Routine third-trimester ultrasound assessment for intrauterine growth restriction

Intrauterine growth restriction significantly impacts perinatal outcomes. Undetected IUGR escalates the risk of adverse outcomes. Serial symphysis-fundal height measurement, a recommended strategy, is insufficient in detecting abnormal fetal growth. Routine third-trimester ultrasounds significantly improve detection rates compared with this approach, but direct high-quality evidence supporting enhanced perinatal outcomes from routine scanning is lacking. In assessing fetal growth, abdominal circumference alone performs comparably to estimated fetal weight. Hadlock formulas demonstrate accurate fetal weight estimation across diverse gestational ages and settings. When choosing growth charts, prescriptive standards (encompassing healthy pregnancies) should be prioritized over descriptive ones. Customized fetal standards may enhance antenatal IUGR detection, but conclusive high-quality evidence is elusive. Emerging observational data suggest that longitudinal fetal growth assessment could predict adverse outcomes better. However, direct randomized trial evidence supporting this remains insufficient.

Utilization of third-trimester fetal transcerebellar diameter measurement for gestational age estimation: a comparative study using Bland-Altman analysis

BACKGROUND

Several studies show that gestational age estimation during the third trimester of pregnancy using fetal transcerebellar diameter is superior to that measured using fetal biometry (biparietal diameter, head circumference, abdominal circumference, and femur diaphysis length). However, the conclusion of the studies stemmed from findings of correlation and regression statistical tests, which are not the recommended statistical analysis methods for comparing the values of 1 variable as measured by 2 different methods.

OBJECTIVE

This study aimed to compare the accuracy of gestational age estimation using transcerebellar diameter to that using fetal biometry during the third trimester of pregnancy using Bland-Altman statistical analysis.

STUDY DESIGN

This was a cross-sectional study on pregnant women who presented for routine antenatal care follow-up in the third trimester of pregnancy (28-41 weeks of gestation) at St. Paul's Hospital Millennium Medical College (Ethiopia) between November 1, 2020, and February 28, 2021. Data were collected prospectively using a structured questionnaire on the Open Data Kit. The primary outcome of our study was the mean bias of gestational age estimation (error in estimating gestational age) using transcerebellar diameter and composite fetal biometry (composite gestational age). Data were analyzed using Stata (version 15; StataCorp, College Station, TX). Simple descriptive analysis, Bland-Altman analysis, and the Kendall τa discordance measurement were performed as appropriate. The mean bias (error) and limits of agreement were used to present the significance of the finding.

RESULTS

A total of 104 pregnant women in the third trimester were included in the study. The mean error (bias) when transcerebellar diameter was used to estimate the gestational age was 0.65 weeks vs a bias of 1.1 weeks using composite biometry, compared with the gold standard method from crown-lump length (in both cases). The calculated estimated limit of agreement was narrower in the case of transcerebellar diameter than in the case of composite fetal biometry (-3.56 to 2.25 vs -4.73 to 2.53). The Kendall τa discordance measurement revealed that gestational age estimations using composite biometry and crown-lump length were 51% to 70%, respectively, more likely to agree than disagree and that gestational age estimations using transcerebellar diameter and crown-lump length were 62% to 77%, respectively, more likely to agree than to disagree (P≤.001).

CONCLUSION

Gestational age estimation using transcerebellar diameter is more accurate than gestational age estimation using composite gestational age (biparietal diameter, head circumference, femur diaphysis length, and abdominal circumference). Transcerebellar diameter should be used to date third-trimester pregnancies with unknown gestational age (unknown last normal menstrual period with no early ultrasound milestone).

The Danish newborn standard and the International Fetal and Newborn Growth Consortium for the 21st Century newborn standard: a nationwide register-based cohort study

BACKGROUND

It is a matter of debate whether 1 universal standard, such as the International Fetal and Newborn Growth Consortium for the 21st Century standard, can be applied to all populations.

