The effects of intrauterine contraceptive devices on the ultrastructure of the endometrium in relation to bleeding complications

Application of the RCOG Risk Assessment Model for Evaluating Postpartum Venous Thromboembolism in Chinese Women: A Case-Control Study

BACKGROUND Since China has not yet constructed its own risk assessment model (RAM) for pregnancy-related venous thromboembolism (VTE), more and more hospitals use the RCOG RAM for VTE risk prediction. However, the RCOG RAM was established based on Western populations, and its applicability in China is still uncertain. Thus, we aimed to evaluate the validity of the RCOG RAM in predicting postpartum VTE in Chinese maternity. MATERIAL AND METHODS This retrospective case-control study was conducted at the International Peace Maternity and Child Health Hospital (IPMCHH) from June 2016 to June 2020. The VTE group consisted of 38 women with postpartum VTE. For each VTE patient, 4 women without VTE who gave birth on the same day were randomly selected as the control group (n=152). The receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the discrimination, accuracy, and validity of the RCOG RAM. Univariable analysis and multivariable logistic regression analysis were used to identify other related factors for postpartum VTE. RESULTS Compared with the low-risk group, the risk of VTE was 9.75-fold greater in the intermediate-risk group, and 90.00-fold greater in the high-risk group. The area under curve (AUC) of the model was 0.828 (95% CI: 0.762-0.894), with a score of 2 as its best cut-off value, which exactly matched the criterion recommended by the RCOG guidelines for pharmacological thromboprophylaxis. The calibration curves and DCA of the model also showed good accuracy. In addition to the factors included in the RCOG RAM, glucocorticoid therapy during pregnancy (adjusted OR=6.72, 95% CI: 1.56-28.91) and previous use of IUD (adjusted OR=7.11, 95% CI: 1.45-34.93) were associated with increased risk of postpartum VTE. CONCLUSIONS The RCOG RAM was found to be effective in predicting postpartum VTE, and has certain guiding significance for postpartum thromboprophylaxis in China.

Effects of progestin-only contraceptives on the endometrium

INTRODUCTION

The contraceptive activity of synthetic progestins is mediated through three basic mechanisms: (a) An anti-gonadotrophic action leading to the inhibition of ovulation; (b) Changes in cervical mucus characteristics that inhibit sperm penetration and (c) desynchronization of the endometrial picture necessary for implantation.

AREAS COVERED

Mechanisms involved in the progestin-induced endometrium desynchronization are individually reviewed for each of the routes of administration and, whenever possible, by individual members of the various families of synthetic progestin derivatives.

EXPERT OPINION

For contraceptive purposes, progestins are today administered through several routes: orally, as injections, subdermally and via the vagina or the uterine cavity. Given this variety of modalities, their effects may differ, depending on the route of administration, concentration reached at the level of the endometrium and the duration of use. These are characterized by inactivation of the endometrium. Progestin-only contraception provides a safe and effective control of fertility regulation, although, they are associated with the problem of endometrial break through bleeding that may lead to discontinuation. Unfortunately, in spite of a major research effort over two decades, there is not, as yet, an established long-term intervention available to manage bleeding irregularities, making mandatory a deeper understanding of the mechanisms involved is required.

The Patient with Non-Pregnancy-Associated Vaginal Bleeding

Abnormal uterine bleeding (AUB) unrelated to pregnancy affects 20% to 30% of women at some point in life and is a common emergency department (ED) and urgent care (UC) presentation. AUB is a complex condition with extensive terminology, broad differential diagnosis, and numerous treatment options, yet few published evidence-based guidelines. In the ED or UC setting most affected patients are often more frustrated than acutely ill. These factors can make for a challenging patient encounter in the EC/UC setting. This article reviews acute and chronic AUB in the nonpregnant patient and suggests a simplified approach for its evaluation and management.

Endometrial vascularization in levonorgestrel intrauterine device users; computerized microvessel measurement study

Levonorgestrel use in the levonorgestrel intrauterine device (LNG-IUS) induces vascular distension within the superficial layer of the endometrium and massive pseudodecidualization. With a computer-assisted image analysis system, we objectively measured the vascular bed in LNG-IUS users and compared it to the physiological endometrium. A study was undertaken on 25 women using LNG-IUS, in an outpatient procedure at the time of removal of the IUS and compared with 11 normally cycling women (control group). Suction curette specimens were obtained just after retrieval of the IUS, and immunohistochemistry was carried out with a specific marker of the endothelial cells (CD31). Number of vessels decreased in the LNG-IUS group to 60/mm2 versus 124/mm2 in the control group, and mean vessel area increased to 1255 microm2 versus 157 microm2, respectively, in the control group. The decrease in mean vascular density and the increase of mean vessel area in the LNG-IUS group, compared to the control group, were both highly significant (p<.001).

