Induced abortion is one of the most commonly performed gynaecological procedures in Great Britain. Around 180000 terminations are performed annually in England and Wales and around 12000 in Scotland. Around 1 in 3 British women will have had an abortion by the age of 45. Over 98% of abortions in Britain are undertaken on the grounds that the pregnancy threatens the mental or physical health of the woman or her children. It is these abortions which form the focus of this review.
Access to NHS abortion provision varies considerably, with over 98% of terminations in Scotland being undertaken in NHS hospitals, in contrast with England and Wales where NHS agency arrangements complement NHS hospital provision and a significant proportion are obtained privately.
The law and abortion
Legal criteria for abortion are individual to the country of practice. It should be noted that in Northern Ireland, legal abortion is unavailable except to save the life of the mother or to prevent grave permanent injury to her physical or mental health.
Current abortion legislation in Great Britain is based on the 1967 Abortion Act as amended by the Human Fertilisation Embryology Act 1990. Abortion is legal in Great Britain if two doctors decide in good faith that a particular pregnancy is associated with factors that satisfy one or more of five grounds specified in the Regulations. Most abortions are undertaken on statutory grounds C or D, which state that the pregnancy has not exceeded its 24th week and if it continues would involve risk greater than if the pregnancy were terminated of injury to the physical or mental health of the woman or of the existing children of her family. There are further legal requirements in relation to Certification Notification of abortion procedures and a Certificate signed by two medical practitioners authorizing the abortion requires to be retained for a period of at least 3 years and the ‘operating’ practitioner must complete a notification form for each termination. This form is forwarded to the Chief Medical Officer (CMO) for the relevant UK country within 7 days. Doctors looking after women requesting abortion care should also apply principles of good practice as described in the GMC document Duties of a Doctor. There is a conscientious objection clause within the Abortion Act and the British Medical Association (BMA) have produced a helpful overview on the legal and ethical position. Practitioners with a conscientious objection should provide advice and perform the preparatory steps for arranging an abortion if the request meets the legal requirements; this will usually include referral to another doctor as appropriate. Doctors and nurses have the right to refuse to take part in an abortion, but not to refuse to take part in any emergency treatment.
In general, in addition to fulfilling legal statute, a clinician will wish to be certain that a woman has considered her options carefully and is sure of her decision for abortion and gives informed consent. Gestation is a major determinant of options available for terminating a pregnancy and a decision is usually reached by the woman in consultation with her medical carers and pregnancy counsellor. The method chosen has to be acceptable to the woman as well as being safe and effective. Full guidelines for good practice have been published by The Royal College of Obstetricians and Gynaecologists (RCOG).
Medical termination in the first trimester
The anti-progestogen mifepristone is used in combination with prostaglandin doses to achieve medical abortion. The contraindications to medical termination are few, but include suspected ectopic pregnancy, chronic adrenal failure, long-term steroid use, haemorrhagic disorders, treatment with anti-coagulants, known allergy to mifepristone or misoprostol, smokers over 35 years of age with electrocardiogram (ECG) abnormalities and breast-feeding women. Medical abortion is performed in hospital or premises registered for abortion. The patient attends briefly to take the mifepristone dose and attends subsequently for day-patient admission 36-48 hours later. It is customary for legal reasons to supervise the swallowing of the mifepristone tablets, but side effects are trivial and the women can leave after 10 minutes. Women may bleed slightly in the 48 hours after taking the mifepristone and a very small number may miscarry.
The prostaglandin route of administration and regimes vary and it is customary for the women to remain under supervision for 4-6 hours after prostaglandin administration, during which time the majority will expel the fetus. Nursing staff confirm passage of the products. The amount of bleeding is variable, often similar to a heavy period, and increases with gestation. A minority of women will have some lower abdominal cramp and will require oral analgesia and a minority (less than 5%) might require opiate analgesia. Length of gestation influences the success rate and complications, but this is more of an issue at 9-13 weeks’ gestation. At these gestations, the risk of continuing pregnancy, in particular, remains a problem, and units undertaking medical termination at these gestations are cautious in counselling women regarding this. For women who pass minimal or no products of conception, ultrasound should be carried out. Unrecognized ongoing pregnancies would be of particular concern because of the risk of fetal abnormality.
Complete abortion rates of 97.5% are quoted for medical termination up to 9 weeks. At gestations over 9 and less than 13 weeks, in a review of 1076 medical terminations undertaken in Aberdeen, the complete abortion rate was 95.8%. The ongoing pregnancy rate was 1.5%. Surgical intervention is indicated for ongoing pregnancy, missed abortion, incomplete abortion and very heavy bleeding. The surgical intervention rate showed a progressive rise from 2.7% at 9-10 weeks’ gestation to 8% at 12-13 weeks’ gestation. All this is relevant to counselling the women about her choice, and of course is relevant to those involved in service planning. Data, however, is accumulating for the high uptake, acceptability and efficacy of medical termination at 9-13 weeks and, although still unlicensed at these gestations, it is likely to be offered as a choice for women undergoing abortion in many units.