OBJECTIVE

The primary objective was to establish a Danish newborn standard based on the criteria of the International Fetal and Newborn Growth Consortium for the 21st Century standard to compare the percentiles of these 2 standards. A secondary objective was to compare the prevalence and risk of fetal and neonatal deaths related to small for gestational age defined by the 2 standards when used in the Danish reference population.

STUDY DESIGN

This was a register-based nationwide cohort study. The Danish reference population included 375,318 singletons born at 33 to 42 weeks of gestation in Denmark between January 1, 2008, and December 31, 2015. The Danish standard cohort included 37,811 newborns who fulfilled the criteria of the International Fetal and Newborn Growth Consortium for the 21st Century standard. Birthweight percentiles were estimated using smoothed quantiles for each gestational week. The outcomes included birthweight percentiles, small for gestational age (defined as a birthweight of 3rd percentile), and adverse outcomes (defined as either fetal or neonatal death).

RESULTS

At all gestational ages, the Danish standard median birthweights at term were higher than the International Fetal and Newborn Growth Consortium for the 21st Century standard median birthweights: 295g for females and 320 g for males. Therefore, the estimates of the prevalence rate of small for gestational age within the entire population were different: 3.9% (n=14,698) using the Danish standard vs 0.7% (n=2640) using the International Fetal and Newborn Growth Consortium for the 21st Century standard. Accordingly, the relative risk of fetal and neonatal deaths among small-for-gestational-age fetuses differed by SGA status defined by the different standards (4.4 [Danish standard] vs 9.6 [International Fetal and Newborn Growth Consortium for the 21st Century standard]).

CONCLUSION

Our finding did not support the hypothesis that 1 universal standard birthweight curve can be applied to all populations.

Decreasing urgent repeat cesarean sections by offering complimentary ultrasounds and consultation in rural Burundi: The zigama mama project

Objective

Repeat urgent cesarean sections (CS) carry an increased risk of severe maternal outcomes. As CS increase in sub-Saharan Africa, creative strategies are necessary to reduce the rate of urgent repeat CS. The Zigama-Mama Project in rural Burundi uses complimentary ultrasounds to create a clinical touchpoint to counsel women with a prior CS for a hospital-based delivery.

Methods

From July 2019 to June 2020, complimentary ultrasounds were offered to all antenatal patients with prior CS, along with counseling for monitored trial of labor after cesarean (TOLAC) or scheduled repeat CS. Community engagement and feedback from district health centers were evaluated.

Results

In total, 500 women with a prior CS presented for a complimentary ultrasound. During the intervention year, a relative and absolute reduction in urgent repeat CS (baseline: n = 114 {70.8%}, intervention: n = 97{49.7%}, p < 0.001) was observed, with no significant change in maternal mortality or ruptured uteri. All health center personnel agreed the project improved their confidence in referring women with prior CS.

Conclusion

Offering complimentary ultrasounds as a clinical touchpoint for scheduling a monitored delivery or CS for women at high risk for delivery complication may be an affordable and creative strategy to care for women with previous CS during subsequent deliveries.

The amniotic fluid index and oligohydramnios: a deeper dive into the shallow end

Second- and third-trimester obstetrical ultrasound examinations include an amniotic fluid volume assessment. Professional organizations' clinical guidance recommends using semiquantitative techniques, such as the single deepest vertical pocket or amniotic fluid index, for this purpose. The single deepest vertical pocket is described as the preferred method of assessing amniotic fluid volume based on fewer oligohydramnios diagnoses and labor inductions with no demonstrable difference in pregnancy outcomes compared with the amniotic fluid index. We offer an alternative interpretation of the evidence for this advice, drawn from 6 randomized clinical trials and 2 meta-analyses comparing the single deepest vertical pocket to the amniotic fluid index. Individually and collectively, these reports are underpowered to detect significant differences in maternal and perinatal outcomes by study group. Moreover, randomized clinical trials comparing maternal and perinatal outcomes resulting from a policy of labor induction at or beyond 37 weeks of gestation vs expectant care consistently favor labor induction, the very intervention paradoxically cited as favoring the single deepest vertical pocket vs the amniotic fluid index. We conclude that the amniotic fluid index should be considered a reasonable method for third-trimester amniotic fluid assessment and diagnosing oligohydramnios.

