Good health and nutrition before pregnancy may be at least as important as during pregnancy because the time around conception is vital for the development of the baby.

The researchers found very few women, who later got pregnant, were taking enough folic acid or met recommendations on alcohol intake.

During the study, the researchers interviewed 12,445 non-pregnant women aged 20-34 between 1998 and 2002, and examined the degree to which women complied with the recommendations before they became pregnant.

A total of 238 women became pregnant within three months of interview.

At interview, 23 pct of the 238 women who became pregnant said that they did not anticipate trying for a baby in the next 12 months.

In the ''unplanned'' group, only one woman who became pregnant complied with the alcohol and folic acid recommendations, but among the remainder, who were, in some sense, ''planning'' a pregnancy, the percentage was only slightly higher at 3.3pct.

It was found that women who became pregnant were only marginally more likely to comply with the alcohol and folic acid recommendations than those who did not become pregnant, reports British Medical Journal.

Only 2.9 pct of the women were taking the recommended daily dose of 400µg folic acid, and drinking no more than four units of alcohol per week, compared with 0.66 pct of those who did not become pregnant.

Women in both groups were equally likely to consume five or more portions of fruit and vegetables per day, but only 57 pct of those who became pregnant had taken any strenuous exercise in the past three months compared with 64pct of those who did not become pregnant.