Pre-eclampsia in Pakistan: give the magnesium before you send her

Somewhere in Pakistan tonight, a woman with severe pre-eclampsia will be put in an ambulance and driven to a tertiary hospital. Whether she arrives having already had her magnesium sulphate, or arrives to receive it, is one of the largest single decisions anyone will make about her care — and it is made by whoever sees her first.

The Society of Obstetricians and Gynaecologists Pakistan is explicit about which it should be. From the SOGP Hypertensive Disorders in Pregnancy guideline, section 13.3.5:

Offer Magnesium sulfate for seizure prophylaxis before referral/in utero transfer to tertiary care hospital.

Before. Not on arrival. Magnesium is cheap, it is stocked in most district hospitals, and the evidence behind it is among the strongest in obstetrics. The gap in Pakistan has never really been supply or knowledge of the drug — it is the sequence.

The regimen, with the dilutions

Loading dose: 4 g intravenously, slowly, over 20 minutes. Using a 20 mL syringe, draw 4 g of 50% magnesium sulphate — that is 8 mL — and add 12 mL of sterile water or saline to make a 20% solution.

Maintenance: 1–2 g per hour by infusion pump. Add 4 g to 200 mL of normal saline and run at 1 g per hour, that is 50 mL/hour, until 24 hours after delivery or 24 hours since the last fit.

Toxicity is four things: respiratory rate below 10 per minute or saturation below 92%, muscle paralysis, absent reflexes, urine output below 30 mL/hour. If you suspect it, stop the infusion, send a level, and give calcium gluconate 10 mL in 100 mL of normal saline IV over 10 to 20 minutes. Routine magnesium levels are not needed — the guideline says measurement is unnecessary unless there are signs of toxicity. The therapeutic range is 5–8 mg/dL.

One honest caveat. The maintenance regimen assumes an infusion pump, as does the hydralazine infusion below, and the fluid section asks for pumps or dial flows too. Plenty of facilities here do not have one. The guideline publishes no intramuscular alternative, so this article will not invent one — if you have no pump, follow your hospital protocol for magnesium administration and escalate early. The loading dose and the transfer still matter more than anything else you will do in that hour.

The pressure: which drug, and how far to drop it

Order of preference is labetalol, then nifedipine, then methyldopa.

Oral maintenance: labetalol 100–2400 mg daily; nifedipine 10 mg three times daily increasing to 20 mg three to four times daily, maximum 120 mg/day (extended release 30–90 mg once daily); methyldopa 250–750 mg eight-hourly.

Intravenous labetalol: one ampoule is 20 mL = 100 mg, so 2 mL = 10 mg. Give 10–20 mg IV, then 20–80 mg every 20–30 minutes to a maximum of 300 mg. For an infusion, add 200 mg (40 mL) to 60 mL of 0.9% saline to make 100 mL — 2 mg/mL — and run at 1–2 mg/min. Label the bag.

Intravenous hydralazine: dilute 20 mg in 20 mL of water for injection and give 5 mg as a bolus, with BP recorded every 10 minutes and continuous CTG running. If severe hypertension persists at 20 minutes, give a second 5 mg bolus; at 20 minutes more, a third. Only after three boluses does the guideline move to an infusion — 80 mg in 90 mL of saline at 5 mg/hour, increasing every 30 minutes to a maximum of 15 mg/hour.

And the number that stops people over-treating: aim for systolic 140–160 and diastolic 90–100. Dropping the pressure further reduces placental perfusion and compromises the fetus. Severe hypertension needs prompt treatment because of stroke and eclampsia — but the target is control, not normality.

Stop ACE inhibitors, ARBs, renin inhibitors and mineralocorticoid receptor antagonists — all teratogenic. Thiazide diuretics should not be used, because they restrict the plasma volume expansion of normal pregnancy.

The 80 mL rule

In severe pre-eclampsia, limit intravenous fluid to 80 mL/hour unless there is a specific indication otherwise. The guideline puts the reason plainly: fluid overload can lead to maternal death.

With that: hourly urine output through an indwelling catheter, regular auscultation of the lungs in anyone on IV fluids, no diuretics unless there is pulmonary oedema, no volume expansion unless hydralazine is being given, and mechanical thromboprophylaxis with compression stockings.

