasonographic Determination of Gestational Age in Yankasa Ewes

The aim of this study was to determine the application of transabdominal ultrasonography in estimating gestational age in Yankasa ewes through the measurement of crown-rump length (CRL), bi-parietal diameter (BPD) and femoral length (FL). Fifteen (15) ewes were first oestrus-synchronized and mated to establish pregnancy. Transabdominal ultrasonography, using a real time B-mode ultrasound scanner, was carried out on weekly basis to determine gestation and estimate gestational age by measurement of CRL, BPD and FL, using real time B-mode ultrasound scanner. The relationships between gestational age and each of the parameters were plotted as linear regression and expressed as a straight line equation. Results obtained clearly demonstrated that CRL, BPD and FL were significantly (P

Prediction of gestational age in beetal goats by ultrasonic fetometry

Astudy was aimed to design reference charts and gestational age of Beetal goats by real-time ultrasonography utilizing measurements of crown rump length, biparietal diameter, trunk diameter, placentome diameter, umbilical thickness and length of kidney. Trans-rectal (7.5 MHz) and trans-abdominal ultrasonography (4.2 MHz) was performed from day 20 to 120 of pregnancy on six healthy pregnant Beetal goats. From day 20 to 60, the data were recorded bi-weekly and later on weekly intervals. Embryonic vesicle was first determined by trans-rectal ultrasonography at 20 days of gestation. All the parameters significantly (P<0.05) increased with the advancement of gestational age. Among different parameters, fetal trunk diameter was highly correlated with the gestational age. It was concluded that age of fetus in Beetal goats can be predicted by ultrasound measuring of crown rump length, biparietal diameter, trunk diameter, placentome diameter, umbilical thickness and length of kidney.

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P15.17: Prediction for fetal prognosis by biparietal diameter measurement from 11 to 13 weeks of pregnancy

<scp>P</scp>15.17: Prediction for fetal prognosis by biparietal diameter measurement from 11 to 13 weeks of pregnancy

Prediction of Parturition Time in Queens using Radiography and Ultrasonography.

This study investigated the prediction of parturition in queens, as well as the effects of the queens' age and weight and the litter size on the accuracy of the prediction. A prospective study was performed in 24 purebred queens of 11 different breeds, all in normal body condition, using radiographic and ultrasonographic measurements of foetal femoral length (FL) and biparietal diameter (BPD) of fœtal skull that apply to different breeds. Pregnant queens with aborted or malformed foetuses were excluded. The examinations were performed up to three times during the second half of pregnancy; litter size was obtained with radiography, and FL and BPD measurements were taken of each foetus using both radiography and ultrasonography. The maximal FL and the transversal BPD were recorded for each foetus. Radiography showed the number of foetuses accurately but did not allow accurate prediction of time of parturition. However, ultrasonography did establish the best predictive model according to the data with the FL. This model corresponded to the formula Y=37.864-0.193×FL+1.227×W-0.615×LS-0.832×A using the FL (10(-1) mm), litter size (LS, number of foetuses per queen) and maternal parameters (weight (W, kg) and age (A, years)). Time to parturition correlated positively with the queen's weight and negatively with her age (P<0.01). The ultrasonographic FL associated with pregnancy and maternal factors appeared to be an accurate model to predict parturition.

Intra- and inter-observer reproducibility study of gestational age estimation using three common foetal biometric parameters: Experienced versus inexperienced sonographer

AimTo assess reproducibility of estimating gestational age (GA) of foetus using femur length (FL), biparietal diameter (BPD) and abdominal circumference (AC) within experienced and inexperienced sonographers and between the two. Patients and methodsTwo sets of GA estimates each were obtained for FL, BPD and AC by the two observers in 20 normal singleton foetuses. The first estimates for the three biometric parameters were made by the experienced sonographer. Subsequently, the inexperienced sonographer, blind to the estimates of the first observer obtained his own estimates for the same biometric parameters. After a time interval of ten minutes the process was repeated for the second set of GA estimates. All the gestational age estimates were made following standard protocol. Statistical analysis was performed by Pearson's and intraclass correlations, coefficient of variation and Bland–Altman plots. Statistical inferences were drawn at p < 0.05. ResultsThe Pearson's and intraclass correlations of between GA estimates within and between both observers from measurement of FL, BPD and AC were very high and statistically significant (p < 0.05). Coefficient of variation for duplicate measurements for GA estimates within observers and between observers were quite negligible. Between observers, the first and second GA estimates from FL measurements showed the least variation. Estimates from BPD and AC measurements showed greater degree of variation between the observers. ConclusionReproducibility of GA estimation using FL, BPD and AC within experienced and inexperienced sonographers and between the two was excellent. Therefore, a fresh Nigerian radiography graduate with adequate exposure in obstetric ultrasound can correctly determine the gestational age of foetus in routine obstetric ultrasound without supervision.

