N164 Maternity Exam 3 study guide

Two broad categories of antepartum fetal surveillance tools

Biophysical assessment, which uses fetal biophysical activity or imaging, and biochemical assessment, which uses lab analysis of maternal blood or fetal tissue and fluid

Examples of biophysical assessment tools

Daily fetal movement count, ultrasonography, Doppler blood flow analysis, biophysical profile, and the nonstress test and contraction stress test

Examples of biochemical assessment tools

Amniocentesis, chorionic villus sampling, percutaneous umbilical blood sampling, and maternal assays such as alpha-fetoprotein and cell-free DNA screening

Daily fetal movement count methods

Once a day for 60 minutes, or 2 to 3 times daily after meals for 2 hours each

Reassuring daily fetal movement count

10 movements within a 12-hour period

Biophysical profile (BPP)

A test combining 5 components, 4 ultrasound observations plus the nonstress test, to assess fetal well-being, with each component scored 2 or 0

The 5 components of the biophysical profile

Fetal breathing movements, gross body movement, fetal tone, reactive fetal heart rate on the NST, and qualitative amniotic fluid volume

Normal finding for fetal breathing movements on a BPP

1 or more episodes of rhythmic breathing lasting 30 seconds or more within 30 minutes

Normal finding for gross body movement on a BPP

3 or more discrete body or limb movements within 30 minutes

Normal finding for amniotic fluid volume on a BPP

1 pocket of fluid measuring at least 2 cm in vertical axis

BPP score indicating a reassuring result

8 to 10 with normal fluid, indicating low risk of chronic fetal asphyxia

BPP score indicating strong suspicion of chronic fetal asphyxia

4 or less, requiring further evaluation and likely birth

Modified biophysical profile

Combines the nonstress test with the amniotic fluid index only

A fetus scores 2 on breathing movements, 2 on body movement, 0 on tone, 2 on the NST, and 0 on amniotic fluid volume. What is the total BPP score and what does it suggest

A score of 6, which is equivocal and suggests chronic fetal asphyxia should be suspected, usually prompting repeat testing within 24 hours

Nonstress test (NST) theory

A healthy fetus with an intact autonomic nervous system will show acceleration of the fetal heart rate with fetal movement

Reactive NST

2 or more FHR accelerations peaking at 15 beats per minute or more above baseline, each lasting 15 seconds or more, within a 20-minute window

Nonreactive NST

Fails to meet reactive criteria after 40 minutes of monitoring

Purpose of vibroacoustic stimulation during an NST

To wake a sleeping fetus or elicit an FHR response if the tracing is nonreactive

Contraction stress test (CST) purpose

Evaluates the respiratory function of the placenta by observing the fetal heart rate response to uterine contractions, giving an earlier warning of fetal compromise than the NST

How contractions are stimulated for a CST

Nipple stimulation or IV oxytocin, until 3 contractions lasting 40 seconds or more occur within a 10-minute window

Negative CST result

No late decelerations with any contraction, a normal result

Positive CST result

Late decelerations follow 50 percent or more of contractions, an abnormal result

A patient undergoing a CST has late decelerations after more than half of her contractions. How should the nurse document this result

As a positive CST, indicating an abnormal result

Ultrasound uses relevant to a diabetic pregnancy

Confirming gestational age, serial assessment of fetal growth to detect macrosomia, evaluating fetal anatomy for congenital anomalies, and assessing amniotic fluid volume for hydramnios

Why serial ultrasounds are important in gestational diabetes

To monitor for macrosomia and hydramnios, both recognized complications of diabetes in pregnancy

Normal physiologic dyspnea of pregnancy

Caused by progesterone increasing tidal volume and sensitizing the respiratory center to carbon dioxide, occurring with mild exertion or at rest without other signs of distress

Pathologic causes of dyspnea in pregnancy that must be ruled out

Cardiac disease, pulmonary embolism, asthma exacerbation, severe anemia, pulmonary edema, and amniotic fluid embolism

Most common symptom of heart disease in pregnancy

Dyspnea on exertion

A pregnant patient reports mild shortness of breath at rest in her third trimester with normal vital signs. How should the nurse interpret this

As likely normal physiologic dyspnea of pregnancy, since it occurs without other signs of distress

A pregnant patient reports sudden dyspnea with chest pain and tachycardia. What should the nurse suspect

A pathologic cause such as pulmonary embolism, requiring urgent evaluation rather than being dismissed as normal pregnancy dyspnea

Two-step screening approach for gestational diabetes

A 1-hour 50-g oral glucose tolerance test with no fasting required, followed by a 3-hour 100-g OGTT for diagnosis if the first test is elevated

