Heartburn is one of the most common complaints in pregnancy — around eight in ten women report it at some stage, most often in the second half of gestation. The cause is a combination of hormonal relaxation of the lower oesophageal sphincter and mechanical pressure from the growing uterus on the stomach.
The practical question at the pharmacy counter is what's safe. This guide runs through the licensed UK options in 2026, the non-drug steps that often help more than people expect, and the red flags that shift a consultation into a GP appointment.
The treatment ladder
UK primary care and pharmacy practice follow the NICE Clinical Knowledge Summary on pregnancy-associated dyspepsia. The ladder runs: lifestyle first, then alginates, then antacids, then acid-suppressing medication only if symptoms persist.
The order matters. Many women get enough relief from posture, meal timing and trigger avoidance that they never need a medicine. The medicines come in only when the conservative steps are not enough.
Non-drug steps that often work
| Step | What to try |
|---|---|
| Meal size | Smaller, more frequent meals rather than three large ones |
| Meal timing | Finish eating at least three hours before lying down |
| Position | Slightly elevated head of bed, left-side sleeping |
| Trigger foods | Reduce spicy, fatty, acidic and caffeinated foods |
| Clothing | Looser around the waist and stomach |
The evidence base for these is mostly observational but the risk profile is zero — and in many pregnancies they deliver most of the benefit.
Alginates
Alginates are the first-line medicine for pregnancy heartburn in the UK. They work mechanically rather than chemically: after ingestion they form a viscous raft that floats on top of stomach contents, physically preventing acid reflux into the oesophagus.
The most widely available UK products are:
| Product | Format | Notes |
|---|---|---|
| Gaviscon Advance | Liquid, tablets | Licensed for use in pregnancy; contains sodium alginate and potassium bicarbonate |
| Peptac Peppermint | Liquid | Generic equivalent to Gaviscon Original; widely stocked |
| Gaviscon Double Action | Liquid, tablets | Alginate plus antacid combination |
| Rennie Deflatine | Tablets | Calcium/magnesium carbonate with simeticone |
Gaviscon Advance in particular has a long safety track record in pregnancy. It is the product most UK midwives and GPs suggest first.
Calcium-based antacids
Calcium carbonate (Rennie, own-brand chewable antacids) is safe in pregnancy for short-term, intermittent use. It provides fast relief from immediate symptoms but does not have the mechanical anti-reflux effect of the alginates.
Sodium bicarbonate-based antacids are generally avoided in pregnancy because of the sodium load. Aluminium-based antacids are avoided for the same reason in the third trimester.
What about H2 blockers and PPIs?
Famotidine, ranitidine (now withdrawn), omeprazole and lansoprazole are all categorised by the UK Teratology Information Service as having reassuring human safety data in pregnancy, but they are not first-line. The standard approach is alginate first, add a regular antacid if needed, and only escalate to an acid-suppressing medicine with GP input if symptoms remain significant.
Omeprazole in particular has been used in pregnancy for decades and bumps (the UK Teratology Information Service patient leaflet service) describes the human safety data as "not suggestive of an increased risk of major malformations". It is a GP-initiated medicine in this context — not a pharmacy counter supply.
Red flags that mean see a GP now
Heartburn in pregnancy is almost always benign, but a small number of presentations need prompt medical review. The clinical features to watch for:
- Severe pain in the upper abdomen, especially if constant or radiating to the back
- Nausea and vomiting that prevents food or fluid intake
- Vomiting blood or passing black or very dark stools
- Difficulty swallowing, or food sticking on the way down
- Unintentional weight loss
- New severe headache with upper abdominal pain (possible pre-eclampsia, especially after 20 weeks)
- Right upper quadrant pain with jaundice or itching (possible obstetric cholestasis)
The last two are obstetric emergencies dressed up as indigestion. Any upper abdominal pain in the third trimester with a severe headache or with itching deserves same-day midwifery or obstetric review, not a Gaviscon.
What the pharmacist will check
A community pharmacy consultation for pregnancy heartburn will typically confirm the gestation, check whether the symptoms fit typical reflux, ask about any red flags, and suggest the appropriate rung on the ladder. If the woman is already on a regular medicine that interacts with antacids — the big one is levothyroxine, which must be taken at least four hours apart from any antacid — the pharmacist will flag the timing.
A pharmacist will not initiate omeprazole or ranitidine-family medicines at the counter in pregnancy. Those require a GP or midwife.
Where to get advice
The UK Teratology Information Service's patient leaflets at medicinesinpregnancy.org are the single best UK public resource on medicine safety in pregnancy. The NHS.uk pregnancy section has plain-English advice on heartburn and other common pregnancy symptoms. For local pharmacy locations and opening hours, PharmSee's pharmacy finder covers every community pharmacy in England.
For a broader look at heartburn in the general population, including step-up options outside pregnancy, see PharmSee's heartburn and reflux guide.
Caveats
Advice above summarises the published NICE CKS on pregnancy-associated dyspepsia and bumps leaflets as of April 2026. Individual clinical situations vary, particularly where there is a history of reflux disease before pregnancy, and the decision to step up to prescribing-strength medicine rests with the GP or obstetric team.