Prenatal cerebellar growth trajectories and the impact of periconceptional maternal and fetal factors

STUDY QUESTION

CAN WE assess human prenatal cerebellar growth from the first until the third trimester of pregnancy and create growth trajectories to investigate associations with periconceptional maternal and fetal characteristics?

SUMMARY ANSWER

Prenatal growth trajectories of the human cerebellum between 9 and 32 weeks gestational age (GA) were created using three-dimensional ultrasound (3D-US) and show negative associations with pre-pregnancy and early first trimester BMI calculated from self-reported and standardized measured weight and height, respectively.

WHAT IS KNOWN ALREADY

The cerebellum is essential for normal neurodevelopment and abnormal cerebellar development has been associated with neurodevelopmental impairments and psychiatric diseases. Cerebellar development is particularly susceptible to exposures during the prenatal period, including maternal folate status, smoking habit and alcohol consumption.

STUDY DESIGN, SIZE, DURATION

From 2013 until 2015, we included 182 singleton pregnancies during the first trimester as a subgroup in a prospective periconception cohort with follow-up until birth. For the statistical analyses, we selected 166 pregnancies ending in live born infants without congenital malformations.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We measured transcerebellar diameter (TCD) at 9, 11, 22, 26 and 32 weeks GA on ultrasound scans. Growth rates were calculated and growth trajectories of the cerebellum were created. Linear mixed models were used to estimate associations between cerebellar growth and maternal age, parity, mode of conception, geographic origin, pre-pregnancy and first trimester BMI, periconceptional smoking, alcohol consumption, timing of folic acid supplement initiation and fetal gender.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 166 pregnancies provided 652 (87%) ultrasound images eligible for TCD measurements. Cerebellar growth rates increased with advancing GA being 0.1691 mm/day in the first trimester, 0.2336 mm/day in the second trimester and 0.2702 mm/day in the third trimester. Pre-pregnancy BMI, calculated from self-reported body weight and height, was significantly associated with decreased cerebellar growth trajectories (β = -0.0331 mm, 95% CI = -0.0638; -0.0024, P = 0.035). A similar association was found between cerebellar growth trajectories and first trimester BMI, calculated from standardized measurements of body weight and height (β = -0.0325, 95% CI = -0.0642; -0.0008, P = 0.045, respectively).

LIMITATIONS, REASONS FOR CAUTION

As the study population largely consisted of tertiary hospital patients, external validity should be studied in the general population. Whether small differences in prenatal cerebellar growth due to a higher pre-pregnancy and first trimester BMI have consequences for neurodevelopmental outcome needs further investigation.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings further substantiate previous evidence for the detrimental impact of a higher maternal BMI on neurodevelopmental health of offspring in later life.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Department of Obstetrics and Gynecology, Erasmus MC University Medical Centre and Sophia Children's Hospital Fund, Rotterdam, The Netherlands (SSWO grant number 644). No competing interests are declared.

Advanced genomic testing may aid in counseling of isolated agenesis of the corpus callosum on prenatal ultrasound

OBJECTIVE

Isolated agenesis of the corpus callosum on fetal ultrasound has a varied prognosis. Microarray and exome sequencing (ES) might aid in prenatal counseling.

METHOD

This study includes 25 fetuses with apparently isolated complete corpus callosum (cACC) on ultrasound. All cases were offered single nucleotide polymorphism array. Complementary ES was offered postnatally in selected cases. Clinical physical and neurodevelopmental follow-up was collected.

RESULTS

Eighteen cases opted for single nucleotide polymorphism array testing, which detected a causal anomaly in 2/18 (11.1%; 95% CI 2.0%-31%). Among ongoing pregnancies without a causal anomaly on microarray, 30% (95% CI 8.5%-60%) showed intellectual disability. Postnatal magnetic resonance imaging and physical examination often (64%; 95% CI 38%-85%, and 64%; 95% CI 38%-85%, respectively) revealed additional physical anomalies in cases without a causal anomaly on microarray. Two cases appeared truly isolated after birth. Postnatal sequencing in 4 of 16 cases without a causal anomaly on microarray but with intellectual disability and/or additional postnatal physical anomalies revealed 2 single-gene disorders. Therefore, the estimated diagnostic yield of ES in chromosomally normal cACC fetuses is between 2/4 (50%; 95% CI 11%-89%) and 2/16 (13.3%; 95% CI 2.4%-36%).

CONCLUSION

In accordance with current guidelines, we conclude that microarray should be offered in case of isolated cACC on ultrasound. ES is likely to be informative for prenatal counseling and should be offered if microarray is normal.

