By Dr. Tosin Ogunjimi
Blood Screening Tests
The following laboratory tests/assessments should be performed as early as possible in pregnancy and some of these should be repeated at least once between 24 and 36 weeks of pregnancy (gestation). During your first visit, some of the following tests may be offered:
|Blood group type
|· You may need a blood transfusion during pregnancy or delivery.
· The Blood group test also tells your Rhesus status (see next test).
|· A blood test is usually carried out during pregnancy to see if a mother’s blood is Rhesus negative or positive.|
Red Blood Cell Count (RBC)
|· A Complete Blood Count (CBC) helps to measure the number and types of the different cells in the blood (i.e. your Red blood cells, White blood cells and Platelets). Your CBC values during pregnancy should be different from pre-pregnancy values. It can also help indicate a person’s general state of health and immunity. The RBC measure can also help with proper anaemia diagnosis.
· The HCT test determines the number of red blood cells a person has, in relation to the total amount of blood contained in their body. The HCT should be carried out every trimester. It can help indicate anaemia.
|· Test to determine the amount of hemoglobin in your blood in grams.
· Can help indicate anaemia.
|White blood cell count (WBC)
|· Your White Blood Cell (WBC) count (or leukocyte count) can help indicate how well you are (that is how strong your immune system is).
· The normal range for the three trimesters in pregnancy should fall between 5.6 trillion – 17.0 trillion WBCs per litre of blood.
· Values outside the normal range could indicate immune and blood disorders. A high count could also mean the body is fighting against an infection.
|Ratio of antibodies to blood group antigens||
|· Checks for Hepatitis A/B/C and HIV
· Syphilis and rubella (might not be offered in some test centers),
|· At-risk individuals may need testing for toxoplasmosis. This includes those who work in the farm/garden, as well as those who keep cats as pets or those who work with cats e.g. vets.
· It can cause serious harm to an unborn baby if it is transmitted to a pregnant woman.
|Gestational diabetes||· Women with prior gestational diabetes should be given early, 1-hour post-glucose testing.|
Other more extensive tests can be done in selected patients.
Testing for protein, glucose and ketones in your wee (urine) should be done at every prenatal visit.
- The presence and amount of protein in your urine will be detected and measured. Measurement which detects excess protein of more than 300 milligrams (Proteinuria) may indicate kidney (renal) dysfunction. If there is a history or possibility of relative hypertension, it could also indicate the onset or progression of preeclampsia.
- If high glucose levels (glucosuria) are detected, this may suggest that the kidney is processing too much glucose.
- During pregnancy, the presence of ketones in your wee (urine) usually indicates that your carbohydrate intake is too little. Watching the amount of food you eat during pregnancy is fine but you need to make sure that you eat all the right nutrients in the right proportions. Detecting Ketone presence alone cannot indicate if the unborn baby (foetus) is in jeopardy or if a pregnant woman has maternal diabetes. Your diet should be evaluated by your doctor in this case to make certain that your carbohydrate intake is inadequate or adequate as the case may be.
Ultrasound scans enable a pregnant woman to view constructed images of her unborn baby on a sonograph. Scans are offered to pregnant women twice, at about 11-14 weeks (date/dating scan) and 20-21weeks (anomaly scan).
You may be offered more than two scans if you:
- Are carrying multiple babies (foetuses).
- Are over 35 years old or under 21 years old.
- Have pregnancy complications.
- Have been advised to do so by your medical practitioner for any other reason.
- You choose to have one for any other reason.
An ultrasound is very important as it:
- Gives an accurate pregnancy dating –age of the foetus. It tells you how long you have been pregnant for.
- It can help to diagnosis multiple gestation (presence of two or more babies)
- It can be used to conduct chorionic villus sampling i.e. diagnosis if there are any structural and chromosomal abnormalities
- Can indicate if there are any risks to the pregnancy
Subsequent antenatal visits
After your first antenatal visit, you should be asked to attend subsequent antenatal visits every four weeks until you are 28 weeks pregnant. Then afterwards, every two weeks until you are 36 weeks pregnant. After you hit the 36 week mark you will be asked to go for antenatal visits every week until you deliver your baby.
During each visit, your weight gain, blood pressure, fundal height and findings from abdominal examination by Leopold’s maneuvers would be recorded.
Additionally, your baby’s Fetal Heart Rate (FHT) will be monitored to ensure that everything is fine. Your urine should always be checked for glucose and protein. These findings will normally be reviewed by your gynaecologist/medical practitioner and compared with those of previous examinations.
Chamberlain G, Morgan M., Organization of antenatal care. ABC of antenatal care, Fourth edition, 2002, page 1-4.
Bernstein HB, Weinstein M: Normal Pregnancy & Prenatal Care, Current Obstetrics and Gynaecology, 2006, page 187-202.
Mandara MU, Otubu JAM: Antenatal care, Text book of Obstetrics and Gynaecology for medical students (ed) Akin Agoola.2006, pg 257-264.