Is all Prenatal Testing Needed?

One of the first things your caregiver will require when you find out you are pregnant, is to have certain routine testing done. These will include the following:

Blood tests which will determine your blood type and Rh factor. If your blood is Rh negative and the father’s Rh positive, you could develop antibodies that might prove dangerous to your baby. This is treatable.

Iron levels are also tested and tests to check for hepatitis B, syphilis, and HIV are completed. You are also tested for immunity to chicken pox and rubella (German Measles).

Urine tests check for kidney infections and signs of gestational diabetes and pregnancy-induced high blood pressure (which can cause a specific protein to show in the urine).

Cervical (internal) checks for STDs (such as chlamydia and gonorrhea), cervical cancer, and Group B streptococcus infection. Group B streptococcus, which are bacteria that are not transmitted sexually, can cause serious infections in newborns.

Ultrasound testing and Glucose testing are done later on, usually around 17-18 weeks.

At each visit, your urine is checked for signs of protein and glucose.

Now, the question is, what is necessary and what is not? Many of the tests are harmless and involve little invasiveness. These include most of the blood tests. Most women are aware of their medical history, and if you already know that you are immune to Measles and Chicken Pox, or not, you can decide at this point whether to be tested for this. As well, for Sexually Transmitted Diseases, you are likely to know whether it is a possibility or not. Either way, the tests for these require only blood and are not invasive in other regards.

Internal checks of the cervix require a bit more consideration. Many women find them to be uncomfortable, invasive and there is a risk of infection (though most professionals say this is slight). Again, this is an issue where you need to weigh the pros and the cons of receiving the test. Pap smears, for example have a risk of false positives which necessitate further testing, as well as worry. The monthly checks of urine for protein and glucose require little effort on your part, and can be useful in determining whether more care needs to be taken with your nutrition.

Ultrasound testing in pregnancy is relatively new. In the mid 1970’s it began to become more routine, though many older caregivers were reluctant to use it unless they deemed it necessary. In recent years, it has become a stable part of routine testing in pregnancy, whether there are pregnancy concerns or not.

Ultrasound was not intended for use in pregnancy, originally. It was invented during World War I by Paul Langevin, to detect submarines. In the 1950s a B-scan was developed for medical use.

Concerns have arisen in recent years over the safety of routine and excess use of ultrasound. Critics cite the following concerns (as stated in the book, Ultrasound? Unsound from the Association for Improvements in the Maternity Services [AIMS] coalition in the United Kingdom).

1. "Scans which were originally intended for women with potential problems are now given to almost every pregnant woman and are part of routine care.

2. There is no adequate evidence that this is beneficial and huge resources are involved.

3. The number of scans per baby has increased--some members report nine or more.

4. The machines have become more powerful and there is inadequate information or control on levels of output.

5. Many scans are being carried out by staff who are poorly trained and do not understand potential risks and how to minimize them.

6. Scans are being used on more women in very early pregnancy when major organs are being formed.

7. With the development of the vaginal probe the ultrasound now gets nearer to the baby with less intervening protective tissue.

8. There is more use of Doppler ultrasound (which may carry greater risk) to study blood flow in the uterus and the baby.

9. Some clinicians and researchers are exposing women and babies to long periods of ultrasound--an hour or more."
v Another issue that many overlook is that the Doppler is ultrasound and is generally used at each midwife or doctor appointment from approximately 12 weeks until birth. All in all, this is a large exposure to ultrasound waves for the baby.

However, even those who caution against the use of ultrasound in pregnancy are not entirely against it’s use, just caution it’s overuse. There are certain situations and circumstances where it can be helpful and the benefits outweigh the risks. The suggestion is to decide with great consideration and understanding of why it is needed on a case by case basis.

Many professionals discount any idea of risk and consider it completely safe. However, studies have shown possible increased risk including premature birth, miscarriage, more left-handedness, growth retardation in babies, more learning disabilities, delayed speech and perinatal deaths. These concerns should not be ignored, but considered carefully by practitioners and mothers.

