Women who have experienced sexual abuse are at a higher risk for experiencing postpartum post-traumatic stress disorder.
I was recently asked about resources for these women, and I came upon a blog called "Survivor Moms Speak Out", created by the authors of the book "Survivor Moms: Women's Stories of Birthing, Mothering & Healing After Sexual Abuse." If you or someone you know falls into this category, this site and book may be of help and/or comfort to you.
Other resources for you to consider:
TABS – Trauma & Birth Stress, an organization based in New Zealand.
PTSD After Childbirth – A Guide for Survivors of Child Sexual Abuse
An article about remembering sexual abuse in childbirth