In Overcoming Infertility I write that a small amount of alcohol (particularly wine) is probably no bad thing when it comes to getting pregnant. New studies have been published to support this view.

It can help both of you relax and make sex fun again (more on scheming for this on WebPage 19 in the Member's Area!).

When I first published my book, the information I based this reassurance on several papers published in the 1980s, and particular one from 1994 by Dr Boukje Zaadstra and colleagues from Public Health departments in Holland and published in the journal, Fertility and Sterility.

Dr Zaadstra found that moderate alcohol consumption improves (slightly) the chance of getting pregnant in women who had never had the chance of getting pregnant.

What's more, Zaadstra found that the more alcohol they drank (up to moderate levels) the better the chance they had of getting pregnant.

Then in 1998, just after the first edition of my book was published, two studies suggested the opposite -- that alcohol could delay conception.

Dr Tina Kold Jensen and others from the Department of Growth and Reproduction of the National University Hospital in Copenhagen reported in the British Medical Journal that just 55% of women drinking a moderate amount of alcohol got pregnant within 6 months of starting to try, whereas 64% of women who didn't drink at all got pregnant in this time.

Notably, the more alcohol that was consumed, the lower the apparent fertility of the women. The kind of alcohol made no difference: it included wine.

In the other study, from a 1989 to 1991 study at two semiconductor factories published in Fertility and Sterility, volunteers who were not using the birth control pill or an IUD had a dose-related decrease in conception rates the more alcohol they consumed.

These were "prospective" studies (meaning "planned ahead" studies with a suitable comparison group). So they had to be considered seriously.

But there was a major problem with each study.

When you look at how the women were recruited there was a possible bias in favor of recruiting women who used alcohol and had low fertility for other reasons.

Not all the women who enrolled in the studies had been using effective contraception before they started trying. (Only one third of the women in the Denmark study had been using the birth control pill.)

Let's face it, it's much easier to make a mistake with your condoms, or your diaphragm, or your withdrawal echnique, if you've had a few drinks. And if this had already led to pregnancy you did not enroll in the study.

On the other hand if you slipped up on your contraception after a few drinks but did not get pregnant (because of a problem like blocked tubes), you could still enrol in the study. You might have even have wondered a bit about how you got away with it and so (subconsciously) you might have been more likely to contact the investigators and agreed to take part in the trial.

IF THIS WAS TRUE -- and the authors of the Denmark study agree it COULD have been -- THEN THE RESULT IS MOST LIKELY SPURIOUS.

The reason is described in Appendix 1 of Overcoming Infertility and in the Members' Area ... namely, the longer you have been trying to get pregnant the lower the monthly chance from that time on. (For more of this on the web, look up "time to pregnancy" in the dictionary or the glossary.)

On the other hand the reason Zaadstra's patients had not tried getting pregnant before was accidental -- but statistically important. Their husbands had no sperm. They were studied as they began having donor insemination (DI). This is a much more valid study design.

I used a similar study design in 1986 to show that minimal endometriosis was a cause of decreased fertility.

Incidentally, Zaadstra's study also showed, as expected, that cigarette smoking decreased the chance. Coffee drinking seemed to have mixed effects.

Then in 2002 in another study from Denmark (and co-uthored by Dr J Olsen, who also took part in the earlier Danish study),Dr Juhl Mette describes the time taken for over 39,000 pregnant women to conceive. It's by far the largest study published on the subject.

The women who had been mild and moderate consumers of alcohol conceived more quickly than women who drank no alcohol.

Now, in a second study of their data, Dr Mette, Dr Olson and their colleagues have concluded that the beneficial effect was present with wine but not with other forms of alcohol.

I stress that this is not a licence to get drunk - and remember it's important to seriously restrict alcohol if you are already pregnant.

But if wine helps you relax and to have better sex during an otherwise stressful time, it's probably good to have a glass with your dinner.

For more, go to WebPage 19 in the Members Area.