My husband and I have five-year-old identical twins. However, we have been trying to get pregnant again for four years. Is there such a thing as having fertility problems after you already have children?

G.M.

The situation you report is called secondary infertility, and it is not at all uncommon. It would seem natural that if things worked one time, they should still be OK the next. But it just does not work that way.

The question that first comes to mind concerns your age. You are five years older; if you are now in your late 30s, issues surrounding age-related infertility must be considered. We need to consider also whether there were any complications related to the first pregnancy. Did you have an infection after the delivery? Did you have a cesarean section? Both of these situations may lead to the develop of adhesions that can interfere with normal fallopian tube function. Did you gain weight? Are you more fatigued? stressed? Do you still have breast discharge? Perhaps thyroid or pituitary hormone abnormalities may be the culprit.

Remember, too, to get your husband checked. Many physicians are reluctant to test the husband when initiating an evaluation for secondary infertility, yet quite often, even after a year or two, significant changes in male fertility may be the problem.

As far as the evaluation and management of secondary infertility, the best approach is to consider the same suspects that cause primary infertility. A fertility workup can help you narrow down what's happening in your case.