History

Fact Explanation
Increased maternal age [1] The probability of chromosomal anomalies increases with maternal age. Around half of chromosomal anomalies are accounted for by trisomy 21 (Down syndrome) [1]
abnormal result from non-invasive screening [2] Abnormal results from measuring alpha fetoprotein (AFP), HCG and free estriol (triple test or quadruple test (Inhibin A, when added to the triple test, yields the so-called quadruple test ) [2]
Abnormal ultrasound finding which raises the possibility of a chromosomal / genetic problem [2] Sonographic measurement of nuchal lucency , ultrasonographic evidence of congenital anomaly [1]
chromosomal anomaly in an existing child of the couple’s [2] For example, after the birth of a child with free trisomy, the risk of a numerical chromosomal abnormality is increased by 1% for each subsequent child compared to other parents of the same age [2]
References
  1. TODROS T, CAPUZZO E, GAGLIOTI P. Prenatal diagnosis of congenital anomalies Images Paediatr Cardiol [online] 2001, 3(2):3-18 [viewed 29 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232499
  2. WIEACKER P, STEINHARD J. The Prenatal Diagnosis of Genetic Diseases Dtsch Arztebl Int [online] 2010 Dec, 107(48):857-862 [viewed 29 August 2014] Available from: doi:10.3238/arztebl.2010.0857

Examination

Fact Explanation
Reduced symphisio fundal height [1] A fetus with congenital abnormality / genetic disorder is a high-risk pregnancy.There is an increased risk of intra uterine growth retardation (IUGR) [1]
References
  1. TODROS T, CAPUZZO E, GAGLIOTI P. Prenatal diagnosis of congenital anomalies Images Paediatr Cardiol [online] 2001, 3(2):3-18 [viewed 29 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232499

Differential Diagnoses

Fact Explanation
Pregnancy induced hypertension [1] Patients may have reduced symphisio fundal height due to intra uterine growth restriction caused by abnormalities in placentation. High maternal blood pressure. Ultra sound scan will be normal other than reduction in the size of the fetus [1]
References
  1. 1) LEEMAN L, FONTAINE P. Hypertensive disorders of pregnancy. Am Fam Physician [online] 2008 Jul 1, 78(1):93-100 [viewed 18 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18649616

Investigations - for Diagnosis

Fact Explanation
Ultra sound scan [1] Most structural anomalies are increasingly detected with advancing gestation. In early pregnancy, it is possible to recognise with confidence certain types of fetal malformations, like anencephaly, which can be reliably diagnosed at 10-14 weeks of pregnancy. Ultrasound screening for fetal structural abnormalities is generally recommended at 19-21 weeks of gestational age. The accuracy in detecting malformations by ultrasound, however, shows great variability among centres and operators. omphalocele and limb anomalies are also definable using ultrasound in the first trimester, while other structural anomalies, like urinary tract abnormalities, are detectable later in pregnancy. [1]
Amniocentesis [2] Amniocentesis is typically carried out under ultrasonographic control, between 15 and 17 weeks of pregnancy. The procedure specific risk is 0.5% to 1% . Chromosomal analysis requires prior cell culture, which takes on average two weeks. chromosomes are analyzed numerically and structurally. information can be obtained regarding numerical abnormalities of chromosomes 13, 18 and 21, and the X and Y chromosomes [2]
Chorionic villus sampling (CVS) is typically performed in the 11th to 12th weeks of pregnancy [2] Chorionic villus sampling (CVS) is typically performed in the 11th to 12th weeks of pregnancy. Chromosome analysis is carried out either as a direct preparation or following brief culture (1 day) as well as after full culture (7 to 10 days). [2]
Cordocentesis [2] The commonest indications are suspected fetal anemia in association with rhesus disease, parvovirus B19 infection, or fetal hydrops. Cordocentesis can also be used for rapid karyotyping or molecular genetic diagnosis from 16 to 20 weeks, depending on indication. Cordocentesis is important where a rapid result is needed late in pregnancy, for example in the presence of ultrasonographically detected anomalies or severe growth restriction, which may point to a chromosomal abnormality. [2]
References
  1. TODROS T, CAPUZZO E, GAGLIOTI P. Prenatal diagnosis of congenital anomalies Images Paediatr Cardiol [online] 2001, 3(2):3-18 [viewed 29 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232499
  2. WIEACKER P, STEINHARD J. The Prenatal Diagnosis of Genetic Diseases Dtsch Arztebl Int [online] 2010 Dec, 107(48):857-862 [viewed 29 August 2014] Available from: doi:10.3238/arztebl.2010.0857

Investigations - Fitness for Management

Fact Explanation
Maternal serum alpha-fetoprotein (AFP) [1] Identifying neural tube defects may ideally involve ultrasound examination in conjunction with maternal serum alpha-fetoprotein screen. In the presence of a raised AFP level, acetylcholinesterase is measured as a marker of neural tube defects [1]
Fetal echocardiography [1] Should be performed in groups selected on the basis of patient history and sonographic anomalies or markers, including extracardiac anomalies, maternal diabetes, infection, suspicious scan on screening, chromosomal aberrations. Fetuses with diagnosed extracardiac anomalies should be evaluated with fetal echocardiography because the detection of a cardiac anomaly may dramatically affect prognosis [1]
References
  1. TODROS T, CAPUZZO E, GAGLIOTI P. Prenatal diagnosis of congenital anomalies Images Paediatr Cardiol [online] 2001, 3(2):3-18 [viewed 29 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232499

