Ultrasound using height frequency sound waves to produce an image of internal organs or tissues. Our responsibility is to make sure bladder is full. This pushes the uterus up so it can be easily viewed. It also provides a good landmark. US has no harmful effects on the fetus.

Done for the following reasons:

confirm pregnancy

placenta location

determine gestational age

pelvic problems

Amniocentesis: sample of amniotic fluid to be used to study. Done on the 14-16 weeks because fetus is not considered viable and a decision to abort can be made. Bladder should be full because US is used to locate. Must have a consent. Mom is concerned about injury to baby, loss of amniotic fluid, cramping and bleeding, infection.

Why is it done: to detect chromosomal anomalies, neural tube defects, lung status.

After amniocentesis is done, an Rh(-) mom gets RhoGAM.

Before an amniocentesis is done a serum maternal alpha-fetoprotein is drawn (MSAFP). It is an antigen that is carried by the fetus found in amniotic fluid and maternal blood. Mom’s blood can be tested. If those levels are high or abnormal then an amniocentesis is done. Increased levels of AFP may indicate neural tube defects. Decreased levels may indicate chromosomal anomalies such as Down’s syndrome (also called Trisomy 21). Low AFP, low estriol and high HCG usually indicate Down’s. This is called the triple test. Estriol usually increases because the fetus urinates in the amniotic fluid and mom’s urine should be increased in estriol. Tested to assess fetal/placental function.

Thalassemia can also be detected. This is when the baby does not produce RBC’s.

G-6-PD: glucose 6 phosphate dehydrogenase. This is an enzyme disorder that shortens the life (normally 120 days) of the RBC.

L/S ratio can be determined to assess lung maturity. Should mature by 34 week. (2:1).

Phosphatidyl-glycerol (PG): component of more mature surfactant. Presence of PG and L/S ratio of 2:1 = mature lungs and could breathe on their own.

Creatinine levels (nitrogenous waste product occurs from breakdown of protein in the liver) should rise and would indicate fetal maturity. >1.8mg/dL at maturity.

Greenish amniotic fluid: meconium stained and indicated hypoxia. If GI tract becomes hypoxic there is relaxation of anal sphincter and meconium comes out. This is normal in a breech presentation.

Orange amniotic fluid: Normally the liver breaks down RBC’s after 120 days. If this takes longer, there is an excess of bilirubin. If mom and baby have different ABO group, this causes an incompatibility and an intrauterine transfusion may have to be done.

Chorionic villi sampling: can be done much earlier than amniocentesis, as early as 10 weeks. Can put a catheter thru the vagina or a needle thru the abdomen. US is also used to locate placenta and embryo.

Check fetal heart tones manually (fetoscope or dopplar) or electronically.

Manual: If presentation is cephalic or vertex, listen for FHT in the lower maternal abdomen. If presentation is breech the FHT is heard more clearly in the upper portion of the abdomen. Count for 1 full minute. Should be between 110-160. May hear funic or uterine soufle.

Electronic: Internal or external.

A. External: non-invasive procedure. Will have 2 transducers. One is similar to an US, placed over where FHT would be heard and strap in place. The other transducer is called a toco. It is put over the fundus and strapped down. Can hear FHT and can also see uterine contractions. Used during stress tests.

B. Internal: done for high risk pregnancy. Cervix must be dilated at least 2cm and membranes have to be ruptured. MD or trained person will insert a soft water filled catheter into the uterus passed the presenting part of the fetus. Will connect to a gauge to measure uterine pressure. MD will take a spiral electrode and attach to fetal scalp to monitor FHR.

There are two types of contraction tests that help determine well being of fetus. External electronic monitoring is used for these.

1. Non-stress test: looking at response of the fetus (FHR) in relation to fetal movement. Baby should move 2-4 times in 10 minutes per hour. The FHR should go up at least 10-15 beats and last 10-15 seconds. If all of this occurs, it is considered to be positive or reactive.

If non-reactive, this could indicate hypoxia and it is not a good response. If there is 3 negatives in a row it is non-reactive.

N Non-reactive

N Non-stress is

N Not good.

If not moving, the baby could be asleep. A vibroacoustic stimulation is used. This is a loud sharp noise.

Positive is good.

2. Contraction-stress test: Uses oxytocin or nipple stimulation.

Nipple: causes the pituitary to release oxytocin and the goal is 3 contractions in a 10 minute period with a FHR assessment in relation to the contractions.

Oxytocin (OCT): if nipple stimulation is not successful, oxytocin is started at 0.5mU and woman will continue to get 0.5mU until she has 3 contractions in a row for a 10 minute period. Then the Pitocin is stopped.

This should be done when the baby is mature enough to be delivered. This is done to see how well baby will react under the stress of labor.

In relation to a contraction, the FHR typically goes down. This happens because blood supply is cut off briefly to the fetus.

Positive is not good.

Bradycardia = <100

Tachycardia = >160

Acceleration = a reassuring FHR pattern; it’s not dangerous; goal of NST.

Deceleration = non-reassuring pattern. A drop in FHR. Need to see if normal or abnormal in relation to the contraction. Must look at where it occurs in the contraction.

A. Early: head compression, mirrors contraction, rarely drops below 100/min, usually do not have to do any interventions.

B. Late: Utero/placental insufficiency (UPI), trouble started late after contraction, contraction over and still low HR, almost V shaped. Intervention: Left side, 8-10 oxygen, increase fluids, stop oxytocin (RN).

C. Variable: cord compression, can occur before, middle or at end of contraction, serious sign, shapes on a strip are going to be varied. Intervention: Put in Trendelenburgh position, emergency C-section.

Causes of variability: narcotics, immaturity, hypoxia, acdosis.

Note: There should be a variable between FHR to let us know autonomic nervous system is working.