Suspicion of intrauterine growth restriction: Use of abdominal circumference alone or estimated fetal weight below 10%

Objective. To determine, among patients at risk for intrauterine growth restriction (IUGR), the peripartum outcomes and predictive accuracy for those with normal abdominal circumference (AC) and estimated fetal weight (EFW) for gestational age (GA; group 1) versus those with AC ≤ 10% for GA but EFW>10% (group 2) versus those with AC and EFW ≤ 10% for GA (group 3).

Study design. We identified, retrospectively, non-anomalous singleton pregnancies with reliable GA, and delivery within 21 days of the examination who were referred for possible IUGR. Odds ratios (OR) and 95% confidence intervals (CI) were calculated, as were likelihood ratios (LR) for detection of small for gestational age (SGA) (birth weight ≤ 10% for GA; SGA).

Results. Among the 169 consecutive patients who met the inclusion criteria, the prevalence of SGA was significantly higher for group 3 (80%) than group 1 (42%; OR 4.26, 95% CI 1.94–9.16) or group 2 (49%; OR 5.49, 95% CI 2.13–13.85). The rate of admission to the neonatal intensive care unit (67%, 34%, and 36% for groups 3, 2, and 1, respectively) and the combined perinatal morbidity (35%, 23%, and 15%) were different for the three groups. The LR for detection of SGA was 1.2 (95% CI 1.0–1.4) for group 2 and 2.8 (95% CI 1.6–4.9) for group 3.

Conclusions. Among patients suspected for IUGR, the peripartum outcome is poorest for those with AC and EFW ≤ 10% for GA, than for those with AC ≤ 10% but EFW>10%. The detection of SGA is poor regardless of whether just AC or AC plus EFW are ≤ 10%.     

Added value of cerebro-placental ratio and uterine artery Doppler at routine third trimester screening as a predictor of SGA and FGR in non-selected pregnancies

Objectives: The objective of this study is to determine the added value of cerebroplacental ratio (CPR) and uterine Doppler velocimetry at third trimester scan in an unselected obstetric population to predict smallness and growth restriction.

Methods: We constructed a prospective cohort study of women with singleton pregnancies attended for routine third trimester screening (32⁺⁰–34⁺⁶ weeks). Fetal biometry and fetal–maternal Doppler ultrasound examinations were performed by certified sonographers. The CPR was calculated as a ratio of the middle cerebral artery to the umbilical artery pulsatility indices. Both attending professionals and patients were blinded to the results, except in cases of estimated fetal weight Results: A total of 1030 pregnancies were included. The mean gestational age at scan was 33 weeks (SD 0.6). The addition of CPR and uterine Doppler to maternal characteristics plus EFW improved the explained uncertainty of the predicting models for SGA (15 versus 10%, p?p?=?.03). However, the addition of CPR and uterine Doppler to maternal characteristics plus EFW only marginally improved the detection rates for SGA (38 versus 34% for a 10% of false positives) and did not change the predictive performance for FGR.

Conclusions: The added value of CPR and uterine Doppler at 33 weeks of gestation for detecting defective growth is poor.     

Defining fetal growth restriction: abdominal circumference as an alternative criterion

Purpose: The purpose of this study is to determine if using abdominal circumference percentile (AC) to define fetal growth restriction (FGR) improves ultrasound at ≥36 weeks as a screening test for small for gestational age (SGA).

Materials and methods: All non-anomalous singletons undergoing ultrasound at a single center at ≥36 weeks during 12/2008–5/2014 were included. FGR was defined as (estimated fetal weight) estimated fetal weight (EFW) and/or abdominal circumference (AC)?Results: There were 1594 ultrasounds. Median (IQR) ultrasound GA was 37.3 (36.6–38.0), days to delivery 10.6 (5.0–18.4), and delivery GA 39.29 (38.6–39.9). EFW <10 had the following characteristics: sensitivity 50.6%, FPR 2.0%, PPV 83.8%, and AUC 0.743. Using AC <10, these were 64.0, 2.9, 81.3, and 0.806, respectively. Using AC or EFW <10, these were 67.5, 3.3, 80.3, and 0.821, respectively; this criterion has the largest AUC (p?Conclusions: AC <10 is more sensitive and has a similar PPV compared with EFW <10 for SGA. Using AC <10 or EFW <10 has the best balance of sensitivity and specificity as a screening test and has a low FPR. AC may be a reasonable alternative criterion to EFW for FGR diagnosis.     

