Pre-natal tests can reveal potential problems early so that steps can be taken to ensure a healthy outcome for you and your child. Some screening and diagnostic tests can be done to determine if your child is at risk of certain chromosomal anomalies.
The most common tests include:
- Blood Type: and the presence of antibodies to the Rhesus factor, as problems can occur if the mother has antibodies to the fetal blood, in particular antibody to the Rhesus factor.
- Haemoglobin levels (CBC): helps in the diagnosis of anaemia, a complication of pregnancy that occurs as a result of iron deficiency. It can increase the risk of low birth weight and premature birth. Also, can cause problems if you bleed too much during delivery. It is addressed by a therapeutic dose of iron.
- Test for syphilis (RPR): this is a sexually transmitted disease, often with no symptoms and needs to be treated to prevent transmission of the disease to the child.
- Immunity to rubella screening (IgG): to check if you are immune to German Measles. If you don’t have immunity you should get a vaccine once the child is born while using contraception.
- Hepatitis C virus (HbsAg): to check if you are infected, if this is positive you and the fetus needs treatment.
Blood Pressure Checks
At each antenatal visit all pregnant women should have their blood pressure checked. A rise in blood pressure can be an indication of serious complications for you and the baby. Early discovery and treatment is a necessity. It is unlikely to be diagnosed unless you have regular Blood pressure checks as a rise is without symptoms usually.
At each visit the urine should be checked for glucose for diabetes, protein for the renal function and nitrites for signs of infection.
Between the 24th and 28th week of pregnancy a blood test will be taken after you drink a solution containing 50 grams of glucose. An abnormal glucose level may indicate that the body isn’t producing enough insulin and you may need more testing to see if you have gestational diabetes (diabetes associated with pregnancy).
Examination of Group B Streptococcus GBS
Group B strep is an infection that may be lurking in the vagina or rectum. Samples can be done between the 5th and 37th week of pregnancy, they are taken from the vagina, rectum and perineum, then examined in the lab. If present during delivery it may pass to the fetus, causing severe life threatening pneumonia. If there is a positive test, you will be treated with antibiotics during labour to prevent transmission to the baby.
An ultrasound test is where the doctor uses a handheld device called a transducer, which uses sound waves that the computer translates into video and produces images of the baby.
1st Trimester Ultrasound Screening
Done between 11 wks +6 days and 13 wks +6 days. The aim of this examination is to confirm viability of the fetus, and the basic structure (not detailed anatomy that is done at 18-20 weeks ).
The test can then also be used as a screening technique for chromosomal anomalies in conjunction with blood tests giving you a total risk according to which you will decide your options . This is particularly important in women over 35 years of age who are automatically at a higher risk of chromosomal anomalies in the baby .
In the ultrasound here is a specialized one looking into the nasal bone of the baby and the Nuchal thickness ()( fluid behind the neck). The blood test is for two hormones are beta HCG and PAPPA. This blood test in conjunction with the result of the ultrasound give a risk value. If the risk is high your doctor will be recommending a diagnostic test such as an amniocentesis.
Done between 18 and 20 weeks
This test will check that; the baby is growing sufficiently, the amniotic fluid level, the status and location of the placenta, details of the fetal limbs, brain, chest, bladder, stomach, and spine.
The above tests are normally done on all pregnant women, usually in the 1st trimester.