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Screening for fetal anomalies

Screening for structural anomalies

  • Ultrasound screening for fetal anomalies should be routinely offered, normally between 18 weeks 0 days and 20 weeks 6 days
  • At the first contact with a healthcare professional, women should be given information about the purpose and implications of the anomaly scan to enable them to make an informed choice as to whether or not to have the scan. The purpose of the scan is to identify fetal anomalies and allow:
    • reproductive choice (termination of pregnancy)
    • parents to prepare (for any treatment/disability/palliative care/termination of pregnancy)
    • managed birth in a specialist centre
    • intrauterine therapy
  • Women should be informed of the limitations of routine ultrasound screening and that detection rates vary by the type of fetal anomaly, the woman's body mass index and the position of the unborn baby at the time of the scan
  • If an anomaly is detected during the anomaly scan pregnant women should be informed of the findings to enable them to make an informed choice as to whether they wish to continue with the pregnancy or have a termination of pregnancy
  • Fetal echocardiography involving the four-chamber view of the fetal heart and outflow tracts is recommended as part of the routine anomaly scan
  • Routine screening for cardiac anomalies using nuchal translucency is not recommended
  • When routine ultrasound screening is performed to detect neural tube defects, alpha-fetoprotein testing is not required
  • Participation in regional congenital anomaly registers and/or UK National Screening Committee-approved audit systems is strongly recommended to facilitate the audit of detection rates

Screening for Down's syndrome

  • All pregnant women should be offered screening for Down's syndrome. Women should understand that it is their choice to embark on screening for Down's syndrome
  • Screening for Down's syndrome should be performed by the end of the first trimester (13 weeks 6 days), but provision should be made to allow later screening (which could be as late as 20 weeks 0 days) for women booking later in pregnancy
  • The 'combined test' (nuchal translucency, beta-human chorionic gonadotrophin, pregnancy-associated plasma protein-A) should be offered to screen for Down's syndrome between 11 weeks 0 days and 13 weeks 6 days. For women who book later in pregnancy the most clinically and cost-effective serum screening test (triple or quadruple test) should be offered between 15 weeks 0 days and 20 weeks 0 days
  • When it is not possible to measure nuchal translucency, owing to fetal position or raised body mass index, women should be offered serum screening (triple or quadruple test) between 15 weeks 0 days and 20 weeks 0 days
  • Information about screening for Down's syndrome should be given to pregnant women at the first contact with a healthcare professional. This will provide the opportunity for further discussion before embarking on screening. Specific information should include:
    • the screening pathway for both screen-positive and screen-negative results
    • the decisions that need to be made at each point along the pathway and their consequences
    • the fact that screening does not provide a definitive diagnosis and a full explanation of the risk score obtained following testing
    • information about chorionic villus sampling and amniocentesis
    • balanced and accurate information about Down's syndrome
  • If a pregnant woman receives a screen-positive result for Down's syndrome, she should have rapid access to appropriate counselling by trained staff
  • The routine anomaly scan (at 18 weeks 0 days to 20 weeks 6 days) should not be routinely used for Down's syndrome screening using soft markers
  • The presence of an isolated soft marker, with the exception of increased nuchal fold, on the routine anomaly scan, should not be used to adjust the a priori risk for Down's syndrome
  • The presence of an increased nuchal fold (6 millimetres or above) or two or more soft markers on the routine anomaly scan should prompt the offer of a referral to a fetal medicine specialist or an appropriate healthcare professional with a special interest in fetal medicine

Screening for infections

Asymptomatic bacteriuria

  • Women should be offered routine screening for asymptomatic bacteriuria by midstream urine culture early in pregnancy. Identification and treatment of asymptomatic bacteriuria reduces the risk of pyelonephritis

Asymptomatic bacterial vaginosis

  • Pregnant women should not be offered routine screening for bacterial vaginosis because the evidence suggests that the identification and treatment of asymptomatic bacterial vaginosis does not lower the risk of preterm birth and other adverse reproductive outcomes

Chlamydia trachomatis

  • At the booking appointment, healthcare professionals should inform pregnant women younger than 25 years about the high prevalence of chlamydia infection in their age group, and give details of their local National Chlamydia Screening Programme
  • Chlamydia screening should not be offered as part of routine antenatal care


  • The available evidence does not support routine cytomegalovirus screening in pregnant women and it should not be offered

Hepatitis B virus

  • Serological screening for hepatitis B virus should be offered to pregnant women so that effective postnatal interventions can be offered to infected women to decrease the risk of mother-to-child transmission

Hepatitis C virus

  • Pregnant women should not be offered routine screening for hepatitis C virus because there is insufficient evidence to support its clinical and cost effectiveness


  • Pregnant women should be offered screening for HIV infection early in antenatal care because appropriate antenatal interventions can reduce mother-to-child transmission of HIV infection
  • A system of clear referral paths should be established in each unit or department so that pregnant women who are diagnosed with an HIV infection are managed and treated by the appropriate specialist teams


