IUD insertion forces: effects of recent childbirth and lactation

Clinical characteristic and intraoperative findings of uterine perforation patients in using of intrauterine devices (IUDs)

Background

Intrauterine devices (IUDs) are the most popular form of contraception used worldwide; however, IUD is not risk-free. IUD migrations, especially uterine perforations, were frequently occurred in patients. The aim of this study was to investigate the clinical characteristics and intraoperative findings in patients with migrated IUDs.

Results

29 cases of uterine perforation associated with migrated IUDs and 69 control patients were followed between January 2008 to March 2015. Patients who used IUDs within first 6 months from the last delivery experienced a characteristically high rate of the perforation of the uterine wall. A significantly larger number of IUD insertion associated with uterine perforation were performed in rural hospitals or operated at a lower level health care system. There was no clear difference in the age and presented symptoms in patients between two groups. Majority of contraceptive intrauterine devices was the copper-releasing IUDs. Furthermore, patients who used V-shaped IUD showed significantly higher incidence of pelvic adhesions when compared with the users of O-shaped IUDs.

Conclusions

Unique clinical characteristics of IUD migration were identified in patients with uterine perforation. Hysteroscopy and/or laparoscopy were the effective approaches to remove the migrated IUDs. Improving operating skills is required at the lower level of health care system.

Role of uterine forces in intrauterine device embedment, perforation, and expulsion

BACKGROUND

The purpose of this study was to examine factors that could help reduce primary perforation during insertion of a framed intrauterine device (IUD) and to determine factors that contribute in generating enough uterine muscle force to cause embedment and secondary perforation of an IUD. The objective was also to evaluate the main underlying mechanism of IUD expulsion.

METHODS

We compared known IUD insertion forces for "framed" devices with known perforation forces in vitro (hysterectomy specimens) and known IUD removal forces and calculated a range of possible intrauterine forces using pressure and surface area. These were compared with known perforation forces.

RESULTS

IUD insertion forces range from 1.5 N to 6.5 N. Removal forces range from 1 N to 5.8 N and fracture forces from 8.7 N to 30 N depending upon device. Measured perforation forces are from 20 N to 54 N, and calculations show the uterus is capable of generating up to 50 N of myometrial force depending on internal pressure and surface area.

CONCLUSION

Primary perforation with conventional framed IUDs may occur if the insertion pressure exceeds the perforation resistance of the uterine fundus. This is more likely to occur if the front end of the inserter/IUD is narrow, the passage through the cervix is difficult, and the procedure is complex. IUD embedment and secondary perforation and IUD expulsion may be due to imbalance between the size of the IUD and that of the uterine cavity, causing production of asymmetrical uterine forces. The uterine muscle seems capable of generating enough force to cause an IUD to perforate the myometrium provided it is applied asymmetrically. A physical theory for IUD expulsion and secondary IUD perforation is given.

Intrauterine contraception after cesarean section and during lactation: a systematic review

BACKGROUND

All postpartum women, including those who are breastfeeding or have had a cesarean section, appear potentially suited to intrauterine contraception, a long acting reversible contraceptive (LARC). Like any other method used after delivery, it should not interfere with lactation or be affected by cesarean section.

STUDY DESIGN

We searched the MEDLINE, PubMed, Popline, Google Scholar, and Clinicaltrials.gov databases from January 1968 through to December 2012. Studies were included if they reported event rates in women who had a cesarean section and event rates and clinical outcomes in lactating women or their infants in the breastfeeding group. Summary odds ratios were not calculated because of the diverse methods of reporting event rates in the cesarean section group and the heterogeneity of the results in the breastfeeding group.

RESULTS

We found 26 articles on event rates in interval and post-placental intrauterine device (IUD) use, and 18 on event rates and clinical outcomes in breastfeeding IUD users. Four prospective studies and one retrospective study showed an increased expulsion rate in interval insertion. There were 19 studies, of which five were controlled in post-placental IUD insertion after cesarean section. Four studies had expulsion rates of 10 or more per 100 woman-years of use and 15 expulsion rates below 10 per 100 woman-years of use. Three studies showed that event rates for lactating IUD users are the same as those for non-lactating users. Fifteen controlled studies showed that the IUD had no effect on milk production and seven of these showed no effect on infant growth. Pharmacovigilance databases report an increased rate of IUD perforations in lactating women, while the event rate studies report that insertion is generally easier and less painful than expected. These were uncontrolled reports.

CONCLUSION

The IUD is a long-acting reversible method of contraception with expulsion rates of 5-15 per 100 woman-years of use when used as a post-placental method immediately after cesarean section. As an interval procedure (6 or more weeks after cesarean section) it appears to have a high expulsion rate (5% or higher) notably in older devices. The IUD does not affect breastfeeding and is easy to insert in these women, but appears to be associated with a higher perforation rate (>1 per 100). Providers should not be deterred from using this contraception method, especially in developing countries, but should be attentive to preventing these potential problems.

Contraception during lactation

The probability of pregnancy is very small during the first 2 months after delivery if the mother breast-feeds. The risk remains small for 6 months if the mother is fully breast-feeding her infant, is still amenorrhoeic and the child does not receive additional food. Under these conditions there is only about a 2% chance of pregnancy. Even full breast-feeding does not inhibit ovarian function after 6 months. Breast-feeding is a very important and efficient contraceptive method in the developing countries, but it is also a useful method in developed countries during the early puerperium. Barrier methods and progestogen-only hormonal methods (pills, implants and injectables) are the primary contraceptive alternatives during breast-feeding. They have no adverse effects on lactation, the condition of the infant or on maternal ovarian function. Sterilization is only a good alternative if the family wants a permanent method of contraception. Careful insertion of an IUD is possible even before the first menstrual period. Puerperal insertion of an IUD needs expertise and training because of the vulnerability of the very soft puerperal uterine wall. Combined oral contraceptives diminish milk production and therefore combined oral contraceptives are not recommended during lactation.

Insertional pain and other IUD insertion-related rare events for breastfeeding and non-breastfeeding women--a decade's experience in developing countries

The possible effect of breastfeeding on intrauterine device (IUD) insertion events was investigated. Analysis included a total of 6493 women who enrolled in multicenter IUD clinical trials over a ten-year period. Findings indicate that breastfeeding exerts a protective effect on the incidence of moderate to severe insertional pain and reduces the need for cervical dilatation to facilitate insertion. The pain protection effect was most evident in breastfeeding women who were still in lactational amenorrhea. Subjects with amenorrhea, both breastfeeding and non-breastfeeding, had a significantly lower incidence of pain at IUD insertion than the corresponding menstruating subjects. This effect may be related to a higher secretion of beta-endorphin in the breastfeeding and lactational amenorrheic subjects.