Suspicion of intrauterine growth restriction: Use of abdominal circumference alone or estimated fetal weight below 10%.

OBJECTIVE: To determine, among patients at risk for intrauterine growth restriction (IUGR), the peripartum outcomes and predictive accuracy for those with normal abdominal circumference (AC) and estimated fetal weight (EFW) for gestational age (GA; group 1) versus those with AC < or = 10% for GA but EFW>10% (group 2) versus those with AC and EFW < or = 10% for GA (group 3). STUDY DESIGN: We identified, retrospectively, non-anomalous singleton pregnancies with reliable GA, and delivery within 21 days of the examination who were referred for possible IUGR. Odds ratios (OR) and 95% confidence intervals (CI) were calculated, as were likelihood ratios (LR) for detection of small for gestational age (SGA) (birth weight < or = 10% for GA; SGA). RESULTS: Among the 169 consecutive patients who met the inclusion criteria, the prevalence of SGA was significantly higher for group 3 (80%) than group 1 (42%; OR 4.26, 95% CI 1.94-9.16) or group 2 (49%; OR 5.49, 95% CI 2.13-13.85). The rate of admission to the neonatal intensive care unit (67%, 34%, and 36% for groups 3, 2, and 1, respectively) and the combined perinatal morbidity (35%, 23%, and 15%) were different for the three groups. The LR for detection of SGA was 1.2 (95% CI 1.0-1.4) for group 2 and 2.8 (95% CI 1.6-4.9) for group 3. CONCLUSIONS: Among patients suspected for IUGR, the peripartum outcome is poorest for those with AC and EFW < or = 10% for GA, than for those with AC < or = 10% but EFW>10%. The detection of SGA is poor regardless of whether just AC or AC plus EFW are < or = 10%.     

Third trimester ultrasound for fetal macrosomia: optimal timing and institutional specific accuracy

Purpose: To determine the performance of third trimester ultrasound in women with suspected fetal macrosomia.

Materials and methods: We performed a retrospective cohort study of fetal ultrasounds from January 2004 to December 2014 with estimated fetal weight (EFW) between 4000 and 5000?g. We determined accuracy of birth weight prediction for ultrasound performed at less than and greater than 38 weeks, accounting for diabetic status and time between ultrasound and delivery.

Results: There were 405 ultrasounds evaluated. One hundred and twelve (27.7%) were performed at less than 38 weeks, 293 (72.3%) at greater than 38 weeks, and 91 (22.5%) were performed in diabetics. Sonographic identification of EFW over 4000?g at less than 38 weeks was associated with higher correlation between EFW and birth weight than ultrasound performed after 38 weeks (71.5 versus 259.4?g, p?Conclusions: Identification of EFW with ultrasound performed less than 38 weeks has greater reliability of predicting fetal macrosomia at birth than measurements performed later in gestation. EFW to birth weight correlation was more accurate than previous reports.     

Second trimester growth velocities: assessment of fetal growth potential in SGA singletons

Objective: To evaluate the validity of second trimester growth velocities as measures of fetal growth potential in Small-for-Gestational-Age (SGA) singletons.

Methods: Second trimester growth velocities for biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur diaphysis length (FDL) were determined by linear regression analysis or direct measurement in 53 SGA singletons with normal growth outcomes (SGA N Group) and 73 with growth restriction (SGA GR) based on a composite fetal growth pathology score (FGPS1). The latter were subdivided into six groups based on their growth restriction pattern (Patterns group). Similar data were available for 118 singletons with normal neonatal growth outcomes (NNGO group). Coefficients of determination (R²) and growth velocities for each anatomical parameter were compared between Patterns subgroups and the SGA N, SGA GR and NNGO groups.

