What are the management strategies for common medical conditions during pregnancy, such as gestational diabetes, hypertension, and preeclampsia?

Management of Medical Conditions in Pregnancy

Hypertensive Disorders of Pregnancy

Blood pressure ≥160/110 mmHg requires urgent treatment in a monitored setting with oral nifedipine, intravenous labetalol, or intravenous hydralazine. 1, 2

Blood Pressure Thresholds and Treatment Initiation

• For gestational hypertension or pre-existing hypertension with organ damage/symptoms: initiate antihypertensive treatment at BP ≥140/90 mmHg 1
• For other hypertensive pregnant women without complications: initiate treatment at BP ≥150/95 mmHg 1
• Target diastolic BP of 85 mmHg and systolic BP between 110-140 mmHg to reduce severe maternal hypertension while minimizing impaired fetal growth 1, 2, 3
• Reduce or cease antihypertensives if diastolic BP falls below 80 mmHg 1

First-Line Antihypertensive Agents

Acceptable medications for chronic BP management include:

• Methyldopa, labetalol, oxprenolol, and nifedipine as first-line agents 1, 3
• Second or third-line: hydralazine and prazosin 1
• Avoid atenolol; other beta-blockers may be used if necessary 1
• Never use ACE inhibitors, angiotensin receptor blockers, or direct renin inhibitors during pregnancy—stop immediately at conception 1
• Chronic diuretic use is not recommended as it restricts maternal plasma volume and may reduce uteroplacental perfusion 1

Preeclampsia-Specific Management

Women with preeclampsia should be assessed in hospital at initial diagnosis; stable cases may transition to outpatient management with reliable BP monitoring and symptom reporting. 1

Maternal Monitoring Requirements

• BP monitoring with clinical assessment including clonus evaluation 1, 2
• Repeated proteinuria assessments if not already present 1
• Laboratory tests (hemoglobin, platelets, liver enzymes, renal function, uric acid) at minimum twice weekly 1
• Uric acid elevation is associated with worse maternal and fetal outcomes 1

Fetal Surveillance

• Initial ultrasound assessment to confirm fetal well-being 1
• In presence of fetal growth restriction, serial surveillance with fetal biometry, amniotic fluid assessment, and umbilical artery Doppler 1, 2

Magnesium Sulfate Prophylaxis

All women with preeclampsia who have proteinuria plus severe hypertension, OR hypertension with neurological signs/symptoms, must receive magnesium sulfate for seizure prophylaxis. 1, 2

Delivery Indications for Preeclampsia

Deliver at 37 weeks and 0 days gestation, or earlier if any of the following develop 1:

• Repeated severe hypertension despite 3 classes of antihypertensives
• Progressive thrombocytopenia
• Progressively abnormal liver or renal function tests
• Pulmonary edema
• Severe intractable headache, repeated visual scotomata, or convulsions
• Nonreassuring fetal status

Gestational Hypertension Without Preeclampsia

• Delivery can be delayed until 39 weeks and 6 days if BP is controlled, fetal monitoring is reassuring, and preeclampsia has not developed 2, 3
• Approximately 25% of gestational hypertension cases progress to preeclampsia, especially when diagnosed before 34 weeks 3

Postpartum Hypertension Management

• BP typically rises over the first 5 days postpartum 1
• Avoid methyldopa postpartum due to risk of postnatal depression 1
• Monitor BP for at least 6 weeks postpartum 2
• Women with hypertensive disorders have 4-fold increased risk of future hypertension and 2-fold increased risk of ischemic heart disease—counsel on lifestyle modifications and cardiovascular risk factor control 1

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Diabetes in Pregnancy

Preconception Management for Pre-existing Diabetes

Achieve optimal glycemic control before conception with target HbA1c <6.1% to minimize risk of congenital malformations and preeclampsia. 1, 4

Essential Preconception Components

• Comprehensive nutrition assessment with meal planning and correction of dietary deficiencies 1
• Diabetes self-management education covering insulin resistance changes, glycemic goals, and pregnancy risks 1
• Folic acid supplementation 400 mcg daily 1
• Stop ACE inhibitors, ARBs, and statins at conception 1
• Screen for and manage diabetic complications: retinopathy, nephropathy, neuropathy, cardiovascular disease 1
• Comprehensive ophthalmologic exam, ECG if age ≥35 years with risk factors, lipid panel, serum creatinine, TSH, urine albumin-to-creatinine ratio 1
• Contraceptive plan to prevent pregnancy until glycemic goals achieved 1

Glycemic Targets During Pregnancy

Stricter targets than non-pregnant state 1:

• Fasting glucose <95 mg/dL
• One-hour postprandial <140 mg/dL OR two-hour postprandial <120 mg/dL 1, 5