  • Rubella susceptibility screening should be offered early in antenatal care to identify women at risk of contracting rubella infection and to enable vaccination in the postnatal period for the protection of future pregnancies

Group B streptococcus

  • Pregnant women should not be offered routine antenatal screening for group B streptococcus because evidence of its clinical and cost effectiveness remains uncertain


  • Screening for syphilis should be offered to all pregnant women at an early stage in antenatal care because treatment of syphilis is beneficial to the mother and baby
  • Because syphilis is a rare condition in the UK and a positive result does not necessarily mean that a woman has syphilis, clear paths of referral for the management of pregnant women testing positive for syphilis should be established


  • Routine antenatal serological screening for toxoplasmosis should not be offered because the risks of screening may outweigh the potential benefits
  • Pregnant women should be informed of primary prevention measures to avoid toxoplasmosis infection, such as:
    • washing hands before handling food
    • thoroughly washing all fruit and vegetables, including ready-prepared salads, before eating
    • thoroughly cooking raw meats and ready-prepared chilled meals
    • wearing gloves and thoroughly washing hands after handling soil and gardening
    • avoiding cat faeces in cat litter or in soil

Screening for clinical conditions

Gestational diabetes

  • For guidance on assessing risk of gestational diabetes, see the section on risk assessment in the NICE guideline on diabetes in pregnancy


  • Blood pressure measurement and urinalysis for protein should be carried out at each antenatal visit to screen for pre-eclampsia
  • At the booking appointment, the following risk factors for pre-eclampsia should be determined:
    • age 40 years or older
    • nulliparity
    • pregnancy interval of more than 10 years
    • family history of pre-eclampsia
    • previous history of pre-eclampsia
    • body mass index 30kg/m2 or above
    • pre-existing vascular disease such as hypertension
    • pre-existing renal disease
    • multiple pregnancy
  • More frequent blood pressure measurements should be considered for pregnant women who have any of the above risk factors
  • The presence of significant hypertension and/or proteinuria should alert the healthcare professional to the need for increased surveillance
  • Blood pressure should be measured as outlined below:
    • remove tight clothing, ensure arm is relaxed and supported at heart level
    • use cuff of appropriate size
    • inflate cuff to 20–30 mmHg above palpated systolic blood pressure
    • lower column slowly, by 2 mmHg per second or per beat
    • read blood pressure to the nearest 2 mmHg
    • measure diastolic blood pressure as disappearance of sounds (phase V)
  • Hypertension in which there is a single diastolic blood pressure of 110 mmHg or two consecutive readings of 90 mmHg at least 4 hours apart and/or significant proteinuria (1+) should prompt increased surveillance
  • If the systolic blood pressure is above 160 mmHg on two consecutive readings at least 4 hours apart, treatment should be considered
  • All pregnant women should be made aware of the need to seek immediate advice from a healthcare professional if they experience symptoms of pre-eclampsia. Symptoms include:
    • severe headache
    • problems with vision, such as blurring or flashing before the eyes
    • severe pain just below the ribs
    • vomiting
    • sudden swelling of the face, hands or feet
  • Although there is a great deal of material published on alternative screening methods for pre-eclampsia, none of these has satisfactory sensitivity and specificity, and therefore they are not recommended

Preterm birth

  • Routine screening for preterm labour should not be offered

Placenta praevia

  • Because most low-lying placentas detected at the routine anomaly scan will have resolved by the time the baby is born, only a woman whose placenta extends over the internal cervical os should be offered another transabdominal scan at 32 weeks. If the transabdominal scan is unclear, a transvaginal scan should be offered

Fetal growth and well-being

  • Symphysis—fundal height should be measured and recorded at each antenatal appointment from 24 weeks
  • Ultrasound estimation of fetal size for suspected large-for-gestational-age unborn babies should not be undertaken in a low-risk population
  • Routine Doppler ultrasound should not be used in low-risk pregnancies
  • Fetal presentation should be assessed by abdominal palpation at 36 weeks or later, when presentation is likely to influence the plans for the birth. Routine assessment of presentation by abdominal palpation should not be offered before 36 weeks because it is not always accurate and may be uncomfortable
  • Suspected fetal malpresentation should be confirmed by an ultrasound assessment
  • Routine formal fetal-movement counting should not be offered
  • Auscultation of the fetal heart may confirm that the fetus is alive but is unlikely to have any predictive value and routine listening is therefore not recommended. However, when requested by the mother, auscultation of the fetal heart may provide reassurance
  • The evidence does not support the routine use of antenatal electronic fetal heart rate monitoring (cardiotocography) for fetal assessment in women with an uncomplicated pregnancy and therefore it should not be offered
  • The evidence does not support the routine use of ultrasound scanning after 24 weeks of gestation and therefore it should not be offered

© NICE 2016. Antenatal care for uncomplicated pregnancies. Available from: www.nice.org.uk/guidance/CG62. All rights reserved. Subject to Notice of rights.

NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication. 

First included: April 2016.