Results: Median R² values in the six Patterns subgroups ranged from 98.2% (Pattern 2, FDL) to 99.9% (Pattern 5, AC). Within each anatomical parameter set, no significant differences were found (Kruskal–Wallis). Patterns subgroup data were pooled to form the SGA GR group for each anatomical parameter. Mean values for the three main groups ranged from 98.4% (SGA N, FDL) to 99.6% (SGA N, HC). No significant differences between groups (ANOVA) were found for any anatomical parameter (ANOVA). Only 1.7–3.8% had R² values <95th%. No significant differences in median second trimester growth velocities among different Patterns subgroups were found for any anatomical parameter. In the SGA N and SGA GR groups, mean BPD and HC values did not differ but were significantly smaller than the NNGO group values. No differences in mean FDL values were seen. With AC, all three means were significantly different, having the following order: NNGO?>?SGA N?>?SGA GR. Of all 504?second trimester growth rates, 92.5% were within their respective 95% reference ranges.

Conclusion: Growth in the second trimester is linear in fetuses at risk for growth restriction. Except for FDL, growth velocities were lower than those for fetuses with NNGO. Only AC had mean velocities that differed between the SGA N and the SGA GR groups. Since most velocities (92.5%) were within normal reference ranges, they are reasonable measures of growth potential in fetuses at risk for growth restriction.     

Growth restriction: identifying fetuses at risk

Purpose: Examine risks of intrauterine growth restriction (IUGR) and composite perinatal outcomes with estimated fetal weights (EFW) 10–20th%, and compare outcomes using umbilical artery Doppler (UAD).

Materials and methods: Retrospective, cohort evaluating ultrasound (US) EFW 10–20th%, between 2002 and 2012. Cases were identified with EFW % 10–20. Controls, EFW?>20th% were obtained for each case, matched by gestational age, and US date. Unadjusted and adjusted logistic regression was used for outcomes.

Results: Seven hundred and sixty-seven cases met criteria with matched controls. Fetuses having EFW 10–20th% (GA 33.6?±?3.7 weeks) had increased IUGR on follow up ultrasound (OR 26.5[10.2–68.7], p?p?p?p?p?Conclusions: Pregnancies with EFW 10–20th% at the time of initial US are at increased risk for developing IUGR and being SGA at birth, with more NICU admissions and composite perinatal outcomes; abnormal UAD evaluation in cases conveyed further increase in outcomes.     

What is the accuracy of an early third trimester sonogram for identifying LGA infants born to GDM patients diagnosed with the one-step approach?

Purpose: The one-step approach for screening of GDM will increase the incidence 2- to 3-fold. These larger cohorts may need to target high-morbidity subsets to be cost-effective. We asked whether ultrasound could stratify the GDM patients with the highest risk for a large for gestational age (LGA) infant.

Materials and methods: A retrospective analysis was performed on 413 GDM patients diagnosed using the one-step approach. Ultrasound data from 28 weeks 0?day to 34 weeks 6 days was studied. The abdominal circumference (AC) and EFW at thresholds between 70 and 95% were examined for their prognostic utility. The primary outcome was an LGA infant.

Results: Both the AC and EFW at all gestational ages were predictive of a LGA infant. The AC and EFW at 28–32 weeks 6 days using a threshold of ≥70% showed the following test characteristics: sensitivity (73 versus 66%), specificity (61 versus 77%), positive predictive value (PPV) (30 versus 40%), and negative predictive value (NPV) (91 versus 91%). The specificity of the EFW was significantly higher than the AC (p?Conclusion: Among GDM patients diagnosed using the one-step approach, an elevated AC and EFW in the early third trimester are predictive of a LGA infant. This is a possible cost-effective way to stratify the one-step GDM pregnancies at highest risk for neonatal morbidity.     

Is the fetal cerebroplacental ratio better that the estimated fetal weight in predicting adverse perinatal outcomes in a low risk cohort?

Objective: In high-risk pregnancies combining the cerebro–placental ratio (CPR) with the estimated fetal weight (EFW) improves the identification of vulnerable fetuses. The purpose of this study was to assess the CPR and EFW’s ability to predict adverse obstetric and perinatal outcomes in a low-risk pregnancy, when measured late in gestation.

