1.1 Antepartum Maternal Medical Conditions & Assessment

1.1 Antepartum Maternal Medical Conditions & Assessment

High-risk antepartum nursing care requires a precise understanding of how preexisting and pregnancy-induced maternal medical conditions impact both maternal organ systems and fetal development. Effective inpatient and outpatient antepartum management hinges on early risk identification, continuous diagnostic surveillance, tailored pharmacological intervention, and structured patient education.

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Diabetes Mellitus in Pregnancy

Diabetes in pregnancy is categorized into Preexisting (Pregestational) Diabetes (Type 1 or Type 2) and Gestational Diabetes Mellitus (GDM). Pregestational diabetes carries significant risk during organogenesis (the first 3 to 8 weeks of gestation), whereas GDM typically develops in the second half of pregnancy due to placental hormone-induced insulin resistance.

Pathophysiology & Placental Hormones

Starting around 20 to 24 weeks gestation, human placental lactogen (hPL, also known as human chorionic somatomammotropin), human placental growth hormone, progesterone, cortisol, and prolactin surge. These hormones act as insulin antagonists, raising maternal blood glucose to ensure an uninterrupted glucose gradient across the placenta for the growing fetus. In GDM, the maternal pancreas cannot compensate with adequate additional insulin secretion.

Pregestational Diabetes & Glycemic Targets

• Glycated Hemoglobin (HbA1c): Optimize control before conception (commonly aiming below 6.5%) and use an individualized pregnancy goal; a value below 6% may be optimal when achievable without significant hypoglycemia. Higher periconception glucose increases congenital-anomaly risk, so provide counseling and early anatomic surveillance without assigning an unsupported individual percentage.
• White's Classification: Ranges from Class A1 (diet-controlled GDM) and Class A2 (medication-controlled GDM) to advanced pregestational classes involving microvascular and macrovascular end-organ damage:
  • Class B: Onset age >= 20, duration < 10 years.
  • Class C: Onset age 10-19, duration 10-19 years.
  • Class D: Onset age < 10, duration >= 20 years, or benign retinopathy.
  • Class R: Proliferative retinopathy or vitreous hemorrhage.
  • Class F: Nephropathy with proteinuria > 500 mg/day.
  • Class H: Ischemic heart disease.
  • Class T: Renal transplant.

GDM Diagnostic Screening Guidelines

Obstetric protocols use a 1-step or 2-step GDM diagnostic strategy at 24 to 28 weeks. At the initial prenatal visit, assess risk and test for previously unrecognized pregestational diabetes when indicated; do not automatically label early abnormal glycemia as routine GDM without applying the current diagnostic protocol:

Blood Glucose Targets & Medical Management

For both pregestational and gestational diabetes, strict self-monitoring of blood glucose (SMBG) is required (fasting plus 1-hour or 2-hour postprandial levels):

• Fasting: < 95 mg/dL (5.3 mmol/L)
• 1-Hour Postprandial: < 140 mg/dL (7.8 mmol/L)
• 2-Hour Postprandial: < 120 mg/dL (6.7 mmol/L)
• Overnight (2 AM–4 AM): > 60 mg/dL

First-Line Therapy: Individualized medical nutrition therapy, regular activity when safe, and glucose monitoring. Meal timing and carbohydrate distribution should be tailored to glucose patterns, nutrition needs, culture, access, and medication plan rather than imposed as one universal macronutrient prescription.

Pharmacotherapy: If nutrition and activity do not meet targets, insulin is the preferred medication and does not cross the placenta. Select basal and mealtime components and titrate from actual glucose patterns, gestational needs, hypoglycemia risk, access, and the maternal-fetal medicine plan. Metformin crosses the placenta and may be used after counseling in selected patients; glyburide is not a preferred first-choice substitute for insulin.

Fetal and Neonatal Complications of Diabetes

• Macrosomia: Estimated fetal weight >= 4,000 to 4,500 grams, driven by maternal hyperglycemia causing fetal hyperinsulinemia and deposition of subcutaneous fat over the shoulders and abdomen.
• Polyhydramnios: Fetal hyperglycemia leads to osmotic diuresis, increasing amniotic fluid volume (AFI >= 24 cm).
• Neonatal Hypoglycemia: Post-delivery loss of maternal glucose influx while fetal insulin remains elevated creates early hypoglycemia risk. Screen and treat by postnatal age, symptoms, risk status, measurement method, and the nursery protocol rather than one universal cutoff.
• Delayed Fetal Lung Maturity: High fetal insulin levels inhibit surfactant production by suppressing phosphatidylglycerol (PG) synthesis.