One-step screening approach for gestational diabetes

A 2-hour 75-g OGTT after an overnight fast, with diagnosis made if any one value is met or exceeded

Target fasting blood glucose in pregnancy

95 mg per dL or less

Target 1-hour postprandial blood glucose in pregnancy

140 mg per dL or less

Target 2-hour postprandial blood glucose in pregnancy

120 mg per dL or less

First-line treatment for gestational diabetes

Medical nutrition therapy and exercise

Traditional first-line medication for gestational diabetes when diet and exercise are insufficient

Insulin, since it does not cross the placenta

Postpartum follow-up recommended after a diagnosis of gestational diabetes

A 2-hour 75-g OGTT at 6 to 12 weeks postpartum, since these women carry an increased lifelong risk for type 2 diabetes

Classic neonatal finding in an infant of a diabetic mother

Macrosomia, caused by fetal hyperinsulinemia in response to chronically elevated maternal glucose crossing the placenta

Why does an infant of a diabetic mother develop hypoglycemia after birth

The newborn continues producing high insulin levels after the maternal glucose supply is cut off at birth

Priority nursing interventions for a newborn of a diabetic mother

Early and frequent carbohydrate feedings, serum glucose monitoring, and adequate thermoregulation

A newborn of a diabetic mother appears large with a round, full face and becomes jittery 2 hours after birth. What should the nurse suspect and do

Neonatal hypoglycemia, and the nurse should check blood glucose promptly and initiate early feeding

Most common cause of hyperthyroidism in pregnancy

Graves' disease

Hyperthyroidism symptoms in pregnancy

Weight loss, heart rate over 100, goiter, heat intolerance, and nervousness

Hypothyroidism symptoms in pregnancy

Weight gain, lethargy, decreased exercise capacity, and cold intolerance

Preferred antithyroid medication in the first trimester for hyperthyroidism

Propylthiouracil (PTU)

Treatment for hypothyroidism in pregnancy

Thyroid hormone supplementation with levothyroxine, with the dose often needing to increase during pregnancy

Thyroid storm

A life-threatening exacerbation of uncontrolled hyperthyroidism with high fever, severe tachycardia, and heart failure

Why pregnancy increases risk of sickle cell crisis

The increased metabolic demands, physiologic hemodilution, and hypercoagulable state of pregnancy

Maternal risks of sickle cell anemia in pregnancy

Increased risk for preeclampsia, infection, pulmonary complications such as acute chest syndrome, and painful vaso-occlusive crises

Fetal risks of sickle cell anemia in pregnancy

Intrauterine growth restriction, preterm birth, and increased perinatal mortality from chronic placental hypoxia

Why folic acid supplementation is important in sickle cell anemia

Increased red blood cell turnover increases folate needs

Systemic lupus erythematosus (SLE) in pregnancy

An autoimmune disease that can flare during pregnancy, most commonly in the first and second trimester and the immediate postpartum period

Pregnancy risks associated with active lupus nephritis or antiphospholipid antibodies

Higher risk for preeclampsia, intrauterine growth restriction, and pregnancy loss

Most serious manifestation of neonatal lupus

Congenital heart block, caused by transplacental passage of maternal antibodies

Tobacco use effects in pregnancy

Ectopic pregnancy, placenta previa, placental abruption, preterm PROM, orofacial clefts, IUGR, low birth weight, and increased perinatal mortality

Safe amount of alcohol during pregnancy

No safe amount at any time in pregnancy

Most commonly used illicit drug in pregnancy

Marijuana

Cocaine and methamphetamine effects in pregnancy

Increased preterm labor, placental abruption, preeclampsia, IUGR, and low birth weight from vasoconstrictive effects

Why universal screening for substance use is recommended in pregnancy

All pregnant women should be screened regardless of age, race, or socioeconomic status, since risk cannot be reliably predicted by demographics alone

Barriers to substance abuse treatment in pregnancy

Social stigma, fear of losing custody or criminal prosecution, and treatment programs that don't address issues specific to pregnant women

Gestational hypertension

Blood pressure 140 over 90 mm Hg or higher on 2 occasions at least 4 hours apart, after 20 weeks gestation, without proteinuria or other signs of preeclampsia

Preeclampsia definition

Gestational hypertension plus proteinuria, or hypertension with evidence of other end-organ dysfunction even without proteinuria

Eclampsia

Seizure activity or coma in a woman with preeclampsia, with no other cause for the seizure

