11.5: Care in the Third Trimester of Pregnancy
By the end of this section, you will be able to:
- Analyze the subjective and objective patient data obtained in the patient interval history and physical exam
- Explain the purpose of the laboratory tests obtained during the third trimester
- Provide the patient education during the third trimester
Third trimester follow-up prenatal visits, like the prenatal visits in the first and second trimesters, include obtaining the interval history data, a limited physical exam, appropriate laboratory and diagnostic tests, and patient education. Fetal movement is also assessed. Ultrasound scans are performed to monitor fetal weight when the fundal height is more than 2 cm below or above the expected measurement. Additional laboratory testing is performed at 36 weeks of gestation. The pregnant patient continues to be screened for complications of the pregnancy. If the pregnancy continues to be normal, the follow-up visits are scheduled for every 2 weeks until 36 weeks of gestation and then weekly until delivery.
Prenatal Care: Part 1
Brianne is a 36-year-old high school teacher who has come to the OB/GYN office because of a positive home pregnancy test.
Brianne states she and her partner, Trey, had discussed having children and stopped using birth control 6 months previously. Trey came with Brianne to the office. Brianne also informs the nurse she has noticed her breasts are tender and her most recent period was 6 weeks ago.
| Past medical history (PMH) |
Medical history:
Family history: Father has type 2 diabetes mellitus and mother has HTN Social history : Brianne and Trey live in a two-bedroom apartment on the second floor in a building with only a freight elevator. They have a small dog named Candy. Trey works for a construction company and is 40 years old. Neither Candy nor Trey smokes. Trey does drink an occasional beer. Candy does not drink alcoholic beverages. No current medications and allergy to penicillin |
| Flowchart |
Height: 5 ft 3 in.
Weight: 135 lb BMI: 26.9 First prenatal visit BP: 112/72 |
| Lab results |
Initial prenatal visit
Rubella titer nonimmune Urine culture positive for GBS 26 weeks’ gestation 1-hour GCT 155 Hemoglobin 11.8 Hematocrit 34.2 |
| Diagnostic tests/imaging results |
Initial prenatal visit
Intrauterine pregnancy Fetal heart rate 160 6 weeks’ gestation 20 weeks’ gestation Ultrasound negative for congenital anomalies Fetal heart rate 148 |
| Provider’s orders |
Initial prenatal visit
Prenatal vitamins: one tablet daily 26 weeks’ gestation Nutritional consult RhoGAM workup |
Interval History Data
In the third trimester , the nurse obtains intake data comparable to data obtained in the second trimester. The interval history data include reviewing the pregnant patient’s chart and pertinent data list, taking the patient’s blood pressure, weighing the patient, and performing the dipstick urinalysis if indicated. The nurse assesses the patient’s nutritional status if the patient’s weight gain is more or less than expected at each prenatal visit. An elevated BP of 140/90 or higher in the third trimester can be a sign of preeclampsia (ACOG, 2020a).
The interval history data include asking the patient if the fetus is moving in a normal pattern. The nurse asks the patient if they are aware of any Braxton Hicks contractions . The results of any laboratory tests from the previous prenatal visit are reviewed with the patient before the nurse completes the interval history.
The interval history is obtained at each visit in the third trimester to screen the patient for complications of pregnancy . The list of symptoms is the same in the third trimester as for the second trimester and includes the following:
- vaginal discharge, bleeding, or leaking of fluid
- persistent vomiting
- epigastric or abdominal pain
- pelvic pressure or uterine cramping
- Braxton Hicks contractions
- back pain or dysuria
- dizziness or syncope
- headache
- edema in the legs, hands, or face
- visual disturbances
- decrease in fetal movements
The nurse asks follow-up questions and, when the patient has an affirmative response to any of the symptoms, determines if any additional testing is needed. Table 11.10 delineates each patient sign or symptom and links it with the associated complication of pregnancy in the third trimester of pregnancy.
| Symptom | Possible Complication |
|---|---|
| Decreased fetal movement | Intrauterine fetal demise or fetal distress |
| Persistent vomiting | Hyperemesis gravidarum, dehydration |
| Dysuria, intermittent back pain | UTI |
| Pelvic pressure, lower abdominal cramping | Preterm labor |
| Vaginal bleeding | Placenta previa or placental abruption |
| Temperature >38.3° C (101° F) | Infection |
| Persistent abdominal pain, epigastric pain | Cholelithiasis, liver disease, GERD, preeclampsia, HELLP |
| Frequent dizziness | Anemia, dehydration, infection, heart disease |
| Leaking of fluid from the vagina | Vaginitis, ROM |
| Headache | Hypertension |
| Edema | Hypertensive disorders of pregnancy |
Physical Exam
The physical exam of the pregnant patient in the third trimester includes measuring the fundal height , auscultating the fetal heart rate , and assessing for edema. After 36 weeks of gestation, the measurement of the fundal height in centimeters no longer approximates the number of weeks of gestation. At this point in the pregnancy, the fetus begins descending into the pelvis of the pregnant patient in preparation for labor and birth. If the patient responded yes to any of the symptoms at the interval history, relevant data are obtained at this time, such as by drawing blood for a liver function panel if the pregnant patient has epigastric pain.
Leopold’s Maneuvers
At 32 weeks or more of gestation, the physical exam of the pregnant patient includes Leopold’s maneuvers . Leopold’s maneuvers are a set of four steps (maneuvers) performed by the nurse when palpating the pregnant patient’s abdomen. The maneuvers determine the fetal lie, fetal presentation, location of the fetal back, and fetal position in the pelvis. The fetal lie is the relationship of the fetal spine to the pregnant patient’s spine. In the longitudinal lie , the fetal spine lines up vertically with the pregnant patient’s spine. In the transverse lie , the fetal spine is horizontal to the pregnant patient’s spine, like the plus (+) sign. When the fetal spine lines up diagonally with the pregnant patient’s spine, the fetus is in an oblique lie (Figure 11.6).
