Pregnancy Comp 2

Rh Incompatibility and Isoimmunization

• Definition and Mechanism:

  • Rh Factor: A surface antigen located on red blood cells (RBCs) that the immune system can identify and potentially create antibodies against.

  • Rh Incompatibility: Occurs when a pregnant woman who is Rh-negative (lacks the surface antigen) is exposed to Rh-positive blood (contains the antigen), typically from the fetus.

  • Isoimmunization: The process by which the mother’s immune system, upon contact with fetal Rh-positive blood, produces antibodies against the Rh antigen. These antibodies have the capacity to cross the placenta and destroy fetal red blood cells.

• Exposure Triggers: Contact with fetal blood can occur during various events, including:

  • Spontaneous abortion.

  • Trauma.

  • Invasive obstetric procedures.

  • Normal childbirth.

• Progression in Subsequent Pregnancies:

  • The fetus in the first pregnancy is rarely affected as the sensitization process is occurring.

  • In subsequent pregnancies with an Rh-positive fetus, the mother's sensitized immune system produces Rh antibodies that cross the placenta into fetal circulation.

  • Antigen-Antibody Complexes: Once in fetal circulation, these antibodies form complexes with fetal Rh-positive RBCs, leading to their destruction.

  • Alloimmune-Induced Hemolytic Anemia: The medical condition resulting from the massive destruction of fetal RBCs due to this incompatibility.

• Signs/Symptoms and Diagnostic Testing:

  • Maternal Symptoms: The woman will physically notice no symptoms of Rh incompatibility.

  • Indirect Coombs’ Test: A routine prenatal laboratory test performed on the mother’s serum to detect antibodies against RBCs that could induce hemolysis.

  • Direct Coombs’ Test: Performed on the umbilical cord blood at the time of birth to determine if antibodies are attached to the baby's RBCs.

  • Agglutination: A positive test result indicated by the clumping of red blood cells.

    • In a Direct Coombs’ test, agglutination suggests antibodies are present on the patient's RBCs, and hemolysis may persist.

    • In an Indirect Coombs’ test, agglutination suggests circulating antibodies that could react to foreign RBCs, such as during a transfusion.

• Medical and Nursing Management:

  • Blood Typing: All pregnant women must have their blood type and Rh factor determined early in pregnancy.

  • Antibody Monitoring: If the mother is Rh-positive, the fetus is not at risk. If Rh-negative, the mother is evaluated for antibody levels and the fetus is monitored closely.

  • RhoGAM (Rhophylac):

    • Standard Administration: Administered at $28$ weeks of gestation.

    • Purpose: Prevents the formation of antibodies in the mother against Rh-positive blood.

    • Emergency/Procedure Administration: Administered after abortion, chorionic villus sampling, amniocentesis, or trauma.

    • Postpartum Administration: If the baby is Rh-positive, RhoGAM must be administered within $72$ hours of childbirth.

  • Amniocentesis: May be used to evaluate the amount of bilirubin in the amniotic fluid. A rise in bilirubin indicates the fetus is losing an excessive amount of red blood cells.

  • Nursing Responsibilities: Encouraging compliance with blood tests, providing emotional support for sensitization (positive titer), and ensuring cord blood is sent to the lab at birth.

Multiple Gestations

• Risk Factors: Risk increases if the mother uses fertility drugs, is older, has a family history of multiples, or utilizes assisted reproductive technologies (ART).

• Signs and Symptoms:

  • Rapid weight gain during the first trimester.

  • Intense nausea and vomiting due to higher hormone levels.

  • Extreme breast tenderness caused by increased hormones.

• Medical Care:

  • Nutrition: Mothers of twins should gain at least $35$ to $45$ pounds and require increased intake of calories, protein, and nutrients like iron.

  • Provider Visits: Frequent checkups are necessary to detect complications early.

  • Activity: Increased rest or bedrest may be required, often beginning in the middle of the second trimester.

  • Specialty Care: Referral to a perinatologist for specialized testing and coordination of care.

• Potential Complications:

  • Incompetent cervix.

  • Preterm labor.

  • Pre-eclampsia.

  • Gestational diabetes.

  • Placental abruption.

  • Infants Small for Gestational Age (SGA).

  • Increased risk for Cesarean birth.

