Dunstan 2003.

Methods	Randomised controlled trial. Dunstan 2003 was the main trial with 12 publications at different times with different outcomes. All 12 publications are included in the references to included studies.
Participants	Setting: Australia. 98 pregnant atopic women whose fetus was considered to be at high risk of allergic disease. All women had a history of physician‐diagnosed allergic rhinitis and/or asthma and 1 or more positive SPT to common allergens. Exclusions: women who smoked, had other medical problems, complicated pregnancies, seafood allergy or if normal dietary intake exceeded 2 meals of fish per week.
Interventions	Intervention: 4 (1 g) n‐3 LCPUFA capsules per day comprising a total of 3.7 g of n‐3 LCPUFAs with 56.0% as DHA and 27.7% as EPA to give 2.07 g of DHA and 1.03 g of EPA (n = 52). Control: 4 (1 g) capsules of olive oil per day containing 66.6% n‐9 oleic acid and < 1% n‐3 LCPUFAs (n = 46). Duration of intervention: 20th week of gestation until delivery.
Outcomes	Dunstan 2003 reported. Primary outcomes: allergen‐specific T‐cell responses in cord blood. Secondary outcomes: medically‐diagnosed allergies including incidence of asthma, atopic eczema, and food allergy at 1 year of age. The diagnosis of asthma was made in children with recurrent wheezing; i.e. 3 or more episodes with at least 1 episode confirmed by a paediatrician or general practitioner. Atopic eczema diagnosis was made in infants exhibiting typical skin lesions or physician‐diagnosed eczema response to topical steroids. The severity was scored according to the modified assessment clinical tool called SCORing Atopic Dermatitis (SCORAD). The SPT was performed using a standardised technique and allergen extracts (egg, milk, peanut, house dust mite, cat), the positive control was histamine and negative control glycerin, a wheel diameter of ≥ 2 mm was considered positive.
Notes	Contacted authors to determine if they diagnosed IgE‐mediated allergies ‐ no response received to date. Supported by grants from the National Health and Medical Research Council and Raine Medical Research Foundation, Australia.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The groups were block‐randomised according to parity, prepregnancy BMI, age and maternal allergy".
Allocation concealment (selection bias)	Low risk	Quote: "Randomization and allocation of capsules occurred at a different centre separate from the recruitment of participants. Capsules were administered to the participants by someone separate from those doing the allocation".
Blinding of participants and personnel (performance bias) All outcomes	Low risk	The capsules in the 2 groups were image matched, and the participants, research scientists, and paediatrician remained blinded to the groups for the duration of the trial.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Participants, research scientists, and paediatrician remained blinded to the groups for the duration of the trial.
Incomplete outcome data (attrition bias) All outcomes	High risk	Randomised n = 98 (52 intervention, 46 control). At birth 15 (15%) excluded (12 treatment, 3 control): 8 discontinued intervention due to nausea (7 treatment, 1 control), 1 cord blood not collected (control), 4 gestation < 36 weeks (3 treatment, 1 control), 2 unrelated infant disease (treatment), (85% follow‐up rate; intervention 77%, control 94%). Outcomes were reported on n = 83 (85%) at 1 year of age (fish oil group n = 40, 77% and control group n = 43, 94%). Of the 83, telephone interviewed n = 11, clinic visit and SPT n = 72.
Selective reporting (reporting bias)	High risk	Trial registered at anzctr.org.au Identifier: ACTRN12611000041954. Prespecified outcomes were reported in this trial according to their protocol. Unable to determine IgE‐mediated allergy from results reported although both medically diagnosed allergy and SPT results reported separately (authors contacted for information).
Other bias	Unclear risk	Preterm infants were excluded from their analysis after randomisation.