Shingles is chickenpox reactivated, but is apparently less contagious than chickenpox and if you're had it as a child I'd guess you're probably safe. Erm, and this website agrees with me www.patient.co.uk/showdoc/23068942/ but there's probably other one's that differ! I'm not sure, could you ring an on call doctor/midwife and ask?
I have no idea why it's safer to drink a little... I'm not sure that there is an available unanimous scientific opinion anyway.
Found this though:
Wine and Pregnancy
More than this, not even one study carried out since the mid-1980s has shown a direct correlation between moderate alcohol consumption and birth defects. One study, of 33,300 California women showed that even though 47% drank moderately during their pregnancies that none of their babies met the criteria for Fetal Alcoholic Syndrome. The authors of this study concluded "that alcohol at moderate levels is not a significant cause of malformation in our society and that the position that moderate consumption is dangerous, is completely unjustified."
Some studies go as far as to indicate that light to moderate drinking may actually improve the chance of successful pregnancies. A 1993 study published in the "American Journal of Epidemiology" by Ruth Little and Clarence Weinberg concluded, for example, that there were fewer stillbirths and fewer losses of fetus due to early labor among women who consumed a moderate level of alcohol. That some alcohol can be protective against preterm birth is also supported by Dr. Martha Direnfeld of Haifa University who points out that when used properly, alcohol is known to stop unwanted uterine contractions, and thus has "saved many pregnancies that might otherwise have spontaneously aborted." More than this, Dr. Robert Sokol of the National Institute on Alcohol Abuse in Detroit has shown that it is light drinkers and not abstainers who have the best chance of having a baby of optimal birth weight and in their book "Alcohol and the Fetus" and Doctors Henry Rosset and Lynn Wiener have presented data that shows that children of moderate drinkers tend to score highest on developmental tests at the age of 18 months.