Society for Maternal-Fetal Medicine Special Statement: Best-practice recommendations for ultrasound network connectivity

Prenatal ultrasound is an indispensable tool used by obstetrical care providers to assist in the everyday care of their pregnant patients. Alongside advancements in imaging, the electronic systems that support this technology have become more advanced. However, it is currently difficult for these individual systems to communicate with each other "out of the box." There is also minimal standardization of the type and format of data transmitted within these systems. Clinicians and system vendors must work collaboratively to create clinical and technical standards to serve as the foundation for increased interoperability among the various systems within each institutional network. Therefore, the Society for Maternal-Fetal Medicine Clinical Informatics Committee established an Ultrasound Electronic Health Record Subcommittee to facilitate collaboration between clinicians, including maternal-fetal medicine subspecialists, and ultrasound network component vendors. Based on the work of this subcommittee, the purpose of this document is to provide: (1) a basic understanding of ultrasound network architecture and capabilities, and (2) best-practice recommendations for electronic health record order design, obstetrical clinical data standards, and billing and coding practices.

A Glimpse at the Size of the Fetal Liver-Is It Connected with the Evolution of Gestational Diabetes?

Gestational diabetes mellitus (GDM) is defined as an impairment of glucose tolerance, manifested by hyperglycemia, which occurs at any stage of pregnancy. GDM is more common in the third trimester of pregnancy and usually disappears after birth. It was hypothesized that the glycemic status of the mother can modulate liver development and growth early during the pregnancy. The simplest modality to monitor the evolution of GDM employs noninvasive techniques. In this category, routinely obstetrical ultrasound (OUS) examinations (simple or 2D/3D) can be employed for specific fetal measurements, such as fetal liver length (FLL) or volume (FLV). FLL and FLV may emerge as possible predictors of GDM as they positively relate to the maternal glycated hemoglobin (HbA1c) levels and to the results of the oral glucose tolerance test. The aim of this review is to offer insight into the relationship between GDM and fetal nutritional status. Risk factors for GDM and the short- and long-term outcomes of GDM pregnancies are also discussed, as well as the significance of different dietary patterns. Moreover, the review aims to fill one gap in the literature, investigating whether fetal liver growth can be used as a predictor of GDM evolution. To conclude, although studies pointed out a connection between fetal indices and GDM as useful tools in the early detection of GDM (before 23 weeks of gestation), additional research is needed to properly manage GDM and offspring health.

Myelomeningocele sac associated with worse lower-extremity neurological sequelae: evidence for prenatal neural stretch injury?

OBJECTIVE

To determine whether the presence of a myelomeningocele (MMC) sac and sac size correlate with compromised lower-extremity function in fetuses with open spinal dysraphism.

METHODS

A radiology database search was performed to identify cases of MMC and myeloschisis (MS) diagnosed prenatally in a single center from 2013 to 2017. All cases were evaluated between 18 and 25 weeks. Ultrasound reports were reviewed for talipes and impaired lower-extremity motion. In MMC cases, sac volume was calculated from ultrasound measurements. Magnetic resonance imaging reports were reviewed for hindbrain herniation. The association of presence of a MMC sac and sac size with talipes and impaired lower-extremity motion was assessed. Post-hoc analysis of data from the multicenter Management of Myelomeningocele Study (MOMS) randomized controlled trial was performed to confirm the study findings.

RESULTS

In total, 283 MMC and 121 MS cases were identified. MMC was associated with a lower incidence of hindbrain herniation than was MS (80.9% vs 100%; P < 0.001). Compared with MS cases, MMC cases with hindbrain herniation had a higher rate of talipes (28.4% vs 16.5%, P = 0.02) and of talipes or lower-extremity impairment (34.9% vs 19.0%, P = 0.002). Although there was a higher rate of impaired lower-extremity motion alone in MMC cases with hindbrain herniation than in MS cases, the difference was not statistically significant (6.6% vs 2.5%; P = 0.13). Among MMC cases with hindbrain herniation, mean sac volume was higher in those associated with talipes compared with those without talipes (4.7 ± 4.2 vs 3.0 ± 2.6 mL; P = 0.002). Review of the MOMS data demonstrated similar findings; cases with a sac on baseline imaging had a higher incidence of talipes than did those without a sac (28.2% vs 7.5%; P = 0.007).