The morphologic changes of endometrial spiral arterioles in IUD-induced menorrhagia

To investigate the relationship between IUD-induced menorrhagia and spiral arteriolar function, we examined the endometrium under light and electron microscope on samples obtained within 24 hours after the onset of premenstrual spotting. These samples included an IUD bleeding group (20 cases), an IUD non-bleeding group (20 cases) and an IUD non-user group (10 cases) as controls. Compared with the IUD non-user group the degenerative changes of spiral arteriolar wall were more severe and dilation of the spiral arteriolar lumen was more obvious, especially in the spongeous layer. In the IUD non-user group these changes were mild, suggesting that IUD-induced menorrhagia might be correlated with poor contractility of spiral arterioles in the spongeous layer.

The effect of postplacental insertion of the spiked and the standard Lippes loop on uterine involution

The spiked Lippes loop was inserted in 53 women and the standard loop in 55 women immediately following the delivery of the placenta after normal vaginal delivery. A group of 50 recently delivered women with no IUD was studied as a control. The cases were followed up for 1 year. Ultrasonic scanning was performed during the 6th week after insertion for 47 cases with the spiked loop and 43 cases with the standard loop. All loops were correctly positioned within the uterine cavity except in two cases; one using the spiked and the other using the standard loop. The loops were found displaced downwards and as there was excessive bleeding, the devices were removed. Regarding the effect of the IUD on uterine involution, it was found that the fundus to internal os length for the cases with IUDs was shorter than that among the controls, also this length among the standard loop users was significantly shorter than that of the controls (P less than 0.01). Postplacental IUD insertion did not delay uterine involution, on the contrary, it helped involution. Regarding the effect of lactation, the fundus to internal os length for the fully lactating women either using a loop or not, was found to be significantly shorter than that of the non-lactating cases (P less than 0.002).

Endometrial morphological changes in IUD users: a review

The introduction of an intrauterine device into the uterine cavity induces a foreign body reaction in the surrounding endometrium which is characterized by the infiltration of polymorphonuclear leucocytes and macrophages into the endometrial stroma and subsequently through the surface epithelium. Leucocyte migration is greater with copper IUDs than with inert IUDs. Ulceration of the surface epithelium, haemorrhage of erythrocytes and microthrombosis of stomach capillaries occur in the functional endometrium in contact with inert and copper IUDs. In endometrium adjacent to, but not in contact with, the IUD gaps appear in the endothelial lining of small blood vessels without a haemostatic response. The most striking response in endometrium exposed to progesterone-releasing IUDs is the occurrence of dilated, thin-walled vesicles, associated with a thinning of the surface epithelium and a decidual reaction in the stroma. A uniform suppression of the endometrium in progesterone IUD users is always found after six months of treatment, whereas the insertion of IUDs releasing 20-30 micrograms levonorgestrel induce a profound uniform suppression of the functional endometrium throughout the uterus after only four weeks.

The role of prostaglandins and allied substances in uterine haemostasis

This review addresses itself to summarizing the more recent studies published on the bioconversion of arachidonic acid in the human endo- and myometrium during the normal menstrual cycle and in women with increased menstrual blood loss. The data indicate an increased ability of the endo- and myometrium from women with menorrhagia to produce prostaglandins with vasodilator and platelet anti-aggregatory properties, viz., prostacyclin and prostaglandin E2. The data on prostaglandin production in endometria of IUD wearers is reviewed and discussed in relation to present knowledge on morphological findings in IUD-influenced endometrium.

A morphometric study of the effect of oral norethisterone or levonorgestrel on endometrial blood vessels

A morphometric study was undertaken to quantitate vessel numbers in uterine biopsies from a control group of patients, patients with dysfunctional uterine bleeding and patients taking low dose norethisterone or levonorgestrel. Vessels were counted at the endometrial/myometrial junction and in the functional endometrium just below the surface epithelium. The number of arteries at the endometrial/myometrial junction was found to be decreased in patients taking norethisterone and levonorgestrel. An increase was found in the total number of veins and in the number of dilated veins in the functional endometrium of the progestogen-treated specimens. Dilated veins were frequently found close to the endometrial surface and it is possible that they may be the major cause of the irregular bleeding associated with low dose oral progestogens.