The herbs for inducing fertility are usually discontinued once pregnancy is suspected or confirmed. In most cases, it is not necessary to use herbs during pregnancy. Women with a history of miscarriage or who are deemed at high risk for miscarriage (somewhat more common among women who have experienced prolonged infertility) may wish to take herbs that are traditionally used in such cases by Chinese women. Certain herbs can be used during pregnancy to enhance the health of the mother and to counteract symptoms of morning sickness. In addition, it is reported that labor can be made easier by proper application of herbs and acupuncture. Books on the subject of herbal health care for pregnancy and nursing can be traced back to such important works as A Precious Medical Book on Obstetrics for Home Use, published in 1184 A.D.