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Chronic Hypertensive Disorders in Pregnancy

Chronic hypertension in pregnancy is defined as blood pressure >= 140 mmHg systolic or >= 90 mmHg diastolic present prior to pregnancy or diagnosed before 20 weeks gestation, or persisting beyond 12 weeks postpartum.

Clinical Management & Antihypertensive Dosages

For chronic hypertension in pregnancy, initiate or titrate maintenance therapy at 140/90 mmHg. Treatment goals are individualized; the CHAP trial did not establish a single ideal lower target.

1. Labetalol (Combined Alpha/Beta-Blocker): First-line. Dose: 100 to 400 mg PO BID or TID; maximum total daily dose 2,400 mg. Contraindicated in maternal asthma, severe bradycardia, or heart block.
2. Nifedipine Extended-Release (Calcium Channel Blocker): First-line. Dose: 30 to 60 mg PO once daily; maximum dose 120 mg daily. Avoid sublingual immediate-release nifedipine due to risk of rapid uncontrolled hypotension.
3. Methyldopa (Central Alpha-2 Agonist): Second-line due to sedating effects and mild efficacy. Dose: 250 to 500 mg PO BID or TID; maximum dose 3,000 mg daily.

CONTRAINDICATION WARNING: Renin-angiotensin system blockers—including ACE Inhibitors (e.g., enalapril, lisinopril), Angiotensin II Receptor Blockers (ARBs, e.g., losartan), and Direct Renin Inhibitors—are strictly contraindicated in pregnancy. Exposure causes fetal renal dysgenesis, severe oligohydramnios, pulmonary hypoplasia, intrauterine growth restriction (IUGR), and neonatal skull hypoplasia.

Preeclampsia Risk Reduction

Patients with chronic hypertension, pre-gestational diabetes, multifetal gestation, renal disease, or autoimmune disease are at high risk for super-imposed preeclampsia. ACOG recommends low-dose aspirin (81 mg/day) between 12 and 28 weeks gestation (ideally initiated before 16 weeks) and continued until delivery.

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Maternal Thyroid Disorders

Hypothyroidism

Overt hypothyroidism is identified with pregnancy- and assay-specific thyroid reference ranges, typically an elevated TSH with low free T4; fixed 2.5/3.0 mIU/L cutoffs should not replace laboratory and clinical context. Left untreated, it increases the risk of preeclampsia, low birth weight, placental abruption, and permanent fetal neurocognitive impairment.

• Treatment: Levothyroxine (Synthroid). Patients already taking levothyroxine commonly need an early empiric increase of roughly 20% to 30% after pregnancy is confirmed, followed by prompt testing and individualized titration. Recheck TSH about every 4 weeks during the first half of pregnancy and after dose changes, then at least once near 30 weeks, using pregnancy- and assay-specific targets.
• Administration: Instruct patient to take levothyroxine in the morning on an empty stomach 30 to 60 minutes before breakfast, separated from iron, calcium, and prenatal vitamins by at least 4 hours.

Hyperthyroidism (Graves' Disease)

Hyperthyroidism is characterized by suppressed TSH (< 0.1 mIU/L) and elevated free T4/T3. Untreated Graves' disease can trigger maternal thyroid storm, heart failure, and fetal hydrops or intrauterine growth restriction.

• First Trimester Treatment: Propylthiouracil (PTU) (100 to 150 mg PO TID). PTU is preferred in the first trimester because methimazole is associated with rare teratogenic embryopathy (aplasia cutis and choanal atresia).
• Second & Third Trimester Treatment: Switch from PTU to Methimazole (10 to 20 mg PO daily) at 14 weeks gestation to avoid PTU-induced severe maternal hepatotoxicity.

