The effect of fetal sex on customized fetal growth charts

Objective: To evaluate the effect of fetal sex on singleton pregnancy growth charts customized for parental characteristics, race, and parity

Methods: In a multicentric cross-sectional study, 8070 ultrasonographic examinations from low-risk singleton pregnancies between 16 and 40 weeks of gestation were considered. The fetal measurements obtained were biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL). Quantile regression was used to examine the impact of fetal sex across the biometric percentiles of the fetal measurements considered together with parents’ height, weight, parity, and race.

Results: Fetal gender resulted to be a significant covariate for BDP, HC, and AC with higher values for male fetuses (p?≤?0.0009). Minimal differences were found among sexes for FL. Parity, maternal race, paternal height and maternal height, and weight resulted significantly related to the fetal biometric parameters considered independently from fetal gender.

Conclusion: In this study, we constructed customized biometric growth charts for fetal sex, parental, and obstetrical characteristics using quantile regression. The use of gender-specific charts offers the advantage to define individualized normal ranges of fetal biometric parameters at each specific centile. This approach may improve the antenatal identification of abnormal fetal growth.     

Growth charts of fetal biometry: a longitudinal study

Objective: The aim of this study was to construct reference charts for fetal biometry in Karachi, Pakistan. Methods: This was a prospective longitudinal study involving 1228 women with singleton pregnancies. Biparietal diameter, head circumference, abdominal circumference and femur length were measured repeatedly until delivery. Regression analysis and multilevel modeling was used to construct charts. Results: The mean age of the women in this study was 28.0 years with standard deviation of 4.6. For each gestational age percentiles were calculated and charts were then constructed. Conclusion: Our reference percentiles for fetal biometry measurements are the first of their kind in Karachi, Pakistan. They will not only help us in the diagnosis and management of fetal growth restriction but will provide the basis to develop charts at the national level.     

A novel reference chart and growth standard of fetal biometry in the Taiwanese population

ObjectiveThe purpose of this study was to establish a new reference chart and growth standards for fetal biometry in Taiwan.Materials and methods2047 singleton pregnancies were enrolled in this study with 15,813 fetal scans between 18 and 40 gestational weeks. A reference chart and normal range for fetal biparietal diameter (BPD), abdominal circumference (AC) and femur length (FL) was established by longitudinal quantile regression model. 330 women with comorbidities including gestational hypertension, preeclampsia and gestational diabetes were excluded and 1717 pregnant women were enrolled for the growth standard.ResultsThe new reference values were significantly larger across all gestational ages compared with the prior National Taiwan University reference chart in 1983. Compared with Intergrowth-21st, the BPD was larger at 18–23 weeks, the AC was larger at 18–24 weeks and the FL was larger at 18–36 weeks whereas they were all smaller at 29–40 weeks for the BPD, at 32–40 weeks for the AC and at 38–40 weeks for the FL. A quantile regression equation of biometry was established. BPD, AC, and FL had weekly growth of 2.5, 9.87 and 2.15 mm. Prepregnancy body weight, height, age, and gestational diabetes increased fetal size. Both gestational and chronic hypertension decreased fetal size.ConclusionTo promote maternal-fetal safety, a new reference chart and growth standard for fetal biometry is necessary to measure fetal growth.     

Fetal ultrasound biometry for pregnant population in the County of Primorje-Gorski Kotar (Croatia)

Objective.?To create curves of three most commonly used biometric parameters for singleton pregnancies from 22 to 41 weeks of gestation in the County of Primorje-Gorski Kotar (Croatia) and to compare results with other studies.

Methods.?From January 2002 to December 2009, ultrasound examination was performed on fetuses of 1248 pregnant women with uncomplicated pregnancy. Values for biparietal diameter, femur length, and fetal abdominal circumference were measured. Results were compared with studies pertaining to European and North American population. Mean, percentile scale, and Wilcoxon's matched pairs test were used. Regression analysis was applied to analyze data correlation and to determine correlation quotients.

Results.?Total of 2178 measurements for fetal biometry charts were performed. Established mean and centile values for fetal biometry parameters are reported numerically and graphically. Comparison of obtained values with values of identical fetal biometric parameters of other world populations has revealed statistically significant differences (p?<?0.01).

Conclusion.?Normal fetal biometry charts for population of pregnant women in the northern coastal region of Croatia were constructed. Due to existence of statistically significant differences in ultrasound fetal biometry values among various populations under comparison, construction of own charts and their implementation in routine obstetrical work are justified.     

