Anchored Versus Non-Anchored Post-Placental Intrauterine Device Placement at Cesarean Section: A Systematic Review and Meta-Analysis

Introduction

Cesarean section (CS) is a common surgical procedure. It is unique in that it empties the uterus of a fetus, allows direct observation of the uterine cavity with the naked eye and is an ideal time to provide long-acting reversible contraception (LARC).¹ Rates of CS are rising in many countries for various reasons affording the opportunity to provide immediate post-placental intrauterine devices (IUD) as LARC.² The increased access to gynecological counseling and care in the antepartum period and at the time of CS is ideal to raise patient awareness of the importance of contraception following delivery. Even in developed settings, many women (10–40%) fail to attend the postpartum follow-up consultation.³ Importantly, 40–75% of women who indicated prior to CS they would use an IUD in the postpartum period, do not follow through.³ The idea of immediate post placental contraception is not new and was first attempted by Zerzawy in 1967 using the Birnberg Bow.⁴ Each successive new generation of IUD development saw new attempts to develop successful methods for using the devices at CS. The results were generally suboptimal. Numerous methods have been tried to help maintain the IUD within the endometrial cavity at CS and in harmony with it. Most have not been very successful. The reason for this is that it is difficult for IUDs to anchor (and maintain their position) in the large post-partum uterine cavity. CS remains the only time that an IUD can be placed directly in the uterine cavity, albeit enlarged and not the usual state, under direct vision and this affords an opportunity to solve this problem.

The Anchor Problem

In the non-pregnant state the uterus can generate large forces and expel its content.⁵ A foreign body like an IUD will only remain in place in the uterus if it is anchored, either physiologically (where the uterine forces acting on it produce a net zero vector summation) and it is in harmony with these intrauterine forces⁵ or by being anchored in place by a tie or tether.⁶ Unlike framed devices, frameless IUDs cannot form a physiological anchor and must always be tethered. After delivery the size of the uterine cavity is large, so it is difficult to form a physiological anchor (for framed devices) leading to increased expulsion (and malposition).^7,8 A physiological anchor will only be formed in the post-partum uterus when the renewed fundal myometrial downward forces are matched by the renewed upward myometrial promontory forces, achieving a net zero vector summation of forces acting on the newly placed device.⁵ An additional challenge of immediate post placental insertion (IPPI) of a framed IUD following CS is that the uterine dimensions prior to and following the pregnancy are unknown. There is no guarantee that the uterine dimensions post involution will allow for geometrical compatibility between the uterus and IUD. The uterus may well be significantly smaller or bigger than the postpartum IUD, leading to either embedment or partial expulsion (displacement). Attempts have been made to solve the expulsion problem of post-partum IUD insertion at CS by i) modifying the device,⁹ ii) modifying the insertion technique,¹⁰ and iii) anchoring the device by tethering it to the uterine fundus.^11,12 The creation of a tethered anchor should in theory be preferable to waiting for the involuting uterus to form the capability of producing a physiological anchor.

The aim of this study was to evaluate the literature to determine if creating a physically tethered anchor at IPPI of an IUD at cesarean section was superior to awaiting the development of a physiological anchor (in the non-physically anchored devices) during the involution, by evaluating the results of randomized clinical trials (RCTS) comparing tethered anchoring with direct placement and/or placement using a modified technique.¹⁰ The creation or addition of a tethered anchor may help to avoid the most common problem related to placing an IUD at CS, namely downward migration of the device to a sub-optimal position (lower segment placement, partial or complete expulsion) which occurs in the early stages at a rate of 5–15%¹³ while perhaps helping to avoid some of the secondary problems including pain, bleeding and unintended pregnancy. The use of an anchor in uncontrolled studies has a reported expulsion rate of 0–4%.^12,14

Methods

This study is an evaluation of RCTS, which compared the results of physically anchoring an IUD at CS versus simply placing it (by whatever technique) in the uterine cavity. The primary endpoint was the displacement rate at 3 months (or closest available time period) but where available it was intended to secondarily evaluate problems such as displacement/expulsion beyond 3 months, bleeding, removal because of pain, endometritis and pregnancy. Only randomized controlled trials with at least 30 patients in each arm were considered. Reports in any language would be considered eligible but a specific search of the leading English language data bases and the more accessible Chinese language databases was conducted. The search strategy, analysis and reporting have been performed according to the PRISMA 2020 guidelines.¹⁵ The study protocol is stored on Open Science Framework (OSF) and is available on request from the corresponding author.

