Appendix one: Glossary of terms

Term

Definition

Amniocentesis

Antenatal procedure involving the removal of a sample of amniotic fluid for the purposes of chromosomal or genetic testing.

Antenatal

The period from conception to birth.

Antenatal diagnosis

A diagnosis made in a live fetus at any gestation.

Birth prevalence

The total number of babies diagnosed with a congenital anomaly (live births, stillbirths, late miscarriages, and terminations of pregnancy for fetal anomaly) compared to the total number of births (live births and stillbirths).

Births or total births

Live births and stillbirths as recorded by the Office for National Statistics

Case ascertainment

Proportion of notifications of congenital anomalies reported to NCARDRS out of all cases of congenital anomaly in the population.

Chorionic villus sampling (CVS)

Antenatal procedure involving the removal of a sample of placental tissue for the purposes of chromosomal or genetic testing.

Confidence interval (see Technical Guidance document for more information)

Expresses the uncertainty of a statistic as a range in which the true value would be expected to be found on repeat sampling.

Congenital anomaly

Present at delivery, probably originating before birth, and includes structural, chromosomal, genetic, and biochemical anomalies.

Congenital hydronephrosis

An obstruction of the urinary flow from kidney to bladder. Cases are registered where the renal pelvis measurement is ≥10 mm after birth as defined by EUROCAT.

Estimated date of delivery (EDD)

The estimated delivery date of a pregnancy, calculated as 40 weeks gestation.

EUROCAT

European Surveillance of Congenital Anomalies – European network of population-based registries for the epidemiological surveillance of congenital anomalies.

NHS Fetal Anomaly Screening Programme (FASP)

NHS screening for specified structural and chromosomal anomalies during pregnancy using laboratory and/or ultrasound tests.

FASP conditions

The 11 auditable conditions screened under the Fetal Anomaly Screening Programme (FASP) are:

• Anencephaly (Q00*)

• Spina bifida (Q05*)

• Transposition of great arteries (Q20.3)

• Atrioventricular septal defect (Q21.2*)

• Tetralogy of Fallot (Q21.3, Q21.82)

• Hypoplastic left heart (Q23.4)

• Cleft lip +/- palate (Q36*, Q37*)

• Bilateral renal agenesis (Q60.1)

• Lethal skeletal dysplasia (Q77.0*, Q77.1, Q77.2, Q77.8*, Q78.0*)

• Congenital diaphragmatic hernia (Q79.0*)

• Exomphalos (Q79.2)

• Gastroschisis (Q79.3)

• Trisomy 21 (Q90*)

• Trisomy 18 and Trisomy 13 (Q91*)

Fetal medicine

Sub-speciality of antenatal care focused on high-risk pregnancies including those with a congenital anomaly.

Feticide

A procedure to stop the fetal heart and cause the demise of the fetus in the uterus as defined by the Royal College of Obstetricians and Gynaecologists.

Full karyotype

Visual inspection of all chromosomes down the microscope, enabling assessment of chromosome number and integrity.

Genetic anomalies

Includes chromosomal anomalies, skeletal dysplasias, genetic syndromes and microdeletions as defined by EUROCAT.

Hospital Episode Statistics (HES)

Database of all admissions, A&E attendances, procedures, and outpatient appointments at NHS hospitals in England.

Infant deaths

Deaths from birth to under 1 year of age as recorded by Child and infant mortality data from the ONS

Infant mortality

The number of infant deaths per 10,000 live births.

Invasive testing

Antenatal tests including amniocentesis and chorionic villus sampling used to diagnose chromosomal and genetic anomalies. In these tests, a needle is inserted directly into the uterus to take a sample.

Late miscarriage

Late fetal deaths from 20 to 23 completed weeks of gestation.

Live birth

A baby showing signs of life at birth as recorded by the Office for National Statistics

Live birth prevalence

The total number of babies diagnosed with a congenital anomaly that are live born compared to the total number of live births.

Major congenital anomaly subgroup (see Technical Guidance section for more information on these subgroups)

The high-level body system and anomaly type groupings of congenital anomalies as defined by EUROCAT.

National Down Syndrome Cytogenetic Register (NDSCR).

The NDSCR collected cytogenetic or DNA reports of trisomies 21, 18 and 13, and their cytogenetic variants, occurring in England and Wales between 1989 and April 2015, when this function was transferred to NCARDRS.

Non-genetic anomalies

Includes anomalies with no known genetic cause. Not all babies undergo genetic testing, so it is likely that some of these anomalies are of genetic origin.

Non-invasive prenatal testing (NIPT)

Screening test for specific chromosomal disorders by testing fragments of fetal DNA found in the maternal blood stream.

Office for National Statistics (ONS)

Body responsible for collection and production of statistics related to the economy, population, and society of the UK.

Outcome of pregnancy

Outcome of the end of the pregnancy, as distinct to the registerable nature of the birth. Still births or live births preceded by a termination are categorised as a termination. Medical care for a condition focusing on relief of symptoms rather than treating the underlying condition.

Palliative care

Medical care for a condition focusing on relief of symptoms rather than treating the underlying condition.

Perinatal deaths

Stillbirths and deaths under 7 days of age as recorded by the Office for National Statistics.

Perinatal mortality

The number of perinatal deaths per 10,000 total births.

Post-neonatal period

From 28 days of life to 1 year of age.

Rapid aneuploidy testing

A genetic test with a short turnaround time; it counts the copy number of specific regions on chromosomes 13, 18, 21, X and Y.

Rare Diseases

Non-cancerous, usually non-infectious diseases that affect <1:2000 in the population at risk with an Orphanet Rare Disease classification.

Severe congenital heart disease (CHD)

This includes the following congenital heart anomalies:

•common arterial truncus

•transposition of great vessels

•single ventricle

•atrioventricular septal defect

•tetralogy of Fallot

•tricuspid atresia and stenosis

•Ebstein’s anomaly

•pulmonary valve atresia

•aortic valve atresia/stenosis

•hypoplastic left heart

•hypoplastic right heart

•coarctation of aorta

•total anomalous pulmonary venous return

Severe microcephaly

Where the head circumference is less than – 3 standard deviations for sex and gestational age as defined by EUROCAT.

Stillbirths

A baby born after 24 or more completed weeks of gestation and which did not, at any time, breathe or show signs of life as recorded by the Office for National Statistics.

Statistical significance (see Technical details document for more information)

Statistical testing is undertaken by comparing the confidence intervals to see if they overlap – with non-overlapping confidence intervals being considered as statistically significantly different.

Teratogen

Substance or other factor that can cause congenital anomaly by affecting fetal development.

Termination of pregnancy for fetal anomaly (TOPFA)

Term used to describe the deliberate ending of a pregnancy with the intention that the fetus will not survive and which is carried out when the fetus is diagnosed prenatally as having a major congenital anomaly.

This includes terminations of pregnancy for fetal anomaly as well as terminations of pregnancy for other medical reasons where a fetal anomaly was present.

Where a pregnancy ends in a TOPFA, the baby may be born dead, or if parents have not opted for prior feticide, the baby may be born alive but die shortly after. Depending on the gestation at which a TOPFA takes place (before or after 24 weeks), it may also be registered as a stillbirth.

Tertiary service

A hospital which provides specialist care following referral from a local provider, this may include antenatal or postnatal specialities.

Total births

Total number of live births and stillbirths.