From: Antenatal screening and its possible meaning from unborn baby's perspective
Type of test | Detectable conditions | Stage of pregnancy |
---|---|---|
Invasive: mother only | Â | Â |
MSAFP | Â | Â |
Estimation of maternal serum | Neural tube defects; Down's | 16th-18th week. |
alphafetoprotein in maternal | syndrome. | Â |
blood. | Â | Â |
Combined maternal blood | Â | Â |
test | Â | Â |
Estimation of MSAFP, chorionic | Down's syndrome. | 16th-18th week. |
gonadotropin and/or | Â | Â |
unconjugated oestriol. | Â | Â |
Invasive: both fetus and | Â | Â |
mother | Â | Â |
Amniocentesis | Â | Â |
A test involving the insertion, | Chromosomal disorders; a | 12th-14th week. |
through the mother's abdomen, | number of hereditary disorders | Â |
of a fine needle into the | caused by a single gene; neural | Â |
amniotic sac and the removal of | tube disorders. | Â |
amniotic fluid. | Â | Â |
Chorion biopsy | Â | Â |
A test involving the introduction | Chromosomal disorders; a | 8th-12th week. |
through the mother's vagina or | number of hereditary disorders | Â |
abdomen of a needle into the | caused by a single gene. | Â |
womb and the removal of tissue | Â | Â |
surrounding the fetus. | Â | Â |
Fetoscopy | Â | Â |
A test involving the introduction | Chromosomal disorders; | 16th-18th week. |
through the mother's abdomen | disorders detectable by fetal | Â |
of an instrument enabling the | blood sampling; malformations. | Â |
examiner to see the fetus. | Â | Â |
Cordocentesis | Â | Â |
A test involving the insertion of | Chromosomal disorders; | 15th week |
a needle through the mother's | disorders detectable by fetal | onwards. |
abdomen (where the umbilical | blood sampling. | Â |
cord of the fetus is attached to | Â | Â |
the placenta) and then the | Â | Â |
removal of fetal blood. | Â | Â |
Non-invasive | Â | Â |
Ultrasound scan | Â | Â |
An instrument is passed over | Fetal growth and development; | Any time but often |
the mother's bare abdomen | multiple pregnancy; | about the 16th |
and a picture of the fetus is | malformations, including neural | week to check |
produced on a screen. | tube defects. | dates and |
 |  | development. |
Radiography | Â | Â |
The mother's abdomen is X- | Skeletal abnormalities requiring | 20th week |
rayed. This is hardly ever done | a picture of the whole skeleton. | onwards. |
today. | Â | Â |