CONCLUSIONS

In fetuses with open spinal dysraphism, the presence of a MMC sac was associated with fetal talipes, and this effect was correlated with sac size. The presence of a larger sac in fetuses with open spinal dysraphism may result in additional injury through mechanical stretching of the nerves, suggesting another acquired mechanism of injury to the exposed spinal tissue. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Does transvaginal ultrasound at 13-15 weeks improve anatomic survey completion rates in obese gravidas?

Objective: Obesity increases the difficulty of completing the fetal anatomic survey. This is of added concern in obese gravidas who are at higher risk of congenital fetal anomalies. We hypothesized that incorporation of an early transvaginal assessment could improve the completion rate of the fetal anatomic survey in obese women.Methods: We performed a prospective, longitudinal, blinded study of obese gravidas (BMI ≥ 35 kg/m²) comparing the use of a single early second trimester transvaginal ultrasound in addition to midtrimester transabdominal ultrasound versus traditional serial midtrimester ultrasound alone for completion of the anatomic survey. Transvaginal ultrasound for anatomy was performed between 13 0/7 and 15 6/7 week followed by midtrimester anatomic ultrasound, with each patient serving as her own control. Structures were marked as optimally or suboptimally viewed after each ultrasound. Sonographers and reviewers were blinded to images from the transvaginal ultrasound. Completion rates and gestational age at completion were compared between groups.Results: Fifty subjects were included. Fetal anatomic survey was completed in 62% using standard midtrimester assessment versus 78% with the addition of early transvaginal assessment (p = .04). The survey was completed at an earlier gestational age utilizing the transvaginal approach (22 0/7 ± 6 3/7) compared to traditional midtrimester transabdominal ultrasound approach (25 2/7 ± 5 3/7) p < .0005.Conclusions: Incorporation of an early transvaginal assessment of anatomy in obese women improved the rate of completion and led to earlier gestational age at completion of the fetal anatomic survey. Consideration should be given to including an early transvaginal sonogram as part of routine assessment of women with a BMI ≥ 35.

Sonographic assessment of placental location: a mere notional description or an important key to improve both pregnancy and perinatal obstetrical care? A large cohort study

During a standard obstetrical sonogram, the assessment of placental location (PL) is often limited to a mere notional description without formulating any association to possible implications on pregnancy and childbirth. The aim of the study was to speculate if different sites of PL may have a role in influencing fetal presentation-(FP) at birth and if certain pregnancy-complications may be more closely associated with one rather than with another PL. We conducted an observational-prospective-cohort study on pregnant women referred to the Ob/Gyn Unit of Padua University for routine third-trimester ultrasound scan. For all eligible patients we evaluated the correlation between sites of PL and perinatal maternal/fetal outcomes. Non-cephalic presentation was found in 1.4% of anterior, 8.9% of posterior, 6.2% of fundal and 7.2% of lateral insertions. FP at the beginning of the third trimester as opposed to presentation at birth was concordant in 90.3% of anterior, 63.3% of posterior and 76.5% of lateral insertions. Considering only non-cephalic fetuses we observed a decreasing probability for spontaneous rotation in the following lies: 88% anterior-PL, 80% posterior-PL, 77% lateral-PL, and 70% fundal-PL. Patients with posterior-PL (significantly associated with previous-CS) had a significantly higher CS-rate (due to previous-CS and breech-presentation). Significant differences were found in terms of gestational-hypertension and fresh-placental-weight between different sites of PL. In conclusion our data showed that an understanding of the role that PL plays in influencing the incidence of certain maternal-fetal conditions may assist Clinicians in improving perinatal maternal/fetal outcomes.