Chinese fetal biometry: reference equations and comparison with charts from other populations

Objective: This study aimed to construct new reference charts and equations for fetal biometry from Chinese fetuses at 15–40 weeks and to compare them with previous references.

Method: This was a prospective, cross-sectional study of singleton pregnancies in patients with a confirmed gestational age who underwent ultrasound examinations between the 15th and 40th weeks of gestation. Each woman was selected only once for this study. Biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL) were recorded. For each measurement, separate regression models were fitted to estimate the mean and standard deviation at each menstrual age. Z-scores were calculated with our reference equations for comparison with other references.

Results: New charts and reference equations involving 7553 Chinese women were created for BPD, HC, AC, and FL. Reference equations were cubic models. Prediction intervals for the new reference charts were similar to those of previous references, but with some slight differences. The main difference in our fetal biometric measurements compared with those of Korea and Hong Kong was the FL.

Conclusions: We report new Chinese reference charts and equations for fetal biometry. These reference charts and equations are available for clinical use in obstetric ultrasound studies for the Chinese population.     

Identification of small for gestational age by population-based and customized growth charts in newborns of obese and normal-weight primiparous women

Objective: Our hypothesis was that newborns of obese mothers would be more likely to be classified as small for gestational age (SGA) by their customized growth curves than by the standard growth curves when compared to newborns of normal-weight mothers.

Methods: This is a retrospective cohort of primiparous patients delivering between 1 July 2008 and 30 June 2012. Normal-weight was defined as BMI?≤25?kg/m² and obese as BMI?≥?30?kg/m². Infant birth-weight was characterized as SGA or non-SGA from the Lubchenco curve, the Fenton Preterm Growth Chart, and the customized growth curve.

Results: Infants were more likely to be classified as SGA on the customized curve compared with Lubchenco curve. Odds ratio was 2.8 (CI: 1.7–4.4; p?=?0.001) for obese women and was 2.9 (CI: 1.7–5.1; p?<?0.001) for normal-weight women. Infants were also more likely to be classified as SGA based on the customized curve compared with the Fenton Preterm Growth Curve. The odds ratio was 2.3 (CI: 1.4–3.8; p?=?0.001) for obese women and was 1.5 (CI: 1.01–2.33; p?=?0.04) for normal-weight women.

Conclusions: Population-based curves may mask SGA in obese women. Our study demonstrates that customized growth curves identify more SGA than population-based growth curves in obese and normal-weight women.     

The customized fetal growth potential: a standard for Ireland

Objective

To identify maternal and pregnancy-related physiological and pathological variables associated with fetal growth and birthweight in Ireland and to develop customized birthweight centile charts for the Irish population that will aid in appropriate identification and selection of growth-restricted fetuses requiring increased antenatal surveillance.

Study design

Prospectively collected outcome data of 11,973 consecutive ultrasound-dated singleton pregnancies between 2008 and 2009 from six maternity units in Ireland (Dublin, Galway, Limerick and Belfast) were included for analysis. Maternal weight and height at booking, parity and ethnicity were recorded and combined with birthweight, fetal gender and pregnancy outcomes. Coefficients were derived by backward multiple regression using a stepwise backward elimination approach.

Results

A total of 11,973 ultrasound-dated singleton pregnancies were included in the analysis. Over 90% of women (n = 10,850) were of Irish or European descent, 3.4% (n = 407) were African or African Caribbean, 1.7% (n = 208) were Indian; 42.2% (n = 5057) were nulliparous, 32.8% (n = 3923) had one previous delivery after 24 weeks’ gestation, 15.6% (n = 1872) had two previous deliveries and 9.4% (n = 1121) had three or more previous deliveries. Mean term birthweight for a standard Irish mother was 3491grams. Babies of all other ethnic origins were smaller than their Irish counterparts. African Caribbean, Bangladeshi, Indian and Pakistani babies were on average 237 g, 196 g, 181 g and 181 g lighter, respectively, when compared to the average Irish offspring. Pathological factors significantly affecting term birthweight were pre-gestational diabetes (+137 g; p < 0.001), smoking (−225 g; p < 0.001), pregnancy-induced hypertension (−37.6 g; p = 0.009) and maternal obesity (−41.6 g; p = 0.012).

