Martins 2014.

Methods	Randomised controlled clinical trial (N = 60 randomised). Study conducted in 'Basic Healthcare Units' in São Paulo, Brazil.
Participants	Inclusion criteria: Pregnant women (singleton only); between 12 and 32 weeks' gestation; self‐reported LBP or PGP marked on a pain chart of the human body. For women reporting LBP only, an increase in pain precipitated by bending forward, circling the trunk or on palpation of paraspinal muscles confirmed the diagnosis. The 4P test was used to assist diagnosis of PGP. Exclusion criteria: Twin pregnancy; contraindication to exercise; use of analgesics; receiving any physiotherapy for their symptoms.
Interventions	Intervention group (N = 30/21 analysed): Hatha yoga. 10 sessions, once a week, each lasting 1 hour (up to 10 participants/group). Class consisted of a 10‐minute warm‐up to gain focus, 40 minutes of poses and breathing exercises focusing on stretching, strengthening, endurance, muscle resistance, self‐control, concentration and self‐confidence, and a 10‐minute relaxation at the end. Control group (N = 30/24 analysed): information pamphlet on postural orientation and advice on ADL's, sleeping positions sitting with adequate foot and lumbar support,
Outcomes	Pain intensity (VAS 0 to 10) with facial expressions positioned at 3 points on the scale corresponding to weak/median/severe pain. This was assessed at the beginning and end of each yoga session. 4P test, lumbar flexion test.
Condition (LBP, PP, LBPP)	LBPP.
Notes	Study conducted in Brazil; part of Doctoral thesis.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated list of random numbers for 60 participants using SAS software.
Allocation concealment (selection bias)	Low risk	Sealed, opaque, sequentially numbered opaque envelopes.
Blinding of participants and personnel (performance bias) All outcomes	High risk	No detail provided on blinding. however it is not possible to blind a yoga intervention. there was also no mention of whether participants were yoga naive.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No detail provided on blinding of outcome assessment.
Incomplete outcome data (attrition bias) effect of intervention	High risk	Attrition and exclusions were reported along with reasons, and the numbers included in the analysis add up. Lost to follow‐up: N = 9 in the yoga group, N = 6 in the control group, therefore risk is high (20%+).
Selective reporting (reporting bias)	High risk	The sample included N = 10 (17%) with LBP, N = 12 (20%) PGP, and N = 38 (63%) with LBPP however the authors did not present baseline data according to intervention groups and did not present any findings for those who had combined LBPP.
Other bias	Unclear risk	Adverse events were described and similar between groups. Interim data collection was not completed for control group, just the intervention group.