The incidence of hemorrhoids varies depending on the period from pregnancy to delivery. According to an overseas report of women who developed hemorrhoids by period, the incidence was 1.6% in early pregnancy (up to 13 weeks and 6 days), 61% in late pregnancy (from 28 weeks and 0 days), and 37.4% within 1 month after delivery. The risk of onset increases from late pregnancy to after delivery. Since the risk of onset greatly increases particularly in late pregnancy, attention should be paid.
Risk factors for hemorrhoids (piles) and anal fissure include constipation, straining for at least 20 minutes during delivery, giving birth to a baby weighing 3,800 g or more, and a history of anal disease.
[Reference]
1) Poskus, T. et al: BJOG, 13: 1666, 2014.