Another controversial routine test in pregnancy is the Fasting Glucose Tolerance test. Gestational Diabetes has been considered one of the biggest concerns in pregnancy.

With only a few exceptions, testing for GD is two-tiered. The one hour challenge is used to screen women for GD and determine who needs to take the 3 hour test. The one hour test should not be used to diagnose GD, only the 3 hour test can do this (GTT). Only 15% of women who go on to have the 3 hour GTT end up being diagnosed with GD.

There are exceptions to this, one being a very high result on the 1 hour test. Henci Goer, a well renowned author and childbirth educator has questioned the validity of Gestational Diabetes diagnosis in her book Obstetric Myths vs. Research Realities, noting that the GD glucola tests are well known for being unreliable and that women can get different results at different times. Tests should have the same results or very similar results in spite of being taken at different times and on different days, i.e. it should be reproducible. If it is not, than it’s usefulness is rather questionable.

In “A Guide to Effective Care in Pregnancy and Childbirth” the authors note: The diagnosis of 'gestational diabetes', as currently defined, is based on an abnormal glucose-tolerance test. This test is not reproducible at least 50-70% of the time, and the increased risk of perinatal mortality and morbidity said to be associated with this 'condition' has been considerably overemphasized. As no clear improvement in perinatal mortality has been demonstrated with insulin treatment for gestational diabetes, screening of all pregnant women with glucose-tolerance testing is unlikely to make a significant impact on perinatal mortality or morbidity...The available data provide no evidence to support the wide recommendation that all pregnant women should be screened for 'gestational diabetes.'

Another concern is that the Glucose tests do not reflect real life situations as women rarely consume that much straight pop at one sitting, outside of the test. Even so, when high amounts of carbohydrates are consumed, it is usually with fats and proteins, which lower the blood sugar response. Therefore, abnormal results may occur after the testing, but not after normal meals. Other concerns regarding testing protocols include

• Inconsistencies in testing conditions

• Whether one test can adequately measure the changing nature of glucose tolerance during pregnancy

• Relationship of the test results to fetal outcome

• Susceptibility of tests results to life factors such as stress and illness

• Whether the diagnostic levels should be stricter or looser based on fetal outcome

• Cost-effectiveness of a nearly universal screening program One way to prevent possible gestational diabetes however is to keep strict adherence to nutritious eating habits and regular exercise and stress control. Daily exercise is very beneficial and keeping refined carbohydrates and sugars to a bare minimum will go far in keeping your health in proper check.

If you do decide to take the test, Dr Tom Brewer suggests loading up on carbohydrate foods three days prior to the test to help the liver store glycogen in preparation for the fasting, to help stabilise the blood sugar levels while you are without food.

Two tests that are not routine (at least for younger mothers) are amniocentesis and chorionic villi sampling. These tests are very invasive and are quite risky. Both are done to test for genetic defects.

CVS is generally completed at around 9 weeks gestation. It involves obtaining a sample of tissue through biopsy. A catheter is passed through the closed cervix and a sample of villi is removed. This villi is to become the placenta. This sampling creates a higher risk of infection and miscarriage as well as, at the very least disrupting villi, causing blood flow to certain parts of the growing baby to be cut off. It is not as commonly done now, but some caregivers still use it.

In amniocentesis, a needle is inserted through the abdomen into the fluid filled sac surrounding the baby and a sample of this fluid is taken. Risks include miscarriage, infection, puncturing the baby (though ultrasound is used to avoid this) and false positives.

All in all, prenatal testing is up for debate. The important thing to remember is that you deserve to know why a test is being performed, what your risk is in taking the test and what the benefits are. Before deciding to submit to any tests, make sure any concerns and questions are properly answered. It is the least you, and your baby, deserve.

Written by Mary Seiver

CBE/Certified NFP & Mother of three children born naturally at home

This article first appeared in the spring 2004 issue of Mother's Milk Magazine ©2004.