What blood tests are done at 36 weeks pregnant

Acquired Immunodeficiency Syndrome (AIDS): A group of signs and symptoms, usually of severe infections, in a person who has human immunodeficiency virus (HIV).

Anemia: Abnormally low levels of red blood cells in the bloodstream. Most cases are caused by iron deficiency (lack of iron).

Antibiotics: Drugs that treat certain types of infections.

Antibodies: Proteins in the blood that the body makes in reaction to foreign substances, such as bacteria and viruses.

Bacteria: One-celled organisms that can cause infections in the human body.

Birth Defects: Physical problems that are present at birth.

Cells: The smallest units of structures in the body.

Cervix: The lower, narrow end of the uterus at the top of the vagina.

Chlamydia: A sexually transmitted infection caused by bacteria. This infection can lead to pelvic inflammatory disease and infertility.

Chromosomes: Structures that are located inside each cell in the body. They contain the genes that determine a person’s physical makeup.

Complications: Diseases or conditions that happen as a result of another disease or condition. An example is pneumonia that occurs as a result of the flu. A complication also can occur as a result of a condition, such as pregnancy. An example of a pregnancy complication is preterm labor.

Diabetes Mellitus: A condition in which the levels of sugar in the blood are too high.

Fetus: The stage of human development beyond 8 completed weeks after fertilization.

Gene: Segments of DNA that contain instructions for the development of a person’s physical traits and control of the processes in the body. The gene is the basic unit of heredity and can be passed from parent to child.

Genetic Counselor: A health care professional with special training in genetics who can provide expert advice about genetic disorders and prenatal testing.

Gestational Diabetes: Diabetes that arises during pregnancy.

Glucose: A sugar in the blood that is the body’s main source of fuel.

Gonorrhea: A sexually transmitted infection that can lead to pelvic inflammatory disease, infertility, and arthritis.

Group B Streptococcus (GBS): A type of bacteria that many people carry normally and can be passed to the fetus at the time of delivery. GBS can cause serious infection in some newborns. Antibiotics are given during labor to women who carry the bacteria to prevent newborn infection.

Hepatitis B: An infection caused by a virus that can be spread through blood, semen, or other body fluid infected with the virus.

Hepatitis C: An infection caused by a virus that can be spread through infected blood.

Human Immunodeficiency Virus (HIV): A virus that attacks certain cells of the body’s immune system. If left untreated, HIV can cause acquired immunodeficiency syndrome (AIDS).

Immune: Protected against infectious disease.

Intravenous (IV) Line: A tube inserted into a vein and used to deliver medication or fluids.

Measles–Mumps–Rubella (MMR) Vaccine: A shot given to protect against measles, mumps, and rubella. The shot contains live viruses that have been changed to not cause disease. The shot is not recommended for pregnant women.

Obstetrician–Gynecologist (Ob-Gyn): A doctor with special training and education in women’s health.

Preeclampsia: A disorder that can occur during pregnancy or after childbirth in which there is high blood pressure and other signs of organ injury. These signs include an abnormal amount of protein in the urine, a low number of platelets, abnormal kidney or liver function, pain over the upper abdomen, fluid in the lungs, or a severe headache or changes in vision.

Rectum: The last part of the digestive tract.

Rh Factor: A protein that can be found on the surface of red blood cells.

Rubella: A virus that can be passed to the fetus if a woman becomes infected during pregnancy. The virus can cause miscarriage or severe birth defects.

Sexually Transmitted Infections (STIs): Infections that are spread by sexual contact. Infections include chlamydia, gonorrhea, human papillomavirus (HPV), herpes, syphilis, and human immunodeficiency virus (HIV, the cause of acquired immunodeficiency syndrome [AIDS]).

Syphilis: A sexually transmitted infection (STI) that is caused by an organism called Treponema pallidum. This infection may cause major health problems or death in its later stages.

Trimester: A 3-month time in pregnancy. It can be first, second, or third.

Tuberculosis (TB): A disease that affects the lungs and other organs in the body. TB is caused by bacteria.

Urinary Tract Infection (UTI): An infection in any part of the urinary system, including the kidneys, bladder, or urethra.

Vaccine: A substance that helps the body fight disease. Vaccines are made from very small amounts of weak or dead agents that cause disease (bacteria, toxins, and viruses).

Vagina: A tube-like structure surrounded by muscles. The vagina leads from the uterus to the outside of the body.

Reviewed by Traci C. Johnson, MD on August 30, 2020

These tests are common in the third trimester of pregnancy:

Blood and urine tests: Your doctor will continue to check your urine for protein and sugar and any signs of infection, keeping a close eye for signs of preeclampsia, a complication that is most common in the last weeks of pregnancy. You may have blood tests again for anemia.

Other measurements: Weight, blood pressure, and fundal height measurements also continue. Your baby's heartbeats are loud and clear!

Pelvic exams: In the last few weeks of pregnancy, your doctor will start doing pelvic exams again. This is to see if the cervix has started the ripening process for birth. Ripening is the softening, thinning, and opening (dilating) of the cervix.

These changes can happen slowly or quickly during the weeks, days, or hours before birth. So it's not uncommon to dilate a few centimeters a few weeks before your due date and then to stop dilating. This process is somewhat unpredictable.

Group B streptococcus screening: Vaginal and rectal swabs are taken at 35 to 37 weeks of pregnancy to detect group B strep bacteria. Although group B strep can be present in up to 30% of all healthy women, it's the leading cause of life-threatening infections in newborns and can also cause intellectual disability, impaired vision, and hearing loss. Women who test positive are treated with antibiotics during delivery to protect the baby from contracting the infection at birth. As an alternative, your physician or midwife may choose not to test for strep but to treat you in labor if certain risk factors develop.

Electronic fetal heart monitoring: Electronic fetal heart monitoring is done during pregnancy, labor, and delivery to monitor the heart rate of the fetus. The fetal heart rate can indicate whether the fetus is doing well or is in trouble and can be done any time after 20 weeks.

Nonstress test: Done weekly in many high-risk pregnancies, such as in cases where a women is carrying more than one fetus, or has diabetes or high blood pressure, this test involves using a fetal monitor strapped across the mother's abdomen to measure the baby's heart rate as it moves. It's also used for monitoring overdue babies.

Contraction stress test: Also done in high-risk pregnancies, a fetal monitor measures the baby's heart rate in response to contractions stimulated either by oxytocin (Pitocin) or nipple stimulation. Doctors use the measurements to predict how well the baby will cope with the stress of labor.

Ultrasound: Most pregnant women have just one or perhaps two ultrasounds. If you're having twins, you'll have this test more often, perhaps right up until birth, to check the position and growth of your babies. When needed, doctors can combine non-stress tests with ultrasound. This allows your doctor to check the babies' breathing motions, body movements, and muscle tone as well as the amount of amniotic fluid.

Biophysical profile: Can be done with just an ultrasound or with a combination of a nonstress test and an ultrasound.

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