Now that you have decided you're ready (or almost ready) to have a baby, it's a good time to see your ob-gyn for a pre-pregnancy checkup, says George Attia, MD, director of the division of reproductive endocrinology and infertility at University of Miami in Florida. Ideally this appointment should take place three months before conception.

First and foremost, "you want to make sure that any pre-existing medical diseases and illnesses such as high blood pressure, diabetes, or thyroid problems are well under control," he says.

Such a checkup should also involve basic screening tests, including:

• A Pap smear
• A clinical breast exam
• Routine blood work to test cholesterol, triglycerides, liver function, and glucose (blood sugar) levels

"It is also a good idea to have tests done for sexually transmitted diseases including HIV, the AIDS virus, and herpes," Attia says.

At this visit, "your doctor can also give you a prescription for prenatal vitamins if you are not already taking them," he says. Women should take at least  400 to 800 micrograms of folic acid per day and this should be started at least one to two months before conception. Folic acid has been shown to decrease the risk of neural tube birth defects.

Also, "If you are missing any vaccines or not up to date, it's definitely better to get them before you become pregnant," adds Donnica Moore, MD, a women's health expert based in Far Hills, N.J. "Rubella and the chicken pox can both have devastating effects during pregnancy."

While many women have heard about various genetic screening tests that are now available to couples before they conceive, this is a personal decision usually based on family and personal history, Moore says. Such tests can determine if either parent has a series of genes that would predispose their infant to a host of medical conditions. Both partners would need the susceptibility gene to increase such risk.

Examples include:

• Sickle cell anemia
• Cystic fibrosis
• Duchenne muscular dystrophy

Even if you don't have the disorder yourself, you may carry the defect in your genes and can pass it along to your baby.

"If you have a family history of genetic medical disorders or birth defects, talk to your doctor about the right time to undergo these tests," Moore says.