Chronic hypertension in pregnancy

Hypertension present before pregnancy or diagnosed before 20 weeks gestation, persisting after birth, without proteinuria

Chronic hypertension with superimposed preeclampsia

A sudden increase in previously controlled blood pressure or new onset proteinuria in a woman with chronic hypertension

Strongest risk factors for preeclampsia

Multifetal pregnancy, chronic hypertension, history of preeclampsia in a previous pregnancy, and pregestational diabetes

Fetal risk from hypertensive disorders in pregnancy

Reduced placental perfusion causing IUGR, oligohydramnios, preterm birth, and placental abruption

Blood pressure criteria for preeclampsia diagnosis

Systolic 140 mm Hg or higher, or diastolic 90 mm Hg or higher, on 2 occasions at least 4 hours apart, after 20 weeks gestation

Proteinuria criteria for preeclampsia diagnosis

300 mg or more in a 24-hour urine collection, or a protein to creatinine ratio of 0.3 or higher

Blood pressure defining preeclampsia with severe features

Systolic 160 mm Hg or higher, or diastolic 110 mm Hg or higher, on 2 occasions at least 4 hours apart

Laboratory findings that define preeclampsia with severe features

Thrombocytopenia below 100,000 per microliter, impaired liver function, and renal insufficiency with creatinine above 1.1 mg per dL

Symptoms that define preeclampsia with severe features

New onset headache unresponsive to medication, visual disturbances, and pulmonary edema

Underlying pathophysiology of preeclampsia

Disruptions in placental perfusion and endothelial cell dysfunction leading to generalized vasospasm

Deep tendon reflex findings concerning for worsening preeclampsia

Hyperreflexia and clonus

Immediate priority during an eclamptic seizure

Maintaining a patent airway and patient safety

Treatment goal for gestational hypertension or preeclampsia without severe features

Deliver as close to term as possible, around 37 weeks, with outpatient monitoring including twice-weekly BP checks and fetal surveillance

Is strict bed rest currently recommended for hypertensive disorders of pregnancy

No, activity restriction is no longer recommended since no evidence supports benefit

Prevention strategy for preeclampsia in high-risk women

Low-dose aspirin therapy

Magnesium sulfate loading dose for preeclampsia seizure prophylaxis

4 to 6 g IV over 20 to 30 minutes

Magnesium sulfate maintenance dose

1 to 4 g per hour

Therapeutic magnesium level for seizure prophylaxis

4 to 7.5 mEq per L, or 5 to 8 mg per dL

Signs of magnesium sulfate toxicity

Respiratory rate fewer than 12 breaths per minute, absent deep tendon reflexes, urine output less than 25 to 30 mL per hour, and altered level of consciousness

Antidote for magnesium sulfate toxicity

Calcium gluconate

Contraindications to magnesium sulfate

Myasthenia gravis, hypocalcemia, and renal failure

Maximum total IV intake while on magnesium sulfate

125 mL per hour

A patient on magnesium sulfate has a respiratory rate of 10 and absent deep tendon reflexes. What should the nurse do first

Stop the magnesium sulfate infusion immediately and prepare to administer calcium gluconate

General principle for interpreting the color of vaginal bleeding

Dark red blood is typically venous in origin while bright red blood is typically arterial in origin

Color of bleeding in placental abruption

Dark red

Color of bleeding in placenta previa

Bright red

Pain characteristic of placental abruption

Present, ranging from mild to agonizing unremitting uterine pain

Pain characteristic of placenta previa

Absent

Uterine tone in placental abruption versus placenta previa

Increased and possibly tetanic in abruption, versus normal and relaxed in previa

Why a vaginal exam should never be performed on a woman with active third-trimester bleeding until previa is ruled out

A digital exam can provoke severe hemorrhage if placenta previa is present

Hyperemesis gravidarum

Excessive vomiting in pregnancy accompanied by dehydration, electrolyte imbalance, ketosis, and acetonuria, distinct from normal morning sickness

Risk factors for hyperemesis gravidarum

History of hyperemesis in a prior pregnancy, carrying a female fetus, and multifetal gestation

Why thiamine is given before dextrose in severe hyperemesis gravidarum

To prevent Wernicke encephalopathy

HELLP syndrome

Hemolysis, Elevated Liver enzymes, and Low Platelets, a laboratory diagnosis representing a severe complication of preeclampsia

Risks associated with HELLP syndrome

Pulmonary edema, acute renal failure, disseminated intravascular coagulation, placental abruption, liver hemorrhage, and stroke

Macrosomia definition

Estimated fetal weight greater than 4000 to 4500 g, or greater than the 90th percentile for gestational age