Methods: This was a retrospective study of women who birthed at Mater Mothers Hospitals, Brisbane, Australia between 2010 and 2015. We included all nonanomalous singleton pregnancies that had an ultrasound scan performed between 36 and 38 weeks gestation. Excluded was any major congenital abnormality, aneuploidy, multiple pregnancy, preterm birth, maternal hypertension, or diabetes. The primary outcome was a severe composite neonatal outcome (SCNO) defined as severe acidosis (umbilical cord artery pH <7.0, cord lactate ≥6?mmol/L, cord base excess ≤-12?mmol/L) Apgar score ≤3 at 5 minutes, admission to the neonatal intensive care unit (NICU), and death. A low CPR was defined as <10th centile for gestation and small for gestational age (SGA) was defined as an EFW <10th centile and appropriate for gestational age (AGA) was defined as EFW ≥10th centile.

Results: Of 2425 pregnancies, 13.2% (321/2425) had a fetus with a CPR <10th centile and 13.7% (332/2425) with an EFW <10th centile. Both a low CPR and SGA predicted the SCNO. Individually a low CPR and SGA had sensitivity for detection of SCNO of 23.3% and 24.7%, respectively which increased to 36.7% when combined. Both were associated with emergency caesarean for nonreassuring fetal status (NRFS), as well as early-term birth and admission to NICU. Stratifying the population into EFW <10th centile and EFW ≥10th centile, a low CPR maintained its association with the SCNO, early-term birth and emergency caesarean for NRFS in the cohort with an EFW <10th centile but SCNO lost its association with a low CPR in the EFW >10th cohort. Stratifying the population into CPR <10th centile and CPR >10th centile, a low EFW was associated with early-term birth, induction of labor, admission to NICU, and the SCNO.

Conclusions: In a low-risk cohort both the CPR and EFW individually and in combination predicts adverse obstetric and perinatal outcomes when measured late in pregnancy. However, the predictive value was enhanced when both were used in combination.     

The influence of fetal sex on the antenatal diagnosis of small for gestational age

Objective: We evaluated the influence of fetal sex on the antenatal diagnosis and detection of small for gestational age (SGA).

Methods: The cohort consisted of unselected singleton pregnancies, undergoing routine biometry and cerebroplacental ratio (CPR) assessment at 36 weeks. Locally fitted equations for centiles and Z scores were used. “Ultrasound SGA” was defined as estimated fetal weight (EFW)?Results: Among 4112 pregnancies, there were 235 female “ultrasound SGA” fetuses and 177 male; (odds ratios (OR) 1.502 (1.223???1.845)); the detection rate of SGA at birth was 50.6% and 40.9%, respectively (OR 1.479 (0.980???2.228)). In “ultrasound SGA” girls the abdominal circumference growth velocity (ACGV) between 20 and 36 weeks was less frequently in the lowest decile (OR 0.490 (0.320???0.750)), with no differences in CPR.

Conclusions: Females are more commonly diagnosed as SGA; those diagnosed may be at less risk than males.     

Ultrasound estimation of fetal weight in small for gestational age pregnancies

Objective.?Approximately half of small for gestational age (SGA) cases are due to maternal or fetal pathology, and may result in significant neonatal morbidity and mortality. The estimated fetal weight (EFW) measurement is the cornerstone of ultrasonographic findings when diagnosing and managing SGA pregnancies. Our objective was to determine the ultrasound accuracy of EFW in SGA pregnancies.

Methods.?A retrospective chart review was performed of all pregnancies complicated by SGA from a single institution (Stanford University) over a 2-year-period (2004–2006). SGA was defined as EFW?≤?10%. 98 neonates whose last ultrasound for EFW occurred within 7 days of delivery were included in the study. The absolute differences between the EFW and birthweight (BW) were analyzed, and the absolute percent errors were calculated as (EFW???BW)/BW?× 100. The mean absolute differences and mean absolute percent errors were analyzed across all gestational ages (GA) and EFWs using one-way analysis of variance.

Results.?The mean absolute percent error for the entire cohort was 8.7% (±6.3%). There was no statistically significant difference in the mean absolute percent error across all GAs (<32 weeks, 32–36 weeks, >36 weeks), and EFWs (<1500?g, 1500–2000?g, >2000?g).

Conclusion.?Ultrasound measurement of EFW in SGA pregnancies is consistent across all GAs and EFW measurements.     

Specific formulas improve the estimation of fetal weight by ultrasound scan

Abstract

Objective: To develop and evaluate local, sex specific, small for gestational age (SGA) specific, large for gestational age (LGA) specific and combined (biometry, sex and Doppler indices) formulas for ultrasound estimated fetal weight (EFW).

