The aims of study were to investigate risk factors associated with attempted and completed suicide. This nested case-control study was conducted using the medical and death data of nearly all pregnant women for the period 2002-2012 in Taiwan. A total of 139 cases of attempted suicide and 95 cases of completed suicide were identified; for each case, 10 controls were randomly selected and matched to the cases according to age and year of delivery. A conditional logistic regression model was used. The mean attempted and completed suicide rates were 9.91 and 6.86 per 100,000 women with live births, respectively. Never having married and postpartum depression also increased the risk of attempted suicide (OR = 2.06; 95% CI = 1.09-3.88 and OR = 2.51; 95% CI = 1.10-5.75, respectively) and completed suicide (OR = 20.27; 95% CI = 8.99-45.73 and OR = 21.72; 95% CI = 8.08-58.37, respectively). Other factors for attempted suicide included being widowed or divorced, and having a caesarean delivery or suicide history. Other factors for completed suicide included lower education level, low infant birth weight, and diagnosis of anxiety or mood disorder. These results suggest that people should appropriately assess potential risk factors and provide assistance for postnatal women to reduce the occurrence of suicide events.