Conclusion

Birthweight in this Irish maternity population is subject to similar influences to those observed in studies from the UK, Sweden, USA and Australasia. The derived coefficients can be used for customized assessment of fetal growth potential in Ireland. The implementation of these customized centile charts and their free online availability will aid clinicians in Ireland in the interpretation of fetal weight estimation.     

Placental growth factor as a predictor of the efficacy of tadalafil treatment for fetal growth restriction

Purpose: We recently demonstrated the efficacy of tadalafil treatment for fetal growth restriction (FGR). This study aimed to evaluate the utility of serum placental growth factor (PlGF) level for predicting the efficacy of tadalafil for the treatment of FGR.

Materials and methods: The correlations between serum level of PlGF and fetal growth velocity were retrospectively assessed in nine pregnant women receiving tadalafil for FGR before 30 weeks’ gestation.

Results: Median gestational age was 26 weeks (range 26–28 weeks), and median deviation of estimated fetal weight from standard weight was ?2.1 standard deviations (SD) (?2.2 to ?1.9 SD) at the beginning of tadalafil treatment. The median serum PlGF level was 227?pg/ml (40.2–427.0?pg/ml) before tadalafil treatment and 278?pg/ml (66.2–729.5?pg/ml) more than 2 weeks after initiation of tadalafil treatment (median gestational week at measurement of PlGF after treatment, 33 weeks [28–33 weeks]). The median fetal growth velocity from enrollment to birth was 17.5?g/day (12.1–20.3?g/day). Maternal serum PlGF levels were increased after tadalafil treatment in all nine cases (median increase in PlGF, 73.1?pg/ml [26.0–281.5?pg/ml]). Notably, maternal serum PlGF level before tadalafil treatment significantly correlated with fetal growth velocity (R²?=?0.63, p?Conclusions: Tadalafil treatment may increase maternal serum PlGF levels. Our results suggest that maternal serum PlGF levels can be used as a predictor of the efficacy of tadalafil treatment for FGR.     

Third trimester abdominal circumference,estimated fetal weight and uterine artery doppler for the identification of newborns small and large for gestational age

Objective

To understand if ultrasound biometric evaluation at 30–32 weeks of gestation is a valuable screening tool for the detection of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) infants at birth in a low risk population.

Study design

We enrolled 1848 pregnant women with singleton pregnancy undergoing routine fetal biometry. We divided the infants into four groups: moderate SGA, severe SGA, moderate LGA and severe LGA. We considered third-trimester estimated fetal weight (EFW), abdominal circumference (AC), EFW centile (EFWc), AC centile (ACc) and compared their prediction toward SGA and LGA to determine which of these parameters was the best estimator for fetal size. Then we took the strongest predictive value and added all history-related and ultrasound factors to run a stepdown multivariate logistic regression. All the variables were then dichotomized and sensitivity models only for statistically significant parameters were calculated.

Results

We identified the following predictive factors for each outcome: for severe SGA: EFWc with p < 0.001, uterine artery pulsatility index (UtA PI) with p < 0.002. For moderate SGA: EFWc with p < 0.001, UtA PI with p < 0.004, maternal preeclampsia p < 0.002. For moderate and severe LGA: EFWc with p < 0.001.

Conclusion

We can detect in a low-risk population a group at risk of growth deviations. Adding Doppler velocimetry to 30–32 weeks EFWc improves the specificity (84%) regarding SGA newborns, maintaining a good sensitivity (71%), and reducing the population to be re-screened from 27 to 17%. An ultrasound examination at 34–36 weeks or the clinical assessment of maternal risk factors remain the best tools for LGA newborns.     

Intrauterine growth restriction: new concepts in antenatal surveillance, diagnosis, and management

Intrauterine growth restriction (IUGR) remains one of the main challenges in maternity care. Improvements have to start from a better definition of IUGR, applying the concept of the fetal growth potential. Customized standards for fetal growth and birthweight improve the detection of IUGR by better distinction between physiological and pathological smallness and have led to internationally applicable norms. Such developments have resulted in new insights in the assessment of risk and surveillance during pregnancy. Serial fundal height measurement plotted on customized charts is a useful screening tool, whereas fetal biometry and Doppler flow are the mainstay for investigation and diagnosis of IUGR. Appropriate protocols based on available evidence as well as individualized clinical assessment are essential to ensure good management and timely delivery.     

Pregnancy outcome after false diagnosis of fetal growth restriction

Objectives: To evaluate pregnancy outcome following false diagnosis of fetal growth restriction (FGR).

