Chronic Hypertension and Gestational Hypertension
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Direct answer
Chronic hypertension and gestational hypertension are separated by when the raised blood pressure began. Chronic hypertension is present before pregnancy or before 20 weeks, whereas gestational hypertension is new after 20 weeks without proteinuria or organ involvement. The decisive point is whether proteinuria or end-organ dysfunction appears, because that converts the picture into pre-eclampsia, including superimposed pre-eclampsia.
What you must remember
- Chronic hypertension: blood pressure of 140/90 mmHg or more present before pregnancy or before 20 weeks, persisting beyond 12 weeks postpartum.
- Gestational hypertension: new hypertension after 20 weeks with no proteinuria or organ dysfunction, normalising by 12 weeks postpartum.
- Pre-eclampsia: hypertension after 20 weeks with proteinuria, or with platelets below 100,000/μL, creatinine above 1.1 mg/dL, transaminases twice normal, pulmonary oedema, or new headache or visual disturbance.
- Superimposed pre-eclampsia: chronic hypertension with new proteinuria after 20 weeks, a sudden rise in blood pressure or proteinuria, or new organ dysfunction.
- Severe range: systolic 160 mmHg or more, or diastolic 110 mmHg or more, persisting for about 15 minutes, which needs urgent treatment.
- Surveillance: serial blood pressure, urine protein, platelets, creatinine and liver enzymes, plus fetal growth scans and Doppler in high-risk pregnancies.
How the disorders differ at a glance
Classification questions turn on onset, proteinuria and postpartum course. The table below separates the four disorders on those three features.
| Disorder | Onset | Proteinuria or organ involvement | Postpartum course |
|---|---|---|---|
| Chronic hypertension | Before 20 weeks or pre-pregnancy | Absent unless superimposed | Persists beyond 12 weeks |
| Gestational hypertension | After 20 weeks | Absent | Resolves by 12 weeks |
| Pre-eclampsia | After 20 weeks | Present, or organ dysfunction | May worsen in the first days after birth |
| Superimposed pre-eclampsia | Chronic hypertension plus new change | New proteinuria or organ dysfunction after 20 weeks | Hypertension continues with added features |
The distinction between gestational hypertension and pre-eclampsia decides how closely the fetus and mother are monitored. Superimposed pre-eclampsia changes both monitoring and the timing of delivery.
Examiners often give a vignette with a blood pressure reading, a dipstick result and a gestational age, and the answer depends entirely on that timeline. Read onset first, then proteinuria, then the postpartum plan. A woman still hypertensive beyond 12 weeks postpartum is classed as chronic, whatever her course in pregnancy.
Where the exam tries to catch you
Most errors come from misreading the timeline and the urine dipstick.
- Trap: Calling any hypertension that persists after delivery gestational. Correct: Hypertension still present beyond 12 weeks postpartum is chronic hypertension.
- Trap: Labelling a woman with chronic hypertension and new proteinuria as simply chronic. Correct: This is superimposed pre-eclampsia, with its own monitoring and delivery decisions.
- Trap: Diagnosing hypertension from a single reading. Correct: Two readings at least four hours apart confirm the diagnosis, except in severe-range emergencies.
Frequently asked questions
What distinguishes gestational hypertension from pre-eclampsia?
Gestational hypertension is new hypertension after 20 weeks without proteinuria or organ dysfunction. Pre-eclampsia is hypertension after 20 weeks accompanied by proteinuria or new organ involvement. Gestational hypertension usually resolves by 12 weeks postpartum, and this difference drives surveillance and the timing of delivery.
When is hypertension in pregnancy called chronic hypertension?
Chronic hypertension is diagnosed when raised blood pressure exists before pregnancy or is present before 20 weeks of gestation. It is also confirmed when raised pressure persists beyond 12 weeks after delivery. Chronic hypertension in pregnancy therefore needs antenatal surveillance and a review of drug therapy.
What is superimposed pre-eclampsia?
Superimposed pre-eclampsia is new proteinuria or organ dysfunction arising after 20 weeks in a woman who already has chronic hypertension. A sudden rise in blood pressure or proteinuria also suggests it. Superimposed pre-eclampsia changes the timing of delivery and the intensity of monitoring.
Which tests are used to monitor pre-eclampsia in the third trimester?
Platelet count, serum creatinine, liver enzymes such as AST and ALT, and urine protein are the core tests. Pre-eclampsia severity is judged on these results together with blood pressure and symptoms such as headache or visual disturbance. Lactate dehydrogenase may be added in severe disease.