|Methods||Cluster-randomised trial carried out in the Netherlands (unit of randomisation was GP practices).|
|Participants||Women aged 18 to 40 years attending for care with 67 GPs (in 54 GP practices).|
There were a total of 27,226 women aged between 18 and 40 years attending the 30 intervention practices during the 3-year study period (it was not clear what the figure was for control practices; information on the 37 control practices and women attending these practices was not provided in the study publications).
In the intervention practices, GPs excluded 12,306 (45%) of women on grounds of completed family, infertility or sterility, inability to understand Dutch, or adverse family circumstances.
Of 14,915 women offered preconception care, 45% responded (6782). Of these 1820 (27%) intended to get pregnant within the next 5 years. 348 women attended for preconception counselling over the 3-year study period (representing 1.3% of the women in the relevant age group eligible for the study intervention). Results reported in study publications relate to those women attending for care.
|Interventions||Intervention group: women were asked to express an interest in pre-conception care. Those expressing interest were sent a risk assessment questionnaire and invited to attend with their partner for pre-conception care provided by their GP. Advice addressed both general risk factors and specific advice on risks identified from the risk assessment questionnaire.|
Control group: women received routine care (no routine invitation to attend for pre-conception care).
|Outcomes||Knowledge, anxiety, pregnancy rates, changes in lifestyle and behaviour to reduce pregnancy risk factors (folic acid use, alcohol, smoking, infection, exposure to hazardous substances).|
|Notes||Thanks to Dr Elsinga for providing helpful additional information about the study.|
The analyses for this trial were not carried out by randomisation group. Women in the intervention group who attended for pre-conception care (a small proportion of the eligible age group) were matched with women attending for routine care. Information is not available on the whole randomised sample. We have been unable to include the data from the trial in the analyses in this review.
|Risk of bias|
|Adequate sequence generation?||Unclear||Cluster randomisation. Randomisation was stratified.|
|Allocation concealment?||Unclear||Not described.|
|No||It is not feasible to blind clinical staff to this type of intervention.|
|Unclear||Most analyses were not according to randomisation group. It may have been possible to blind outcome assessors to group allocation for some outcomes.|
|Incomplete outcome data addressed? |
|No||Large numbers of women were excluded from the intervention group by their GP both before and after the intervention. Response rates were low and attendance for care was low.|
|Free of selective reporting?||No||Due to low attendance for care, an ITT analysis was not performed. Rather, women in the intervention group who had attended for care were matched with women from the comparison group. Figures on outcomes were not available for all women randomised who became pregnant during the study period.|