Aflatoonian 2009.

Methods	Parallel group study Number of women randomised: 390 (195 in the intervention group; 195 in the control group) Number of women analysed: 385
Participants	Country of authors: Iran Inclusion criteria: couples undergoing assisted reproduction with at least 5 years of subfertility Exclusion criteria: none reported Mean age ± SD: intervention group: 29.4 ± 4.4 years; control group: 29.6 ± 4.9 years Mean duration of infertility ± SD: intervention group: 8.7 ± 3.8 years; control group: 9.0 ± 3.9 years Women with primary infertility: not reported Setting: assisted reproduction programme in Iran
Interventions	Intervention: vaginal intercourse at least once during the 12 hours following embryo transfer Control: abstinence during the entire ART cycle
Outcomes	Clinical pregnancy defined as the presence of a gestational sac or fetal cardiac activity three weeks after embryo transfer
Notes	Pregnancy outcome was unknown for five women in the intervention arm. The corresponding author was contacted but was not able to provide missing data either for the five women with unknown primary outcome or other unreported outcome measures.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Equal number of paper slips for each method put in a bag
Allocation concealment (selection bias)	Low risk	Drawing paper slips from the bag on the day of embryo transfer
Blinding of participants and personnel (performance bias) All outcomes	High risk	Couples in the control group could have had intercourse without informing the investigators and contaminated the results
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Objectively assessed outcome measure
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Pregnancy outcome missing for 5 women in the intervention group
Selective reporting (reporting bias)	Low risk	Clinical pregnancy rate was reported
Other bias	Low risk	No other cause of potential bias identified