Method: Low-risk singleton pregnancies that delivered within 7 days from ultrasound examination were assessed. A formula-generating group (1407 pregnancies) and a validation group (469 pregnancies) were created. Fractional regression analysis was used to develop the formulas. Systematic error, random error, fraction within the 10% of actual birth weight and Bland–Altman analysis were used.

Results: The local formula and the Hadlock formula with local co-efficients performed better than the Hadlock formula. The SGA-specific formula, the LGA-specific formula and the combined formula had the lower systematic error (MSE: +0.0022291, ?0.4226888, +0.8386222, respectively) and the narrower 95% LOA (?292.8 to +292.23, ?485.6 to +461.5, ?425.7 to +450.46, respectively). The SGA- and the LGA-specific formulas had higher fraction within the 10% of actual birth weight (81.5% and 84%, respectively).

Conclusions: Local formulas improve the EFW calculation. The combined formula can further optimize the accuracy and precision. Application of specific formulas for the small and the large fetus had the most pronounced effect in improving fetal weight estimation.     

Small for gestational age newborns – does pre-recognition make a difference in pregnancy outcome?

Objective: We aimed to evaluate whether pre-recognition of small for gestational age (SGA) at late preterm or term pregnancies, has an impact on pregnancy outcome.

Methods: Retrospective analysis of SGA newborns, stratified to those with suspected or unsuspected IUGR according the sonographic estimated fetal weight (EFW), below the 10th percentile for gestational age (n?=?619), with fetuses not suspected as SGA (EFW ≥10th percentile) preformed up to 7 days prior to delivery (n?=?1770).

Results: SGA was correctly diagnosed prior to delivery in 26% of the fetuses. Women with suspected SGA were delivered earlier (37.9?±?1.7 versus 38.8?±?1.4 weeks, p?<?0.001) and at a lower birth weight (2280?±?321 versus 2454?±?263 grams, p?<?0.001). They also had higher rates of induction of labor (19.1% versus 6.2%, p?<?0.001) and cesarean delivery (29.1% versus 19.8%, p?<?0.001). Fetuses suspected for SGA had higher rate of neonatal adverse outcome, but on multivariate analysis suspected SGA (aOR 0.41, 95% CI 0.20–0.86), birthweight (aOR 0.67, 95% CI 0.5 to ?0.77 for each additional 50?g), gestational age at delivery (aOR 0.63, 95% CI 0.56–0.71 for each additional week) and spontaneous vaginal delivery (aOR 0.88, 95% CI 0.19–3.89) were independently associated with an improved neonatal composite outcome.

Conclusion: Identification of SGA may improve neonatal outcome. However, by itself, it is not an indication for intervention, which may lead to adverse outcome.     

Comparison of customized and cohort-based birthweight standards in identification of growth-restricted infants in GUSTO cohort study

Background: The aim was to evaluate the ability of customized and cohort birthweight standards in discriminating intrauterine growth retardation (IUGR).

Methods: Birthweights (BWs) of GUSTO singleton infants born at gestational age (GA) 35–41 weeks were converted using two standards: (a) GUSTO cohort-based BW centile adjusted for GA and baby gender; (b) customized BW percentile calculator adjusted for maternal height and weight, race, parity, GA and gender. Infants were classified into three groups: (1)?<?10th BW centile by customization– customized-SGA, (2)?<?10th BW centile by GUSTO– GUSTO-SGA; and (3)?>?10th BW centile by both standards – BOTH-non-SGA.

Results: Of the 1011 infant–mother dyads, 68 were customized-SGA and 104 were GUSTO-SGA, with concordance of 61% (n?= 63) for SGA. While 5 (7%) of customized-SGA were not SGA by GUSTO-charts, 41 (39%) of GUSTO-SGA were not SGA by customized-charts. Customized-SGA had significantly the least growth in abdominal circumference (AC) and highest head circumference (HC): AC growth ratio between second and third trimester; and the lowest mean BW, ponderal index and placental weight than other groups.

Conclusion: Customized-SGA standard was a better discriminator of pathologic fetal growth based on AC growth. It improved strength of association with pathology and in our population reduced false positives (41/104?=?39%) in the assessment of SGA.     

