Epidemiology

Induced abortions are performed all over the world. About one in five pregnancies worldwide end in an abortion. Sedgh et al reviewed the worldwide induced abortion figures and estimated that there were 42 million induced abortions in 2003 as compared with 46 million abortions in 1995. The induced abortion rate was 29/1000 women aged 15–44 years in 2003 compared with 35/1000 in 1995. There was a huge variation in abortion rates in different parts of the Western world, the lowest being in Western Europe at 12/1000 women. Abortion rates were 17/1000 in northern Europe, 18/1000 in southern Europe and 21/1000 women in northern America. There are approximately 20 abortions per 1000 fertile age women ( Table 1 ).

According to the Department of Health Statistics in England and Wales (2008), the total number of abortions was approximately 201 600 in 2007 with a rise of 2.5% compared with 2006. The age-standardised abortion rate was 18.6 per 1000 women aged 15–44 years. There is evidence to suggest that an increasing proportion of abortions are now carried out medically. Medical abortions account for 35% of abortions compared with 30% in 2006, showing a rise in the uptake of medical abortion. Scottish data published in 2008 showed 13 817 (Rate: 13.1/1000 women) induced abortions. United States had an estimated 1 206 200 abortions during 2006–07.

Although induced abortion is a safe procedure in the Western and the resource-rich countries, there still remains a concern as regards unsafe abortions, which are being carried out worldwide, leading to a large number of maternal deaths. In the UK, the Abortion Act 1967 has ensured that when there is a concern about maternal well-being, two doctors can accede to the women’s request for an induced abortion. The most recently published Clinical Enquiry into Maternal and Child Health (CEMACH) report has cited one maternal death directly attributable to sepsis after unsafe abortion. Nearly half (48%) of all induced abortions worldwide were estimated to be unsafe in 2003. A great majority of them (97%) were carried out in the developing world. Unsafe abortions account for 13% of maternal deaths. An estimated 5 million women are hospitalised each year for abortion-related complications such as haemorrhage and sepsis. Abortions cause approximately 68 000 deaths and 5 million disability adjusted life years (disability adjusted life years) per year worldwide. Unsafe abortions account for 13% of maternal deaths. By achieving safe abortions and with the provision of adequate contraception, we will be able to reduce maternal mortality substantially and protect maternal health.

Amongst unsafe abortions, infective complications occur most frequently, resulting in significant morbidity and mortality. Infective complications are seen in 1–45% of women following induced abortions. This rate varies globally, being prevalent at the rate of 1–4.8% in developed countries and up to 45% in developing countries. The rates of infections are particularly high in unsafe abortions where women seek medical help late. Pelvic infections not only increase short-term morbidity and mortality but also have long-term health consequences such as chronic pelvic pain, infertility (4–7-fold increase in risk, and recurring infections double the risk) and ectopic pregnancies.

Causative organisms for post-abortion infections

Post-abortal genital tract infection including pelvic inflammatory disease (PID) of varying degrees of severity occurs in about 10% of induced abortions. Post-abortal sepsis is known to be polymicrobial. Various organisms causing post-abortion sepsis are Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG) and endogenous vaginal anaerobes such as Gardenerella vaginalis (GV), Ureaplasma urealyticum (UU) and Mycoplasma genitalium (MG) causing bacterial vaginosis (BV).

Chlamydia is an obligate Gram-negative intracellular bacterium commonly causing asymptomatic prolonged infections. N. gonorrhoea (NG) is a Gram-negative facultative intracellular aerobic diplococcic bacterium. They produce lipopolysaccharide endotoxins, which are highly toxic. BV is a polymicrobial condition where the lactobacilli – the normal commensal in the vagina – are replaced by anaerobic bacteria such as GV, UU and MG. These anaerobic organisms produce enzymes such as amino-peptidases and de-carboxylases that degrade proteins and convert amino acids to amines, which account for the characteristic ‘fishy odour’. The anaerobic organisms are thought to be permissive organisms facilitating the infection by Chlamydia , gonorrhoea and other aerobic organisms. They alter ‘the cervical mucous through enzymatic degradation of proteolytic barrier’. Organisms present in the lower genital tract that is, upper vagina and cervix, can therefore lead to ascending infections in the endometrium, fallopian tubes or the pelvic cavity.