English Language References

The English language references were generated from the following databases: MEDLINE, EMBASE, Global Health, and ClinicalTrials.gov using the terms, Cesarean section, IUD, post-partum and post-placental. The search included references up to September 2025. References were further searched where indicated by following their PubMed and Google Scholar links. The search produced four articles which met our inclusion criteria.^16–19 The search methodology is given in Figure 1.

Figure 1 Results of search of English and Chinese language databases.

Chinese Language References

Chinese language studies were obtained by searching and reviewing publications on CNKI and Wanfang Data up to September 2025 using the Chinese words for postpartum intrauterine device. The search included references until September 2025. Chinese abstracts were auto-translated if they were not accessible in English. Potentially relevant articles were retrieved, fully translated and evaluated in terms of the inclusion criteria. There were two studies which met the inclusion criteria.^20,21 The results of the search are presented in Figure 1.

Where necessary, we contacted the authors to clarify the missing information. In one study,¹⁸ the type of IUD being evaluated was not specified, and this was resolved by contacting the author who also confirmed that the study was indeed an RCT as this was not clearly stated in the article.

Statistical methods

The odds-ratios were calculated with a confidence level of 95%. The Mantel-Haenszels method was used to calculate common effects estimate. Continuity corrections of 0.5 were applied for studies with 0 values.

Level of Evidence

Level of evidence was designated according to the criteria described by the definitions of the Canadian Task Force on Preventive Health Care. A category of I is assigned to all randomized controlled trials.

Risk of Bias

The “Risk of Bias” for each study was calculated using the short version of the revised Cochrane risk-of-bias tool for randomized trials (RoB 2). The risk of bias in the various domains is presented in Table 1.

Table 1 Risk-of-Bias Domains Evaluated Using the Revised Cochrane Risk-of-Bias Tool for Randomized Trials (RoB 2, Version 22 Aug 2019)

Results

There were six eligible studies, of which there were two each from Egypt and China, one from Turkey and one from Indonesia. The type of IUD, its manufacturer and the number placed is given in Table 2. There were three studies in which the anchored IUD was the TCu380A^16–18 and three in which it was a frameless device specifically designed to be used after placental delivery at CS.^19–21 The non-anchored IUDs were TCu380A devices in five studies and the Yuan Gong in one. The anchored IUDs were fixed with vicryl, egycryl or chromic catgut 2.0 threads so that anchored support for the framed IUDs varied between about 2–5 weeks (with vicryl lasting longer than egycryl or chromic catgut) as these sutures have no tensile strength after that. The post-partum CS devices Gyn-CS and GeneFlex PP are versions of the standard frameless devices, which also have an initial retention suture which is resorbed but they are subsequently held in place by a non-absorbable anchoring knot, similarly to the mechanism in non-pregnant (standard) use. During the involution, the Gyn-CS¹⁹ is retained with a vicryl retention suture as a temporary, secondary anchor. The GeneFlex PP²¹ is similarly retained by means of a conical polycaprolactone cap that is placed over the non-absorbable knot for better retention in the soft postpartum myometrial tissue.²² The authors of articles 16–19 attempted to match demographic data for the groups under study, while in one study¹⁷ the groups were matched for demographic data as well as for the parity at CS and whether it was elective or emergency.