• Nursing Care and Patient Education:

  • Instruct the patient on signs of Preterm Labor: contractions, cramping, low back ache, increased vaginal discharge, loss of mucous plug, pelvic pressure, or a sudden gush of fluids.

  • Continuous fetal heart rate monitoring during labor.

  • Ensuring extra medical staff (nurses and physicians) are present at birth for potential newborn complications.

  • Reporting signs of hypertension: increased edema, headaches, and visual disturbances.

Prenatal Urinalysis Guidelines

• Procedure: A clean-catch urine specimen is requested at each prenatal visit to screen for early complications.

• Components Checked:

  • Protein: High levels may indicate a urinary tract infection (UTI), kidney disease, or pre-eclampsia (if combined with high blood pressure later in pregnancy).

  • Sugar: While some leakage is normal during pregnancy, high levels may indicate Gestational Diabetes.

  • Ketones: Presence indicates the body is breaking down fats instead of carbohydrates for energy, suggesting dehydration or inadequate nutritional intake.

  • Bacteria, Leukocytes, and Nitrites: These indicators point toward a potential urinary tract infection.

  • White Blood Cells: Related to bladder or kidney infections.

Hypertension Disorders in Pregnancy

• Classifications:

  • Gestational Hypertension: Blood Pressure (BP) of $\ge 140/90\,mm\,Hg$ for the first time during pregnancy (after $20$ weeks), with no proteinuria. BP returns to normal less than $12$ weeks postpartum.

  • Chronic Hypertension: BP of $\ge 140/90\,mm\,Hg$ existing before pregnancy or occurring before $20$ weeks' gestation.

  • Pre-eclampsia: BP of $\ge 140/90\,mm\,Hg$ occurring after $20$ weeks' gestation accompanied by proteinuria and often edema.

  • Severe Pre-eclampsia (SPE): BP $\ge 160/110\,mm\,Hg$ with high levels of proteinuria, oliguria, possible pulmonary edema, and abnormal liver function tests.

  • Eclampsia: Includes all signs of pre-eclampsia plus the presence of seizures or coma.

• Pathophysiology of Pre-eclampsia:

  • The condition is believed to originate in the placenta. During implantation, placental villi do not develop into arteries properly, leading to placental hypoxia.

  • The hypoxic placenta releases antiangiogenic proteins into maternal circulation, causing systemic endothelial cell injury and vasospasms.

  • Cardiovascular Effects: Vasoconstriction increases BP. Damage to endothelial cells increases capillary permeability, decreasing intravascular volume and predisposing the mother to pulmonary edema. There is also a hyper-reponse to angiotensin-II and epinephrine.

  • Renal Effects: Vasospasms lead to poor renal perfusion and loss of protein (proteinuria), which reduces colloid osmotic pressure and leads to edema. Labs show elevated Blood Urea Nitrogen (BUN), creatinine, and uric acid.

  • Hepatic Effects: Vasospasms impair liver function, causing hepatic edema, bleeding, and necrosis. This results in elevated liver enzymes and epigastric pain.

  • Nervous System Effects: Cerebral edema and vasospasms can lead to frontal throbbing headaches, visual disturbances (flashing lights, auras, blurry vision, or dark spots), and seizures.

• Fetal Impact of Pre-eclampsia:

  • Intrauterine growth retardation (IUGR).

  • Placenta abruption.

  • Persistent fetal hypoxia.

  • Fetal death.

Medical and Nursing Management of Hypertensive Disorders

• Medical Care for Chronic and Gestational HTN:

  • Frequent prenatal checkups and daily rest (left-side positioning) to improve placental perfusion.

  • Sodium restriction to $1,500\,mg$ daily and avoidance of canned foods/table salt.

  • Medications: Preferred antihypertensives include Methyldopa and Nifedipine.

• Management of Pre-eclampsia:

  • Mild: Home bedrest, regular monitoring of BP and urine protein, and kick counts.

  • Severe: Hospitalization is required.

  • Magnesium Sulfate Therapy: Used to prevent seizure activity.

    • Loading Dose: $4$ to $6\,g$ administered IV over $5\,min$ via infusion pump.

    • Maintenance Dose: $2\,g/hour$.

    • Toxicity Signs: Hyporeflexia (diminished deep tendon reflexes) and depressed respirations.

  • Labor Induction: Labor may be induced with Prostaglandin gel (for cervical ripening) or Oxytocin. Vaginal delivery is preferred.