Type 1 Diabetes Management

• Insulin is the preferred treatment; never interrupt basal insulin therapy due to high risk of ketoacidosis 5
• Referral to registered dietitian nutritionist essential for carbohydrate counting and insulin-to-carbohydrate ratios 1
• Continuous glucose monitoring and insulin pump technology should be implemented as appropriate 1

Type 2 Diabetes Management

• Insulin is the preferred treatment for type 2 diabetes in pregnancy 1
• Often requires much higher insulin doses than type 1 diabetes, sometimes necessitating concentrated insulin formulations 1, 5
• Metformin added to insulin showed less maternal weight gain and fewer cesarean births, but doubled small-for-gestational-age neonates in one RCT 1
• Recommended weight gain: 15-25 lb for overweight women, 10-20 lb for women with obesity 1

Gestational Diabetes Mellitus (GDM)

• Screen all pregnant patients between 24-28 weeks gestation 6
• Management combines insulin administration and medical nutrition therapy to achieve same glycemic targets as pre-existing diabetes 1
• Women with history of GDM have 10-fold increased risk of type 2 diabetes: 20% at 10 years, 30% at 20 years, 40% at 30 years, 50% at 40 years, 60% at 50 years 1

Diabetes and Hypertension Interaction

The severity of gestational diabetes and prepregnancy BMI independently increase preeclampsia risk; optimizing glucose control may decrease preeclampsia rates even in severe GDM. 7

• Women with fasting plasma glucose >105 mg/dL have significantly higher preeclampsia rates (13.8% vs 7.8%) 7
• In poorly controlled GDM (mean blood glucose >95 mg/dL), fasting glucose >115 mg/dL increases preeclampsia risk 2.56-fold 7
• Each 1% decrement in HbA1c reduces preeclampsia risk, with strongest effect at 34 weeks gestation (OR 0.47) 4
• HbA1c ≥8.0% in early pregnancy increases preeclampsia risk 3.68-fold compared to optimal control 4

Labor and Delivery Management for Diabetes

Switch from subcutaneous insulin to intravenous insulin infusion during active labor for type 1 and type 2 diabetes, with concurrent 10% glucose infusion to prevent hypoglycemia and ketosis. 5

Timing of Delivery

• Delivery recommended by 38-39 weeks gestation to balance stillbirth risk against neonatal complications 5
• Earlier delivery indicated for poor glycemic control, hypertensive disorders, abnormal fetal testing, or fetal growth restriction 5
• Fetal surveillance should intensify during last 8-10 weeks with weekly antenatal testing reasonable after 32 weeks 5

Intrapartum Insulin Protocol

• Monitor blood glucose frequently during labor 5
• For insulin pump users: preferably switch to IV insulin, though pump retention possible with personalized protocol 5
• Maintain maternal glucose 4.0-7.0 mmol/L (72-126 mg/dL) during labor 5
• Never interrupt insulin in type 1 diabetes—high risk of ketoacidosis even with moderately elevated glucose 5

Immediate Postpartum Management

• Insulin requirements decrease dramatically immediately after placental delivery 5
• Type 1 diabetes: resume basal-bolus at 80% of pre-pregnancy doses OR 50% of end-pregnancy doses 5
• Type 2 diabetes: continue insulin at half-dose pending diabetologist consultation 5
• Target postpartum glucose 6-8.8 mmol/L (110-160 mg/dL) after vaginal delivery, slightly lower after cesarean for wound healing 5
• Vigilance for hypoglycemia essential, especially during breastfeeding and irregular sleep 5

Preeclampsia Prevention in Diabetes

Women with type 1 or type 2 diabetes should receive low-dose aspirin 100-150 mg daily (162 mg suggested) starting at 12-16 weeks gestation to reduce preeclampsia risk. 1, 6

• Aspirin >100 mg required for effectiveness; doses <100 mg are not effective 1
• Continue through 36 weeks of pregnancy 2

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Common Pitfalls and Critical Safety Points

Hypertension Management

• Severe hypertension (≥170/110 mmHg) is an emergency requiring hospitalization 1
• Home BP monitoring is mandatory for white-coat hypertension management 1, 2
• Proteinuria detection requires quantification with urine protein/creatinine ratio ≥30 mg/mmol (0.3 mg/mg) 1

Diabetes Management

• Interruption of basal insulin in type 1 diabetes rapidly leads to ketoacidosis 5
• Excessive postpartum insulin dosing causes severe hypoglycemia as requirements drop dramatically 5
• Inadequate glucose infusion during labor leads to maternal hypoglycemia and ketosis 5
• Insulin requirements that decrease to zero during first stage labor return during active pushing in second stage 5