Foetal fractional thigh volume: an early 3D ultrasound marker of neonatal adiposity

BACKGROUND

The predisposition for obesity is suggested to originate in the prenatal period. Prenatal markers are needed to identify foetuses at risk for neonatal adiposity, as early marker of childhood obesity.

OBJECTIVE

The aim of this study is to assess the association between foetal fractional thigh volume (TVol) and neonatal percentage fat mass from mid-gestation onward.

METHODS

In this perinatal cohort study, singleton pregnancies with term born infants were included. Foetal TVol was measured on three-dimensional ultrasound scans (3D US) obtained at 22, 26 and 32 weeks of gestation. Neonatal body composition measurement (percentage body fat (%BF)) was planned between 42⁺⁰ and 42⁺⁶ -week postmenstrual age. Cross-sectional and longitudinal linear regression analyses were performed.

RESULTS

Seventy-nine mother-child pairs were included. Median (interquartile range) TVol increased from 7.6 (7.1; 8.5) cm³ at 22 weeks to 36.5 (33.8; 40.9) cm³ at 32 weeks. Median neonatal %BF was 14.3% (11.7; 17.0). TVol at 22 weeks (β = -1.58, 95% CI -2.45; -0.70, explained variance 31%) was negatively associated with %BF, but no associations were found at 26 and 32 weeks of gestation. TVol growth between 22 and 32 weeks of gestation (explained variance 18%) was also statistically significantly negatively associated with %BF.

CONCLUSIONS

Foetal TVol is a promising 3D US marker for prediction of neonatal adiposity from mid-gestation onward.

New Ultrasound Measurements to Bridge the Gap between Prenatal and Neonatal Brain Growth Assessment

BACKGROUND AND PURPOSE

Most ultrasound markers for monitoring brain growth can only be used in either the prenatal or the postnatal period. We investigated whether corpus callosum length and corpus callosum-fastigium length could be used as markers for both prenatal and postnatal brain growth.

MATERIALS AND METHODS

A 3D ultrasound study embedded in the prospective Rotterdam Periconception Cohort was performed at 22, 26 and 32 weeks' gestational age in fetuses with fetal growth restriction, congenital heart defects, and controls. Postnatally, cranial ultrasound was performed at 42 weeks' postmenstrual age. First, reliability was evaluated. Second, associations between prenatal and postnatal corpus callosum and corpus callosum-fastigium length were investigated. Third, we created reference curves and compared corpus callosum and corpus callosum-fastigium length growth trajectories of controls with growth trajectories of fetuses with fetal growth retardation and congenital heart defects.

RESULTS

We included 199 fetuses; 22 with fetal growth retardation, 20 with congenital heart defects, and 157 controls. Reliability of both measurements was excellent (intraclass correlation coefficient ≥ 0.97). Corpus callosum growth trajectories were significantly decreased in fetuses with fetal growth restriction and congenital heart defects (β = -2.295; 95% CI, -3.320-1.270; P < .01; β = -1.267; 95% CI, -0.972-0.562; P < .01, respectively) compared with growth trajectories of controls. Corpus callosum-fastigium growth trajectories were decreased in fetuses with fetal growth restriction (β = -1.295; 95% CI, -2.595-0.003; P = .05).

CONCLUSIONS

Corpus callosum and corpus callosum-fastigium length may serve as reliable markers for monitoring brain growth from the prenatal into the postnatal period. The clinical applicability of these markers was established by the significantly different corpus callosum and corpus callosum-fastigium growth trajectories in fetuses at risk for abnormal brain growth compared with those of controls.

Growth trajectories of the human embryonic head and periconceptional maternal conditions

STUDY QUESTION

Can growth trajectories of the human embryonic head be created using 3D ultrasound (3D-US) and virtual reality (VR) technology, and be associated with second trimester fetal head size and periconceptional maternal conditions?

SUMMARY ANSWER

Serial first trimester head circumference (HC) and head volume (HV) measurements were used to create reliable growth trajectories of the embryonic head, which were significantly associated with fetal head size and periconceptional maternal smoking, age and ITALIC! in vitro fertilization (IVF)/intra-cytoplasmic sperm injection (ICSI) treatment.

WHAT IS KNOWN ALREADY

Fetal growth is influenced by periconceptional maternal conditions.

