Pregnancy Testing Methods: Hospital Procedures Explained

Pregnancy tests are typically done at hospitals or a healthcare provider's office to determine if a woman is pregnant. These tests can be performed in two ways: using a urine sample or a blood sample. Urine tests are usually carried out at home or at a doctor's office, while blood tests are performed at a hospital or laboratory by a healthcare provider. Both tests detect the presence of human chorionic gonadotropin (HCG), a hormone produced during pregnancy. Blood tests can also determine the amount of HCG, providing valuable information about the pregnancy and the health of the unborn baby.

Urine tests

There are two main types of pregnancy tests: urine tests and blood tests. Urine tests can be done at home or at a healthcare provider's office. They are typically performed by urinating into a cup and then either dipping a test strip into the urine or placing the test strip under the urine stream. The test strip contains chemicals that detect the presence of human chorionic gonadotropin (HCG), a hormone produced during pregnancy.

To ensure the accuracy of a urine test, it is recommended to use the first morning urine, as HCG levels are typically more concentrated at this time. Additionally, it is important to read and follow the instructions provided with the test. If a negative result is obtained but symptoms of pregnancy are still present, it is advised to wait a week and retake the test or contact a doctor for a blood test.

While urine tests are a convenient and effective way to determine pregnancy, they may not be suitable for certain high-risk situations. In cases where a patient reports a previously positive pregnancy test or exhibits symptoms of potential pregnancy complications, a serum HCG test may be more appropriate for accurate diagnosis.

Blood tests

During pregnancy, blood tests are offered to help protect the health of the mother and the baby. These tests are important and can help in making decisions about care before and after birth. They can be used to determine blood type, check for anemia, and screen for conditions such as diabetes, kidney disease, preeclampsia, and infections like rubella. Blood tests can also be used in combination with ultrasounds for genetic screening to assess the risk of the fetus having certain birth defects.

Ultrasound scans

There are two main types of ultrasound imaging techniques: 2D and 3D. 2D ultrasound is the most common type and provides a flat picture of the baby. 3D ultrasound exams are used when more detailed information is needed. In addition, there are two main types of ultrasound procedures: abdominal ultrasound and transvaginal ultrasound. Abdominal ultrasound involves applying gel to the abdomen and gliding the ultrasound transducer over the gel to create an image. Transvaginal ultrasound uses a smaller transducer that is inserted into the vagina and produces a sharper image, making it useful for early pregnancy scans.

Amniocentesis

Before the procedure, the clinician may mark the insertion point on the patient's skin with a surgical pen. The patient's skin is then cleaned with an antiseptic solution and draped with sterile towels. Using sterile gloves, the clinician places an ultrasound transducer covered with a sterile glove or plastic wrap on the patient's skin to guide the needle insertion.

During the procedure, the clinician inserts a syringe into the amniotic fluid while using real-time ultrasound guidance to ensure accurate placement. The first 2-4 mL of amniotic fluid is aspirated and discarded, as it may be contaminated with maternal cells. Once the desired amount of fluid is collected, the syringe is removed from the needle, and the fluid is poured into containers for testing. The needle is then quickly pulled out to reduce discomfort, and fetal heart tones are assessed.

The analysis of fetal DNA, RNA, chromosomes, or metabolites obtained from the amniocentesis sample can accurately determine the presence or absence of multiple genetic disorders. Results are typically available within 10 days to two weeks. Amniocentesis is particularly useful for detecting open neural tube defects, which cannot be identified through other prenatal tests such as CVS (chorionic villus sampling).

CVS testing

CVS, or Chorionic Villus Sampling, is a prenatal test that can be performed early in pregnancy to detect birth defects, genetic diseases, and other problems. CVS is a genetic test that examines chorionic villus cells, which are found in the placenta, to determine if a baby has certain health conditions. These cells contain the same chromosomes as the developing baby, so a CVS test can identify chromosomal abnormalities and some other genetic problems.

The procedure involves taking a small sample of chorionic villi cells from the placenta, which can be done through the vagina or abdomen. An ultrasound is used to confirm the gestational age and placenta location, and then guide the collection of the sample. The test is considered generally safe, but there are some risks, including a slightly higher risk of miscarriage compared to amniocentesis, as well as the possibility of infection and, in rare cases, limb defects in the baby.

Results from CVS testing are usually available within 10 days to two weeks, and they can provide clear answers for women carrying twins, where blood screening tests may be less reliable. It is important to note that CVS does not diagnose or screen for neural tube defects, and a follow-up blood test is often required between 16 and 18 weeks of pregnancy to screen for these defects.

Frequently asked questions