1. Pregnant Women with IBD (Case) Inclusion Criteria 1. Be pregnant or planning pregnancy 2. To have confirmed IBD 3. To plan giving birth in Hong Kong Exclusion Criteria 1. Pregnancy complications, such as intrauterine fetal demise/stillbirth, preeclampsia, hyperemesis gravidarum, active infection, including chorioamnionitis or sepsis 2. Fetus chromosomal or structural abnormalities 3. Known history of HIV 4. History of Colectomy or ileo-anal pouch