PREGNANT and breastfeeding women should take vitamin and mineral supplements for their health and the development of their baby, obstetricians say.

Worried by the increasing frequency of vitamin D and iodine deficiency in expectant mothers, Australia's leading women's health group has for the first time issued guidelines outlining which supplements pregnant women need.

But the Royal Australian and New Zealand College of Obstetricians and Gynaecologists says there is no evidence that drinking small amounts of alcohol occasionally can damage foetal development.

The College refuses to back a ban on women drinking during pregnancy despite recommendations by the National Health and Medical Research Council's draft revised guidelines, issued last October, which say abstinence is the only safe choice. The final guidelines will be released in about a month.

The College's Women's Health Committee chairman Ted Weaver said a lot of women were confused about which, if any, supplements they should take.

The College says the highly-popular omega-3 supplements should be avoided, especially in the first trimester, in case of unknown side-effects, and too much vitamin A can be dangerous.

But Dr Weaver said there's good evidence to link a lack of iodine, folate, vitamin D and iron to problems for mother and baby. It is estimated that seven out of 10 cases of neural tube defects such as spina bifida can be prevented by increasing the mother's intake of folate or folic acid before and during early pregnancy.

Dark-skinned and veiled women are increasingly presenting with vitamin D deficiency, a condition previously unheard of in sun-drenched Australia while the push to reduce salt in our diets has lead to iodine deficiency.

Drinking at high levels throughout pregnancy is known to cause stillbirth, growth retardation and fetal alcohol syndrome, however the College maintains a "safe" or "no-risk" drinking level remains unknown.