Amniotic fluid index and estimated fetal weight for prediction of fetal macrosomia: a prospective observational study

Objective: The purpose of this study was to assess the value of combining the estimated fetal weight (EFW) and amniotic fluid index (AFI) measured in term patients early in labor with intact membranes for prediction of macrosomia.

Methods: In a single center, prospective observational study, 600 patients in the first stage of labor before rupture of membranes in whom ultrasonography was performed to measure AFI and EFW, and these data were analyzed statistically to evaluate prediction of fetal macrosomia.

Results: Macrosomia occurred in 64 cases (10.6%). The AFI was significantly higher in the macrosomic group (p?=?0.001). It was noted that the area under receiver operating characteristic (ROC) curves for EFW was 0.93 and that of AFI was 0.67. Based on suggested combined EFW and AFI cutoffs of 4000?g and 164?mm, respectively, the positive predictive value (PPV) for combined parameters (92.3%) was higher than that of EFW (75%) and that of AFI (27%) and the likelihood ratio for combination (93.7%) was higher than that of EFW (24.7%) and that of AFI (21%).

Conclusion: Combined use of EFW and AFI improves prediction of macrosomia at birth rather than the EFW alone.     

A scoring system for detection of macrosomia and prediction of shoulder dystocia: A disappointment

Objective. To develop a scoring system for the detection of a macrosomic fetus (birth weight (BW) ≥ 4000 g) and predict shoulder dystocia among large for gestational age fetuses.

Study design. We retrospectively identified all singletons with accurate gestational age (GA) that were large for GA (abdominal circumference (AC) or estimated fetal weight (EFW) ≥ 90% for GA) at ≥37 weeks with delivery within three weeks. The scoring system was: 2 points for biparietal diameter, head circumference, AC, or femur length ≥90% for GA, or if the amniotic fluid index (AFI) was ≥24 cm; for biometric parameters <90% or with AFI <24 cm, 0 points. The predictive values for detection of shoulder dystocia were calculated.

Results. Of the 225 cohorts that met the inclusion criteria the rate of macrosomia was 39% and among vaginal deliveries (n = 120) shoulder dystocia occurred in 12% (15/120; 95% confidence interval (CI) 7–20%). The sensitivity of EFW ≥4500 g to identify a newborn with shoulder dystocia was 0% (95% CI 0–21%), positive predictive values 0% (95% CI 0–46%), and likelihood ratio of 0. For a macrosomia score >6, the corresponding values were 20% (4–48%), 25% (5–57%) and 2.3.

Conclusion. Though the scoring system can identify macrosomia, it offers no advantage over EFW. The scoring system and EFW are poor predictors of shoulder dystocia.     

Association between small for gestational age and intrauterine fetal death: comparing a customized South Korean growth standard versus a population-based fetal growth chart

Objective: To determine if a customized growth standard developed for an ethnically homogeneous South Korean population is better at identifying (SGA) fetuses at risk for intra-uterine fetal death (IUFD), compared with a current population based-growth standard.

Study design: A retrospective cohort study comparing the identification of SGA fetuses at risk for IUFD using a customized versus a population based-chart. The association between a SGA infant defined as a birth weight <10th percentile using the South Korean population chart versus the customized chart and IUFD were compared. Intrauterine fetal death was defined as fetal demise occurring after 20 weeks gestation. Statistical analyses including OR, 95% confidence interval (CI), and screening accuracy using each chart were performed.

Results: The customized singleton chart identified 11 (8.2%) of the SGA pregnancies detected by the population chart and classified 15 additional fetuses as SGA. Those identified as SGA using the customized chart had an OR for IUFD that was approximately 15 times as high as those identified using the population chart. The customized chart also showed a higher sensitivity and specificity for identifying SGA pregnancies at risk for IUFD.

Conclusion: In this ethnically homogenous population, the customized growth chart showed improved discrimination in identifying SGA pregnancies at risk for fetal death than the population-based growth chart.     

Can a single preterm ultrasound accurately predict birth weight in gestational diabetes?

Objective: To evaluate the accuracy of the gestation-adjusted projection method of birth weight prediction, as compared to near delivery ultrasound estimated fetal weight, in a gestational diabetic population.

