|Last use||Usage has declined in U.S. since the 1970s.|
|United States||0.9% (2003)|
Instillation abortion is a rarely used method of induced abortion, performed in the second trimester, by injecting a solution into the uterus to cause uterine contractions.
Instillation abortion is performed by injecting a chemical solution consisting of either saline, urea, or prostaglandin through the abdomen and into the amniotic sac. The cervix is dilated prior to the injection, and the chemical solution induces uterine contractions which expel the fetus.  Sometimes a dilation and curettage procedure is necessary to remove any remaining tissue. 
Instillation methods can require hospitalization for 12 to 48 hours.  In one study, when laminaria were used to dilate the cervix overnight, the time between injection and completion was reduced from 29 to 14 hours. 
The method of instillation abortion was first developed in 1934 by Eugen Aburel.  It is most frequently used between the 16th and 24th week of pregnancy, but its rate of use has declined dramatically in recent years.  In 1968, abortion by the instillation of saline solution accounted for 28% of those procedures performed legally in San Francisco, California.  Intrauterine instillation (of all kinds) declined from 10.4% of all legal abortions in the U.S. in 1972 to 1.7% in 1985,  falling to 0.8% of the total incidence of induced abortion in the United States during 2002,  and 0.1% in 2007. 
In a 1998 Guttmacher Institute survey, sent to hospitals in Ontario, Canada, 9% of those hospitals in the province which offered abortion services used saline instillations, 4% used urea, and 25% used prostaglandin.  A 1998 study of facilities in Nigeria which provide abortion found that only 5% of the total number in the country use saline. 
Once in common practice, abortion by intrauterine instillation has fallen out of favor, due to its association with serious adverse effects and its replacement by procedures which require less time and result in less physical discomfort. 
Saline is in general safer and more effective than the other intrauterine solutions because it is likely to work in one dose. However, it poses a risk of medical emergency if it enters the blood stream. Prostaglandin is fast-acting, but often requires a second injection, and carries more side effects, such as nausea, vomiting, and diarrhea. 
Instillation of either saline or prostaglandin is associated with a higher risk of immediate complications than surgical D&C.  Dilation and evacuation is also reported to be safer than instillation methods.  One study found that the risk of complications associated with the injection of a combination of urea and prostaglandin into the amniotic fluid was 1.9 times that of D&E. 
The rate of mortality reported in the United States between 1972 to 1981 was 9.6 per 100,000 for instillation methods. This is in comparison to rates of 4.9 per 100,000 for D&E and 60 per 100,000 for abortion by hysterotomy and hysterectomy. 
There have been at least two documented cases of unsuccessful instillation abortions that resulted in live births.
See also 
- James, Denise. (2006). Therapeutic Abortion. Retrieved February 24, 2009.
- UIHC Medical Museum. (2006) The Facts of Life: Examining Reproductive Health. Retrieved August 14, 2006.
- Stubblefield, Phillip G., Carr-Ellis, Sacheen, & Borgatta, Lynn. (2004). Methods of Induced Abortion. Obstetrics & Gynecology, 104 (1), 174-185. Retrieved August 14, 2006.
- Potts DM (January 1970). "Termination of pregnancy". Br. Med. Bull. 26 (1): 65–71. PMID 4904688.
- Goldstein P, Stewart G (May 1972). "Trends in therapeutic abortion in San Francisco". Am J Public Health 62 (5): 695–9. doi:10.2105/AJPH.62.5.695. PMC 1530244. PMID 5024298.
- Lawson, Herschel W., Atrash, Hani K., Saftlas, Audrey F., Koonin, Lisa M., Ramick, Merrell, & Smith, Jack C. (1989). Abortion Surveillance, United States, 1984-1985. Morbidity and Mortality Weekly Report. Retrieved August 14, 2006.
- Strauss, Lilo T., Herndon, Joy, Chang, Jeani, Parker, Wilda Y., Bowens, Sonya V., Berg, Cynthia J. Centers for Disease Control and Prevention. (2005-11-15). Abortion Surveillance - United States, 2002. Morbidity and Mortality Weekly Report. Retrieved 2006-02-20.
- Pazol, Karen, Zane, Suzanne B., Parker, Wilda Y., Hall, Laura R., Gamble, Sonya B., Hamdan, Saeed, Berg, Cynthia, Cook, Douglas A., Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control. (2011-02-25). Abortion Surveillance - United States, 2007. Morbidity and Mortality Weekly Report. Retrieved 2011-08-24.
- Ferris LE, McMain-Klein M, Iron K (1998). "Factors influencing the delivery of abortion services in Ontario: a descriptive study". Fam Plann Perspect 30 (3): 134–8. doi:10.2307/2991628. JSTOR 2991628. PMID 9635262.
- Henshaw, Stanley K., Singh, Susheela, Oye-Adeniran, Boniface A., Adewole, Isaac F., Iwere, Ngozi, & Cuca, Yvette P. (1998). "The Incidence of Induced Abortion in Nigeria". International Family Planning Perspectives 24 (4): 156–64. doi:10.2307/2991973. JSTOR 2991973.
- Trupin, Suzanne R. (2006). Abortion. Retrieved August 14, 2006.
- Ferris LE, McMain-Klein M, Colodny N, Fellows GF, Lamont J (June 1996). "Factors associated with immediate abortion complications". CMAJ 154 (11): 1677–85. PMC 1487918. PMID 8646655.
- Grimes DA, Schulz KF (July 1985). "Morbidity and mortality from second-trimester abortions". J Reprod Med 30 (7): 505–14. PMID 3897528.
- Elliott, Jane. "'I survived an abortion attempt'." (December 6, 2005.) BBC News. Retrieved April 26, 2007.
P. Clarke, J. Smith, T. Kelly, MJ Robinson (January 2005). "An infant who survived abortion and neonatal intensive care". Journal of Obstetrics and Gynaecology 25 (1): 73–4. doi:10.1080/01443610400025945. PMID 16147706.