Amniocentesis has been done for many years and it is suggested that perhaps one woman in every 150 many miscarry, over and above the normal incidence of miscarriage. A Brief Guide To Prenatal Tests These days, a pregnant woman receiving prenatal care will find that having a baby can involve complex technology and testing. This booklet presents the most common prenatal test
and procedures and discusses what they test, how accurately they test, and what risks or side effects there are. As these questions are answered, it will be easier for you as a pregnant woman or expectant couple to decide which tests are appropriate for you.

Prenatal tests can be divided into two categories: those which give information about the status of the mother and baby ( such as urine samples, blood counts, glucose tolerance test, fetal heart tones, and ultrasound ), and those which information about the genetic makeup and possible congenital abnormalities of the baby ( such as Alpha-Fetoprotein
[ AFP ], Chorionic Villus Sampling [ CVS ], amniocentesis, and ultrasound ).

Test For Maternal And Fetal Well-Being
Urine samples can give healthcare providers important information about how you and your baby are doing. They are first used to determine pregnancy; then you will probably be asked to give urine samples at each prenatal visit. You or your practitioner will insert a small paper stick into your urine to measure the amounts of protein, sugar, and sometimes ketones. Usually, none or only a trace of these will be found. Too much protein in your urine is one of three symptoms of pre-eclampsia ( also known as toxemia or pregnancy-induced hypertension ). All three symptoms ( protein in the urine, high blood pressure, and usual swelling ) must be present for toxemia.

Too much sugar may be an indication of gestation diabetes, a form of diabetes which is found only5 in pregnant women and usually disaqppears soon after birth.

Ketones in the urine, particulary a problem in early pregnancy, may indicate actual weight loss for the mother, which can be unhealthy for the fetus.

All of these test are indicators and further testing would be necessary to determine if there is a problem and how serious it is. These are conditions which can be controlled diet, exercise, and rest.

Urine test are also used to screen for drugs, such as cocaine, marijuana, and alcohol. Results take two to three days. Such testing sometimes requires informed consent, meaning you must understand the purpose of the test and give your permission to have it administered.

Urine tests are done in the practitioner’s office and results are given immediately, with no risk or side effects. Your informed consent is not required. The results are most accurate when you give a “ clean sample, “ meaning that you clean your vulva well with soap and some antiseptic and give urine from the middle of your flow, although such accuracy is usually not required each time you go in. Urinary tract infections, not uncommon for pregnant women, are detected in urine samples. These results take one to two days.

Blood tests are taken several times throughout pregnancy. Your blood contains a wealth of information about you and the fetus. It can be used to confirm pregnancy and / or duration if there is reason to think that the urine test was not accurate. It is most often used to measure the amount of iron in the blood. It is normal for pregnant women to have lower iron ( in proportion to their blood volume ) than non-pregnant women, but it is important to make sure there is enough iron to support mother and fetus. Results are given immediately or within a day or so depending on which type of blood test is done and whether or not there is equipment to run the test in your practitioner’s office. Most blood test do not require informed consent, and accuracy depends on what you are checking.

Alpha-fetoprotein ( AFP ) is a blood test for indication of congenital and chromosomal anomalies ( deviations from normal ) in the baby.

HIV/AIDS testing is also a blood test. The results take about three weeks, and accuracy depends on when the test is done in relation to when you may have been exposed to the virus. If you have shared IV needles or been otherwise exposed to the AIDS virus in the last eight to twelve years, then you are at risk for HIV/AIDS. If exposure was more than six months before the test, then the results are considered very accurate. Scientists and practitioners do not yet understand how HIV is transmitted from mother to fetus. It is important to have some kind of counseling before and after the test to learn the implications of this test for you and your baby.

Glucose tolerance testing is used to test for gestational diabetes. Some doctors do this test routinely, and others do so only when there is some other indication of a possible problem either from symptoms or a urine test.

The test involves drinking a very sweet substance ( sometimes on empty stomach ) and testing your blood an hour later. If this test indicates problems, then a more accurate test is done in which you drink the sweet substance and then have blood drawn one, two, and they are considered to be accurate, particularly the three-hour test. Risks of drinking such a sweet substance are unknown. Side effects can include nausea or headache for a few hours after the test.

Weight gain is another indication of the baby’s growth and your general health in pregnancy. You will probably be weighed at each prenatal visit. There should be consistent, even weight gain throughout the pregnancy, and you should gain 25 to 45 pounds altogether. Sudden gain or loss of weight may indicate problems which need to be investigated further.

Measurement of fundal height is used to assess growth of the fetus. You will be asked to lie on your back, and the practitioner will use a tape measure or special fundal height ruler to measure the distance from the top of your uterus to your pubic bone. This is done at each prenatal visit from about 20 weeks on, with no risks but possible discomfort from having to lie on your back for those few moments.
Sometimes ultrasound scans are used to determine size and position of fetus or placenta. They can also be used to determine certain congenital anomalies. Be sure you know what the practitioner hopes to learn from an ultrasound scan before you agree to have one. Details of the test are discussed under Fetal heart tones.

Blood pressure is another indication of maternal and fetal well-being which will be measured at each visit. It is normal for blood adjusts to the increased volume of blood in your system, but a sharp rise in blood pressure could indicate a serious problem. Often weight gain and blood pressure problems are solved by changes in diet, exercise, and rest.

Fetal heart tones will be checked at each prenatal visit after the first 12 or 17 weeks, depending on what type of equipment is used. The Doppler, a handheld device which magnifies the sound of the heartbeat, uses ultrasound technology to pick up the baby’s heartbeat. Long-term effects of ultrasound exposure are not known.

It is possible to hear the heartbeat earlier in the pregnancy with a Doppler than with a fetoscope ( a stethoscope designed to measure fetal heart tones ), but the value of this is not clear. Fetal heart rate should be about twice as fast as that of an adult. A slow or irregular heartbeat many indicate that the fetus is or has been in some distress.

Amniocentesis is a surgical test in which a needle is inserted through the abdomen into the womb to withdraw a sample of amniotic fluid. This fluid contains urine and skin cells from the baby which can be analyzed to discover its chromosomal or genetic makeup.

Today it is possible to detect about 200 chromosomal disorders, most of which are very unusual. This test may be useful if you know that such a disorder runs in your family. It is most commonly used to detect neural tube disorders and Down’s syndrome.

The test is done in the 14th to 18th week of pregnancy and results take several weeks. Risks include possible miscarriage ( 1 % ), infection, vaginal bleeding, leaking from the place where the needle went in, isoimmunization if mother is Rh+ and fetus is Rh-, and harm to the baby from the needle. These are rare, but they do occur.

The test is sometimes performed in the practitioner’s office, but most often in a hospital or genetic testing center, It is preceded by an ultrasound to determine the location of the fetus. A local anesthetic is injected into the area where the needle will be inserted. Results are considered to be very accurate, although factors such as maternal cell contamination, cell culture failure, and artifacts ( in which the cells in the lab do not reproduce themselves exactly ) can affect accuracy of results. The test is sometimes uncomfortable and can produce considerable anxiety in the two to four weeks between taking the test and receiving the result.

Results take one to two weeks. Risks include infection, bleeding, harm to the fetus, and miscarriage. Long-term risks of this procedure are unknown.