What laboratory tests are pregnant?
What laboratory tests are necessary during pregnancy? When are they done?
Zofia Borowiec, MD: Laboratory tests in the first trimester of pregnancy – what’s all this for?
When leaving the doctor’s office after the first maternity visit, many expectant mothers will certainly ask themselves: „Is that such number of tests really necessary?!”
Dear Mums, fortunately, such a long list of tests is ordered only during the first appointment, for the next one, a general urine test and morphology blood test are usually sufficient. Below is a brief overview.
Screening tests in the first trimester of pregnancy are constantly discussed in the scientific circles of obstetrician-gynaecologists, and the current set of tests is the most basic panel developed by the Ministry of Health and the Polish Gynaecological Society, allowing for the earliest possible detection of the risk of more serious complications in pregnancy.
They are performed in order to prevent possible infectious agents from penetrating the placenta as much as possible and thus to protect the foetus from the effects of congenital infections and to detect maternal abnormalities at an early stage.
Below is a brief overview of the research panel.
- Blood group and Rh factor– knowledge of the blood group and Rh factor are essential in pregnancy: it is best to carry the original test result with you along with your identity card and pregnancy card throughout your pregnancy. Mainly because both the entire period of pregnancy, natural vaginal delivery and caesarean section may be associated with heavy bleeding, requiring in some cases blood transfusion, which requires a precise determination of the blood type of the woman giving birth – and it usually takes about 2 hours!! So it’s worth knowing in advance, right?
- Immune antibodies (anti-erythrocytes) or Coombs test – these tests are used to prevent serological conflict but also to detect unusual antibodies in the mother’s blood. Testing for the presence of immune antibodies in all pregnant women is ordered in the first trimester, and in Rh-negative women, it is performed three times during pregnancy.
- Blood morphology evaluation– detecting the risk of gestational anaemia, gestational thrombocytopenia and other haematological disorders.
- Urinalysis– it is used to assess the basic function of the kidneys (proteinuria, haematuria, biochemical abnormalities and pathological components of urine sediment) and to detect urinary tract infections
- Fasting blood sugar test – screening for gestational diabetes, which allows to distinguish a group of pregnant women particularly at risk of developing gestational diabetes and to implement a diabetic diet early, diabetes counselling and further diagnostics.
- VDRL – formerly known as „Wasserman’s test” or „syphilitic test” – one of the first tests introduced for screening diagnostics in pregnant women as early as the mid-twentieth century. It is used to detect syphilis infection, which, although it is relatively rare these days, has very serious consequences for both the infected mother and the foetus. After detecting syphilitic infection, easy, cheap and effective treatment can be used, so it is important to carry out the diagnosis as early as possible in pregnancy. Like many infections diagnosed in the first trimester, syphilis can give subtle and difficult to detect symptoms and go unnoticed by the mother without a blood (serological) test.
- Anti-HIV antibodies. The confirmation of HIV infection during pregnancy is an indication for immediate counselling in a specialist centre, antiviral therapy in order to prevent the penetration of viruses through the placenta into the foetus and thus infection of the child. Due to the high effectiveness of such a procedure (according to WHO data it is possible to reduce the risk of congenital infection from 30-60% to 1%), it is advisable to test each pregnant woman. It should not be considered that the doctor only orders this test to women from higher risk groups of infection – each of us is exposed through sexual contact, through visits to hairdressing and beauty salons, and to the dentist. It is worth getting tested – for yourself and for your child.
PLEASE NOTE: in laboratories, this test is preceded by the need to express a written consent for its performance, which is a statutory requirement.
- Anti-HCV antibodies(HCV or Hepatitis C Virus) – is a test for infection with the virus that causes hepatitis C (hepatitis C). The routes of infection are the same as in the case of HIV, but the probability of infection after contact with, for example, contaminated blood is 60% (where for HIV: 0.6%!) Due to the spread of the virus in the human population and the unawareness of possible carriers, maternal examination to prevent congenital infections of the foetus is highly recommended.
