This scan, also called “the 20-week ultrasound” (most likely performed when you’re 18 to 22 weeks pregnant) will check your baby’s morphology, in other words, the baby’s body structures. This time, the sonographer will not measure the nuchal translucency (the accumulation of fluid in the nape of the fetus). This detailed ultrasound makes it possible for the technician and your doctor to analyze the baby’s heart (the four chambers), head, spine, face (whether or not there is a cleft lip/palate), arms and legs, the size of bones and internal organs such as the stomach and kidneys. If you have not yet been able to find out your baby’s birth sex, during this ultrasound, it will be hard to miss – unless the baby is in a position where the genitals are hidden.
If everything checks out ok during this scan, it is very unlikely for the child to be born with any syndromes or malformations. However, if anything seems to be atypical, further tests may be requested to confirm a diagnosis. During the 20-week scan, the sonographer also checks the placenta, the volume of amniotic fluid, the umbilical cord, and uterine arteries.
Glycemia Measurement, Glucose Screening, and Glucose Tolerance Test
Around your 24th week of pregnancy, your blood sugar will be tested. It starts with glycemia measurement when you get your blood drawn for a regular blood test.
Then there is the glucose screening, you will be asked to drink a syrup-like solution, after an hour, a blood sample will be taken, and glucose level analyzed to determine the probability for gestational diabetes. Depending on what the test reveals, you will undergo a Glucose Tolerance Test – after fasting overnight and drinking a syrupy solution with a higher dose of glucose; your blood will be sampled every half an hour over a period of time and tested for abnormal levels of glucose.
It works like a regular ultrasound, but this test specifically observes the structures of the fetus’s heart and how it is functioning, making sure it all checks out according to what’s expected of a healthy heart.
Specific target tests
In special cases or high-risk cases, your Ob-Gyn may ask for some of the following:
· Amniocentesis: the genetic testing can be offered to older moms (usually over 35) or when a high risk of certain conditions is suspected. It can be done as soon as week 15. Amniocentesis is a procedure in which amniotic fluid is removed from the uterus for detecting tube defects and a wide range of chromosomal abnormalities such as Down Syndrome.
· Chorionic Villus Sampling (CVS): prenatal test that involves taking a sample of tissue from the placenta to test for genetic problems. The test can be done as early as ten weeks of pregnancy.
· Cardiotocography (CTG): it monitors the fetal heart and contractions of the uterus to establish whether the fetus is under stress.
· Fetal and placenta doppler ultrasound: it measures blood circulation in the placenta.
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