1. Patterns of contraception in IDDM in the UK
RA Lawrenson, GM Leydon, TJ Williams, RB Newson, MD Feher*
Department of Epidemiology and Public Health,
*Department of Clinical Pharmacology
Imperial College School of Medicine

2. Contraception in women with IDDM
No UK studies
No comparative studies
Important to prevent unwanted pregnancies
Risks of contraceptive use may have more serious consequencies in women with IDDM

3. Oral contraceptive use
Commonest method used in the UK
Combined oral contraceptives with high doses of oestrogen may increase risk of cardiovascular disease and increase requirement for insulin
CHD risk may be due to changes in lipids. New generation oral contarceptives (gestodene and desogestrel) seem to increase HDL and decrease LDL

4. Oral contraceptive use (POPs)
Progestogen only pills have less risk of cardiovascular problems.
However they are less effective with 3 pregnancies per 100 women years of use
Also have the problem of irregular bleeding

5. Percentage of women by age using combined oral contraceptives for contraception

6. Percentage of women by age using third generation combined oral contraceptives

7. Percentage of women by age using second generation combined oral contraceptives

8. Preferential prescribing of third generation oral contraceptives ?
Proportion of women with IDDM using a third generation oral contraceptive was 60% compared with 58% in women with no diabetes - OR 1.06 which was not statistically significant.

9. Percentage of women by age using oral progestogen preparations for contraception

10. Percentage of women by age using injectable progestogen preparations for contraception

11. Percentage of women by age using diannette progestogen preparations for contraception

12. Comparison of different hormonal contraception usage in women with IDDM and women without diabetes in 1994

13. Summary of use of oral contraceptives in women with IDDM
Women with IDDM are less likely to be prescribed an oral contraceptive
If they are prescribed an oral contraceptive it is most likely to be a combined oral contraceptive
Women with IDDM are twice as likely to be prescribed a POP
There is no evidence of preferential prescribing of third generation COCs to women with IDDM in 1994

14. IUCD
IUCD use has been associted with increased risk of pelvic inflammatory disease
One series in 30 women with diabetes resulted in 11 pregnancies in the first year (contradicted by other studies)

15. Percentage of women by age using an intra uterine device for contraception

16. IUCD summary
2.9% use in women with IDDM and 2.2% in those with no diabetes adjusted OR 1.21 (0.80,1.82)
No evidence that it is being avoided as a method in women with IDDM

17. Barrier methods Under reporting on GP records
Diaphragm or cap 0.8% in women with IDDM and 0.4 in comparison group adjusted OR 1.64 (0.72,3.74)
Condom use 0.3% in IDDM and 0.9% in others adjusted OR 0.32 (0.10,1.02)

18. Percentage of women by age with a prescription for condoms

19. Surgery May be under recording of hysterectomy and sterilisation
No information of vasectomy in partners
In high risk women with IDDM pregnancy maybe such a risk that sterilisation is recommended (Steel)

20. Proportion of women by age with a record of sterilisation prior to 1995

21. Proportion of women by age with a record of a hysterectomy prior to 1995

22. Use of sterilisation
5.8% women with IDDM had a record of sterilisation compared with 3.7% of others. adjusted OR 1.32 (0.98,1.79)
Hysterectomy rate was 3.8% vs 3.7% which after adjustment gave an OR of 0.91 (0.63,1.30)
Some evidence of an increased use of sterilisation in women with IDDM

23. Confounding variable
Age
Sexual activity
Smoking
Obesity
Hypertension

24. Age

25. Sexual activity

26. Proportion of women by age in whom there is a record of a claim from the GP for contraceptive services in 1994

27. Evidence of a cervical smear in 1992, 1993 or 1994 - women with IDDM and women with no diabetes

28. Smoking

29. Proportion of women recorded as being current smokers in 1994 by age

30. Proportion of women recorded as being ex-smokers in 1994 by age

31. Smoking
20.4% of women with IDDM and 20.2% without were recorded as being current smokers
More emphasis should be put on this risk factor for women with IDDM

32. Obesity
Obese women have an increased risk of CVD and should therefore be less likely to be prescribed combined oral contraceptives

33. Proportion of women in each BMI category (1 = <20, 2 = 20-25, 3 = 25-30, 4 = 30-35, 5 = 35+)

34. Obesity The mean BMI of women with IDDM was 26.2 (95% CI 25.4,26.9)
Mean BMI in women without diabetes was 24.1 (24.0,24.2)
Differences in the two groups suggest that this should be adjusted for in the analysis

35. Hypertension
Record of a diagnosis of hypertension linked to a prescription in 1994
17/938 (1.8%) women with IDDM and 54/10,000 (0.5%) women without diabetes were being treated for hyertension
Not statistically different

36. Pregnancy Increased risk to mother with IDDM
Increased risk of abnormality in the baby

37. Risk of pregnancy by age group IDDM vs no diabetes in 1994 Overall RR 0.77 (.59,1.02)

38. Proportion of women with a record of a pregnancy in 1994 by age

39. Use of oral contraceptives in women with IDDM from different countries

40. Use of progestogen only pills in women with IDDM from different countries

41. Use of IUCD in women with IDDM from different countries

42. Use of female sterilisation in women with IDDM from different countries

43. Use of vasectomy in the partners of women with IDDM from different countries

44. Use of barrier methods of contraception in women with IDDM from different countries

45. Conclusions