The fetal presentation is the part of the fetus entering the pregnant patient’s pelvis first. When the fetal head enters the pelvis first, the presentation is cephalic . When the fetal buttocks (or legs) enter the pelvis first, the presentation is breech . When the fetus is in a transverse lie, the presentation is shoulder (Figure 11.7).
Performing Leopold’s maneuvers assists the nurse in determining the best place on the pregnant patient’s abdomen to auscultate the fetal heart rate. The fetal heart rate is heard loudest through the fetal back around the shoulder blades of the fetus. The movement of the fetal arms and legs interferes with the nurse’s ability to auscultate the fetal heart rate through the fetal chest, especially when using a Doppler monitor. The nurse counts the fetal heart rate for 1 minute and assesses the rhythm. Leopold’s maneuvers, along with the measurement of the fundal height, can also be used to estimate the fetal weight.
The four Leopold’s maneuvers are as follows:
- Palpate the sides of the pregnant patient’s abdomen to determine the fetal lie.
- Palpate the fetus to determine the location of the fetal back.
- Palpate the fundus and identify the fetal parts in the fundus.
- Palpate the suprapubic area to identify the fetal presentation.
Descriptions of how to perform Leopold’s maneuvers are found in Chapter 16 Electronic Fetal and Uterine Contraction Monitoring.
Vaginal Exam
Starting at 36 weeks’ gestation or later, a vaginal exam is performed when indicated by the interval history or upon request by the pregnant patient. Using a gloved hand, the health-care provider places their lubricated index and adjacent finger gently into the patient’s vagina. Using the two fingers, the health-care provider locates the cervix and estimates its length and then inserts one or both fingers into the cervical os to determine if the cervix is open. Next, the health-care provider palpates and identifies the fetal presenting part and determines how far down inside the pelvis the presenting part has descended. One purpose of the vaginal exam is to determine if the cervix is ripening. The softening and opening of the cervix as it prepares for labor is called cervical ripening , and it may occur as early as 37 weeks for multiparas and is more likely to occur at 39 weeks or later for primiparas.
Laboratory Tests
Laboratory testing on pregnant patients during the third trimester occurs at 36 weeks of gestation. The testing includes an H&H or CBC, VDRL or RPR, vaginal and rectal swab check for group B beta-hemolytic streptococcus (GBS), and cervical cultures for chlamydia and gonorrhea . The testing is performed at 35 to 37 6/7 weeks to have the results before the patient goes into labor and is valid for up to 5 weeks (ACOG, 2020b). A blood sample for the H&H or CBC is drawn to monitor the pregnant patient for anemia and a low platelet count. The VDRL or RPR and the cervical cultures for chlamydia and gonorrhea are repeated at 36 weeks of gestation. If testing is positive for any of the three STIs, there is time to treat the pregnant patient before labor and birth, decreasing the chance of newborn infection.
Group B beta-hemolytic streptococcus is one of the leading causes of newborn infection. Twenty-five percent of pregnant patients are carriers of GBS. The vaginal and rectal swab for GBS is performed to identify carriers of GBS, if not already identified earlier in the pregnancy. If the GBS culture is positive, the pregnant patient is provided the results and treatment with antibiotics is recommended during the labor process. Treatment is delayed until labor because the GBS bacteria can recolonize the vagina before the birth when treated antepartum.
Education in the Third Trimester
In the third trimester of pregnancy, patient education topics are very similar to the topics discussed in the second trimester and include the following:
- fetal growth and development
- fetal movement counts
- reinforcement of health promotion activities
- travel
- physiologic changes during the third trimester of pregnancy
- psychologic changes during the third trimester of pregnancy
- signs and symptoms of labor
- childbirth education
- choosing a health-care provider for the newborn
- signs of complications
- laboratory testing and results
- breast-feeding
- childbirth preparation
- completion of birth plan
The nurse continues to reinforce a healthy diet and regular exercise in the third trimester and provides education on fetal health. The importance of daily fetal movement counts is emphasized throughout the third trimester. As long as the pregnancy remains normal, pregnant patients can fly throughout the pregnancy (ACOG, 2018). If the pregnant patient is traveling a long distance by automobile, the patient is encouraged to stop frequently (hourly) to void and take a 5-minute walk. Additional topics for patient education are the need to choose a health-care provider for the newborn, childbirth education classes, and the signs and symptoms of labor.
The pregnant patient can screen for fetal health by performing fetal movement counts every day, but not until the end of the second trimester. The nurse teaches the patient how to perform a daily fetal movement count . The patient is instructed to do the following:
- Choose a start time when the fetus (baby) is most active.
- Count each time the baby moves.
- Note the amount of time it takes the baby to move a minimum of ten (10) times.
The fetus is expected to move a minimum of 10 times within 2 hours. If the fetus does not move 10 times within the 2 hours, the patient needs to call their health-care provider. Decreased fetal movement has been linked with low blood sugar in the pregnant patient and poor placental perfusion, resulting in fetal stress and distress.
Patient education in the third trimester focuses on many of the same signs of complications of pregnancy as the second trimester. Vaginal bleeding can occur with a known placenta previa or placental abruption, or it can simply indicate normal bloody show of labor. The presence of edema is associated with hypertensive disorders of pregnancy, or the edema may just be dependent edema in the lower extremities due to the weight of the gravid uterus. See Table 11.10 for additional signs and symptoms of complications to discuss with the patient in the third trimester of pregnancy.