Hypertension in pregnancy for GPs: white coat vs chronic hypertension, aspirin before 16 weeks, pre-eclampsia and the postnatal danger window

Speaker

Obstetrician and gynaecologist in private practice (presenter not named in the recording). The speaker says they have been working “out of here” for about two years, doing both obstetrics and gynaecology, in what the ASR captures as “the busiest O&G practice”. The very first line reads “So I’m a John” on the ASR — this may be a garbled introduction and is not used as a name here. The speaker offered attendees cards with a direct phone number for clinical questions.

Audience

GPs, including shared-care providers; several audience questions (aspirin dosing, bruising on aspirin, ambulatory BP dipping, cervical length, remote-area emergencies) are partly captured.

Session context

Otter title Hypertension Management Seminar · id vMPWJj5zXvuHXgPi1aid6DjkpNg · ~23 min, recorded 21 March 2026 9:27 am AEST. All speakers are labelled only “Unknown Speaker” / Speaker 1–3. No sponsor statement was captured. Summary note: Otter’s auto-summary names the speaker “John” and says emergencies need “rapid IV” treatment — neither is clearly supported by the transcript (see caveats).

Key messages for GPs

• You are usually first. GPs often see women first in pregnancy and are the first to see them postnatally when new symptoms such as headache start — especially women who leave the public system without continuity of care.
• Separate chronic from white coat hypertension at the booking visit: repeat the reading, use the practice nurse, home or pharmacy readings, or a 24-hour ambulatory monitor. Even white coat hypertension carries a higher risk of hypertensive disorders later in pregnancy.
• Chronic hypertension is one of the highest-risk factors in pregnancy — refer early for multidisciplinary care.
• Aspirin 150 mg at night, started before 16 weeks once an intrauterine viable pregnancy is confirmed (the speaker often waits for a normal NIPT at about 10 weeks). If unsure at 15 weeks, start it and say so in the referral — it can always be stopped.
• Pre-eclampsia is multisystem; gestational hypertension is blood pressure alone. Look for proteinuria, abnormal LFTs, falling platelets and fetal growth restriction.
• Don’t drop your guard after birth. The speaker said most eclamptic seizures happen postnatally. Headache, visual “spots”, dizziness, marked oedema plus high blood pressure in the first days after birth needs urgent assessment.
• 160 systolic or 110 diastolic (persistent over a couple of readings) is a hypertensive emergency in pregnancy and postpartum — the patient needs to go to hospital.

Why the GP matters: booking visit and postnatal

The speaker opened by pointing out that whether a woman ends up in public, private or shared care, GPs are often “the first people to see them when they first become pregnant”. In shared care, GPs also see them as the pregnancy goes on.

The group most often missed, in the speaker’s view, is postnatal: women who go through the public system “just have their babies, go home”, and the GP is usually the first to see them “when something changes, like if they get new symptoms, like headaches”. That is an important presentation (see postnatal pre-eclampsia).

Chronic or white coat hypertension?

The first category is hypertension that a woman brings into the pregnancy — defined as any hypertension before 20 weeks (the ASR says “before 20 years”; the context and standard definitions make 20 weeks clear). Many of these women are healthy and have rarely seen a doctor, so the booking visit may be their first blood pressure check in years.

One of the most important distinctions not to miss, the speaker said, is chronic hypertension versus white coat hypertension, “because there’s a fair bit of white coat hypertension around.” If the woman has lots of comorbidities, chronic hypertension may be obvious. Otherwise, the speaker’s practical (and, in their words, “not really evidence based”) steps are:

1. Repeat the blood pressure a couple of times during the consultation to see if it settles.
2. Ask the practice nurse to take it.
3. Book a follow-up and in the meantime ask her to buy a home blood pressure machine (“not cheap, but it’s not that expensive these days”) or have it checked at a pharmacy a couple of times. Normal readings everywhere except with you are “a pretty good sign” of white coat hypertension.
4. More formally, organise 24-hour ambulatory blood pressure monitoring — “often a bit of a pain to organise”, but it can distinguish the two at any point in pregnancy.