Investigations - Followup

Fact Explanation
Magnetic resonance imaging [1] Help to investigate specific anomalies, such as agenesis of corpus callosum, posterior fossa cysts, cerebral cleft, migrational disorders such as lissencephaly. Use of magnetic resonance imaging is nonetheless uncommon in clinical practice, being restricted to specific indications [1]
Serial ultra sound scans [1] A fetus with congenital abnormality / genetic disorder is a high-risk pregnancy on many levels.There is an increased risk of intra uterine growth retardation (IUGR), fetal death, and premature delivery, so careful obstetric follow-up with serial ultrasounds are required to assure fetal well being [1]
References
  1. TODROS T, CAPUZZO E, GAGLIOTI P. Prenatal diagnosis of congenital anomalies Images Paediatr Cardiol [online] 2001, 3(2):3-18 [viewed 29 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232499

Investigations - Screening/Staging

Fact Explanation
Fetal cardiac ultrsound [1] Ultrasound screening for fetal cardiac malformations is part of routine ultrasound screening at 19-21 weeks. the detection is only 40% of fetuses with complex heart disease; most missed cardiac lesions commonly involve outflow tract anomalies such as complete transposition, common arterial trunk, and aortic coarctation or minor anomalies such as atrial septal defects (septum secundum), small ventricular septal defects, mild pulmonary or aortic stenosis [1]
Triple test & quadruple test [2] Alpha-fetoprotein (AFP), unconjugated estriol and human chorionic gonadotropin (hCG) are the serum markers most widely used to screen for Down syndrome. This combination is known as the “triple test” or “triple screen.” AFP is produced in the yolk sac and fetal liver. Unconjugated estriol and hCG are produced by the placenta. The maternal serum levels of each of these proteins and of steroid hormones vary with the gestational age of the pregnancy. With trisomy 21, second-trimester maternal serum levels of AFP and unconjugated estriol are about 25 percent lower than normal levels and maternal serum hCG is approximately two times higher than the normal hCG level. The triple test is usually performed at 15 to 18 weeks of gestation. [2] Inhibin A, when added to the triple test, yields the so-called quadruple test [1]
Ultra sound scan [2] Ultrasound measurement of nuchal translucency has been studied alone and in combination with new biochemical markers as a potentially useful first-trimester screening test for trisomy 21. Estimates are that first-trimester screening by means of maternal age and measurement of nuchal translucency could provide a trisomy 21 detection rate of 63 percent, with a 5 percent false-positive rate [2]
References
  1. TODROS T, CAPUZZO E, GAGLIOTI P. Prenatal diagnosis of congenital anomalies Images Paediatr Cardiol [online] 2001, 3(2):3-18 [viewed 29 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232499
  2. NEWBERGER DS. Down syndrome: prenatal risk assessment and diagnosis. Am Fam Physician [online] 2000 Aug 15, 62(4):825-32, 837-8 [viewed 29 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/10969860

Management - General Measures

Fact Explanation
Genetic counselling in prenatal diagnosis [2] -Presentation of the background risk of congenital disease and anomaly, and individual increased risks (for example increased maternal age) -The options and limitations for prenatal genetic diagnosis -Possible diseases which can be detected -Risks associated with the relevant tests -Conflictual areas in relation to prenatal diagnosis -Alternatives. [2]
References
  1. NEWBERGER DS. Down syndrome: prenatal risk assessment and diagnosis. Am Fam Physician [online] 2000 Aug 15, 62(4):825-32, 837-8 [viewed 29 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/10969860

Management - Specific Treatments

Fact Explanation
Surgical management - gastroschisis and omphalocele [1] In gastroschisis and omphalocele, the ultimate goals are to reduce the herniated viscera into the abdomen and to close the fascia and skin to create a solid abdominal wall with a relatively normal umbilicus while minimizing risks to the baby.This is achieved by specific surgical techniques [1]
Congenital heart defects - prostaglandin infusion, surgical management [2] early communication with a specialist cardiac centre. Often the infant with a duct dependent lesion will improve greatly once ductal patency has been achieved with prostaglandin infusion. Surgical methods are done shortly after birth ( eg:Correcting transposition of the great vessels ) or can be done later in life (eg: atrial septal defect) [2]
References
  1. LEDBETTER DANIEL J.. Gastroschisis and Omphalocele. Surgical Clinics of North America [online] 2006 April, 86(2):249-260 [viewed 29 August 2014] Available from: doi:10.1016/j.suc.2005.12.003
  2. PENNY D J. Management of the neonate with symptomatic congenital heart disease. [online] 2001 May, 84(3):141F-145 [viewed 29 August 2014] Available from: doi:10.1136/fn.84.3.F141