Elsevier

Contraception

Volume 67, Issue 4, April 2003, Pages 273-276
Contraception

Original research article
A comparative randomized study of three different IUDs in nulliparous Mexican women

https://doi.org/10.1016/S0010-7824(02)00519-XGet rights and content

Abstract

With the aim to evaluate the clinical performance of intrauterine devices (IUDs) especially designed for nulliparous women (TCu 380 Nul and ML Cu 375 sl), a prospective randomized, single-blind study comparing them with standard TCu 380 A, was carried out. We included 1170 healthy nulliparous women randomly allocated to receive any of the three types of IUDs and conducted follow-up for 1 year of use. Continuation and termination rates were evaluated by gross cumulative life table analysis and compared by the log-rank test. Continuation rates (95% confidence interval) at the end of the study for TCu 380 A, TCu 380 Nul and ML Cu 375 sl were 29.5% (±12.9), 85.9% (±5.3) and 85.4% (±5.8), respectively (p < 0.001). There were six pregnancies during the first 3 months of use, for a failure rate of 1% (±0.6) in the TCu 380 A group, 0.5% (±0.3) in TCu 380 Nul, and no pregnancy in ML Cu 375 sl (p < 0.05). Especially designed IUDs for nulliparous women had a better clinical profile compared with the standard IUD. This may improve the use of IUD in this population.

Introduction

More women around the world are using intrauterine contraception and this prevalence of use is increasing. In Mexico, intrauterine devices (IUDs) were the main method of choice for women attending the Mexican Institute of Social Security during the year 2000, representing 51.5% of the total among contraceptive users [1]. Currently IUDs offer, during routine use, contraceptive efficacy at least as good as, and possibly better than, that of the combined pill [2]. Furthermore, IUDs have other advantages such as, they are long-lasting (up to 10 years), they offer no interference with sex, freedom from remembering to use and no hormonal side effects, and their contraceptive effect is immediately reversible [3], [4].

This profile of IUDs is suitable for many users, particularly young, nulliparous women. However, there are at least two main factors for an aversion to the fitting of IUDs in these women: the possibility of an increased risk of pelvic inflammatory disease (PID) with subsequent infertility and misgivings regarding the ability of the nulligravid cervix and uterus to allow the fitting and retention of an IUD.

Regarding the former factor, it has been demonstrated that PID and IUDs use are related to higher levels of sexual activity with more sexual partners; the risk then is the result of sexual behavior and not age or parity. Recently, a case-control study [5] seems to confirm this appraisal, concluding that the previous use of a copper IUD is not associated with an increased risk of tubal occlusion among nulligravid women. A careful selection of potential nulliparous users of IUDs precludes this risk.

Furthermore, there is little convincing evidence that the nulligravid cervix and uterus are invariably unable to accept a standard IUD. Petersen et al. [6] found similar clinical performance between standard-length IUDs and short-length IUDs in nulliparous women. In spite of this and with the aim to improve the compliance of intrauterine contraception in young and nulliparous women, the development and marketing of specific mini- or short-stem versions of existing IUDs have continued, leading to the development of at least one IUD that has shown excellent performance in predominantly nulliparous users [7].

Therefore, youth and nulliparity are only relative risk factors for IUD use and the advantages of this form of contraception may be of benefit for this population.

With the aim to evaluate the efficacy and acceptability of intrauterine contraception in nulliparous women, we designed a prospective randomized study comparing the standard TCu 380 A, versus two especially designed IUDs in nulligravid: TCu 380 Nul and ML Cu 375 sl.

Section snippets

Material and methods

The TCu 380 A IUD is a polyethylene, T-shaped device with two copper sleeves swaged on the crossbar, and copper wire wound around the vertical stem, the total surface of copper provided by the wire and sleeves is approximately 380 mm2. The length of the crossbar is 31.6 mm and the vertical stem is 36.2 mm; provided and manufactured for this study by Implementos Plásticos, México.

The TCu 380 Nul, is quite similar in shape and copper content to the TCu 380 A, but the length of the crossbar is

Results

The planned caseload of 117 was achieved at each of the 10 medical units for a total sample of 1170 subjects. Insertions were performed from October to December 1998. Table 1 shows the demographic characteristics of subjects.

As can be seen, the subjects’ allocation to the three study groups was homogenous regarding age, educational level and previous contraceptive use.

Interestingly, the level of education was high in this sample, reflecting a common feature of the population attending IMSS.

Discussion

The effectiveness and acceptability of the TCu 380 A, the TCu 380 Nul and the MLCu 375 sl were evaluated in this multicenter clinical trial. Fortunately, the organization of health services provided by IMSS allows for good rate of follow-up due to the distribution of Family Medical Units in the neighborhoods, guaranteeing easy home visits and recovery of lost patients.

In this study, we unexpectedly found that the insertion of IUDs for nulliparous women was more difficult to perform (TCu 380 Nul

Acknowledgements

We appreciate the invaluable support from the Implementos Plásticos S. A. and Organon Mexicana, who kindly supplied the IUDs used in this study. Furthermore, we are grateful for the unselfish work of all the Family Physicians involved in the clinical follow-up and affectionate care of participating patients.

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