Chronic hypertension: refer early

“Chronic hypertension is one of the highest risk factors in terms of pregnancy,” so refer early to whichever service she will use — public, private or a midwifery/shared-care model (the ASR’s “LGB” is unclear). These women need multidisciplinary care.

• Private care: if possible, refer to a renal physician at the same hospital where she will deliver, so both specialists are on site at the birth. The speaker called this “the best combination”.
• Public care: the public hospital typically takes over, “which is fine”.

Aspirin to prevent preterm pre-eclampsia

Aspirin has been shown in studies to potentially prevent preterm pre-eclampsia. The theory given: pre-eclampsia stems from problems when the placenta first implants, and aspirin’s antiplatelet (“blood thinner”) effect is thought to help implantation and blood flow.

The speaker added a reassuring note for women who arrive late (for example transferring in at 20 weeks) and are upset they were never offered aspirin: with good monitoring, the reality is that either it probably would not have worked for them, or they were not going to develop hypertension anyway.

Who should get aspirin?

The speaker said clinicians are “getting a bit more lax” about the softer markers because the intervention is so low-risk — there is “only a theoretical risk of bleeding”, without evidence of actual increased bleeding (as stated). Examples given: a 38-year-old with an IVF pregnancy and a raised BMI — aspirin “probably warranted”; twins at age 42 — “pretty easy” to decide.

First-trimester pre-eclampsia screening

Asked about pre-eclampsia screening at 13 weeks, the speaker explained it is done alongside combined first-trimester screening and uses:

• Blood tests
• Blood pressure at the visit
• Uterine artery Dopplers, looking for high resistance — the idea being that the body is working hard to get blood to the uterus, so the placenta may not implant as well

These go into an algorithm that gives a risk. More than 1 in 100 is called high risk, and aspirin is started even without other risk factors. Borderline results (the example: 1 in 110, slightly overweight, a little older) become a shared decision — “you’re low risk by the numbers … but the risk [of aspirin] is so low”, so the speaker always gives the woman the option.

When to stop aspirin

• Usually stop at 36 weeks. The studies look at the risk of preterm pre-eclampsia (before 37 weeks), so there is no shown benefit in continuing, and aspirin has a washout period with a theoretical bleeding risk around birth.
• If early birth is expected (for example twins), stop earlier — the speaker usually stops at about 34 weeks for twins.

Antihypertensives in pregnancy

Choice depends on the patient’s risk factors. As the speaker described it:

Check doses and choices against current Australian guidance (e.g. SOMANZ hypertension in pregnancy guidelines), the Australian Medicines Handbook and specialist advice.

Gestational hypertension vs pre-eclampsia

After 20 weeks, the question becomes whether new hypertension is gestational hypertension or pre-eclampsia:

• Gestational hypertension: blood pressure above 140 systolic or 90 diastolic, with everything else “absolutely perfect”.
• Pre-eclampsia: a multisystem disorder — hypertension plus involvement of any other system. The best-known is proteinuria (the speaker quoted “anything more than 30”; the units were not stated — in Australia the urine protein:creatinine ratio is usually reported in mg/mmol). Others include deranged LFTs, changing platelets and fetal growth restriction — “the uterus is an organ system”, so a hypertensive woman with a small baby can meet the definition even if her bloods and urine are perfect.

Monitoring and timing

• Women with gestational hypertension are more likely to progress to pre-eclampsia, so timing of birth matters and regular review is needed to check no other system becomes involved.
• Who reviews depends on the model of care. A privately referred woman would be managed by the obstetrician, keeping the GP in the loop; in public shared care it depends on the reviews arranged.
• Ideally at least fortnightly. Gestational hypertension is usually diagnosed after 30 weeks, so roughly fortnightly visits until 36 weeks and then weekly. Things can change quickly, especially when hypertension starts earlier.
• Once pre-eclampsia is diagnosed, the speaker said birth is likely within about two to three weeks, because the only cure is delivery (of the placenta, and with it the baby).

