Do Fetal Biometrics Predict Toddler Measures of Autistic Traits or Language Development?

Background: The prenatal period is a critical time for development. To date, research has not examined differences in fetal development beyond using the standard measures taken during the ultrasound scan. This is largely due to research being conducted retrospectively, using measures taken at the time of birth or using growth measures from medical ultrasounds. In the Cambridge Ultrasound Project (CUSP) we prospectively measured not just standard fetal markers of fetal growth but also a novel fetal biomarker, anogenital distance (AGD) since this is correlated with prenatal androgen exposure, and androgens are elevated in pregnancies where the fetus is diagnosed with autism postnatally.

Objectives: To test whether markers for fetal growth and novel biomarkers, including AGD, predict autistic traits and language development between 18-20 months of age.

Methods: The sample comprised 150 singleton pregnancies. At the time of abstract submission, 50 of these had completed data (28 males, 22 females). Prenatal ultrasounds were conducted from a research ultrasound between 26-30 weeks pregnancy using a GE 8 Expert Ultrasound system. Fetal head circumference (HC), cerebellum width, and ventricular atrium (VA) measures were taken. HC and cerebellum width were standardised according to UK fetal biometry reference charts. Additionally, anogenital distance (AGD) was measured from the centre of the anus to the base of the scrotum in males, and to the posterior convergence of the fourchette in females. For AGD no biometry reference charts exist, therefore a composite score was created controlling for estimated fetal weight (EFW) for AGD to standardise this measure. Parents were asked to complete the Quantitative Checklist for Autism in Toddlers (Q-CHAT) online when their infant was between 18- and 20-months old, along with the Communication Development Inventory (CDI) as a measure of vocabulary development. Standardised fetal biometry scores were examined against Q-CHAT and CDI scores at 18-20 months. Analysis was carried out separately for each growth parameter and sex. By the Spring, all 150 participants’ complete data will be available.

Results: There was currently no significant effect of fetal biomarkers measured between 26-30 weeks gestation, including AGD on Q-CHAT or CDI at 18-20 months.

Conclusions: These preliminary findings suggest there is no association between fetal physical developmental and toddler measures of autistic traits or language development. This may be because the sample is currently underpowered, but the current data is only about one third of the final sample. Complete data will be reported in the poster as the infants turn 18 months. This study will continue to follow these infants’ development until they are 24-months old to observe subsequent physical and behavioural development and re-administer the Q-CHAT at this time.