Methods: A retrospective cohort was conducted including all women with gestational diabetes who had an ultrasound estimated fetal weight (EFW) between 34^0/7 and 36^6/7 weeks and an additional ultrasound EFW within 7?d of delivery at term. The gestation-adjusted projection (GAP) method was applied to the earlier sonogram, resulting in the GAP predicted birth weight. The GAP predicted weight and the term ultrasound EFW were compared to the actual birth weight. Absolute and percent birth weight errors were compared using paired t-tests.

Results: The mean absolute percent errors and mean absolute errors for the GAP method and term ultrasound were 7.7?±?5.6% versus 7.1?±?5.1% and 256?±?184?g versus 236?±?169?g respectively (p?=?0.22 and p?=?0.29). The sensitivity of predicting birth weight ≥4000?g was 22% for the GAP method and 28% for term ultrasound, with specificity reaching 97% for both the methods.

Conclusion: The GAP method is as accurate as term ultrasound in predicting birth weight in gestational diabetes.     

Classifying neonatal growth outcomes: use of birth weight,placental evaluation and individualized growth assessment

Objective: To compare neonatal growth outcomes determined by birth weight (BW), placental assessment (Plac Assess) and individualized growth assessment (IGA).

Methods: This retrospective analysis was carried out in 45 selected pregnancies at risk for fetal growth restriction. Serial fetal biometry was carried out in the 2nd and 3rd trimester. First and second trimester placental biomarkers, 2nd trimester uterine artery (Ut A) velocimetry and postnatal placental pathology were evaluated as indicators of placental insufficiency. At delivery, weight (WT), head circumference (HC) and crown–heel length (CHL) were measured. BWs were categorized as large-for-gestational-age (LGA), appropriate-for-gestational-age (AGA) and small-for-gestational age (SGA) (<10th, 10th–90th and >90th percentiles). In these categories, neonatal growth outcomes were classified as growth restricted (GR), normal (NORMAL) or macrosomic (MACRO) based on BW plus Plac Assess (Ut A velocimetry, biomarkers, pathology) or IGA [growth potential realization index profile (WT, HC and CHL)].

Results: There were 6 LGA, 14 AGA and 25 SGA neonates in this sample. All 14 AGA neonates were considered NORMAL by both IGA and BW?+?Plac Assess. All six LGA neonates were classified as MACRO by BW?+?Plac Assess but only four by IGA (the remaining two were NORMAL and high NORMAL). The 25 SGA cases could be divided into five subgroups based on IGA and BW?+?Plac Assess. The largest subgroup (56%) was GR and the next largest (24%) was NORMAL by both classification methods. In the remaining 20%, there was some evidence of GR but IGA and BW?+?Plac Assess were not in complete agreement.

Conclusions: Agreement was good for all three methods in the LGA and AGA groups. The SGA group was heterogeneous but agreement between IGA and BW?+?Plac Assess was 89%. These results, using more sophisticated growth assessment methods, confirm placental insufficiency as a primary cause of growth restriction. Most normal and GR SGA neonates can be identified with conventional anatomical measurements if IGA is used.     

Gestational age and fetal growth assessment among obstetricians

Objective: We aimed to characterize gestational age assessment and fetal growth evaluation among obstetricians.

Methods: Observational, cross-sectional study. We applied a questionnaire to obstetrics specialists and residents, during a national congress on obstetrics.

Results: Almost all 179 respondents correct gestational age in the first trimester by ultrasound, but 63% only if there is a difference of 2–9 days. Ultrasound at 11–13 weeks was considered more accurate than at 8–10 weeks by 81%, with a higher proportion of specialists choosing correctly the last answer (p?=?0.05). One-third of the respondents did not correctly point the error associated with the ultrasound estimation of fetal weight (EFW). Of the 88% who use a growth table, only 32% were able to identify it by publication/author. Ninety-eight percent identify fetal growth restriction risk (FGR) with centiles (10th in 76%) and 73% of doctors diagnose FGR without other pathological findings (10th in 49%). 44% finds that a low EFW centile maintenance (4th to 3rd) is more worrisome than the crossing of two quartiles (75th to 24th).

Conclusions: The role of ultrasound in gestational age assessment and use of EFW use for FGR classification was disparate among participants. EFW and respective centiles may be over relied upon.