5 Ways to Prepare for Pregnancy

Understand how your weight can affect your chances of conceiving
The time before pregnancy is also the time to address any weight problems. Studies find that being overweight can increase your risk of gestational diabetes and may even make it harder to get pregnant. Conversely, being underweight can interfere with fertility.

Quit smoking before you get pregnant
And, of course, it's a time to quit smoking. Smoking not only increases the risk of having a low birth-weight baby, but also a baby with Down syndrome and a multitude of other birth defects.

Discuss preconception and genetic counseling with your health care provider and your options for pregnancy
In addition to preconception counseling, women might consider genetic counseling before they get pregnant, says Ms. Reynolds. During genetic counseling, a specially trained counselor takes a detailed medical history of you and your partner, as well as your families, to identify any potential or known genetic disorders. "Often, it is only when a woman becomes pregnant that genetic disorders come up, and for some, it's too late to make a difference in promoting a healthy outcome," she says. But even here, technology can step in.

A relatively new form of in vitro fertilization called preimplantation genetic diagnosis (PGD) can enable couples who carry genes for genetic disorders like Tay-Sachs or sickle cell anemia to have a healthy child. The procedure involves removing one cell from an eight-cell embryo and studying it for any genetic abnormalities. Only those embryos with no obvious problems are implanted into the woman's uterus.