STUDY DESIGN, SIZE, DURATION

We selected 149 singleton pregnancies with a live born non-malformed fetus from the Rotterdam periconception cohort.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Bi-parietal diameter and occipital frontal diameter to calculate HC, HV and crown-rump length (CRL) were measured weekly between 9 + 0 and 12 + 6 weeks gestational age (GA) using 3D-US and VR. Fetal HC was obtained from second trimester structural anomaly scans. Growth trajectories of the embryonic head were created with general additive models and linear mixed models were used to estimate associations with maternal periconceptional conditions as a function of GA and CRL, respectively.

MAIN RESULTS

A total of 303 3D-US images of 149 pregnancies were eligible for embryonic head measurements (intra-class correlation coefficients >0.99). Associations were found between embryonic HC and fetal HC ( ITALIC! ρ = 0.617, ITALIC! P < 0.001) and between embryonic HV and fetal HC ( ITALIC! ρ = 0.660, ITALIC! P < 0.001) in ITALIC! Z-scores. Maternal periconceptional smoking was associated with decreased, and maternal age and IVF/ICSI treatment with increased growth trajectories of the embryonic head measured by HC and HV (All ITALIC! P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

The consequences of the small effect sizes for neurodevelopmental outcome need further investigation. As the study population consists largely of tertiary hospital patients, external validity should be studied in the general population.

WIDER IMPLICATIONS OF THE FINDINGS

Assessment of growth trajectories of the embryonic head may be of benefit in future early antenatal care.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by the Department of Obstetrics and Gynaecology, Erasmus MC University Medical Centre and Sophia Foundation for Medical Research, Rotterdam, The Netherlands (SSWO grant number 644). No competing interests are declared.

[Sonomarkers: subtle ultrasound findings in the 20-week ultrasound examination, which have a low association with some chromosomal and non-chromosomal abnormalities in the fetus]

Currently all pregnant women residing in the Netherlands are offered second trimester ultrasound screening for the detection of fetal congenital structural abnormalities. This routine ultrasound examination takes place at 18 to 22 weeks' gestation. The ultrasound examination may yield soft markers, which are characterized by subtle morphological changes that are often transient and have little or no pathological significance. Soft markers are of interest because of their association with fetal congenital anomalies, in particular aneuploidy. This may create uncertainty for the pregnant woman and the care provider. Information can be found in the literature about the strength of the association of soft markers, when detected as an isolated finding, and the presence of fetal abnormalities. One or more soft markers are detected during routine ultrasound in approximately 5% of pregnant women. 4 markers (echogenic intracardiac focus, echogenic bowel, mild ventriculomegaly and shortened femur) are associated with Down syndrome. Given the low prevalence of Down syndrome in the general population and the relatively low strength of association with the syndrome, the positive predictive value of these markers is very low. The same is true for choroid plexus cysts, which are associated with trisomy 18. Apart from chromosomal abnormalities, some soft markers (echogenic bowel, mild ventriculomegaly and shortened femur) are also associated with non-chromosomal fetal abnormalities. Renal pyelectasis and the 2-vessel (instead of 3-vessel) umbilical cord are associated with non-chromosomal abnormalities only. It is recommended that pregnant women be informed about the nature and implications of these findings before the examination.

Using virtual reality for evaluation of fetal ambiguous genitalia

OBJECTIVE

The utility of a virtual reality system was examined in the visualization of three-dimensional (3D) ultrasound images of fetal ambiguous genitalia.

METHODS

In 2005, fetal ambiguous genitalia were diagnosed in four patients referred to our department for prenatal ultrasound assessment. The patients were examined by two-dimensional (2D) and 3D ultrasound and, subsequently, the volumes obtained on 3D ultrasound were visualized in the BARCO I-Space virtual reality system. This system projects stereoscopic images on three walls and the floor of a small 'room', allowing several viewers to see a 3D 'hologram' of the data being visualized. The results of 2D and 3D ultrasound examination and the virtual reality images of the I-Space were compared with diagnoses made postpartum.

RESULTS

In all cases, prenatal diagnosis was unclear based on 2D ultrasound alone. Surface rendering of 3D data provided an impression of ambiguity, but diagnosis based on these data proved incorrect at birth in three cases. Conclusions based on the evaluation of 3D volumes in virtual reality best fitted the postpartum diagnosis in all cases.

CONCLUSIONS

This study suggests that by evaluation of the genitals in the I-Space, a better impression of genital ambiguity can be established. Binocular depth perception appeared particularly useful in distinguishing either a micropenis or enlarged clitoris from labia minora, since it helps in the estimation of size and position. Therefore, we see potential for the application of virtual reality not only for the evaluation of fetal ambiguous genitalia, but in all those cases where depth perception would improve the visualization of anatomical structures.