What helps pregnancy heartburn safely? Diet, antacids and the evidence

Heartburn — that burning behind the breastbone, often worse lying down — is, in Cochrane's words, "one of the most common gastrointestinal symptoms in pregnant women," and it can appear in any trimester [s1]. The reassuring part is that "serious complications are rare" [s1]. The frustrating part is that the treatments most people reach for rest on surprisingly thin trial evidence. The sensible order is: adjust diet and posture first, then consider antacid-type medicines — with advice, because not every product is suitable in pregnancy.

The NHS attributes pregnancy heartburn to two things at once: "hormonal changes and the growing baby pressing against your stomach" [s2]. That mechanism is why the first-line measures are about reducing pressure and acid exposure rather than taking anything.

What to try first

The NHS lists a set of diet and lifestyle changes: "eat small meals often, rather than larger meals 3 times a day," and avoid eating within three hours of going to bed [s2]. It advises sitting up straight when you eat and just afterwards, "to take the pressure off your stomach," and "cutting down on drinks containing caffeine, and foods that are rich, spicy or fatty" [s2]. For night-time symptoms, "propping your head and shoulders up when you go to bed can stop stomach acid coming up," and "sleeping on your left side can also help" [s2]. None of these carries any medication risk, which is why they lead.

What the medicine evidence shows

When symptoms persist, the NHS says a pharmacist or midwife can recommend a medicine that is safe in pregnancy — "antacids to neutralise the acid in your stomach" or "alginates to relieve indigestion caused by acid reflux" [s2]. Crucially, it adds a safety caveat: "tell them you're pregnant, because some antacids are not suitable," and do not take antacids "within 2 hours of taking folic acid or iron supplements," which they can interfere with [s2].

How well do these actually work? The Cochrane review set out to assess exactly that and found the cupboard emptier than expected. It included nine randomised trials involving 725 women, but only four trials with 358 women contributed usable data, and the trials were at mixed risk of bias [s1]. For the review's main outcome — relief of heartburn — women given a pharmaceutical treatment reported complete relief more often than those on placebo or no treatment (risk ratio 1.85, 95% CI 1.36–2.50, in two trials of 256 women, moderate-quality evidence) [s1]. Data on partial relief were inconsistent and showed no clear difference (average RR 1.35, 95% CI 0.38–4.76, very low-quality evidence), and there was no clear difference in side effects between the treatment and placebo groups (RR 0.63, 95% CI 0.21–1.89) [s1].

One small trial compared a medicine directly against advice alone: 1 g of sucralfate versus dietary and lifestyle guidance. More women in the sucralfate group reported complete relief (RR 2.41, 95% CI 1.42–4.07, in 65 participants) [s1]. That is a single, small study, so it hints rather than proves.

Reading it honestly

The Cochrane authors are explicit that before this review "there has been no evidence-based recommendation for the treatment of heartburn in pregnancy," and the state of the trials has not changed that much [s1]. So the evidence supports two modest claims: an antacid-type medicine relieves heartburn better than nothing, and it may beat advice alone — but the trials are few, small and of limited quality, and they say little about which agent is best or about longer-term safety [s1].

That evidential thinness is precisely why drug choice belongs with a professional. The review notes that the broader class of options includes antacids, sucralfate, histamine-2 receptor antagonists and proton pump inhibitors [s1] — medicines with different safety profiles in pregnancy — and the NHS advice to check suitability first is the practical safeguard [s1] [s2]. This article is informational and not medical advice.

When to seek help

Speak to your midwife or GP if you need help managing your symptoms, or if dietary changes and pharmacy medicines do not work, and check with a pharmacist before taking any medicine — telling them you are pregnant [s2]. Symptoms that are severe, persistent, or accompanied by pain elsewhere, difficulty swallowing or vomiting are a reason to seek a clinician's assessment rather than to keep self-treating.

Sources

• Interventions for heartburn in pregnancy — Cochrane Database of Systematic Reviews, 2015-09-19
• Indigestion and heartburn in pregnancy — NHS, 2024-01-01