Methods: Retrospective analysis of all singleton term deliveries of appropriately grown fetuses (10–90th weight percentiles) in a single medical center (2007–2014). Elective cesarean-section, diabetes, and hypertension were excluded. Cohort was stratified based on third trimester sonographic estimated-fetal-weight (≥32 weeks). Women with false diagnosis FGR (<10th percentile) were compared with the rest (control). Induction of labor, cesarean deliveries, and short-term perinatal outcome were compared. Logistic regression analysis was performed to adjust outcome for birth weight and gestational age at delivery.

Results: Of 34,474 pregnancies, 415 were falsely diagnosed as FGR (1.2%). Women in study group delivered earlier (38.6?±?1.1 versus. 39.0?±?0.9) with lower birth weights (2856?±?270 versus 3271?±?307 grams) and increased rate of labor inductions (19.8% versus 6.4%) and cesarean deliveries (10.8% versus 5.7%). Despite appropriate birth weight, study group neonates had higher rates of NICU admissions (10.6% versus 6.8%), mechanical ventilation (1.7% versus 0.5%), transient tachypnea of the newborn (1.7% versus 0.5%), hypoglycemia (1.7% versus 0.5%), and jaundice (11.3% versus 7.0%). p?Conclusions: False diagnosis of FGR is associated with higher rates of induction of labor, cesarean deliveries, and short-term adverse neonatal outcome.     

Establishing a reference value for the frequency of fetal movements using modified 'count to 10' method

AIMS: To establish a reference value for the frequency of fetal movements perceived by the mother during the second half of pregnancy. METHODS: The study subjects consisted of 705 low risk Japanese pregnant women who continuously received antenatal care. We asked women to record the time required to perceive 10 fetal movements ('count to 10' time) everyday. We asked women to record it, not at a fixed time (i.e. evening time), but whenever they felt the fetus move the most actively. The position during counting (i.e. sitting position) was also not specified, and thus we named this method as modified 'count to 10' method. Satisfactory recordings were obtained from 690 women, which we used for analysis. RESULTS: The 'count to 10' time was almost the same from 22 weeks (10.9; 7.3-18.0 (median; interquartile range)) until 32 weeks (10.0; 6.2-15.6), and it Thirty-two weeks showed the shortest time, which gradually increased toward 40 weeks (14.8; 9.5-24.0). Its 90th percentile was approximately 25 and 35 min at 22-36 weeks and at 37-40 weeks, respectively. CONCLUSIONS: For the first time we established a reference value for perceived fetal movements throughout the second half of pregnancy. The present modified 'count to 10' method requires less time than the previous method. Approximately 98% (690/705) of women gave us satisfactory recordings. This reference value may be of use in identifying mothers with decreased fetal movements.     

Transabdominal ultrasound assessment of the fetal head and the accuracy of vacuum cup application.

OBJECTIVE: To investigate whether the accuracy of vacuum cup placement can be improved by intrapartum ultrasound assessment of the fetal head position during the second stage of labor prior to vacuum extraction for prolonged second stage. METHODS: 50 women undergoing vacuum extraction for prolonged second stage were randomly allocated to either digital examination (n=25) or digital examination together with transabdominal intrapartum ultrasound (n=25) prior to vacuum extraction by the attending obstetrician. The distance between the centre of the chignon and the flexion point was then measured by a midwife immediately after delivery. The flexion point was defined as 6 cm posterior to the anterior fontanelle or 3 cm anterior to the posterior fontanelle. RESULTS: There were no statistically significant differences in the demographic data, duration of labor, incidence of induction/augmentation, and intrapartum complications between the two groups. The mean distance between the centre of the chignon and the flexion point was 2.1+/-1.3 cm in the group with digital examination and ultrasound assessment and 2.8+/-1.0 cm in the group with digital examination alone. The difference in the mean distance between the two groups was statistically significant (p=0.039). CONCLUSION: Intrapartum transabdominal ultrasound assessment of the fetal head position during the second stage of labor improves the accuracy of vacuum cup placement during vacuum extraction for prolonged second stage.     

Divergence of estimated fetal weight and birth weight in singleton fetuses

Objective: To evaluate differences in distribution of estimated fetal weight (EFW) and birth weight (BW) of ongoing fetuses and neonates of the same gestational age.