It is worth sitting with how counter-intuitive that is next to the rest of medicine. The instinct with a sick, oliguric patient is to give fluid. Here, oliguria is a red flag to act on — urine output under 80 mL over four hours — and not a reason to open the drip.

Proteinuria is not required

New-onset hypertension after 20 weeks plus maternal end-organ dysfunction or uteroplacental dysfunction — fetal growth restriction — is pre-eclampsia, with or without protein in the urine. The guideline states it in one line: proteinuria is not essential for the diagnosis.

End-organ dysfunction means platelets below 100,000, creatinine above 1.1 mg/dL, transaminases at least twice normal or severe persistent epigastric or right-upper-quadrant pain, pulmonary oedema, or persistent neurological or visual symptoms — altered mental status, hyperreflexia, clonus, severe headache.

A guideline that tells the truth about its own country

Two passages are worth reading for what they say about how national guidance should be written.

The first is on blood pressure measurement:

SOGP-HDP group recognizes that in many areas of the country only aneroid devices are available and despite their inaccuracy aneroid devices will need to be used. Regardless of the method used, we recommend a minimum of two BP measurements to diagnose hypertension.

International guidance assumes a validated automated or mercury device. This one says out loud what much of the country actually has, declines to pretend otherwise, and compensates by requiring two readings instead of one. That is what adaptation looks like when it is done honestly rather than aspirationally.

The second is on screening. The ideal is first-trimester screening at 11–14 weeks combining maternal characteristics, mean arterial pressure and uterine artery pulsatility index in the free FMF calculator, with a 1-in-100 risk cut-off. Where that is not available, the guideline asks for at least two parameters — maternal factors plus mean arterial pressure — and then rules out the alternative most of us default to:

Maternal risk factors alone should not be used for first trimester PE screening as this would lower the performance of the screening.

The risk-factor checklist is how most doctors here were taught to triage, and it is what several international guidelines rest on. The guideline's position is that a checklist by itself underperforms — and that adding a mean arterial pressure, which costs nothing but the cuff already in your hand, materially improves it.

Two tablets, started early enough

Aspirin 150 mg at bedtime, started before 16 weeks and continued to 36 weeks. The bedtime timing is specified, not incidental.

Calcium 1 gram daily from the 16th week. This is the locally specific half of the pair — calcium supplementation is a recommendation for populations with low dietary calcium intake, which is why it appears in a Pakistani guideline and not in every international one.

And the limit, which is worth saying to patients: prophylaxis prevents preterm pre-eclampsia. It does not prevent pre-eclampsia at term.

Delivery is not the end of it

The number here surprises people: women with pre-eclampsia should stay in hospital 48 to 72 hours because the risk of postnatal eclampsia is 40%.

Check blood pressure four-hourly through that stay and keep asking about red-flag symptoms. Start an antihypertensive if BP is above 150/100 in a woman who was not on one antenatally; if she was, continue while she is above 150/100 and consider reducing below 140/90. If she stays below 130/80 across 72 hours, she does not need one. Enalapril may be offered postnatally with renal function and potassium monitoring; nifedipine, atenolol, labetalol and metoprolol are all safe. Repeat the bloods at 48–72 hours, and if they are normal, stop repeating them.

Discharge needs all three: no symptoms, blood pressure below 150/100 with or without treatment, and blood results stable or improving. Then daily home BP monitoring — at a nearby facility or by a health worker if she has no device — and back to tertiary care if BP has not settled by three months.

The last part of the discharge is a conversation, not a prescription. Recurrence in a future pregnancy is 16–23%. Future cardiovascular risk is increased roughly 1.5 to 3 times. Women who develop preterm pre-eclampsia lose about ten years of life expectancy on average. She should leave knowing that her pregnancy told her something about the next thirty years of her health.

Bottom line

Diagnose it without waiting for protein. Take two readings, even on an aneroid. Screen with a mean arterial pressure and not a checklist alone, and start aspirin and calcium before 16 weeks in the women at risk. When it is severe: control the pressure to 140–160 systolic, cap the fluid at 80 mL/hour, and load the magnesium before she gets in the ambulance. Then keep her 48 to 72 hours after delivery, because that is when four out of ten of the seizures happen.

Our pre-eclampsia pathway lays all of this out step by step with the dilutions, the toxicity signs and the delivery timings in one place. Also in the section: hypertension outside pregnancy, type 2 diabetes, tuberculosis and community-acquired pneumonia.

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