1 November 2010
Clinical Update: Treatment of obese clients
By Patricia Lohr, Medical Director of BPAS.
Q) What determines whether a person is considered to be obese? Does this differ for women undergoing abortion?
Body Mass Index (BMI) is an index of weight in relation to height that is used to classify adults as underweight, overweight and obese (1). It is defined as the weight in kilogrammes divided by the square of the height in metres (kg/ m2). An adult is classified as obese when the BMI is 30 kg/m2 or more. The same classification is used for women undergoing abortion.
Q) What medical risks are associated with obesity?
There are a number of medical conditions associated with obesity including diabetes, gallbladder disease, cardiovascular disease, obstructive sleep apnoea and some malignancies, for example endometrial cancer (2). A recent population based study in France identified important associations between obesity and sexual health (3).
Of 5,535 women surveyed, those who were obese were 30 percent less likely to have had a sexual partner in the last 12 months than normal weight women. However, the odds of reporting an unintended pregnancy or an abortion were four times higher among obese women less than 30 years of age than in normal weight women in the same age group. In addition, obese women were also 70% less likely to report using the oral contraceptive pill and eight times more likely to use less effective methods, such as withdrawal, compared with women with normal BMI.
Having a BMI in the obese range has also been associated with longer time to recognise and test for pregnancy and, therefore, a delay in obtaining abortion care (4). Although the reasons are unclear, it may be because obese women are a higher risk of conditions like polycystic ovarian syndrome which causes menstrual disturbances.
Q) Is there a particular method of abortion that is recommended for obese women?
Surgical abortion in obese women can present technical challenges, largely due to difficulties visualising the cervix and gaining access to the uterine cavity (5). Longer operating times and greater blood loss have been documented in obese women undergoing dilatation and evacuation in the second trimester (6, 7). There is some evidence that obese women are at increased risk of death from thromboembolism following surgical abortion, although this adverse outcome remains rare (8).
Early medical abortion with mifepristone and misoprostol has not been associated with an increased risk of complications and may be preferable. A retrospective chart review of 1,202 medical abortions up to 63 days gestation compared outcomes at less than 30 kg/m2 and greater than or equal to 30 kg/m2 (9). There was no significant difference between the groups in terms of need for surgical intervention, completed abortion within two weeks of medication administration, number of additional follow-up visits or doses of misoprostol.
Surgical procedures under local anaesthetic may also be preferable in obese women as obesity is associated with greater difficulty in airway management, the need for larger doses of medications due to distribution in fatty tissues, and prolonged recovery (10).
Q) What are the other considerations that need to be taken into account when determining whether to treat obese clients?
Prior to performing an abortion, assessment of gestational age and determination of medical fitness for the procedure are important. Identifying a very early pregnancy using abdominal ultrasound scanning may be more difficult in obese women, necessitating the use of vaginal scanning techniques (10, 11). In addition, if blood pressure measurements are needed, use of a larger cuff is often required to obtain an accurate reading.
Longer instruments, additional lighting, steep Trendelenberg positioning and lateral vaginal retraction by assistants may be needed for surgical procedures (10). For morbidly obese women (BMI >40 kg/m2 or > 35 kg/m2 in the presence of co-morbidities), special equipment may also be required, as standard equipment (beds, operating tables and transfer trolleys) is often rated to a lower maximum safe weight (12). Electronically operated beds are also recommended to reduce the potential risk of injury to staff.
Q) In what instances is BPAS unable to treat obese women?
It is BPAS policy to offer clients a choice of procedure and anaesthesia. There are no set restrictions based on BMI for local anaesthetic procedures or medical abortion. However, the appropriateness of undertaking either of these treatments in a BPAS unit must weighed against the ability to manage complications which require general anaesthesia or the ability to refer efficiently to the NHS for management. Co-morbidities must also be considered.
For a surgical abortion under general anaesthetic, in general clients with a BMI of less than or equal to 35 kg/m2 can be treated at any BPAS unit. Clients with a BMI of greater than 35 kg/m2 may be assessed for their fitness to undergo general anaesthetic at selected BPAS units by an anaesthetist. The upper BMI limit for a general anaesthetic at any BPAS unit is 44.9 kg/m2.
BPAS employs a Special Services Manager, Jackie Lydon, for managing complex clients including women who are obese that we cannot treat. She can be reached on 0845 365 0534 and can answer questions about whether a woman can be treated by BPAS, and can assist in finding another provider if necessary.
Abortion Review topic archive: Clinical Update Q&A
1) WHO. Physical status: the use and interpretation of anthropometry. Report of a WHO Expert Committee. WHO Technical Report Series 854. Geneva: World Health Organization, 1995.
2) WHO. Obesity: preventing and managing the global epidemic. Report of a WHO Consultation. WHO Technical Report Series 894. Geneva: World Health Organization, 2000.
3) Bajos N, Wellings K, Laborde C, Moreau C; CSF Group. Sexuality and obesity, a gender perspective: results from French national random probability survey of sexual behaviours. BMJ. 2010;340:c2573.
4) Foster DG, Jackson RA, Cosby K, Weitz TA, Darney PD, Drey EA. Predictors of delay in each step leading to an abortion. Contraception. 2008;77:289-93.
5) Grimes DA, Shields WC. Family planning for obese women: challenges and opportunities. Contraception. 2005;72:1-4.
6) Dark AC, Miller L, Kothenbeutel RL, Mandel L. Obesity and secondtrimester abortion by dilation and evacuation. Journal of Reproductive Medicine. 2002;47:226–230.
7) Marchiano DA, Thomas AG, Lapinski R, Balwan K, Patel J. Intraoperative blood loss and gestational age at pregnancy termination. Primary Care Update for OB/ GYNS. 1998;5:204–205.
8) Kimball AM, Hallum AV, Cates W. Deaths caused by pulmonary thromboembolism after legally induced abortion. American Journal of Obstetrics and Gynecology. 1978;132:169–174.
9) Strafford MA, Mottl-Santiago J, Savla A, Soodoo N, Borgatta L. Relationship of obesity to outcome of medical abortion. American Journal of Obstetrics and Gynecology. 2009;200:e34-6.
10) Paul M, Lichtenberg ES, Borgatta L, Grimes DA, Stubblefield PG, Creinin MD, eds. Management of Unintended and Abnormal Pregnancy: Comprehensive Abortion Care. West Sussex: Wiley-Blackwell, 2009; pp 68, 80, 103-4, 201.
11) Lohr PA, Reeves MF, Creinin MD. A comparison of transabdominal and transvaginal ultrasonography for determination of gestational age and clinical outcomes in women undergoing early medical abortion. Contraception. 2010;81:240-4.
12) AAGBI. Peri-operative Management of the Morbidly Obese Patient. London: AAGBI, 2007.