Standalone exercise in pregnancy was associated with lower depressive symptom scores

Design

Systematic review and meta-analysis of randomised trials

Population

17 trials of pregnant or postpartum women; exercise alone vs usual care

Primary outcome

Depressive and anxiety symptom scores

Effect

Antenatal depression SMD −0.52 (−0.75 to −0.30); postpartum −0.33 (−0.57 to −0.09); antenatal anxiety −0.03 (−0.31 to 0.25)

This meta-analysis pooled 17 randomised trials that tested physical activity on its own — no added counselling or education — against usual care in pregnant or postpartum women, analysing prevention trials and trials in women with symptoms separately.

In prevention trials, exercise was associated with lower depressive symptom scores antenatally (standardised mean difference −0.52, 95% CI −0.75 to −0.30; seven trials, low certainty) and postpartum (−0.33, −0.57 to −0.09; seven trials, very low certainty, I² 86%). There was no clear effect on antenatal anxiety (−0.03, −0.31 to 0.25). In three trials of women already symptomatic, postpartum scores were lower (−0.38, −0.72 to −0.04; very low certainty). Structured programmes about three times a week for 60 minutes looked most favourable, on exploratory analysis.

Exercise is low-cost and already recommended in uncomplicated pregnancy, so the practical step is to frame it as good for mood as well as glycaemia and weight. It is not a substitute for treatment when a woman screens positive for depression.

• Recommend structured activity — around three sessions a week — to women with uncomplicated pregnancies, and say it may help mood.
• Screen for depression antenatally and postpartum (for example the Edinburgh Postnatal Depression Scale) whether or not she exercises.
• Refer a woman who screens positive for assessment and treatment; do not offer exercise as the only plan.
• Check for obstetric contraindications — placenta praevia after 26 weeks, cervical insufficiency, pre-eclampsia — before advising a programme.
• Do not expect exercise to relieve antenatal anxiety; three trials of very low certainty showed no clear effect.

Why it matters

It gives obstetricians a cheap, already-endorsed step against perinatal depression, while showing how thin the evidence for any one number still is.

Don't overread it

Certainty was low to very low and heterogeneity high; the size of the benefit is not established.

The statistics, in plain English

A standardised mean difference of −0.5 is conventionally a moderate effect and −0.3 a small one. I² of 86% means the postpartum trials disagreed a great deal, so the pooled figure is an average of quite different results. The anxiety estimate crosses zero, so it is compatible with no effect at all.

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