Lauritzen 2005.

Methods	Randomised controlled trial. Lauritzen 2004 was the main trial with 9 publications at different times with different outcomes. All 9 publications are included in the references to included studies.
Participants	Setting: Denmark. Recruited from among pregnant women recruited for the Danish National Birth Cohort study based on their intake of n‐3 LCPUFA. Inclusion criteria included: an uncomplicated pregnancy, pre‐pregnancy BMI < 30 kg/m², no metabolic disorders, and the intention to breastfeed for at least 4 months. Infants had to be healthy, term and singleton with normal weight for gestation and Apgar score > 7, women with a fish intake below the population median (< 0.4 g n‐3 LCPUFA/day) were recruited for the randomised intervention trial (n = 122) and women with a fish intake in the upper quartile (> 0.8 g n‐3 LC‐PUFA/day) as a high‐fish‐intake reference group.
Interventions	Intervention: microencapsulated fish oil given in muesli bars. The fish oil supplement provided 1.5 g/day of n‐3 LCPUFA (equivalent to 4.5 g/day of fish oil) with 22.8% as DHA and 10% as EPA to provide 0.342 g per day of DHA and 0.15 g per day of EPA. As an alternative, the supplements were offered in homemade cookies or oil capsules (n = 62) Control: microencapsulated olive oil given in muesli bars . As an alternative, the olive oil supplements were offered in homemade cookies or oil capsules (n = 60). Referance group: 64 women with high fish intake (> 0.8 g n‐3 LC‐PUFA/day). Duration of intervention: 4 months postpartum.
Outcomes	1. Lauritzen 2004 reported Primary outcomes ‐ DHA content of breast milk and infant red blood cell membranes at 2 and 4 months of age, and infant visual acuity at 2 and 4 months of age. 2. Lauritzen 2005 reported Pirmary outcome ‐ immune function assessed by interferon gamma and interleukin 10 production and plasma immunoglobulin E (IgE). Secondary outcomes ‐ parent report of doctor diagnosed allergy: food allergy, wheeze, eczema at 2.5 years of age.
Notes	The high fish intake reference group participants were not included in our meta‐analysis as this group was not randomised. The trial was funded by FOTEK‐The Danish Research and Development program for Food Technology and BASF Aktiengesellschaft.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "After birth, the women with fish intakes below the 50th percentile were randomly assigned to a supplementation group by a randomisation schedule prepared by a person uninvolved in the study".
Allocation concealment (selection bias)	Low risk	Quote: "Owing to the non‐identical appearance of the capsules for the two groups, a person who was not otherwise involved in the project handled the capsules in order to avoid breaking the blinding of the investigators".
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Investigators and families were blinded to the randomisation".
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "A person not otherwise involved in the study handled the capsules in order to avoid breaking the blinding of the investigators".
Incomplete outcome data (attrition bias) All outcomes	High risk	Randomised: trial entry n = 122 (intervention 62, control 60). At 2.5 years of age: n = 65 (53%) (fish oil group n = 37 (60%) and control group n = 28 (47%)). Large losses to follow‐up, all noted as ‘withdrawals’ or no reason given.
Selective reporting (reporting bias)	High risk	Trial registered at ClinicalTrials.gov identifier: NCT00266305. Most of the prespecified review outcomes were not reported in this trial.
Other bias	Low risk	No obvious risk of other bias.