Hormonal profile of the menstrual cycle in Chinese women after tubal sterilization

Hysterectomy With and Without Oophorectomy, Tubal Ligation, and Risk of Cardiovascular Disease in the Nurses' Health Study II

Background: Hysterectomy, oophorectomy, and tubal ligation are common surgical procedures. The literature regarding cardiovascular disease (CVD) risk after these surgeries has focused on oophorectomy with limited research on hysterectomy or tubal ligation. Materials and Methods: Participants in the Nurses' Health Study II (n = 116,429) were followed from 1989 to 2017. Self-reported gynecologic surgery was categorized as follows: no surgery, hysterectomy alone, hysterectomy with unilateral oophorectomy, and hysterectomy with bilateral oophorectomy. We separately investigated tubal ligation alone. The primary outcome was CVD based on medical-record confirmed fatal and nonfatal myocardial infarction, fatal coronary heart disease, or fatal and nonfatal stroke. Our secondary outcome expanded CVD to include coronary revascularization (coronary artery bypass graft surgery, angioplasty, stent placement). Cox proportional hazard models were used to calculate hazard ratios (HR) and 95% confidence intervals (CIs) and were adjusted a priori for confounding factors. We investigated differences by age at surgery (≤50, >50) and menopausal hormone therapy usage. Results: At baseline, participants were on average, 34 years old. During 2,899,787 person-years, we observed 1,864 cases of CVD. Hysterectomy in combination with any oophorectomy was associated with a greater risk of CVD in multivariable-adjusted models (HR hysterectomy with unilateral oophorectomy:1.40 [95% CI: 1.08-1.82]; HR hysterectomy with bilateral oophorectomy:1.27 [1.07-1.51]). Hysterectomy alone, hysterectomy with oophorectomy, and tubal ligation were also associated with an increased risk of combined CVD and coronary revascularization (HR hysterectomy alone: 1.19 [95% CI: 1.02-1.39]; HR hysterectomy with unilateral oophorectomy: 1.29 [1.01-1.64]; HR hysterectomy with bilateral oophorectomy: 1.22 [1.04-1.43]; HR tubal ligation: 1.16 [1.06-1.28]). The association between hysterectomy/oophorectomy and CVD and coronary revascularization risk varied by age at gynecologic surgery, with the strongest association among women who had surgery before age 50 years. Conclusion: Our findings suggest that hysterectomy, alone or in combination with oophorectomy, as well as tubal ligation, may be associated with an increased risk of CVD and coronary revascularization. These findings extend previous research finding that oophorectomy is associated with CVD.

Elevated prolactin secretion during proestrus in mice: Absence of a defined surge

Throughout the reproductive cycle in rodents, prolactin levels are generally low. In some species, including rats, a prolactin surge occurs on proestrus with peak concentrations coinciding with the preovulatory luteinizing hormone (LH) surge. In mice, however, there are conflicting reports relating to the occurrence and timing of a proestrous prolactin surge. To gain further insight into the incidence and characteristics of this surge in mice, we have used serial tail tip blood sampling and trunk blood collection from both C57BL/6J (inbred) and Swiss Webster (outbred) mouse strains to build a profile of prolactin secretion during proestrus in individual mice. A clearly defined LH surge was detected in most animals, suggesting the blood sampling approach was suitable for detecting patterns of hormone secretion on proestrus. Despite this, levels of prolactin were quite variable between individuals. Overall both mouse strains showed a generalized rise in prolactin levels on the day of proestrus compared with levels seen in diestrus. This pattern is quite distinct from the discreet, circadian-entrained surge observed in rats.

Recent progress in advanced biomaterials for long-acting reversible contraception

Unintended pregnancy is a global issue with serious ramifications for women, their families, and society, including abortion, infertility, and maternal death. Although existing contraceptive strategies have been widely used in people's lives, there have not been satisfactory feedbacks due to low contraceptive efficacy and related side effects (e.g., decreased sexuality, menstrual cycle disorder, and even lifelong infertility). In recent years, biomaterials-based long-acting reversible contraception has received increasing attention from the viewpoint of fundamental research and practical applications mainly owing to improved delivery routes and controlled drug delivery. This review summarizes recent progress in advanced biomaterials for long-acting reversible contraception via various delivery routes, including subcutaneous implant, transdermal patch, oral administration, vaginal ring, intrauterine device, fallopian tube occlusion, vas deferens contraception, and Intravenous administration. In addition, biomaterials, especially nanomaterials, still need to be improved and prospects for the future in contraception are mentioned.