Surgical termination is performed in either a hospital or dedicated facility in a designated clinic. General anaesthesia is standard practice in the UK, although use of local anaesthesia (paracervical block) with or without sedation is increasingly being offered. Surgical termination is not recommended at less than 7 weeks’ gestation because of the risk of failure to remove the pregnancy, but manual vacuum aspiration (MVA) is seeing renewed interest under strict protocols. For some women it is not appropriate to defer the abortion to a suitable gestation for surgery, and their preference might not be for medical abortion or indeed, in certain circumstances, there may be contraindications to medical abortion. For all surgical terminations there is evidence that cervical priming ahead of surgery reduces the complications of cervical injury, uterine perforation, haemorrhage and incomplete evacuation. The risk factors for cervical damage include younger patients and increasing gestation, especially in multiparous women. Gemeprost is the licensed preparation, although there is evidence from randomized controlled trials that misoprostol is an effective alternative that costs less and thus is frequently used.
Surgical termination is simple with low complication rates, but skill and experience are important so that serious complications are quickly recognized and remedied. Failed attempts at surgical abortion are recognized, with a quoted failure rate of 2.3 in 1000 abortions from a large series of women at less than 12 weeks’ gestation. Sometimes this is explained by the presence of an unrecognized twin gestation or because the decidua will have been identified but the pregnancy not removed or there is a uterine anomaly. However, most failed surgical abortions occur in patients with normal pelvic anatomy and where the operator is experienced. It is prudent to advise patients regarding the possibility and to advise them to report any pregnancy symptoms persisting 1 week after the procedure so that evaluation for continuing pregnancy can take place and there can be early resort to further evacuation. Very rarely, even with full use of ultrasound, unusual situations can arise such as heterotopic pregnancy (twin pregnancy with one embryo intra-uterine and one ectopic) and it is important to be mindful of such things when clinical history and findings are not straightforward. If there is any doubt about evacuation, the patient must be followed up.
Surgical abortion after the first trimester
Late dilatation and evacuation (D+E) is practised extensively in the US and there are skilled practitioners in England, the Netherlands, France and parts of Australia. It is not widely performed in other parts of the world. In Scotland, mid-trimester terminations are almost exclusively undertaken using modern medical methods. In England, D+E has not found favour among NHS gynaecologists but is more widely used by non-NHS abortion providers. Generally speaking, conventional first-trimester surgical evacuation can be used up to 15 weeks’ gestation, but thereafter, specific techniques of cervical preparation and special instruments for D+E need to be used. Second-trimester abortion entails more risk than earlier procedures. More modern methods of aggressive cervical preparation coupled with extensive clinical experience of the procedure have improved safety. The use of ultrasound scanning during the procedure can also reduce perforation rates. This procedure can really only be safely undertaken by gynaecologists who have been specifically trained in the technique, have the specific instruments to perform the procedure and have a clinical throughput adequate for maintenance of skills. For some patients it could be a welcome choice, but D+E is not widely available and there is an absence of research evidence as to which technique is the safest and most appropriate for more advanced pregnancy.
Mid-trimester medical termination
Medical abortion is achieved at these gestations in a similar way to early medical termination by using oral mifepristone followed by repeated doses of prostaglandins 36-48 hours later. The regimes are safe and effective, although patients may experience minor side effects such as vomiting and diarrhoea associated with the procedure. The induction abortion interval tends to be longer with increasing gestation. Reported cumulative experience suggests that 97% of women abort successfully on the day of treatment within 5 doses of misoprostol. A second or third day of treatment may be required to complete the termination. Surgical evacuation under general anaesthetic may be required to complete the abortion and remove placental tissue. Published evidence suggests that this is required in about 8% of women and this fact should be incorporated into the counselling.
Complications and problems
Legal abortion in developed countries is impressively safe. Sadly, illegal, unsafe abortion remains a major contributor to maternal mortality on a global basis. The risk of complications is increased by older age, multiparity and increasing gestational age. Complications can be categorized into those that occur immediately at the time of the procedure and those that arise subsequently. Most of the immediate complications have been discussed in relation to the medical and surgical procedures outlined. The most common later complication is for a patient to present with problematic bleeding and/or pain where there may be retained products or infection. Ultrasound can be helpful in resolving the situation. Complex emotional feelings are often experienced immediately following termination and these include anger, guilt and regret and often contribute to short-term emotional distress. Most services offer follow-up counselling as required. The bulk of the evidence would support the view that abortion is very safe with few long-term problems, but patients do have concerns regarding their future reproductive health. There is no evidence to suggest that fertility difficulty or pregnancy complications are any more likely in patients who have had a previous abortion.
Legal induced abortion is one of the safest and commonest procedures in medicine. As with any other procedure, complications and failures are not completely avoidable, but they can be minimized by careful attention to detail by the medical providers using available published evidence and guidelines for practice. Gestation age should be accurately assessed and sound aseptic techniques used for interventionist procedures. Medical and nursing staff providing abortion services should be experienced and comfortable with the procedures and they must have a high index of suspicion for possible complications; the patient must have ready access to clinical services for post-abortion advice and the management of complications. The choice of abortion methods continues to extend with new developments and protocol refinements informed by ongoing research studies.