Chronic hypertension
Definition of chronic hypertension in pregnancy
SBP >=140 mmHg or DBP >=90mmHg x2 occasions at least 4 hours apart, present before pregnancy or before 20 weeks of gestation
Risk factors for preeclampsia
Preeclampsia in a previous pregnancy
Nulliparity
Multifetal gestation
Chronic hypertension
Advanced maternal age
Obesity
Pregestational diabetes
SLE, APLS
IVF pregnancy
Etc.
Diagnosis of preeclampsia with severe features
Platelet <100k
LFTs twice upper limit of normal
Cr >1.1 or twice baseline
Pulmonary edema, persistent headaches, visual disturbances, persistent RUQ or epigastric pain
Contraindications to magnesium sulfate
Myasthenia gravis
Hypocalcemia
Moderate-to-severe renal failure
Cardiac ischemia, heart block, myocarditis
Timing of low-dose aspirin for preeclampsia prophylaxis
Between 12 and 18 weeks, ideally before 16 weeks
The physiologic trend of BP in pregnancy
Decrease in systemic vascular resistance leading to lower BP, nadir at 16-18 weeks, return to pre-pregnancy level by the third trimester
Initial workup for preeclampsia
30-60 minutes
Therapeutic range for serum magnesium
4.8 - 9.6 mg/dL (4-8 mEq/L)
Management of supratherapeutic magnesium level/mag toxicity
Stopped magnesium.
Mag level q2h.
Restart at lower rate when <8.4.
Calcium gluconate 10%, 10mL IV if impending respiratory depression
BP goal for patients with cHTN
<140/90
A patient at 34 weeks gestation with no prior diagnosis of HTN, has an isolated BP of 160/110 and proteinuria. What diagnosis does she have?
Preeclampsia.
BP 140/90 or more x2 occasions more than 4 hours apart. OR 160/110 or more x 1 time
AND
Proteinuria OR if no proteinuria, other lab abnormality or symptoms
Medication options for acute treatment of persistent severe range BPs and dosage
Labetalol, 20mg incr, max 300mg
Hydralazine, 5-10mg incr, max 20mg
Nifedipine, 10-20mg incr, max 180mg daily
Timing of onset of action for short-acting labetalol, hydralazine, nifedipine
Labetalol: 1-2min
Hydralazine: 10-20 min
Nifedipine: 5-10 min
Serum magnesium levels and correlating toxicities
>9 Loss of patellar reflexes
>12 respiratory depression
>30 cardiac arrest
Common maintenance antihypertensives used in pregnancy and max dosage
Labetalol, 2400mg max daily
Nifedipine XR, 120mg max daily
Methyldopa, 3000mg max daily
HCTZ, 50mg max daily
Methods of evaluation of proteinuria
From best to worst:
24h urine protein: 300mg or more
UPCR: 0.3 or more
Dipsticks: 2+ protein or more
Conditions that preclude expectant management of patients with preeclampsia w/ SF
Maternal:
- Uncontrolled SR BP
- HELLP, eclampsia
- Cr >1.1
- persistent headaches, persistent RUQ/epigastric pain, visual disturbances/motor deficit, stroke, MI
- Placental abruption
Fetal:
- Fetal death; fetus without expectation for survival
- Abnormal fetal testing
- Persistent REDV of umbilical artery
Delivery timing for gestational hypertension, preeclampsia and preeclampsia with severe features
gHTN and PEC w/o SF: 37+0
PEC w/ SF: 34+0
Number needed to treat with magnesium sulfate to prevent one case of eclampsia in patients with preeclampsia w/ SF
36
Delivery timing for chronic hypertension controlled with and without medications
With medication: 37 - 39+6
Maternal and fetal monitoring for patients with gHTN, preeclampsia and preeclampsia w/ SF
Maternal: frequent BP monitoring, weekly labs
Fetal: EFW, amniotic fluid assessment, antepartum testing 1-2x/week
Diagnosis of HELLP syndrome
Platelet: <100k
AST/ALT: double upper limit of normal, usually in the hundreds
LDH >600
Contraindications/side effects of short-acting labetalol, nifedipine, hydralazine
Labetalol: avoid with asthma, myocardial disease, heart block, bradycardia, decreased EF
Nifedipine: reflex tachycardia, headaches
Hydralazine: higher risk of maternal hypotension, headaches, abnormal EFM
The correct technique to measure blood pressures
Correct cuff size
Patient seated with legs uncrossed and back supported, if laying down: left lateral decubitus position and cuff at level of right atrium.
No caffeine or tobacco at least 30 min before
Patient has rested for at least 10 min or more