Impact of Curcumin on Ovarian Reserve After Tubal Ligation: an Experimental Study

The aim of this study was to evaluate the effects of tubal ligation (TL) via modified Pomeroy method on ovarian reserve and to determine the role of curcumin (Curcuma longa [Indian saffron]) against ovarian reserve decrement after TL. Forty-eight albino Wistar rats were randomly divided into four groups: (1) Control group: a sham operation was performed (n = 12), (2) Tubal ligation group: TL was performed (n = 12), (3) TL+DMSO group: 1 mL/day dimethyl sulfoxide was used for 50 days after TL, (4) TL+Curc group: 100 mg/kg/day curcumin dissolved in DMSO was administrated for 50 days after TL. Pre-operatively and on post-operative day 50, blood samples were collected for AMH evaluation, and oophorectomy was performed for histological and immunohistochemical examinations of ovaries in all groups. No difference in the basal AMH levels was found among the groups (p = 0.249). Compared to the basal, AMH levels were lower in the control, TL, and TL+DMSO groups (p = 0.003, p = 0.004, and p < 0.001, respectively) but not different in the TL+Curc group (p = 0.503) on post-operative day 50. No significant differences in the number of primary, preantral, antral, atretic follicles, and corpus luteum among the groups (p > 0.05) were found. The percentage of granulosa cells stained for caspase-3 in antral follicles and the corpus luteum was higher in the TL+Curc group than in the control and TL groups ([antral follicles; p < 0.01 for both groups], [corpus leteum; p = 0.009 and 0.002 for the control and TL groups, respectively]). It seems that TL does not decrease ovarian reserve and curcumin might have a positive effect on ovarian reserve in the setting of TL.

Patterns of prolactin secretion

Prolactin is pleotropic in nature affecting multiple tissues throughout the body. As a consequence of the broad range of functions, regulation of anterior pituitary prolactin secretion is complex and atypical as compared to other pituitary hormones. Many studies have provided insight into the complex hypothalamic-pituitary networks controlling prolactin secretion patterns in different species using a range of techniques. Here, we review prolactin secretion in both males and females; and consider the different patterns of prolactin secretion across the reproductive cycle in representative female mammals with short versus long luteal phases and in seasonal breeders. Additionally, we highlight changes in the pattern of secretion during pregnancy and lactation, and discuss the wide range of adaptive functions that prolactin may have in these important physiological states.

The comparison of the degree of apoptosis in ovaries and fallopian tubes between two different surgical interventions for tubal ligation: A rat model

Objective:

To compare the degree of apoptosis in ovaries and tubal epithelium observed secondary to tubal ligation either by Pomeroy’s method or bipolar electrocauterization in a rat model.

Material and Methods:

A total of 24 female Sprague-Dawley rats were randomly assigned into 3 study groups: control (n=8), Pomeroy (n=8), and the electrocauterization group (n=8). Apoptotic cells were detected on the primary, secondary, tertiary follicles of the ovaries, and on the tubal epithelium using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling. The apoptotic index was calculated for each group by the percentage of the stained cells.

Results:

The apoptotic index of tubal epithelium was significantly higher in the bipolar electrocauterization group compared with the control and Pomeroy groups (3.1±0.8 vs. 1.4±1.0, p=0.018 and 2.0±1.2, p=0.03, respectively) whereas there was no significant difference between Pomeroy’s method and the control group. The apoptotic index of primary follicles was higher in the bipolar electrocauterization group compared with the control and Pomeroy’s method groups (3.4±0.5 vs. 1.2±0.4, p<0.001 and 1.8±0.8, p=0.005, respectively), but there was no significant difference between Pomeroy’s method and the control group. The apoptotic index of secondary and tertiary follicles was similar for each group.