- HBs antigen(HBsAg, HBV-specific antigen, i.e. Hepatitis B Virus) – is a test for infection with the virus that causes hepatitis B. Although there are currently no treatments available for virally infected pregnant women, the study aims to identify the future group of new-borns who should undergo immunoprophylaxis. Postnatal immunoprophylaxis prevents 85-90% of new-borns from infected mothers from developing an infection. All new-borns of healthy, infected or carriers mothers, who have not been found to have individual contraindications, are vaccinated against hepatitis B after delivery.
- The level of IgG and IgM antibodies towardscytomegalovirus (CMV, cytomegalovirus). Acute cytomegalovirus infection in pregnancy can cause congenital cytomegaly, which in the foetus can manifest as brain, liver and spleen lesions, inhibition of foetal growth, and other abnormalities that are sometimes seen on ultrasound examinations. In a new-born baby, congenital infection can result in hearing loss, eye damage, impaired motor development and others. The management of a pregnant woman infected with cytomegalovirus is currently the subject of intense research in the world.
- The level of IgG and IgM antibodies towards toxoplasmosis. In Poland, the percentage of women who have experienced an infection is estimated at about 40%, so more than half of them remain exposed to primary infection during pregnancy. Toxoplasmosis is a zoonotic disease (anthropozoonosis), which causes extremely uncharacteristic symptoms (flu-like) or is asymptomatic. The seemingly trivial symptoms in the mother may be misleading, but the foetus is at risk of profound impairment, microcephaly, hydrocephalus, retinitis, intracranial changes, growth retardation, thrombocytopenia, and in extreme cases the disease may even cause pregnancy loss. A pregnant woman must pay particular attention to the thorough washing of vegetables and fruit, to eat completely processed meat (boiled, baked, fried), and to wash her hands thoroughly after finishing gardening. Cutlery, dishes and hands contaminated with raw meat should be washed with warm water and detergent. It is also forbidden to clean the cat’s litter box by the future mother – this is where the highest risk of infection with toxoplasmosis was found (during pregnancy, this privilege will have to be delegated to other household members). We mark the level of antibodies up to the 10th week of pregnancy, in women with a negative result – re-determination between the 21st and 26th week.
PLEASE NOTE: Do not succumb to the belief that a pregnancy is at certain risk after a positive result! The obtained result of the laboratory test is always first consulted with the doctor in charge of the pregnancy, because only after the next stages of diagnosis are completed, it is possible to actually confirm the infection with toxoplasmosis and implement appropriate treatment. This principle applies to virtually any laboratory result.
- The level of IgG and IgM antibodies towards rubella– checking whether the mother was infected with the rubella virus before becoming pregnant or whether she was vaccinated against rubella and developed immune antibodies is very important due to the risk of primary (i.e. first-time) infection during pregnancy. The virus is highly teratogenic and getting rubella in the first 12 weeks of pregnancy can most often cause miscarriage (50%) or the development of congenital rubella, resulting in hearing loss, vision impairment, mental retardation and other very serious complications. Infection in the later weeks can result in myocarditis, inflammation of the spleen and liver, and a host of other symptoms. Therefore, women who have not been infected or vaccinated before becoming pregnant must exercise all caution and (especially during the first trimester) avoid contact with preschool and school-age children who have symptoms of rubella, chicken pox, cytomegaly or other acute viral infections.
To sum up: each of the above examinations has its own justification, and its result – an impact on the fate of pregnancy. It is worth remembering about this when visiting the laboratory.
„Ciąża wysokiego ryzyka” („High-risk pregnancy”) III edited by G. Bryborowicz, OWN Poznań 2010
„Zakażenia HIV i AIDS w praktyce lekarskiej” („HIV and AIDS infections in medical practice”) edited by G. Halota SWA 1998 Szczecin
„Rekomendacje Polskiego Towarzystwa Ginekologicznego w zakresie opieki przedporodowej w ciąży o prawidłowym przebiegu” („Recommendations of the Polish Gynaecological Society in the field of antenatal care in the correct course of pregnancy”) 2005
“Regulation of the Minister of health of September 23, 2010 on the standards of conduct and medical procedures in the provision of health services in the field of perinatal care provided to a woman during physiological pregnancy, physiological delivery, puerperium and care for a new-born baby”.