This is particularly true for cervical cancer, the most common type of which occurs in 1 of every 2,000–13,000 pregnancies, for which initiation of treatment "cannot co-exist with preservation of fetal life (unless neoadjuvant chemotherapy is chosen)". Very early stage cervical cancers (I and IIa) may be treated by radical hysterectomy and pelvic lymph node dissection, radiation therapy, or both, while later stages are treated by radiotherapy. Chemotherapy may be used simultaneously. Treatment of breast cancer during pregnancy also involves fetal considerations, because lumpectomy is discouraged in favor of modified radical mastectomy unless late-term pregnancy allows follow-up radiation therapy to be administered after the birth.Exposure to a single chemotherapy drug is estimated to cause a 7.5–17% risk of teratogenic effects on the fetus, with higher risks for multiple drug treatments. Treatment with more than 40 Gy of radiation usually causes spontaneous abortion. Exposure to much lower doses during the first trimester, especially 8 to 15 weeks of development, can cause intellectual disability or microcephaly, and exposure at this or subsequent stages can cause reduced intrauterine growth and birth weight. Exposures above 0.005–0.025 Gy cause a dose-dependent reduction in IQ. It is possible to greatly reduce exposure to radiation with abdominal shielding, depending on how far the area to be irradiated is from the fetus.The process of birth itself may also put the mother at risk.
Grade 2 sprains occur when the ligament is stretched to the point that it becomes loose; this is also referred to as a partial tear. Grade 3 sprains occur when the ligament is completely torn into two pieces, and the knee joint is no longer stable. This is the most common type of ACL injury.Around half of ACL injuries occur in conjunction with injury to other structures in the knee, including the other ligaments, menisci, or cartilage on the surface of the bones. A specific pattern of injury called the "unhappy triad" (also known as the "terrible triad," or "ODonoghues triad") involves injury to the ACL, MCL, and medial meniscus, and occurs when a lateral force is applied to the knee while the foot is fixed on the ground. Prevention
Interest in reducing non-contact ACL injury has been intense. The International Olympic Committee, after a comprehensive review of preventive strategies, has stated that injury prevention programs have a measurable effect on reducing injuries. These programs are especially important in female athletes who bear higher incidence of ACL injury than male athletes, and also in children and adolescents who are at high risk for a second ACL tear.Researchers have found that female athletes often land with the knees relatively straight and collapsing inwards towards each other, with most of their bodyweight on a single foot and their upper body tilting to one side; these four factors put excessive strain on the ligaments on the knee and thus increase the likelihood of ACL tear.