There's nothing like a fetus to keep you honest. No matter how much healthsense you might choose to ignore when the consequences are only yours, it's adifferent ballgame with a baby on the way. So it's natural for women to shununhealthful substances or behavior during pregnancy.

But prenatal sages have a new message these days: You'd better come cleanfirst.

The standard pregnancy do's -- eat right, cut out cigarettes and alcohol,ease up on caffeine -- should all crank into gear three months beforeconception, not after the fact, experts warn. "Pregnancy is no longer ninemonths -- it's 12," says Dr. Robert Cefalo, a maternal-fetal medicinespecialist at the University of North Carolina at Chapel Hill and coauthor of"Preconceptional Health Care: A Practical Guide."

Why all the fuss? Allowing extra prep time to deal with medical, social orenvironmental factors that could complicate your pregnancy is critical becauseit's during the very early weeks after conception -- when most couples stilldon't know they're pregnant -- that a baby's organs are developing. "Thefetus is most sensitive to any little adverse event or drug between 17 and 56days," Dr. Cefalo says.

If you are thinking about getting pregnant, consider these factorsfirst.

Getting Physical

Make sure you're up-to-date on annual physical and dental exams, andschedule a preconception exam with your OB-Gyn to review any medicalconditions, lifestyle habits or hereditary diseases that could complicate yourpregnancy. Your doctor will want to know, for example, if you have diabetes,high blood pressure or another condition that needs to be closely monitoredwhile you're pregnant.

"In reality, the vast majority of women are perfectly fine, but it'sjust a good idea to get all of this on the table beforehand to minimizeanything unexpected," says Michael Zinaman, director of reproductiveendocrinology at Loyola University Medical Center in Chicago.

Your doctor also will scrutinize medications you may be taking to make surethey aren't harmful because even some over-the-counter drugs, like some nasalsprays, can cause birth defects. And if you're taking birth control pills, youmay be advised to use another method until you've had two normal periods beforeyou attempt pregnancy; this will reduce the risk of miscarriage.

The few extra months can help because some conditions are more difficult --or even impossible -- to resolve during pregnancy. Vaccination for rubella(German measles), for instance, must be administered at least three monthsbefore getting pregnant. Even minor surgeries or X-rays, which may take time toschedule, are safer to get out of the way before conception, says Dr. JohnQueenan, chairman of the department of obstetrics and gynecology at GeorgetownUniversity School of Medicine and author of "A New Life" and"Preconceptions: Preparation for Pregnancy." It also takes time to quitsmoking and drinking, and to rid the body of harmful toxins.