Postnatal pre-eclampsia: the danger window

The speaker called postnatal hypertension “a really important one” for GPs. A woman who had a normal pregnancy can present, especially in the first couple of days after birth, with:

• headaches
• dizziness
• visual “spots”
• significant oedema
• and raised blood pressure

Diagnosis is harder after birth: she is probably still bleeding, so a urine sample will likely be contaminated (unless catheterised — not something done in general practice). So rely on bloods and symptoms:

• Hypertensive with abnormal bloods → pre-eclampsia.
• Hypertensive with normal bloods but significant symptoms → still treat seriously.

Examination tips

• Check blood pressure, reflexes and clonus.
• You don’t need a tendon hammer — the speaker hasn’t used one “in 10 years”. If a woman is truly pre-eclamptic and hyper-reflexic, a tap with your hand on the knee will show it; obvious three to four beats of clonus is “diagnostic, basically”.

Severe hypertension: thresholds and first steps

A GP from a remote area asked whether they should give medicine before transfer. The speaker said yes, it is a good idea, and described (as far as the ASR allows):

• The preferred option is a rapid-acting oral antihypertensive — the ASR reads “the theta been rapidly”, most likely immediate-release nifedipine (the drug name is our best reading, not confirmed) — given as 10 or 20 mg, rechecking blood pressure in 10 to 15 minutes. It can be repeated (two or three doses) until the pressure comes down.
• If an IV cannula is available, the speaker mentioned running a bag of fluids slowly while giving the antihypertensive (ASR garbled — “a bag of claws”).
• Hydralazine is a good alternative where available.
• Labetalol will also work but is slower; the rapid-acting option was described as the best.

Important: this was a brief, partly garbled answer. Follow your local obstetric emergency protocol and SOMANZ/state guidance, call the receiving obstetric team and arrange urgent transfer. Do not rely on this summary for drug choice or dose.

Q&A highlights

Bruising on aspirin — stop it?

“Probably not.” If it is purely bruising, with no other clinical concern — pregnancy itself brings bleeding gums and more nosebleeds because of the extra circulating blood — the speaker would continue, unless there is a clinical concern about the pregnancy or actual bleeding somewhere else (the ASR mentions “abdominal”).

No night-time dipping on ambulatory monitoring?

Not significant for the diagnosis itself. Most people have a small drop at night; it becomes important mainly when starting antihypertensives, because a woman whose pressure is high in the day but relatively low overnight could drop too far on treatment.

Cervical length and pre-eclampsia?

“Not particularly” — there is not much link between the two. Cervical length matters for other reasons (the speaker mentioned “more than two and a half centimetres”, depending on risk factors).

GP clinic checklist

1. Take blood pressure at the first pregnancy visit. If raised, repeat it, use the nurse, home or pharmacy readings, or ambulatory monitoring to separate chronic from white coat hypertension.
2. Chronic hypertension (before 20 weeks) → refer early; for private care, a renal physician at the delivering hospital is ideal.
3. Screen for aspirin risk factors: previous pre-eclampsia, chronic hypertension, renal disease, diabetes (especially type 1); softer factors such as IVF, twins, older age and raised BMI.
4. Confirm a viable intrauterine pregnancy (the speaker often waits for a normal NIPT, ~10 weeks), then start aspirin 150 mg at night before 16 weeks if indicated. If unsure, start and document it in the referral.
5. Note the 13-week pre-eclampsia screen result: >1 in 100 = high risk.
6. Stop aspirin at about 36 weeks (about 34 weeks for twins), or as the obstetric team advises.
7. After 20 weeks, new BP ≥140/90 → check urine protein, LFTs, platelets and fetal growth; liaise with the obstetric team.
8. If a woman is on methyldopa, plan a switch after birth given the reported link with postnatal depression.
9. Postnatally, treat headache, visual spots, dizziness or marked oedema with raised blood pressure as possible pre-eclampsia: check BP, reflexes, clonus and bloods.
10. BP ≥160 systolic or ≥110 diastolic on repeat = emergency. Treat per local protocol and transfer urgently.

Transcript caveats

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