Antenatal screening

Wald NJ, Rodeck C, Hackshaw AK, Walters J, Chitty L, Mackinson AM (2003) First and second trimester antenatal screening for Down s syndrome the results of the Serum, Urine and Ultrasound Screening Study (SURUSS) J Med Screen 10 56-104... 

Determination of AFP levels in amnio tic fluid or maternal serum is used for antenatal screening for certain birth defects and chromosomal abnormafities in the fetus (see Chapter 54). Elevated maternal serum AFP indicates the possibility of a neural tube or open abdominal wall defect in the fetus. The levels may also be elevated with multiple fetuses, low birth weight, fetal demise, and incorrect estimation of gestational age. Trisomy 21 (Down syndrome) and trisomy 18 are associated with low maternal serum AFP levels. AFP is also used as a marker for hepatocellular and germ cell carcinomas. For a discussion of the role of AFP as a tumor marker, see Chapter 23. 

Wald NJ, Cuckle H, Brock JH, Peto R, Polani PE, Woodford FP. Maternal serum-alpha-fetoprotein measurement in antenatal screening for anencephaly and spina bifida in early pregnancy. Report of U.K. collaborative study on alpha-fetoprotein in relation to neural-tube defects. Lancet 1977 1(8026) 1323-32. 

Wald NJ, Cuckle HS, Densem JW, Nanchahal K, Canick JA, Haddow JE, et al. Maternal serum unconjugated oestriol as an antenatal screening test for Down s syndrome. Br J Obstet Gynaecol 1988 95 334-41. 

A. Wald NJ, Hackshaw AK, George LM. Assay precision of serum alpha fetoprotein in antenatal screening for neural tube defects and Down s syndrome. J Med Screen 2000 7 74-7. Erratum in J Med Screen 2000 7 168. 

Wald NJ, Hutdy WJ> Hackshaw AK. Antenatal screening for Down s syndrome with the quadruple test. Lancet 2003 361 835-6. 

In many localities, newborn screening has become standard for this disorder, which in the general population has an approximate incidence of 1/250,000 live births. Carrier detection is possible, either by measurement of enzymatic activity in cultured fibroblasts or by study of restriction endonuclease fragments of DNA. Antenatal testing is also available. 

A. Wald NJ, Hackshaw A. Alternative methods of estimating risk and determining detection and falsepositive rates. In Wald NJ, Leek I, eds. Antenatal and neonatal screening. Oxford, England Oxford University Press, 2000 34-5. 

Antenatal hepatitis B screening for all pregnant women followed by active and passive immunization of all infants bom to HBsAg positive mothers is recommended. This procedure has a success rate of 90-97% and also provides long-lasting immunity, as mentioned by Lok 2002 and Marion et al. 1994. 

Figure 49.2 Urinary iodine (UI) excretion in first-trimester women recruited for a controlled antenatal thyroid screening study. The figure shows random spot UI measurements in 643 women from Wales, UK, studied at 11-15 weeks gestation. Numbers on top of columns indicate % of total. Note that only about 41 % of women appear to excrete an amount of iodine consistent with the recommended daily intake in pregnancy.

Ray JG, Vermeulen MJ, Meier C, Wyatt PR Risk of congenital anomalies detected during antenatal serum screening in women with pregestational diabetes. QJM 2004 97 651-653. 

Lazarus JH, Bestwick JP, Channon S, Paradice R, Maina A, Rees R, et al. Antenatal thyroid screening and childhood cognitive function. N Engl J Med 2012 366(6) 493-501. 

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