Taking Drugs While Pregnant

Produced by the Centre for Genetics Education.

Important points

• There are a number of different prenatal tests and procedures available to assess the development of the baby. Each has advantages, disadvantages and limitations

• There is no test that gives a 100% guarantee of a healthy baby. The tests give some information about the baby’s health. They do not find all potential health problems

• Counselling before a test is done, will help the woman decide which test, if any, is best for the woman and the baby

• Each prenatal test is done at a certain time during the pregnancy starting at 8-10 weeks and going through to 20 weeks and include:

– Prenatal screening tests that may identify a baby as being at an increased risk of having a particular problem. All pregnant women, regardless of their age or family health history, may choose to have one of these prenatal screening tests that include ultrasound; early pregnancy (first trimester) screening: nuchal translucency ultrasound with or without testing of the mother’s blood; second trimester screening: testing of the mother’s blood (maternal serum testing)

– Prenatal diagnostic tests that are used to see if the baby actually has a particular problem. Even if the test result is normal, however, the baby could still have some other problem. Prenatal diagnostic tests include ultrasound; chorionic villus sampling (CVS); amniocentesis; cordocentesis

– Preimplantation genetic diagnosis (PGD) is used to test the embryo created via in vitro fertilisation (IVF) therapy prior  to implantation

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What is a Contraction Stress Test?

This test measures your baby’s heart rate during contractions in order to make sure that she is getting the necessary oxygen from the placenta during labor.

When is the Contraction Stress Test Administered?

This test is usually done at the very end of pregnancy, prior to an induction.

What is
the Contraction Stress Test Procedure?

You will lie down on your left side and have two elastic belts with monitors placed on your belly.  One monitors the baby’s heartbeat and the other monitors your contractions.  If you are not having contractions on your own, an injection of Pitocin (Oxytocin) will be given and you will be monitored to see how your baby responds to the contractions via an electronic fetal monitor on your belly.  The test lasts until you’ve had three contractions, each lasting 45 seconds, within a ten-minute span.

What do the Contraction Stress Test Results Mean?

Normal results of a contraction stress test occur when the baby’s heartbeat does not slow in response to the contractions. This is a “normal” or “negative” result and typically means your baby is reacting fine and will do so for at least the next week.

Abnormal results of a contraction stress test occur when the baby’s heart does slow down in response to a contraction (deceleration).  This means the test result is “positive” and signals that your baby may be under stress.  You will typically be recommended for delivery soon and be induced or schedule a cesarean section.

The following tests are routine prenatal tests for each visit to your obgyn or midwife:

Blood Pressure:

At each prenatal visit your blood pressure will be tested by armband. A spike in blood pressure can be an indication of preeclampsia – which can cause the placenta to separate from the wall of the uterus.

Urine:

At each prenatal visit your urine will be tested for protein, sugar, blood and bacteria.  Protein is another sign of preeclampsia, sugar can signal gestational diabetes and blood or bacteria can signal a urinary-tract infection. 

Weight:

You will be monitored to see if you are gaining weight in small intervals.  If you are not gaining weight or gaining weight too rapidly you will be counseled on your diet and nutrition.

Fundal Height:

You will be measured from your pelvic bone to the top of your uterus. This helps to see how your baby is growing.

Baby’s Heart Rate:

After about 12 weeks, your baby’s heartrate can be heard using a Doppler.  The heart rate should be between 120-170 beats per minute and the doctor will check each visit to make sure it is within range.

Glucose test screening checks for gestational diabetes, a short-term form of diabetes that develops in some women during pregnancy. Gestational diabetes occurs in 1 – 3% of pregnancies and can cause health problems for the baby.

When can the Glucose Test be Administered?

The glucose test is typically administered around 24 weeks of pregnancy.

How does the Glucose Test Work?

You will drink a sugar drink and have your blood drawn an hour later and the glucose level is checked.  If the reading is high, you’ll have a glucose tolerance test.  During that test you will drink a glucose solution on an empty stomach and have your blood drawn once every hour for 3 hours.

What do the Glucose Test Results Mean?

If your glucose tolerance test comes back positive, you will be diagnosed with gestational diabetes.  Most women can control their blood sugar levels with diet and exercise. You will probably need to monitor your glucose levels at home. In a small percentage of women, insulin injections are required. In most cases, diabetes disappears soon after giving birth.

Women with gestational diabetes usually do not have an increased risk of having a baby with a birth defect. However, some studies suggest that if your gestational diabetes is severe enough to require treatment with insulin, your baby may be at increased risk of birth defects.

The answer is based on a couple of factors, mostly your knowledge of your own menstrual cycle!

If You Know Your Ovulation Date and Luteal Phase

If you know your ovulation date and your luteal phase length, you can test the day after your luteal phase is over. For instance, if you ovulated on January 15th and your luteal phase is normally 13 days, you can test on January 29th.

If You Know Your Ovulation Date but Not Your Luteal Phase

If you know your ovulation date but have no idea your average luteal phase, you can assume it is the average of four teen days and test on the fifteenth date after your ovulation. For example, if you ovulated on January 15th, you can test on January 30th.

If You Know Your Average Cycle Length

If you know your average cycle length, you can test the day after that cycle is over. For instance, if your average cycle length is 30 days and your last period started on January 1st, you can test on January 31st.

If You Know Nothing About Your Cycle

Assume it is the average of 28 days and test on the 29th day after your last period. For example, if your last period started on January 1st, you can test on January 29th.

The following tests are routine prenatal tests for each visit to your obgyn or midwife:

Blood Pressure:

At each prenatal visit your blood pressure will be tested by armband. A spike in blood pressure can be an indication of preeclampsia – which can cause the placenta to separate from the wall of the uterus.

Urine:

At each prenatal visit your urine will be tested for protein, sugar, blood and bacteria.  Protein is another sign of preeclampsia, sugar can signal gestational diabetes and blood or bacteria can signal a urinary-tract infection. 

Weight:

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The amniocentesis is a test that helps find genetic disorders before birth.  During an amniocentesis, a sample of amniotic fluid is removed from your uterus to be cultured and analyzed. The amniocentesis is performed by inserting a thin needle through your abdomen into your uterus and withdrawing a small amount of fluid. The baby is not harmed during the procedure. Some women feel mild cramping during or after the procedure.  The test is typically offered to women over 35 years of age.  The reason it is not offered to everyone is that it does carry a small risk of miscarriage.

When Can the Amniocentesis be Administered?

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What is the AFP Test?

You can choose to have a blood test for AFP – alpha fetoprotein - when you are between 16 and 18 weeks pregnant. The goal of the AFP test is to tell you whether there is a high risk that your baby has Down’s syndrome or spina bifida. AFP is one of four possible "markers" that your blood can be tested for to give information about how your baby has developed.

When Can the AFP Test be Administered?

The AFP test MUST be done between 16 and 18 weeks of pregnancy to give accurate results.  If you are unsure how far along you are, a dating ultrasound might be the best first step to determining when you should take the AFP.  You will typically get the results of the test between 5 days and 2 weeks after having your blood drawn.

How does the AFP Test Work?

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