Sign in Subscribe
Pregnant women

Ulcerative Colitis in Pregnancy: A Risk Factor for Small-for-Gestational-Age Infants

Strategic Insights

— 2 min read

According to a recent study published in the Journal of Obstetrics and Gynaecology Research, pregnant women with ulcerative colitis are at a higher risk of delivering small-for-gestational-age infants. The research, conducted by a team of investigators at the Kochi University School of Medicine, analyzed data from a large-scale nationwide cohort in Japan. The study found that 214 out of 97,075 pregnancies were complicated by ulcerative colitis, and these women were more likely to have older age and lower smoking rates compared to those without the condition. The proportion of small-for-gestational-age infants was also higher in pregnancies complicated by ulcerative colitis, especially in patients with anemia or inflammation during early pregnancy.

Key Takeaways:

  • Pregnant women with ulcerative colitis are at a higher risk of delivering small-for-gestational-age infants, with a proportion of 3.4% compared to 1.8% in the control group.
  • Women with ulcerative colitis were older (30.8 years vs. 29.4 years) and had a lower smoking rate (12.5% vs. 20.7%) than those without the condition.
  • Gestational weight gain was lower in the ulcerative colitis group (10.3 kg vs. 11.2 kg) compared to the control group.
  • Pregnant women with ulcerative colitis had a higher risk of delivering small-for-gestational-age infants, especially in patients with anemia or inflammation during early pregnancy.
  • The study suggests that further research is needed to assess disease activity and perinatal risk better.
  • The Japan Environment and Children's Study (JECS) provided the data for this research.
  • Marina Minami from the Integrated Center for Advanced Medical Technologies (ICAM-Tech), Kochi University School of Medicine Hospital, was an author on this paper.

Statistics:

  • 214 out of 97,075 pregnancies were complicated by ulcerative colitis.
  • The proportion of small-for-gestational-age infants was 3.4% in pregnancies complicated by ulcerative colitis and 1.8% in the control group.
  • Women with ulcerative colitis were 1.8 times more likely to have a small-for-gestational-age infant compared to those without the condition.
  • Gestational weight gain was lower in the ulcerative colitis group by 0.9 kg compared to the control group.
  • Pregnant women with ulcerative colitis had a higher risk of anemia (18.7% vs. 12.3%) and inflammation (24.3% vs. 15.6%) during early pregnancy.

Sources:

  • NewsRx. Studies from Kochi University School of Medicine Provide New Data on Ulcerative Colitis [Pregnant Women With Ulcerative Colitis Have a Higher Risk of Delivering Small-For-Gestational-Age Infants: The Japan Environment and Children's Study (JECS)]. Gastroenterology Week. October 20, 2025; p 1345.
  • Journal of Obstetrics and Gynaecology Research. "Pregnant Women With Ulcerative Colitis Have a Higher Risk of Delivering Small-For-Gestational-Age Infants: The Japan Environment and Children's Study (JECS)." Journal of Obstetrics and Gynaecology Research 2025;51(10).
  • Journal of Obstetrics and Gynaecology Research. "Wiley, 111 River St, Hoboken 07030-5774, NJ, USA."
  • Kochi University School of Medicine. "Integrated Center for Advanced Medical Technologies (ICAM-Tech), Kochi University School of Medicine Hospital, Nankoku, Kochi, Japan."

Read more