Table 2 Comparative Displacement Values at Three Months After IUD Placement

Displacement at 3 Months-the Primary Evaluation

Displacement was defined as an IUD which was found to be translocated from its fundal position on ultrasound, no longer present on ultrasound, or clinically observed to be in any part of the cervix or macroscopically visible in the vagina or external cervical os. The distinct purpose of anchoring an IUD is to retain it in the most optimal fundal position. Accordingly, the analysis was binary with devices either being at the fundus or considered displaced if they were not, in order to determine if anchoring can prevent early displacement and subsequent expulsion. By definition, any device reported as expelled must have begun with a displacement at some stage, and this analysis helps to avoid the contentious and difficult situation of having to decide at what stage a displacement becomes an expulsion and is clinically relevant, in view of the authors varying reporting methods. The displacement rates at 3 months (or 6 months where the 3-month rate was not available) varied from 5% to 12% for the non-anchored devices, while the displacement rate for the anchored devices varied from 0% to 2%. The displacements for non-anchored and anchored IUDs are given in Table 2 as a fraction of the total number of IUDs placed, as well as the odds ratio. In total, there were 38 displacements out of 438 placements in the non-anchored group and 3 out of 418 for the anchored group. The displacement rates for the different non-anchored devices studies cannot be compared because the method of insertion varied and different placements after CS, even when not fixed, may vary.^10,23 In addition, although the patient characteristics in terms of parity, age and type of CS (elective or emergency) were consistent within individual studies, there was enough variation between studies to invalidate comparisons of the non-anchored devices between the different studies. The author provided statistical significance determination and level of evidence for each study is given in Table 2. Where there was concern of possible risk- of- bias due to lack of information, it was not possible to establish any direction of risk toward either the anchored or non-anchored group. None of the studies showed evidence that they were at high risk of bias, but there was some risk based on the completeness of information. The OR (odds ratio) analysis supports the conclusion that IUD displacement after post-partum CS insertion was more likely if the device was not anchored (Figure 2). The weight of Mahmoud et al¹⁶ Unal et al¹⁹ and Yan et al²⁰ was approximately double of the weight of the other 3 included studies. The OR is only statistically significantly different from the no effect for Mahmoud et al¹⁶ and Unal et al¹⁹ with the 95%CI of the remaining studies crossing over the no effect line. Both the Common effect and Random effects model was calculated. The common effect model considers the methods used for insertion of the IUD – either anchored or free-moving – to be an independent variable, thus having the same effect irrespective of methods and settings. The random effects model accounts for the differences in provider techniques and random effects at the individual study level. It is our hypothesis that variability in the “non-anchored” segment of IPPI-IUD provision is limited but variability, if only in the type of devices and anchoring techniques between studies included in the “anchored” segment, would be substantial. Both effect models OR’s are remarkably close to each other. Their overall effect displays a statistically significant difference. It is 10.47 (Common effects model) or 10.18 (Random effects model) more likely to encounter IUD displacement after IPPI insertion following caesarean section if the device was not anchored in any capacity. The magnitude of heterogeneity is deemed as not important at 0%. This points towards a reliable pooled estimate in which all included studies share the same trend.

Figure 2 Dichotomous outcome measure: Incidence of expulsion of an IUD placed immediately following caesarean section either by: 1. Freely placing it in the uterus. 2. Anchoring it to the fundus uteri.

Secondary Evaluations

Three studies followed subjects up to 12 months^16,20,21 and one to 6 months¹⁶ and two for 3 months.^18,19

Expulsions at 12 Months

At 12 months, any expulsion, which was not identified as a displacement at 3 months, would not be related to whether the device was anchored or not but some other factor. Three studies reported on expulsion rates at 12 months. Mahmoud et al¹⁶ had 15 anchored expulsions at 12 months versus 24 for the non-anchored group. Yan et al²⁰ reported 2 GeneFlex expulsions versus 6 Yuan gong expulsions and Fang et al²¹ reported 0 GeneFlex PP expulsions versus 5 for the TCu380A. The relevance of these numbers is difficult to determine as there were removals for other reasons. Yan et al²⁰ observed one dislocated GeneFlex at 6 months and three dislocated non-anchored Yuan Gongs at 6 months in addition to the reported expulsions.

Pregnancies

Yan et al²⁰ had one pregnancy in the GeneFlex group and two in the Yuan Gong group at 12 months. Abotaleb et al¹⁷ had one pregnancy in the TCu380A non-anchored group and none in the TCu380A anchored group at 6 months post placement. Mahmoud et al¹⁶ had 3 pregnancies in the anchored TCu380A and 2 in the non-anchored TCu380A anchored group at 12 months. They also reported one ectopic pregnancy in each group.

Bleeding, Pain, Infection and Removal

These problems were reported in five of the six studies at various times for both the anchored and non-anchored devices. They were ill-defined and infection was not confirmed as upper or lower genital tract infection. The authors did not report any significant differences in their studies, and the data was not analyzed using the life table method. A compendium of the results is given in Table 3. The data is for the last time period evaluated.