Evidence of second‐trimester changes in head biometry and brain perfusion in fetuses with congenital heart disease

To evaluate the associations between congenital heart disease (CHD) and head biometry and cerebrovascular blood flow dynamics at the time of diagnosis of CHD in the second trimester of pregnancy. This was a study of 95 consecutive fetuses diagnosed with CHD. At the time of diagnosis, fetal biometry was performed and brain perfusion was assessed by middle cerebral artery pulsatility index (MCA-PI), cerebroplacental ratio (CPR) and fractional moving blood volume (FMBV). The results were compared with those of 95 normal fetuses matched for gestational age. Median gestational age at diagnosis was 22 + 3 (range, 20 + 0 to 23 + 5) weeks. Fetuses with CHD showed significantly lower MCA-PI and CPR Z-scores (-0.23 vs 0.34 and -0.37 vs 0.30, respectively; both P < 0.001) and higher FMBV Z-scores (2.35 vs 0.15; P < 0.001). FMBV > 95(th) percentile was observed in 81.1% of cases as compared with 10.5% in controls (P < 0.001). Moreover, cases showed significantly smaller biparietal diameter (BPD) and head circumference (HC) Z-scores (-1.61 vs -0.43 and -0.89 vs 0.09, respectively; both P < 0.001), with a higher proportion of BPD and HC measurements below the 5(th) percentile compared with controls (51.6% vs 13.7% and 26.3% vs 4.2%, respectively; both P < 0.001). These findings were more pronounced in those cases with types of CHD associated with compromised oxygenated blood delivery to the brain, such as left outflow tract obstruction and transposition of the great arteries. A high proportion of fetuses with CHD have a smaller head and increased brain perfusion already in the second trimester, suggesting an early onset of the mechanisms leading to poorer neurodevelopment later in life.

Biparietal diameter-to-crown-rump length disproportion in first-trimester fetuses with holoprosencephaly.

To determine whether the biparietal diameter measurement is altered in first-trimester fetuses with holoprosencephaly. Cases of holoprosencephaly were collected retrospectively from 4 fetal medicine centers, and first-trimester biparietal diameter measurements were reviewed. The diagnosis of holoprosencephaly was established sonographically by the detection of abnormal choroid plexus morphologic characteristics (absent "butterfly" sign) and the identification of a monoventricular cerebral cavity on axial views of the fetal brain. The proportion of fetuses with biparietal diameter measurements below the 5th percentile for crown-rump length was determined. Among 45 cases of holoprosencephaly reviewed, 43 had information on both biparietal diameter and crown-rump length measurements. The biparietal diameter was below the 5th percentile for crown-rump length in 14 (32.6%) fetuses. Chromosomal analysis was available in 41; no statistically significant difference in biparietal diameter measurement between those with associated chromosomal anomalies and those without anomalies was noted. A supplementary analysis using head circumference measurement showed an even greater proportion of fetuses with holoprosencephaly with measurements below the 5th percentile for crown-rump length (18 of 42 [42.9%]). One-third of first-trimester fetuses with a sonographic diagnosis of holoprosencephaly had a biparietal diameter that was smaller than expected for crown-rump length. In this subset of fetuses, the evaluation of intracranial anatomy for signs of holoprosencephaly may be more difficult to perform due to the smaller size of the brain. Therefore, the detection of a biparietal diameter below the 5th percentile as expected from crown-rump length on the first-trimester scan may be a warning sign of holoprosencephaly and should prompt a detailed examination of the intracranial anatomy.

Moderate and late preterm birth: effect on brain size and maturation at term-equivalent age.