C. trachomatis (CT) is the most common bacterial sexually transmitted organism in Europe and Northern America. The prevalence of Chlamydia infection in the pre-abortal population is 4.9–17.9%. In the UK, the prevalence of Chlamydia is approximately 6–8%. The prevalence of Chlamydia -positive patients was 11.4% (range: 5–15%) and NG was 2.6% (range: 1–3%) amongst women seeking first-trimester screening in Illinois. A study from Finland reported a nationwide increase from 23.4 per 10 000 to 29.2 per 10 000 in the incidence rates of CT, especially in the adolescents and young people. Bearing in mind the low prevalence of gonorrhoea (0.2%) among women in the United Kingdom undergoing abortion, screening for gonorrhoea is controversial. CT is detected more often in women with BV and may facilitate CT infection in the upper genital tract. Recurrent infections with Chlamydia lead to long-term problems such as tubal damage, infertility and chronic pelvic pain.

The prevalence of Chlamydia is higher in young women (15–25 years) as they are more prone to infections because of various factors such as discussed in Hillard et al.: cervical ectopy, lower levels of protective antibodies, reduced access to medical care and high risk-taking behaviour.

Causative organisms for post-abortion infections

Post-abortal genital tract infection including pelvic inflammatory disease (PID) of varying degrees of severity occurs in about 10% of induced abortions. Post-abortal sepsis is known to be polymicrobial. Various organisms causing post-abortion sepsis are Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG) and endogenous vaginal anaerobes such as Gardenerella vaginalis (GV), Ureaplasma urealyticum (UU) and Mycoplasma genitalium (MG) causing bacterial vaginosis (BV).

Chlamydia is an obligate Gram-negative intracellular bacterium commonly causing asymptomatic prolonged infections. N. gonorrhoea (NG) is a Gram-negative facultative intracellular aerobic diplococcic bacterium. They produce lipopolysaccharide endotoxins, which are highly toxic. BV is a polymicrobial condition where the lactobacilli – the normal commensal in the vagina – are replaced by anaerobic bacteria such as GV, UU and MG. These anaerobic organisms produce enzymes such as amino-peptidases and de-carboxylases that degrade proteins and convert amino acids to amines, which account for the characteristic ‘fishy odour’. The anaerobic organisms are thought to be permissive organisms facilitating the infection by Chlamydia , gonorrhoea and other aerobic organisms. They alter ‘the cervical mucous through enzymatic degradation of proteolytic barrier’. Organisms present in the lower genital tract that is, upper vagina and cervix, can therefore lead to ascending infections in the endometrium, fallopian tubes or the pelvic cavity.

C. trachomatis (CT) is the most common bacterial sexually transmitted organism in Europe and Northern America. The prevalence of Chlamydia infection in the pre-abortal population is 4.9–17.9%. In the UK, the prevalence of Chlamydia is approximately 6–8%. The prevalence of Chlamydia -positive patients was 11.4% (range: 5–15%) and NG was 2.6% (range: 1–3%) amongst women seeking first-trimester screening in Illinois. A study from Finland reported a nationwide increase from 23.4 per 10 000 to 29.2 per 10 000 in the incidence rates of CT, especially in the adolescents and young people. Bearing in mind the low prevalence of gonorrhoea (0.2%) among women in the United Kingdom undergoing abortion, screening for gonorrhoea is controversial. CT is detected more often in women with BV and may facilitate CT infection in the upper genital tract. Recurrent infections with Chlamydia lead to long-term problems such as tubal damage, infertility and chronic pelvic pain.

The prevalence of Chlamydia is higher in young women (15–25 years) as they are more prone to infections because of various factors such as discussed in Hillard et al.: cervical ectopy, lower levels of protective antibodies, reduced access to medical care and high risk-taking behaviour.

Strategies to diagnosis of infection

Is screening for Chlamydia in the general population worthwhile?

Screening for Chlamydia has been shown to be cost-effective in preventing PID. It has been suggested that all moderate-to-high prevalence population (≥8%) should be screened and treated. However, this observation has been challenged. The authors felt that the cost-effectiveness of previous studies was based on static models and did not take account of the lower uptake of screening, partner notification and lower complication rates.

Screening for Chlamydia in populations with lower prevalence still showed high specificities (98–100%) though clinicians should be aware of higher rates of false positive (as high as 1/3); therefore, a confirmatory test should be performed. These rates may be negligible if specificity of assay exceeds 99.5%.