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Other Maternal Conditions Affecting Fetal/Newborn Care

Infection and STI

Review prenatal results and current risk rather than assuming a negative early screen remains current. Syphilis in pregnancy requires prompt stage-appropriate penicillin treatment and coordinated maternal titer and fetal follow-up; penicillin is the proven therapy for preventing congenital syphilis. For HIV, support continuous antiretroviral therapy, current viral-load review, birth planning, and neonatal prophylaxis. Hepatitis B surface-antigen positivity triggers neonatal vaccine and hepatitis B immune globulin promptly after birth. Rubella or varicella nonimmunity leads to exposure prevention and postpartum vaccination rather than live vaccine during pregnancy. New fever, rash, respiratory illness, genital lesions, or exposure requires organism-specific precautions and maternal-fetal assessment.

Hematologic, Respiratory and Hepatic Disease

Differentiate iron deficiency from hemoglobinopathy or hemolysis before treating anemia. Sickle cell disease raises risk for pain crisis, infection, thrombosis, growth problems, and preterm birth; maintain oxygenation, hydration appropriate to cardiopulmonary status, analgesia, and specialist planning. Thrombocytopenia requires the count trend, cause, bleeding findings, hypertensive disease, medications, and anesthesia/birth plan—not a label alone.

Continue effective asthma control because maternal hypoxemia threatens both patients; assess peak symptoms, triggers, adherence, and rescue use, and escalate respiratory distress early. Pruritus of palms and soles without rash raises concern for intrahepatic cholestasis and prompts bile-acid/liver evaluation and fetal/birth planning. Nausea, pain, jaundice, hypoglycemia, coagulopathy, or encephalopathy late in pregnancy can signal severe hepatic disease such as acute fatty liver and requires emergency multidisciplinary care.

Obesity, Bariatric History and Autoimmune Disease

Use respectful, bias-free care, correctly sized blood-pressure cuffs and equipment, weight-appropriate medication and thromboprophylaxis plans, and early anesthesia/operative readiness when indicated. After bariatric surgery, assess iron, folate, vitamin B12, calcium/vitamin D, protein intake, dumping or hypoglycemia symptoms, and altered medication absorption rather than focusing only on body mass index.

Systemic lupus, antiphospholipid syndrome, and other connective-tissue disorders require disease-activity and medication review. Antiphospholipid syndrome changes thrombosis and pregnancy-loss prevention; anti-Ro/SSA or anti-La/SSB antibodies raise fetal conduction and neonatal-lupus concerns. Do not stop effective medication reflexively—verify pregnancy safety and balance flare risk with fetal risk.

Genetic Screening and Counseling

Obtain a three-generation family and pregnancy history when possible and offer carrier or aneuploidy screening according to current guidance and patient goals. Screening estimates risk; chorionic-villus sampling and amniocentesis are diagnostic procedures with different timing and risks. Use informed, nondirective counseling, qualified interpreters, and genetics referral for a positive screen, structural anomaly, known familial condition, recurrent loss, or patient request.

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Maternal Cardiac Disease

Cardiac disease affects 1% to 3% of pregnancies and remains a leading cause of indirect maternal mortality. Hemodynamic changes peaking between 28 and 32 weeks gestation (a 40% to 50% expansion in cardiac output and blood volume) challenge maternal cardiac reserve.

NYHA Functional Classification in Pregnancy

• Class I: Unrestricted physical activity; no symptoms of cardiac insufficiency.
• Class II: Slight limitation of physical activity; comfortable at rest, but ordinary activity causes fatigue, dyspnea, or angina.
• Class III: Marked limitation of physical activity; less-than-ordinary activity causes symptoms. Requires specialist management and individualized activity planning.
• Class IV: Inability to perform any physical activity without discomfort; symptoms of cardiac insufficiency present even at rest.

High-Risk Cardiac Conditions Requiring Expert Counseling

• Eisenmenger syndrome / severe pulmonary arterial hypertension
• Marfan syndrome with aortic root dilatation > 40 mm
• Severe symptomatic mitral stenosis or aortic stenosis
• Peripartum cardiomyopathy with residual left ventricular dysfunction (LVEF < 30%)

Nursing Assessment & Interventions

• Decompensation Signs: Progressive dyspnea, orthopnea, nocturnal cough, hemoptysis, crackles at lung bases, new or changing murmur, jugular venous distension, and peripheral edema.
• Positioning: Avoid prolonged supine positioning; use lateral positioning when aortocaval compression is suspected and tailor positioning to symptoms and hemodynamics.