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Published: October 2003
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IMMP Insertion Studies of the Multiload® Intrauterine Device

Prescriber Update 24(2): 31-32
October 2003

Dr Mira Harrison-Woolrych BM DM MRCOG DFFP, Senior Research Fellow for IMMP, NZ Pharmacovigilance Centre, Dunedin

Intensive Medicines Monitoring Programme (IMMP) data on over 16,000 New Zealand women using the intrauterine contraceptive device, Multiload® Cu375, have now been analysed and published. The studies showed that general practitioners performed 92% of the reported insertions during the 10-year monitoring period. Whilst insertion problems occurred more often in nulliparous women, incidence rates were reassuringly low. An incidence of 1.6 uterine perforations per 1000 insertions was observed, with 46% of cases not diagnosed until more than one year after insertion.

Large New Zealand cohort for Multiload

The IMMP has collected data on 16,159 New Zealand women who have used the copper intrauterine contraceptive device (IUD) Multiload Cu375 between 1991 and 2001. This cohort is thought to be the largest for any one type of IUD in the world. The database includes records of over 17,400 insertions throughout New Zealand. The median age of the women was 32 years (range 14-56 years) and 40% of insertions were performed in women who had delivered two babies (range 0-11). Approximately 9% of insertions were performed in nulliparous women - a group previously excluded from many clinical trials of IUDs. General practitioners reported the majority (92%) of the insertions. For about 73% (1,244) of all doctors, the number of reported Multiload Cu375 insertions during the ten-year study period was less than ten; 24% (400) of doctors reported 10-50 insertions; 2% (35) between 50 and 100 insertions; and 1% (20) reported inserting more than 100 devices. These numbers were calculated from Multiload Cu375 insertion forms sent in by 1,699 participating New Zealand doctors. Based on these IMMP data, two large studies1,2 looking at the insertion of Multiload Cu375 have been published internationally. The findings of these studies are summarised here.

Low rate of insertion problems found

The first study1 was a detailed analysis of the insertion procedure for Multiload Cu375. Problems fitting the device occurred at a low rate - about 2% of all insertions (1.35% difficult insertion and 0.44% failed insertion). More difficulties were reported for insertions in nulliparous women (3.9%) compared to those in parous women (1.95%). Adverse reactions occurring at the time of insertion, such as pain, bleeding or vaso-vagal episode, were reported in 1.2% of all insertions. Again, nulliparous women had a greater risk of adverse reactions - 3.5% compared with 1.1% in parous women. However, this risk may be acceptable in nulliparous women if they are unable to use other contraceptive methods.

Experience of doctor correlates with insertion problem incidence

Doctors who reported inserting less than ten devices noted an insertion problem incidence of 2.5%, compared to 2.1% for doctors who inserted either 10-49 or 50-99 devices, and 1.3% for doctors who reported 100 or more insertions. The difference between low (<10 devices) and moderate (10-99) rate inserters was not statistically significant (RR = 1.2; 95% CI = 0.9-1.5). However, the difference between low rate inserters and high (≥100) rate inserters was statistically significant (RR = 1.9; 95% CI = 1.3-2.8). There are potential service provision implications of this finding, although the absolute risk of insertion problems occurring with either low or high rate inserters was low, i.e. about one extra woman in every 100 insertions will have an insertion-related problem if the device is put in by a low-rate inserter compared to a high-rate one. In New Zealand there are many other factors, including the availability of IUD insertion in rural areas, which must be taken into account when considering contraception choice for each woman.

Incidence of uterine perforation higher than previously reported

The second study2 was performed to determine the rate of uterine perforation on Multiload Cu375 insertion. A review3 of eight previous studies reported no uterine perforations in over 5,000 IUD insertions. Analysis of the IMMP database identified 28 reports in 17,469 insertions (1.6 per 1000) suggesting that uterine perforation had occurred. Of these reports, 14 cases had been termed "IUD embedded". These were included as 'partial perforations' in the analysis, as it was considered that for an IUD to become embedded, some degree of uterine wall damage must have occurred at the time of insertion. Review of the individual case reports supported this interpretation.

The results suggested that uterine perforation was not suspected at the time of IUD insertion in many women. Only seven of the 28 (25%) uterine perforations were diagnosed immediately or within one week. For 13 cases (46%) the diagnosis was not made until more than one year after insertion. The clinical consequences of uterine perforation included pain, bleeding, pregnancy and surgical removal of the IUD from the pelvic cavity. Whilst this study2 reported a higher incidence than other studies,3 this may still be an underestimate due to undiagnosed cases of perforation, or cases not reported to the IMMP.

Findings of insertion studies reassuring

These two large studies,1,2 based on IMMP data, have provided useful information about the insertion of Multiload Cu375 in both parous and nulliparous women. The results of both studies are reassuring, showing that in clinical practice the insertion of Multiload Cu375 is associated with few complications.

Acknowledgements

The IMMP staff would like to thank all the doctors who submitted IMMP notification forms and follow-up forms for Multiload Cu375. Without your co-operation these studies would not have been possible.

Competing interests (author): none declared.

Correspondence to Dr Mira Harrison-Woolrych, NZ Pharmacovigilance Centre, PO Box 913, Dunedin. E-mail: Mira.Harrison-Woolrych@stonebow.otago.ac.nz

References
  1. Harrison-Woolrych M, Ashton J, Coulter D. Insertion of the Multiload Cu375 intrauterine device; experience in over 16,000 New Zealand women. Contraception 2002;66:387-391.
  2. Harrison-Woolrych M, Ashton J, Coulter D. Uterine perforation on intrauterine device insertion: is the incidence higher than previously reported? Contraception 2003;67:53-56.
  3. Edelman DA, Porter CW. The new intrauterine contraceptive devices: safe and effective. Advances in Contraception 1993;9:83-91.