You'd like to add to your family, but so far, no luck. If you've been trying to conceive for a year (or six months if you're over 35), it's a good idea for you and your partner to have a fertility workup. On the agenda for him: a physical exam and a semen analysis. And for you:

* A detailed medical history and checkup. Don't be surprised if the subject of weight comes up. "If you've gained or lost a lot since the first pregnancy, it may affect ovulation," says Owen Davis, M.D., associate director of the Center for Reproductive Medicine and Infertility at Cornell Medical College, in New York City. If you have endometriosis, ask about ways to treat it that preserve fertility.

* Blood work to measure levels of hormones: follicle-stimulating hormone, estradiol, progesterone, and thyroid-stimulating hormone. These show if you're ovulating normally, whether there's a problem with your eggs (more likely if you're over 35), and if your thyroid's okay (if not, medication can treat it).

* A vaginal ultrasound exam, depending on your medical history. This painless procedure allows the doctor to see images of your ovaries and uterus to check for abnormalities and to monitor your egg follicles.

* To make sure your fallopian tubes are open and your uterus is shaped normally, your doctor may include a hysterosalpingogram (HSG), a hospital procedure in which dye is injected into your uterus and fallopian tubes. Surgery can correct some blockages.

In the end, you and your partner may have "unexplained secondary infertility," as one in seven couples who've already had a child does. If so, it's time to discuss with specialists the effectiveness, and cost, of fertility treatments.

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