Methods: Reference curves for EFW (Hadlock BPD-HC-AC-FL formula, N?=?1191) and BW (N?=?1036) in singleton pregnancies from 24⁺⁰ to 40⁺⁶ gestational weeks were calculated. Multiple pregnancies, fetuses with major or multiple abnormalities or syndromes and iatrogenic preterm deliveries due to preeclampsia or abnormal fetal Doppler were excluded. The standardized residuals for EFW and BW were calculated and compared.

Results: EFW and BW can be accurately described by quadratic equations (R²?=?0.944 and 0.807, respectively). The distribution of standardized residuals for BW using the EFW formula was negative from 28⁺⁰ to 35⁺⁶ weeks. The 50th and 5th centiles of BW were lower than those of EFW throughout prematurity, and they converged at approximately 38 gestational weeks. The 5th centile for BW was 30% lower than the 5th centile for EFW at 27 weeks, 27.5% lower at 30 weeks and 19.4% at 34 weeks.

Conclusions: Preterm infants have lower BW distribution compared to the expected EFW of ongoing pregnancies of the same gestational age, supporting the concept of hidden intrauterine morbidity for a proportion of these infants.     

Fetal size and growth velocity in the prediction of the large for gestational age (LGA) infant in a glucose impaired population

OBJECTIVES: To evaluate the performances of estimated fetal weight (EFW) and fetal growth velocity (FGV) in the prediction of birth weight>95th centile amongst women with impaired glucose tolerance (IGT); the prediction of neonatal hypoglycaemia was a secondary endpoint. STUDY DESIGN: Two hundred and forty-two consecutive women (61 type 1 diabetes mellitus, 14 type 2 diabetes mellitus, 49 gestational diabetics and 118 with impaired glucose tolerance) receiving routine care at the combined diabetes/antenatal clinic, Jessop Hospital for Women, Sheffield. EFW was routinely calculated at approximately two-week intervals in the third trimester with the last EFW prior to delivery used in the analysis. FGV was calculated from two estimates of fetal weight between 21 and 35 days apart. EFW and FGV were both expressed as standard deviation (Z) scores. RESULTS: The mean gestational age at delivery was 37 weeks (range 26-40 weeks). Sixty-five (27%) infants were of birth weight>95th centile. Mean EFW Z scores were 2.7 and 0.99 for >95th and <95th centile, respectively (p<0.001). Receiver operator characteristics (ROC) curve analysis gave area under the curve 0.8; using a cut-off Z score of 1.7 (=95.5 centile), EFW has sensitivity 80% and specificity 72% in predicting an LGA neonate (likelihood ratios 2.8 and 0.27 for positive and negative test). Mean FGV Z scores were 0.85 and 0.4 for >95th and <95th centile, respectively (p>0.05); ROC curve analysis indicated no discriminatory capacity. Estimates of fetal size and growth performed poorly in the prediction of neonatal hypoglycaemia. CONCLUSION: In routine clinical practice, EFW has limited utility in the prediction of the LGA infant. FGV does not identify the LGA infant. EFW and FGV do not predict neonatal hypoglycaemia.     

Effect of human embryonic morphological development on fetal growth parameters: the Rotterdam Periconceptional Cohort (Predict Study)

Research question

Is embryonic morphological development according to the Carnegie stages associated with pregnancy outcome?

Human fetal growth and organ development: 50 years of discoveries

Knowledge about human fetal growth and organ development has greatly developed in the last 50 years. Anatomists and physiologists had already described some crucial aspects, for example, the circulation of blood during intrauterine life through the fetal heart, the liver as well as the placenta. However, only in the last century physiologic studies were performed in animal models. In the human fetus, the introduction of ultrasound and Doppler velocimetry has provided data about the growth and development of the fetus and of the circulation through the different fetal districts. Moreover, in the last 2 decades we have learned about fetal oxygenation and fetal nutrient supply caused by the availability of fetal blood samples obtained under relatively steady state conditions. These studies, together with studies using stable isotope methodologies, have clarified some aspects of the supply of the major nutrients for the fetus such as glucose, amino acids, and fatty acids. At the same time, the relevance of placental function has been recognized as a major determinant of fetal diseases leading to intrauterine growth restriction. More recently, the availability of new tools such as 3-dimensional ultrasound and magnetic resonance imaging, have made possible the evaluation of the growth and development of fetal organs. This knowledge in the healthy fetus will improve the ability of clinicians to recognize abnormal phenotypes of the different fetal organs, thus allowing to stage fetal diseases.