What are the implications for fertility and pregnancy?
In general, women with well-controlled Crohn's disease appear to have similar fertility rates and birth outcomes to women without the disease. Some studies have shown an increaed risk of premature birth (before 37 weeks) and low-birth weight infants. It is felt that those women with active disease are at greatest risk for these negative outcomes. For women with Crohn's disease, we usually recommend that the disease be in remission and that patients discuss their plans for pregnancy with their physician before attempting to conceive. We also recommend consultation with a high-risk obstetrician in a number of cases.
The risk of a disease flare during pregnancy is similar to the non-pregnant population. As mentioned, it is important to maintain the disease in remission prior to attempting pregnancy, as there may be a higher risk of low birth weights infants in women with active disease due to pre-term labor. It is important that patients are not undertreated simply because she is pregnant. In fact, the same treatment principles apply to pregnant and nonpregnant patients alike. Most studies of women who were pregnant while taking either 5-ASA, azathioprine/6MP, steroids, cyclosporin, or anti-TNF therapy have not shown any increase risk of birth defects or detrimental birth outcomes. Thus, continuing those medications that keep the disease quiet is important in women prior to and throughout the pregnancy. The only exceptions to this are the use of methotrexate, thalidomide, and certain antibiotics which must be stopped prior to pregnancy because they can cause birth defects.
In most cases, the type of delivery, C-section versus vaginal delivery, is up to the obstetrician. Only in cases of active perianal disease will a gastroenterologist recommend C-section over a vaginal delivery.
Sulfasalazine can lower sperm counts and adversely affect sperm function, although these effects are reversible with discontinuation of the drug. If men are on sulfasalazine, they can consider tests of sperm count if they are having difficulty with conception. Mesalamine drugs do not affect the sperm and are an option for those men with abnormal semen analyses. While some studies have suggested that men taking azathioprine or 6-MP have a higher rate of birth defects in their offspring, this has not been convincingly confirmed and most physicians will continue 6MP in this situation.