Skip to main content

Briefing note: Scientific information on abortion

This information has been produced by expert reviewers from the RCOG and the Faculty of Sexual and Reproductive Healthcare. It was published in January 2008 to accompany the passage of the Human Fertilisation and Embryology Bill through Parliament.

Induced abortion is a safe procedure which has contributed significantly to women’s health. Before the Abortion Act 1967, there is evidence that at least 20,000, possibly more, illegal abortions were carried out annually (the actual number is unknown, but estimates in the Lane Committee report [the report of the Committee on the Working of the Abortion Act set up under the chairmanship of Mrs Justice Lane and presented to Parliament in 1974] vary between 20,000 and 60,000 per annum). We consider 20,000 to be a realistic minimum estimate. Furthermore, during the period 1964–66 (prior to the Abortion Act) 98 women (32 a year) died as a result of illegal abortions.

Number of abortions performed at late gestation

The Department of Health’s data demonstrates that, in England and Wales, over a four year period (2003–2006) 133 terminations were performed per annum at gestations over 24 weeks for fetal abnormality (i.e. under Section E of the Abortion Act).

Accuracy of determining gestation

The RCOG guideline The Care of Women Requesting Induced Abortion recommends that gestation is routinely confirmed by ultrasound scan prior to termination. Many women will have had an early booking scan from which the gestation is best assessed.

Early gestation scans are more accurate and precise in gestation estimation, as there is less measurement variability between individual fetuses. Before 13 weeks, gestational age can be determined within seven days. However, a two-week margin of variability is normally allowed for scans at 20 weeks of gestation.

The accuracy of a scan is particularly important at later gestation but, at the same time, there is increasing variability as fetuses grow at different rates. Only size, not age, can be measured by ultrasound scan, so a relatively big fetus at 18 weeks will not be distinguishable from a small fetus at 20 weeks.


  • Altman DG, Chitty LS. New charts for ultrasound dating of pregnancy. Ultrasound Obstet Gynecol 1997, 10; 1-18.

Termination of pregnancies complicated by fetal malformations

From the literature we reviewed there is a large range of antenata l detection rates with some abnormalities being diagnosed with almost 100% accuracy and some malformations being diagnosed in less than 50% of cases.

Termination of pregnancy for fetal abnormality (TOPFA) although accounting for only 0.97% of all registered terminations in 2001 in England and Wales, represents a problematic aspect of abortion. The increasing number of TOPFA is explained by the increasingly sensitive antenatal screening programmes (Wicks at el., 2004). A major dilemma facing health professional involved in TOPFA is minimising the risk of the fetus being born with signs of life. Although the RCOG recommends that a procedure (feticide) is performed prior to induction of labour in TOPFA when the gestation is more than 21 weeks 6 days, there is anecdotal evidence that this recommendation is not always being followed. The RCOG recognises that some women may choose not to have feticide in the presence of a lethal abnormality, in such cases discussion must take place within the appropriate team, and the patient’s wishes and agreement sought on the management of the fetus after birth.

Antenatal detection of fetal malformations relies on accurate detection of the disorder from screening programmes using either maternal serum screening, the routine fetal anomaly scan at 18–20 weeks or a combination of both. There is a large range of detection rates, with some abnormalities being diagnosed with almost 100% accuracy and some malformations being diagnosed in less than 50% of cases (Richmond and Atkins, 2005). In addition some fetal malformations are not apparent at the 20-week anomaly scan but are visualised beyond 24 weeks if a need for a scan arises. Examples of this are the hypoplastic left heart syndrome and cerebral ventriculomegaly.

In Europe, data has been examined from 17 European population-based registries of congenital malformations (EUROCAT) for the period 1995–1999 (Garne et al., 2005). All livebirths, fetal deaths and terminations of pregnancy diagnosed with one or more of a number of malformations were included. The overall prenatal detection rate was 64% with a range of 25–88% across regions. The proportion of terminations of pregnancy varied between regions from 15% to 59% of all cases. Sixty-eight percent of prenatal detection was at less than 24 weeks of gestational age (range 36–88%). For individual malformations, the prenatal detection rate was highest for anencephalus (469/498, 94%) and lowest for transposition of the great arteries (89/324, 27%).


  • Wicks E, Wyldes M, Kilby. Late termination of pregnancy for fetal abnormality: medical and legal perspectives. Med Law Review 2004;12:285–305.
  • Richmond S, Atkins J. A population-based study of the prenatal diagnosis of congenital malformations over 16 years. BJOG 2005;112:1349–57.
  • Garne E, et al. Prenatal Diagnosis of severe structural congenital malformations in Europe. Ultrasound Obstet Gynaecol 2005;25:6–11.

Does abortion increase the risk of breast cancer?

From the literature we reviewed there is no established link between induced abortion or miscarriage and development of breast cancer.