Table 3 Bleeding, Pain and Infection Data from the Anchored versus Non-Anchored Studies†

1. Missing threads after post-partum IUD is a big problem in areas where those removing them do not have the correct equipment and training. This impedes the uptake of IUDs in many parts of the world. The average percentage presence of threads after post-CS insertion is only 30%.²⁴ Different methods of placing devices at CS have not proven effective and attempts to alter the threads by extension have had moderate success.²⁵ Unal et al¹⁹ found that after 3 months threads were visible in 58% of the Gyn-CS users and only 22% of the non-anchored TCu380A users. None of the other studies reported the incidence of missing threads.

Discussion

The main purpose of these studies was to evaluate whether anchoring an IUD at CS improves the expulsion (displacement) rate at 3 months and is therefore worth the effort involved. Those studies which went beyond 3 months were not designed to perform IUD performance analysis because of small numbers and absence of acceptable statistical techniques. All studies were confirmed as being randomized controlled studies and satisfying the Canadian Task Force on Preventive Health Care category I status.

In the non-pregnant uterine environment, framed IUDs create a physiological intrauterine anchor which is tolerated with varying degrees of success.^5,7 The formation of the anchor depends on a mechanical compatibility between the shape of the IUD and the size and shape of the endometrial cavity of the uterus into which it is placed. Frameless IUDs cannot create a physiological anchor and must be tethered to the uterus under all circumstances. This review compares the performance of frameless IUDs, which must always be tethered and tethered framed devices placed post-placentally at CS (the anchored group), with non -tethered devices placed at CS (non-anchored group). All six studies appeared to show a lower expulsion in the anchored group, and this was statistically significant in five of the six studies. The necessity of anchoring a frameless device, and the benefit thereof appears to be significant, so the question arises as to how anchoring would benefit the framed devices.

Aulia et al¹⁸ used chromic catgut and Abataleb et al¹⁷ used egycryl to anchor the TCu380A. These products only retain tensile strength for 2 weeks. To understand how anchoring for only 2 weeks can help prevent expulsion, it is necessary to examine the physiological changes, which take place in the uterus in the first few weeks of involution. To understand the forces acting on the device at this time requires knowledge of the intrauterine pressure and surface area. This would allow calculation of these forces as has been done for the non-pregnant uterus.²⁶ This information is not available for the puerperal uterus. Ultrasonic evaluation of the puerperal uterine cavity shows a rapid decline of antero-posterior diameter over the first 2 weeks²⁶ and a reduction of uterine cavity length by 27% from 13.4 cm to 9.7 cm by day 7 after delivery.²⁷ If uterine muscle tone is static, then a smaller cavity (decreased radius) will produce increased pressure and hence force by Laplace’s law (Tension = Pressure x Radius). As uterine muscle tone increases with involution, this will be enhanced even more. These increased forces help restore the physiological anchor and help reduce the expulsion and displacement rates of tethered framed devices at CS. Some investigators have used modified techniques to improve retention of devices placed at the time of CS,¹⁰ and trials comparing placing the IUD using forceps have been compared with placing the device using a similar method to that of Hofmeyr²⁰ which attempts to embed the IUD more firmly in the fundus using the inserter tube resulting in reduced expulsion and displacement rates.^23,28,29 The physiological mechanism by which this introducer-placed method achieves improved results is not explained by the authors.

There appears to be a physiological basis for anchoring a framed IUD with a tether which retains its tensile strength for 2 weeks or more. There also appears to be evidence that anchoring a frameless device at the time of CS with a temporary additional anchor supports the permanent anchoring knot, which will later become the sole means by which the frameless device will be anchored in the involuted uterus. The disadvantages of creating a physical anchor are the increased time that it takes to create one and the inconvenience if rapid removal is required for some reason. In this situation, a hysteroscopy may be required to remove the device. Increased surgical risks of all types are also a consideration. Serial comparative ultrasound measurements in anchored versus non-anchored groups could help to identify the displacement mechanism. Studies comparing anchored and non-anchored levonorgestrel-released IUDs would be interesting because of their effects on uterine physiology.

Conclusion

This review confirms that physically anchoring a framed or frameless IUD at the time of CS will reduce the expulsion rate at 3 months. No other benefits on reducing IUD problems were demonstrated. This was probably due to various aspects of the design of the studies.