A meta-analysis by Watson et al. 2002 showed that non-invasive testing by NAAT for Chlamydia was more effective in detecting asymptomatic Chlamydia infection. The meta-analysis showed that DNA-based tests detected more cases of asymptomatic chlamydial infections than conventional non-culture tests. The odds ratios (ORs) showed a statistically significantly lower rate of false-negative results with urine ligase chain reaction(LCR) (0.33, 95% CI: 0.13, 0.80) and cervix PCR (0.26, 95% CI: 0.12, 0.56) than with the reference standard. The ORs showed no significant differences between the false-negative rates with urine PCR (0.84, 95% CI: 0.37, 1.89), urine gene probe (0.44, 95% CI: 0.15, 1.26), cervix gene probe (1.16, 95% CI: 0.25, 5.47), urine enzyme immunoassay (1.86, 95% CI: 0.39, 8.75), cervix direct immuno-fluorescence (1.05, 95% CI: 0.09, 12.93) and the reference standard. The OR revealed a significantly higher rate of false-negative results for cervix enzyme immunoassay than the reference standard (4.10, 95% CI: 1.15, 14.59). Self-taken vaginal swabs were cost-effective in preventing more cases of PID than other strategies.

Chlamydia infections are associated with short- and long-term morbidity. Current evidence suggests that up to 20% of women with Chlamydia will suffer from PID, 4% from chronic pelvic pain and 3% from infertility.

Should women be screened for BV?

BV occurs in up to 30% of women. It is a known risk factor for infections following induced abortions. The incidence of post-abortal endometritis was 5.6% in women, who had positive swabs for bacterial vaginosis preoperatively. Larsson performed a prospective randomised trial to evaluate the effect of 2% clindamycin cream on post-surgical abortion infection. This treatment resulted in significant reduction in postoperative infections with abnormal vaginal flora (relative risk (RR): 4.2, 95% C.I.1.2–15.9). It is well known that BV makes women more susceptible to other sexually transmitted diseases such as trichomoniasis and the bacterium, Chlamydia. A randomised trial showed that suppression of bacterial vaginosis with twice-weekly metronidazole gel offered the women protection from Chlamydia . Hamark studied the risk factors of post-abortal endometritis in Chlamydia -negative women and identified that women with greater than 20% clue cells had a 5.6% RR of acquiring post-abortal infections. However, a randomised double blind placebo-controlled trial to evaluate the efficacy of metronidazole in preventing post-abortal infections provided weak evidence that metronidazole reduces the risk of infection after first-trimester suction termination. Furthermore, a recent large randomised treatment trial of BV concluded that oral metronidazole with doxycycline did not prevent post-abortal infections.

However, a recently published comprehensive review about treatment of bacterial vaginosis suggests that though the available numbers in various studies are small, the slowly gathering evidence indicates that it is prudent to treat BV in women who are having surgical procedures such as induced abortions. The US Centre for Disease Control and Prevention (CDC) recommends that there are benefits of treatment of BV – reduction of infections following abortion and other operative gynaecological procedures. It has also been suggested that three or more of the following criteria could be used to confirm the diagnosis of BV ‘(i) >20% of squamous cells examined are clue cells, (ii) the bacterial population in the wet prep is dominated by cocci and coccobacilli, (iii) a vaginal pH ≥ 4.7 and (iv) a positive whiff test.’ Various regimes for treatment of BV have been suggested from the literature –metronidazole tablets 500 mg twice daily for 7 days (99% immediate cure rate and 84% cure rate at 6 weeks). Similarly, oral treatment with clindamycin or intra-vaginal metronidazole or clindamycin has also been shown to be effective. Newer therapeutic agent such as tinidazole has also been shown to be useful in the treatment of BV. Having reviewed the published literature on BV, we are of the opinion that, in balance, women with BV should be medically treated and the effectiveness of the treatment should be investigated in properly designed studies.

Prevention of infective morbidity

There are various preventive strategies to reduce infective complications.

Induced abortions are performed for unwanted or unintended pregnancies. Up to 50% of all pregnancies are unintended though not all unintended pregnancies result in abortion. Unintended pregnancies could be due to failure to use contraception, failure of the contraceptive methods mostly due to user dependence, lack of access to facilities or severe maternal disease or foetal anomalies. Various primary prevention strategies will help reduce the number of women needing induced abortions. Patient education, use of effective contraception and improving access to health care in general will reduce the number of abortions, thereby reducing complications. Legalisation of abortions, easy access to non-judgemental services, routine vaccination such as tetanus toxoid and early abortion will all help in primary prevention.