Prenatal Screening Tests — First and Second Trimester

Our approach to screening

Screening is offered, not imposed. We explain the full menu of options, present the strengths and limitations of each, and respect the patient’s informed decision — including the decision not to screen. Where screening is positive, our follow-up pathway (counselling, diagnostic test discussion, multidisciplinary referral) is structured and unhurried.

First-trimester combined screening

NT scan (between 11+0 and 13+6 weeks) combined with maternal serum biomarkers (PAPP-A, free beta-hCG) gives the conventional combined risk for trisomy 21, 18, and 13. Performed to FMF standards.

NIPT (Non-Invasive Prenatal Test)

Cell-free fetal DNA testing from maternal blood. High sensitivity and specificity for the common trisomies. We explain the test’s limitations honestly — it is a screening test, not diagnostic, and positive results require confirmation by amniocentesis or CVS.

Anomaly scan as a screening modality

The second-trimester anomaly scan is the primary screen for structural conditions. The detection rates for major anomalies vary by structure and equipment; we publish realistic numbers, not aspirational ones.

Genetic screening + counselling

Where indicated by family history, ethnic background, or screening findings, more focused genetic counselling and testing pathways open. We integrate these with our fetal medicine practice.

Screening topics

Guidelines we follow

• ISUOG screening guidelines
• ACOG / RCOG / FIGO consensus on prenatal screening
• NIPT clinical implementation guidance

Where this fits

Screening sits alongside scans. Positive screening results may direct toward invasive procedures for diagnostic confirmation, with discussion of the conditions involved.