Four studies published post-RCOG guideline on induced abortion (2004) were reviewed. From these studies there was no established link between abortion or miscarriage and breast cancer. The EPIC study (Reeves et al., 2006) involved 267,361 European women from nine countries recruited between 1992 and 2000. The relative risk of breast cancer among women who had an induced abortion compared to women who had not was 0.95 (95% confidence interval 0.87–1.03).

In the US, the Nurses’ Health Study II (Michaels et al., 2007) included 105,716 women, 29 to 46 years old at the start of follow-up in 1993 and included nearly 1 million person years of follow-up. The hazards ratio for breast cancer among women who had one or more induced abortions was 1.01 (95% confidence interval, 0.88–1.17) after adjustment for established breast cancer risk factors. The relation between induced abortions and the incidence of breast cancer did not differ materially by number of abortions or age at abortion.

Brewster et al. (2004) reported a Scottish record linkage case control study of 2,200 women with breast cancer and 9,781 matched control with a previous miscarriage and 9,888 with previous induced abortion. The risk of breast cancer among women with previous miscarriage was 1.02 (95% confidence interval, 0.88–1.18) compared with 0.80 (0.72–0.89) in previous induced abortion group.

Furthermore, Palmer et al. (2004) reported no relationship between breast cancer and induced abortion.


  • Reeves G, et al. Breast cancer risk in relation to abortion: results from the EPIC study. International Journal Cancer 2006;119:1741–5.
  • Michels KB et al. Induced and spontaneous abortion and incidence of breast cancer among young women: a prospective cohort study. Arch Intern Med 2007;167:814–20.
  • Brewster et al. Risk of breast cancer after miscarriage or induced abortion: a Scottish record linkage case-control study. J Epidemiol Community Health 2005;59:283–7.
  • Palmer et al. A prospective study of induced abortion and breast cancer in African-American women. Cancer Causes and Control 2004;15:105–11.

Is termination of pregnancy linked to preterm labour or intrauterine growth restriction?

From the recent studies reviewed no clear relationship between previous induced abortion or miscarriage and occurrence of preterm labour or intrauterine growth restriction was demonstrable.

Seven studies published since 2004 were reviewed. A recent analysis of a population-based database in Finland (Raatikainen et al., 2006) demonstrated no evidence of adverse pregnancy outcome following induced abortion. Similarly, a study in Denmark (Virk et al., 2007) of women who had had an induced abortion between 1999 and 2004 showed no increased risk of subsequent risk of ectopic pregnancy, miscarriage, premature delivery or low birth weight with medical termination of pregnancy compared to surgical termination of pregnancy.

A study from Italy (Parazzini et al., 2007) reported no increased risk of small for gestational age babies. Similarly, Jackson et al. (2007) from the US did not report increased risk of preterm labour among women who had had a previous termination of pregnancy between 12 and 24 weeks of gestation.

Conversely, two studies from France (Moreau et al., 2005 and Ancel, 2004) reported higher risks of preterm labour, which were directly related to the number of previous induced abortions.

Recently, Brown et al. (2008) has reported an increased risk of low birth weight and preterm labour among women with a history of previous recurrent spontaneous or induced abortions among women who were managed in the 1950s–60s. The association of poor obstetric performance and a history of previous recurrent spontaneous miscarriage is well known. Induced abortion was illegal in the USA during that time and data were missing as regards the methods used and at which stage these abortions were procured. Authors recognise that more work is required to clearly quantify risks related to future obstetric performance.

However, studies published during 1980s–1990s have reported increased risk of preterm labour and a dose response effect – which means that risk estimates rise as the women had more induced abortions.

More research is warranted in this area by prospectively designed studies. Currently a large number of women are having their pregnancies terminated using medical methods, and even those undergoing surgical termination have their cervix pre-treated with prostaglandins. These developments have significantly lowered the previously reported trauma to the cervix and the body of the uterus.


  • Raatikainen K, et al. Induced abortion: not an independent risk factor for pregnancy outcome, but a challenge for health counselling. Ann Epidemiol 2006;16:587–92.
  • Virk J, et al. Medical abortion and the risk of subsequent adverse pregnancy outcomes. JEJM 2007;357:648–53.
  • Parazzini et al. Induced abortion and risk of small for gestational age birth. BJOG 2007;114:1414–18.
  • Jackson et al. Mid trimester dilation and evacuation with laminaria does not increase the risk for severe subsequent pregnancy complications 2007;96:12–15.
  • Moreau et al. Previous induced abortion and the risk of very preterm delivery: results of the EPIPAGE study 2005;112:430–7.
  • Ancel. History of induced abortion as a risk factor for preterm birth in European countries: results of the EUROPOP survey 2004;19:734–40.
  • Brown et al. Previous abortion and the risk of low birth weight and preterm birth. J Epidem Community Health 2008;62:16–22.

Does termination of pregnancy lead to post-traumatic stress disorder?

A prospective randomised study needs to be designed to address this question in which women wishing to terminate their pregnancies would be randomly assigned either to receive a termination or have their request denied without the possibility of them having a termination elsewhere. No such randomised study has taken place so far, or is likely.

