Pregnancy
Patient Education

Patient Guide

Common Tests or Labs Throughout Your Pregnancy

During each obstetrical visit throughout the pregnancy, the medical assistant or nurse will measure weight and blood pressure while sitting. The urine is also tested each time for glucose, protein and blood.

The fundal height, or height of the uterus, is measured from the top of the pubic bone to the top of the uterus. At 20 weeks the fundal height will reach the level of the umbilicus and from then until 35 weeks, there is a consistent relationship between the pregnancy length and fundal height (exceptions include multiple gestation i.e. twins or fibroids). Read more about common tests in this patient education guide.

Common Tests in the First Trimester

Test	Why Test?	What Happens?	Normal Result
Blood Type and Rh	If Rh Negative, will test Father for Rh to ensure compatibility with baby	After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied	Rh Positive is less risk
Complete Blood Count	Checks for anemia	After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied	WBC=4.5-11 RBC=4.1-5.1 Hemoglobin Female= 12-16 Hematocrit Female=36-46%
Screen for Rubella,hepatitis B, syphilis and HIV	Checks for immunity	After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied	IgG antibodies <7IU/mL HIV negative, hep.neg. VDRL negative
Tay-Sachs	Checks for risk of the disease	After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied	Hexosaminidase A: 7.2-9.8 U/L Total Hexosaminidase= 9.8-15.9 U/L
Sickle Cell Anemia	Checks for risk of the disease	After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied	Hemoglobin A (not S)
Ultrasound	Confirms age of fetus Visualizes structural abnormalities in uterus and fetus	After lying down on the table, the technician/doctor places clear water-based gel on your tummy and pelvic area. A hand-held probe is then moved back and forth over the area, transmitting sound waves. The echoes of these waves creates an image on a computer monitor Sometimes a transvaginal ultrasound is performed. Here, you lie on the exam table with knees bent and feet in stirrups. A covered probe is lubricated and placed in the vagina. The probe emits sound waves and the echoes create an image on a computer monitor.	Fetal and uterine size matches the date No structural problems seen
Urine	Presence of glucose, protein, blood	Urine is placed in a cup for analysis. The technician dips a special paper into the urine for analysis with color changes	Glucose, protein and blood should be absent in a normal specimen
Chorionic Villus Sampling	Screens baby for genetic defects at 10-12 weeks	An ultrasound locates the uterine position and placental position in the uterus. The vulva, vagina cervix and abdomen are wiped with an antiseptic wash. A thin plastic tube is inserted through the vagina and cervix to reach the placenta, guided with ultrasound and a small sample of tissue is removed. In the transabdominal approach, a needle is inserted through the abdomen and uterus into the placenta. Tissue is withdrawn into a syringe	The DNA of the baby is analyzed. It fails to detect neural tube defect or Rh incompatibility and an amniocentesis is needed if this is a concern. A normal test means there are no genetic defects.

Common Tests in the Second Trimester

Test	Why Test?	What Happens?	Normal Result
Blood for genetic markers (done in 15-18th wk):	Abnormal markers indicate the need for additional testing (usually a sonogram and possibly an amnio-centesis) Abnormal levels suggest: Down syndrome Spina bifida Twins Defect in fetal abdominal wall Wrong due date Other chromosomal abnormalities Abnormal levels are linked to increased risk of chromosomal abnormality	After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied	Alpha-Fetoprotein Screening (AFP) Normal range is .5-2.0 or 2.t MoM Human Chorionic Gonadotropin (hCG) The hCG levels increase during the pregnancy At 13-16 wks=13,300- 254,000 mIU/ml 17-24 wks=4,060- 165,400 mIU/ml Estriol & Inhibin Estriol and inhibin is elevated more than twice the median value in normal pregnancies with genetic problems
Amniocentesis	Done during the 16-18th gestational week to do the following: Rule out any genetic disorder Determine sex of baby Rule out Tay-Sachs in baby	The doctor inserts a needle through the abdomen and into the uterine sac to remove a small amount of amniotic fluid. The needle is withdrawn and pressure is applied to the puncture site The test is usually done with ultrasound guidance to locate the amniotic fluid.	XX for girl XY for boy Hexosaminidase A is absent
Urine Test	Looks for glucose, protein and blood in the urine	Urine is deposited into a cup. The technician then dips a special paper into the urine which changes color for presence of these three substances.	Normal result is when these are absent
One-Hour Glucose Tolerance Test	Rules out Diabetes	You are given a cup of a 50 gm. sugar solution (orange or cola flavored) to drink. After one hour, blood is drawn and analyzed for sugar level.	Less than 140 mg/dL is normal.

Common Tests in the Third Trimester

Test	Why Test?	What Happens?	Normal Result
Group B Streptococcus Screening	B Strep is associated with Mental retardation	Swabs of the vagina and rectum are taken at 35-37 weeks to screen for presence of group B strep.	Negative presence of bacteria
Non-Stress Test	Indicated in high-risk pregnancies as: Twins Diabetes Overdue High blood pressure	Fetal monitor is strapped across the mother's abdomen with the device over the region of the fetal heart and a tracing is obtained of the fetal heart rate over time. Takes about 20 min.	Normal fetal heart rate is 120-140 beats/minute. Dips (decelerations) or accelerations beyond 140 is not seen
Contraction Stress Test	Predicts how the baby will cope to labor stress	The fetal monitor is strapped across the mother's abdomen. She is then asked to stimulate the nipples to stimulate contractions or pitocin is given intravenously to create contractions. The fetal heart rate is then measured in response to the contractions.	Normal fetal heart rate is 120-140 beats/minute. Dips (decelerations) or accelerations beyond 140 is not seen When decelerations are seen in conjunction to the time of the contractions, it can suggest fetal head compressions.
Biophysical Profile	Gives a more accurate assessment of baby wellness	Most often done between 38-42 wks of pregnancy. Combines a non-stress test with an ultrasound	Rating of 0-2 (with 2 normal) is given for each of the following, with a score of ten as the best: Muscle tone Heart rate Body movement Breathing movement Amniotic fluid levels A total score under 6 is abnormal and calls for delivery.
Electronic Fetal Heart Monitoring	Tests fetal heart rate	A fetal doppler is placed on the mother's abdomen over the fetal heart site	Regular pattern with 120-140 beats/min.
Pelvic Digital Examination	Assess any dilatation or thinning of the cervix and where the position of the fetal head is located in conjunction to the birth canal. Performed during the last 4 weeks of pregnancy	The patient bends her knees with her legs abducted and feet on the bed or in "frog-leg" position. The examiner gently parts the vaginal labia and inserts two fingers into the vagina and palpates the cervix to assess effacement (thinning of the cervix) and dilatation, estimated by the number of fingers that would span the opening. (For example, when the cervix is 3-4 cm dilated, 2-3 fingers would span the opening. When 10 cm. occurs, the opening is equivalent to five fingers.)	Effacement is the thinning out of the cervix in labor which goes from uneffaced at 0% to 100% effaced in normal labor. Dilatation goes from closed to 10 centimeters in normal labor