Chapter three

Some congenital anomalies are detectable during pregnancy and others are not. Screening is offered by NHS maternity services to maximise antenatal detection of specified conditions where women choose, and present in time. NCARDRS provides a separate annual audit of the NHS Fetal Anomaly Screening Programme (FASP) to PHE and to individual NHS providers of maternity services to monitor the performance of this screening.

NCARDRS recognises that women make a personal informed decision whether to have fetal anomaly screening or not. Early diagnosis of a congenital anomaly (as early as possible in the pregnancy) gives women and their partners greater choice about their pregnancy, and enables better planning for the delivery of babies where specialist intervention or palliative care may be required soon after birth.

In this chapter, the timing of diagnosis relates to the first anomaly diagnosed in a baby and so is designated at a case-level. Other anomalies in a baby may be identified at a later stage, and where there are multiple anomalies, the timing of diagnosis of all these subsequently diagnosed anomalies will be when the baby was first suspected as having a congenital anomaly. For example, in a baby with a congenital heart anomaly that was detected antenatally and a digestive anomaly detected postnatally, the timing of diagnosis for the baby (and for both conditions) would be antenatal.

The timing of first diagnosis of a congenital anomaly was known for 12,674 (95.0%) babies. Where the timing of diagnosis was known, 68.0% of babies were diagnosed antenatally in 2019. Table 4 shows that of the 8,616 babies where a congenital anomaly was diagnosed antenatally, 5,154 (59.8%) were born alive and 3,221 (37.4%) resulted in termination of pregnancy for fetal anomaly (TOPFA). It also shows that where a congenital anomaly was first diagnosed in a baby postnatally, 98.2% were diagnosed following a live birth.

Figure 6 shows that where a baby was live born with a congenital anomaly, an anomaly was detected antenatally in 52.8% of cases. This may be an over estimate as anomalies diagnosed postnatally are more difficult to ascertain. Where a baby was stillborn with a congenital anomaly, an anomaly had been detected antenatally in 82.3% of cases.

Figure 6

Timing of first diagnosis and pregnancy outcome (percentage) in England, 2019. The data in this chart can be found in table 4.

Identification of any congenital anomaly-if there are multiple anomalies than this will be the first anomaly detected.

Some types of congenital anomalies are more likely to be diagnosed antenatally than others. Figure 7 shows that babies with abdominal wall, skeletal dysplasia, and nervous system anomalies are most frequently identified antenatally. Babies with genital anomalies are unlikely to be identified antenatally. It should be noted that individual anomalies within these subgroups may not follow these patterns, and also that diagnosis refers to the first suspicion of any anomaly in a baby, and babies with more than one anomaly will be represented in each applicable bar. A more detailed breakdown by specific congenital anomaly, including the number of babies reported, is available in Table 5.

Figure 7

Timing of diagnosis by congenital anomaly subgroup – based on individual anomaly (percentage) in England, 2019. The data in this chart can be found in table 5. Identification of any congenital anomaly-if there are multiple anomalies than this will be the first anomaly detected.

The overall rate of TOPFA for England was 52.5 per 10,000 total births. Table 6 shows that the rate of TOPFA at over 20 weeks gestation was 17.3 per 10,000 total births.

Figure 8 shows that the highest rate of termination of pregnancy with fetal anomaly (TOPFA) was associated with chromosomal anomalies (26.4 per 10,000 births) followed by nervous system conditions (13.7 per 10,000 births). In most babies with chromosomal, nervous system or abdominal wall anomalies that resulted in TOPFA, this was performed before 20 weeks gestation. This outcome is likely to be associated with timing of diagnosis as these conditions are more likely to be diagnosed earlier in the pregnancy. For congenital heart anomalies, the TOPFA rate is higher after 20 weeks gestation than before 20 weeks gestation. Where congenital heart anomalies are diagnosed antenatally, a heart anomaly is often first suspected at the fetal anomaly scan, which takes place at around 20 weeks gestation. Women are then offered referral to a tertiary service provider for specialist confirmation of the specific heart anomalies present.

It is important to note that in Figure 8 babies with multiple anomalies will be represented in each applicable bar. For example, a baby with an oro-facial cleft or limb condition may also have had an associated chromosomal or cardiac condition. More information about the anomalies included in these sub-groups is available in the technical details section.

Figure 8

Prevalence (per 10,000 total births) and 95% confidence intervals of termination of pregnancy with fetal anomaly (TOPFA) in England, 2019. The data in this chart can be found in table 6.