Studies so far reported are far from ideal. Observational studies are more prone to bias as some of them have compared women obtaining termination to those women who become pregnant because they wanted to become pregnant. These two groups are not comparable. They are undoubtedly different in many ways. Populations of women who use abortion differ in many ways from those who do not. At the time of abortion, they are likely to be younger, poorer and less able to reliably use contraception than a sample of the general population of women. These similarities in socio-economic status, stress, access to health care and lifestyle (poverty, domestic violence and impaired partnership relationship) may persist across time and they may actually be associated with adverse health outcomes – in other words, observed associations may stem from other confounding differences between women who choose abortion and those who do not.

Studies also demonstrate that the predominant feeling following abortion is one of relief and diminution of stress. The incidence of severe negative reaction is low, although some factors are known to increase risk (abortion where pregnancy had been planned and late gestation abortion). Where problems do arise there is often a history of susceptibility which predates the abortion procedure.

Of late, Ferguson et al. (2007) from New Zealand have used a study design comparing women who had terminations with those giving birth, including unintended births. This was a 25-year longitudinal study examining the relationship between pregnancy and abortion history prior to age 21. This study reported that young women who had an abortion had significantly better outcomes on six out of ten measures spanning education, income, welfare dependence and domestic violence and higher levels of subsequent educational achievement.


  • Adler NE. Statement on behalf of the American Psychological Association.
  • Adler NE et al. Psychological factors in abortion.
  • Kersting A et al. Trauma and grief of 2–7 years after termination of pregnancy because of fetal anomalies – a pilot study. Journal of Psychosomatic Obstetrics & Gynaecology 2005;26:9–14.
  • Korenromp MJ et al. Long term psychological consequences of pregnancy termination for fetal abnormality: a cross-sectional study. Prenatal Diagnosis 2005;25:253–60.
  • Ferguson DM et al. Abortion among young women and subsequent life outcomes. Perspective on Sexual and Reproductive Health 2007;39:6–12.

Current status of research into fetal awareness and pain

The RCOG reviewed its report Fetal Awareness in 2002. New evidence post-2002 was reviewed in 2007 and we are not aware of any new evidence that warrants alteration to the recommendations in our report . The RCOG will be working with the DH to establish a Working Party to review evidence into fetal awareness and pain when relevant experts in this area will be invited to submit their evidence.

Should nurses be allowed to carry out abortions?

Many hospital based abortion services already rely on nurses to run their medical abortion units. Allowing nurses to take consent for abortion (medical or surgical) would help to make these services run more efficiently. There is no reason why an appropriately trained nurse should not be competent to obtain consent to abortion. Managing a woman in the abortion service requires a number of clinical skills which nurses have demonstrated in other healthcare settings, for example, most services use routine ultrasound scanning to determine gestation and eligibility for medical or surgical abortion. Specialist nurses are now trained to undertake these and other similar procedures (e.g. colposcopy and cervical surgery).

There is also an increasing body of evidence from both developed and developing countries that abortion at home, using mifepristone/Misoprostol is safe, effective and acceptable to many women. More work is needed to assess safety and acceptability in the UK context, but this would require a change in the current law, or a different interpretation of the abortion process within the current law.


  • Warriner IK et al. Rates of complications in first trimester manual vacuum aspiration abortion done by doctors and mid level providers in South Africa and Vietnam: a randomised controlled equivalence trial. Lancet 2006;368:1965–72.
  • Clark WH, et al. Home use of two doses of Misoprostol for medical abortion – A pilot study in Sweden and France. Eur J Contracep Reprod Health Care 2005;10–184

Are two doctors’ signatures necessary?

The current use of the Abortion Act by the population and the profession suggests that in the majority of cases the need for two signatures is anachronistic (98% are done under clause C or D). Overall, women support the right to abortion and the GMC guidance that alternative provision must be offered if the practitioner cannot support a request for abortion is evidence for the woman’s autonomy to seek help. The disadvantage of obtaining two signatures is that it has the potential to cause delay which causes distress and can increase clinical risk. It has been argued that some delay is a good thing since it allows women more time to reflect on the decisions about abortion. However, there is good evidence that the vast majority of women who are referred for abortion are absolutely certain that the pregnancy is unwanted and have no doubts about wanting the procedure. The suggestion is that the need to have two doctors sign the form would help those women who do have some doubt about abortion to make up their minds seems unpersuasive.


  • Allan I. Counselling services for sterilisation and termination of pregnancy, London: Policy Studies Institute No 641. 1985: 97-105.
  • Lakha F, Glasier A. Unintended pregnancy and use of emergency contraception among a large cohort of women attending for antenatal care or abortion in Scotland. Lancet 2006;368:1782–7.

Elsewhere on the site

Human Fertilisation and Embryology Bill
See all RCOG information and opinion about the Human Fertilisation and Embryology Bill
Press centre
Information and contact details for journalists and other members of the media