• Nursing Assessment:

  • Deep Tendon Reflexes (DTRs): Graded on a scale of $0$ (absent) to $+4$ (hyperactive). $+2$ is normal. Report and document $0$, $+3$, and $+4$.

  • Ankle Clonus: Tested by dorsiflexing the foot to stretch the Achilles tendon; a rapid tapping motion indicates hyperreflexia and brain irritability.

  • Vital Signs: BP at least every $2$ hours; hourly monitoring of urine output (minimum $400\,mL$ in $24$ hours).

  • Postpartum: Monitor for $48$ hours as eclampsia can still occur. Improvements include diuresis and normalized BP.

• Seizure Care (Eclampsia):

  • Clear the airway, administer oxygen, and ensure safety.

  • Document the length and description of the seizure.

  • Reorient the patient following the event.

HELLP Syndrome

• Acronym:

  • H: Hemolysis of red blood cells.

  • EL: Elevated Liver enzymes.

  • LP: Low Platelet count.

• Pathology: A severe variation of pre-eclampsia with a $25\%$ mortality rate. Fibrin deposits from hemolysis decrease blood flow to the liver, leading to impairment and potentially hepatic rupture.

• Signs and Symptoms:

  • Pain in the upper right quadrant (RUQ) of the abdomen (epigastric pain).

  • Elevated lactate dehydrogenase (LDH), AST, ALT, BUN, and bilirubin.

  • Low platelet count leading to bleeding issues (nosebleeds, difficulty stopping bleeding).

  • Jaundice, blurry vision, and fluid retention.

  • Often mistaken for gastritis, flu, or gallbladder disease.

• Risk Factors: Caucasian race, age $>25$, history of hypertension, or previous HELLP syndrome.

• Complications:

  • Disseminated Intravascular Coagulation (DIC).

  • Pulmonary edema.

  • Kidney and Liver failure.

  • Placenta abruptio.

• Medical Management: Delivery of the baby as soon as possible, administration of corticosteroids for fetal lung maturity, and blood/platelet transfusions.

Gestational Diabetes Mellitus (GDM)

• Pathophysiology:

  • Insulin resistance caused by placental hormones including estrogen, cortisol, and human placental lactogen (hPL).

  • These hormones block the effect of insulin. Normally, the pancreas increases production to compensate, but if it fails to overcome the resistance, GDM results.

  • Pregnancy also predisposes women to hypoglycemia between meals as the fetus constantly draws glucose.

• Risk Factors: Age $>25$, BMI $\ge 30$, previous macrosomic infant ($>9$ pounds), history of PCOS, African American, Hispanic, Native American, or Asian ethnicity.

• Screening: All pregnant women are screened between weeks $24$ and $28$ using a two-step Glucose Tolerance Test (GTT).

• Signs/Symptoms: Increased thirst, hunger, urination, fatigue, blurred vision, and frequent infections (vagina, bladder, skin).

• Maternal and Fetal Complications:

  • Maternal: Diabetic retinopathy, hypertension, and increased risk of Cesarean birth.

  • Diabetic Ketoacidosis (DKA): Can occur in GDM at lower blood sugar levels, approximately $200\,mg/dL$.

  • Fetal: Accelerated growth (large for gestational age), birth injuries (brachial plexus injury, facial nerve injury, cephalohematoma), and respiratory distress syndrome.

  • Neonatal Hypoglycemia: High maternal glucose causes high fetal insulin; after birth, the glucose source is gone but insulin remains high, risking seizures, coma, and brain damage.

• Fetal Well-being Testing:

  • Kick Counts: Reassuring if $10$ movements in $<2$ hours.

  • Non-Stress Test (NST): Reassuring if two heart rate accelerations occur in $20$ minutes.

  • Contraction Stress Test (CST): Reassuring if no heart rate decelerations occur in response to three contractions in $10$ minutes.

  • Biophysical Profile (BPP): Reassuring score is $8$ in $30$ minutes.

• Management Strategies:

  • Diet: First-line therapy. Six meals per day (three major, three snacks). Carbohydrates should be $\le 50\%$ of the meal and consist of complex carbs.

  • Monitoring: Finger-stick glucose monitoring on awakening, before meals, and $1$ to $2$ hours after meals.

  • Medication: Insulin or oral hypoglycemic medications if diet is insufficient.