Diagnostic testing for Down syndrome screening or those women who have previously had a chromosomal abnormality or who carry a genetic disorder will be offered diagnostic testing, i.e. CVS or amniocentesis.

-CVS can be performed from 11 weeks of pregnancy. - the procedure is carried out transabdominally ,a transcervical (TC) route is needed. -complication of CVS : 1-miscarriage rate 2–3% 2-procedure-related loss rate is closer to 1% (though TC sampling risks are higher). result is at 1–2 days.

If this result shows no evidence of an extra chromosome 21 it can be taken as 99.9% certain that the fetus does not have trisomy 21. 3-placental mosaicism the culture result is available at 14–21 days. Amniocentesis can be performed after 15 weeks . The procedure-related loss rate 0.5%.

Rapid testing using PCR for trisomy 21 need 2–3 days A diagnosis of Down syndrome by using CVS or amniocentesis, but it cannot give certainty 1-the severity of the disorder 2- the quality of life of a particular individual. 3- Responses to a diagnosis will vary, according to - cultural, -social, -moral -religious beliefs.

Screening for haemoglobinopathies -linked with the newborn bloodspot screening programme, - tests for sickle cell disease and thalassaemia. -for families with genetic disorders -Haemoglobinopathies are inherited disorders of hemoglobin and are more prevalent in certain racial groups.

all pregnant women test for electrophoresis screening for haemoglobin and thalassaemia trait). -If the mother is found to be a haemoglobinopathy carrier, partner testing is then recommended and should be offered soon after the result is available. - Genetic ancestry is also important when interpreting screening results. -It is important to establish maternal iron levels when carrier status for thalassaemia is suspected.(e.g. alpha thalassaemia).

Most haemoglobinopathies are recessively inherited, so the fetus would have a 1 in 4 chance of inheriting the disorder and a 1 in 2 chance of being a carrier.

Pre-test information for antenatal haemoglobinopathy screening all women should receive the information booklet Screening tests for you and your baby as early in pregnancy as possible. The information should be provided in an appropriate language. Testing should be performed as early in pregnancy as possible, ideally at 8–10 weeks' gestation, as screening decisions are often gestation-dependent. -Women who book late in pregnancy should be offered haemoglobinopathy screening in the same way at the first point of contact.

when both parents are identified as carriers, they need urgent counseling. -referred trained midwife for specialist counseling or to the combined obstetric/hematology clinic at the booking hospital. - Diagnostic testing by CVS or amniocentesis should be offered. - All women will be offered neonatal blood spot screening at 5 days, which will detect sickle cell disease (but not other haemoglobinopathies).

Ultrasonography for fetal screening -a diagnostic imaging tool since the 1950s -all pregnant women should be offered two routine ultrasound scans. 1-an early pregnancy scan (usually timed to be able to perform the NT measurement 2- an 18–20 week fetal anomaly screening scan.

Action of Ultrasound -works by transmitting sound at a very high frequency, via a probe, in a narrow beam. -When the sound waves enter the body and encounter a structure, some of that sound is reflected back. -fluid does not reflect sound and appears as a black image. -bone reflects a considerable amount of sound and appears as white or echogenic.مولد للصدى -Many structures appear as different shades of grey. - pictures are transmitted in ‘real time’, which enables fetal movements to be seen

Safety aspect of ultra-sound -levels of exposure to ultrasound have increased in pregnancy. Although the technology is considered safe, -it should be used with respect and only when there is good indication, - care should be taken to limit Ultrasound is a diagnostic tool -u\s depends on the expertise of the operator and the quality of the machine. -As abnormalities may be missed or incorrectly diagnosed if the operator is inexperienced or inadequately trained

Women's experiences of ultrasound -women experience ultrasound as a pleasurable opportunity to have visual access to their unborn baby -ultrasound scans have been shown to increase psychological attachment to the fetus -Women tend to regard their scan as providing a general view of fetal well-being: -the fact that the fetus is alive, growing and developing. this reassurance is temporary and begins to wear off after a few weeks -Mothers may then seek other forms of reassurance (e.g. monitoring fetal movements, auscultation of the fetal heartbeat).

Scans may also cause anxiety, , particularly if there is a suspected or actual problem with the fetus. -The identification of fetal abnormality in the antenatal period has differing psychological effects for parents when the pregnancy is to continue.

Some parents have reported feeling grateful that they were able to prepare for the birth of a child with a disability -others have reported feelings of wishing they had not known about their child's problems before birth because this created a powerful image of the fetus as a ‘monster’. -It is necessary for midwives to be mindful of the powerful psychological effects ultrasound scans have on pregnant women and their families,

The midwife's role concerning ultrasound scans -mothers should be fully informed about the purpose of the scan. -Information should be given -Because of the pleasurable aspect of seeing the fetus, mothers undertake without prior discussion and consideration of potential consequences.

Ultrasound screening for fetal abnormality is a screening test and as such women should be counselled so that she can decide whether or not wish to undergo a procedure that may bring unwelcome news. -Women should also understand that a normal ‘scan’ does not guarantee normality in the baby.

De t e ct io n r a t e s f o r co m m o nly a sse sse d f e t a l a bno r m a lit ie s Anencephaly98% Open spina bifida90% Cleft lip75% Diaphragmatic hernia60% Gastroschisis98% Exomphalos( umbilical hernia )80% Serious cardiac abnormalities50% Bilateral renal agenesis84% Lethal skeletal dysplasia (defect ) bone tissue )60% Edw ards' syndrome (trisomy 18)95% Patau's syndrome (trisomy 13)95%

a midwife or counsellor should be available to discuss diffcult news. - Effective multidisciplinary team working and communication are therefore essential. -It is also good practice for the midwife to liaise with the primary healthcare team, who would normally carry out the majority of antenatal care. - Midwives explain and discuss these findings, both in hospital and in the community setting.

Thank you