SAN DIEGO – Embryo transfers are less likely to result in live births when women with ulcerative colitis (UC) have fertility treatments, and the risk of preterm birth is higher, at least for twins, according to a 20-year nationwide cohort study from Denmark. On a brighter note, UC did not increase the risk of low birth weight or birth defects, and prior UC surgeries did not diminish success.
The take home conclusions from the study are that “women with ulcerative colitis may [want] to initiate ART [assisted reproductive technology] treatment” sooner than other women because “they cannot expect the same success per embryo transfer.” The greater risk of preterm birth means that “increased prenatal observation in UC pregnancies after ART should be considered,” but “women with UC should be reassured that surgery before ART treatment does not impact the chance of live birth per embryo transfer,” said senior investigator Dr. Sonia Friedman, a gastroenterologist at Brigham and Women’s Hospital in Boston.
Dr. Sonia Friedman
Although it’s known that UC diminishes fertility in general, it hasn’t been known until now how it affects assisted reproduction. The investigators turned to Denmark to find out because Denmark has one of the highest incidence rates of UC worldwide, especially among women and men 15-29 years old, and the country captures virtually every ART outcome in national databases.
The study included 1,360 embryo transfers in 432 women with UC and 149,094 in 52,661 women without UC from 1994 to 2013. Treatments included in vitro fertilization, intracytoplasmic sperm injection, and embryo transfers. Women in both groups were a median of 33 years old; women with UC had a median disease duration of 8 years.
The chance of live birth per embryo transfer was 22% less in women with UC (odds ratio, 0.78; 95% confidence interval, 0.67-0.91), after adjusting for age, infertility cause, body mass index (BMI), smoking, and other factors, including calendar year, to take into account changes in ART over the years.
The risk of preterm birth was five times higher when singletons and multiple births were considered together (adjusted OR, 5.29; 95% CI, 2.41-11.63), but not statistically elevated when singleton births were analyzed on their own (aOR, 1.80; 95% CI, 0.49-6.62).
About 35% of the women with UC had prior surgeries, most commonly total colon resections. There was no difference in odds of live birth per cycle versus women with UC and without surgery (OR, 0.97; 95% CI, 0.61-1.36) after adjusting for disease duration, comorbidities, year of treatment, and other factors.
The impact of UC is probably related to disease activity. “Even though gynecologists in Denmark tell us they really try to keep their patients in remission before ART, there is some disease activity,” Dr. Friedman said at the annual Digestive Disease Week.
Surgery for Crohn’s disease is known to reduce success in ART, so it was a bit surprising that it didn’t seem to do so in UC. Perhaps it’s because UC surgery is often curative, while Crohn’s operations often are not, so Crohn’s patients may be more likely to have continued disease activity during ART treatment, Dr. Friedman said.
The majority of women in both study groups were normal weight and didn’t smoke. Outside of UC, most were free of comorbidities. In the UC surgery group, about half the women had one procedure, and the rest two or three.
The work was funded by the Crohn’s and Colitis Foundation of America. Dr. Friedman has no disclosures.