Secondary infertility is the inability to become pregnant or carry a pregnancy to term after you’ve already had a baby, and it's more common than you might think, accounting for about 50 percent of infertility cases. In fact, more couples experience secondary infertility than primary infertility (infertility the first time around). It’s especially common in women who wait until their late 30s or even 40s, when fertility takes a nosedive, to have their second babies.
Sometimes problems getting pregnant for a second or subsequent time are related to a complication that occurred in a prior pregnancy or prior to delivery (damage to the uterus, for instance). But most often, secondary infertility is caused by the same factors that would cause primary infertility — issues like advanced age, obesity, ovulation problems and so on.