To compare the size of multiple brain structures, maturation in terms of both brain myelination and gyral development, and evidence of brain injury between moderate and late preterm (MLPT) and term-born infants at term-equivalent age. The study was approved by the human research ethics committees of the participating hospitals, and informed parental consent was obtained for all infants. One hundred ninety-nine MLPT and 50 term-born infants underwent 3-T magnetic resonance (MR) imaging brain examinations at 38-44 weeks of corrected gestational age. T1- and T2-weighted MR images were compared between groups for size of multiple cerebral structures, degree of myelination in the posterior limb of the internal capsule, gyral maturation, signal intensity abnormalities, and presence of cysts by a single assessor who was blinded to the gestational group and perinatal course of the infants. Group differences were compared by using linear regression for continuous variables and logistic regression for categorical variables, and interrater and intrarater reliability was assessed by using intraclass correlation coefficients. Compared with those in the term-born control group, measurements of brain biparietal diameter, corpus callosum, basal ganglia and thalami, and cerebellum were smaller in infants in the MLPT group (all P ≤ .01), while extracerebral space was larger (P < .0001). Myelination of the posterior limb of the internal capsule was less developed, and gyral maturation was delayed in the MLPT group (both P < .001). Signal intensity abnormalities and cysts were uncommon in both groups, with 13 (6.5%) MLPT infants and one (2%) term infant having abnormalities. Inter- and intrarater reliability was good for most measures, with intraclass correlation coefficients generally greater than 0.68. MLPT birth is associated with smaller brain size, less-developed myelination of the posterior limb of the internal capsule, and more immature gyral folding than those associated with full-term birth. These brain changes may form the basis of some of the long-term neurodevelopmental deficits observed in MLPT children. Online supplemental material is available for this article.

PFM.49 Fetuses with gastroschisis have a reduced growth trajectory in the first half of gestation which normalises in late gestation

BackgroundGastroschisis is associated with low birthweight, which is thought to be due to protein leakage into the amniotic fluid from herniated bowel, bowel inflammation, placental chorangiosis and villous oedema. Little...

The effect of maternal body mass index on fetal growth: use of individualized growth assessment and two-level linear modeling.

To determine the effect of maternal body mass index on fetal growth using individualized growth assessment and two-level linear modeling. A retrospective review of biometry in the second and third trimesters from 246 normal, term singleton fetuses was performed. Four to eight biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur diaphysis length (FDL) measurements per fetus were available and used to determine second-trimester growth rates. Expected third-trimester size trajectories were generated from these data and Percent Deviations [%Dev = ((observed - expected)/expected) × 100] were calculated. Two-level linear modeling was used to determine %Dev slopes and the effect of body mass index (BMI) on these slopes. Relationships between individual second- and third-trimester slopes and BMI were evaluated using linear regression. Linear regression analysis of second-trimester growth indicated no significant relationships between the fetal growth rate and the BMI in the second trimester [R(2) (adj): 0.0% to 1.0% except AC in one subgroup (5.6%)]. Regression analysis did not indicate a significant relationship (adj R(2) : 0%-0.2%) between BMI and third-trimester %Dev slopes for any anatomic parameter. Two-level statistical modeling showed no effect of BMI on BPD, AC, or FDL growth and only a moderate effect on the HC growth in the third trimester. Our findings indicate that the maternal BMI does not have an effect on fetal growth in either the second or the third trimester as determined with individualized growth assessment.

The secular growth acceleration: does it appear during fetal life?

Objective: To test if secular growth acceleration occurs during fetal life.Methods: ANOVA Kruskal–Wallis and Mann–Whitney U-test have been used for the biometric characteristics comparison of nowadays fetal population with those three decades ago and to test the hypothesis about the existence of secular growth acceleration during fetal life. For this purpose, we first calculated mean values of particular biometric parameters for the whole pregnancy. During the period 2002–2009 biparietal diameter, fetal length and abdominal circumference measurements in singleton uncomplicated pregnancies between 22 and 41 gestational weeks were obtained. Gestational age was estimated according to Naegele's rule and confirmed with an early ultrasound examination. Pregnancies with fetal cromosomopathies and malformations were excluded as well as those resulting in perinatal death.Results: There were no statistically significant differences of the examined fetal biometric parameters measured by ultrasound between contemporary fetal population and those from 35 years ago.Conclusion: Our investigation did not undoubtedly prove that significant changes of fetal biometric parameters occurred in the last three decades. It is possible that secular growth acceleration does not exist in prenatal period but also the observed time period could have been short for this phenomenon to manifest.