Conclusion:

Pomeroy’s technique, as a permanent contraception method, is associated with lower apoptotic index on ovary and fallopian tube when compared with bipolar electrocauterization.

Tubal Ligation and Risk of Endometrial Cancer: Findings From the Women's Health Initiative

OBJECTIVE

Bilateral tubal ligation (BTL) is a common form of birth control in the United States. There are limited, contradictory data examining BTL and the risk of endometrial cancer and none examining type I and type II cancers separately. We investigated the association between BTL and endometrial cancer risk using the Women's Health Initiative (WHI) Observational and Dietary Modification Studies.

METHODS

Demographic information and history of BTL were obtained from the baseline questionnaires from 76,483 WHI participants in the Observational and Dietary Modification Studies. Univariable and multivariable models were used to examine the association of BTL with type I and type II endometrial cancers.

RESULTS

A total of 1137 women were diagnosed with incident endometrial cancer (972 type I and 128 type II) during a mean follow-up of 11.3 years. Overall, 14,499 (19%) women had undergone BTL. There were no statistically significant associations noted between BTL and age at BTL for type I or type II cancers.

CONCLUSIONS

We examined the largest patient cohort to date in an effort to determine the impact of BTL on endometrial cancer risk. In the WHI trial, we observed no overall effect of BTL on the risk of type I or type II endometrial cancer, suggesting that patients undergoing this popular birth control method likely do not have an associated change in their baseline risk for endometrial cancer.

Examination of the ovarian reserve after generation of unilateral rudimentary uterine horns in rats

Objective. The purpose of this experimental rat model study is to evaluate the changes in the ovarian environment after excision of the rudimentary horn. Methods. Ten female Wistar albino rats were used in this study. One cm of right uterine horn length was excised in the first operation. Two months after the first operation, all animals were sacrificed to obtain ovaries for histological examination. Mann-Whitney U test and Student's t-test were used for statistical analysis purposes. Statistical significance was defined as P < 0.005. Results. The number of primordial follicles (P = 0.415), primary follicles (P = 0.959), preantral follicles (P = 0.645), antral follicles (P = 0.328), and Graafian follicles (P = 0.721) was decreased and the number of atretic follicles (P = 0.374) increased in the right ovarian side. Howeve,r this difference was not found to be statistically significant. Conclusion. The results of this experimental rat model study suggest that the excision of rudimentary horn could have negative effects on ipsilateral ovarian functions.

Ovarian reserve testing before and after laparoscopic tubal bipolar electrodesiccation and transection

OBJECTIVE

To find out whether tubal sterilization leads to loss of ovarian reserve, we assessed the hormonal and ultrasonographic parameters of ovarian reserve in women who underwent laparoscopic tubal sterilization by bipolar electrodesiccation and transection.

STUDY DESIGN

In this preliminary study, laparoscopic tubal sterilization was performed on 49 healthy women who had voluntarily requested elective surgical sterilization. Among the current ovarian reserve indicators, in the early proliferative phases, preoperative (baseline) and postoperative (third month) serum follicle-stimulating hormone (FSH), estradiol (E2), and anti-Mullerian hormone (AMH) levels, ovarian volume, and antral follicle counts (AFCs) were determined. Analysis of these hormonal and ultrasonographic parameters of ovarian reserve preoperatively and postoperatively was the main outcome measure.

RESULTS

Preoperative and third-month postoperative FSH, LH, E2, and AMH levels did not reveal statistically significant differences (p=0.101, p=0.180, p=0.254, and p=0.079; respectively). The ultrasonographic indicators of ovarian reserve did not change in terms of total ovarian volume and total AFC (p=0.793 and p=0.098, respectively).

CONCLUSIONS

Short-term follow-up study results revealed a slight but non-significant change in the current ovarian reserve markers, especially in the AMH levels.

Tubal ligation, hysterectomy and ovarian cancer: A meta-analysis

PURPOSE

The purpose of this meta-analysis was to determine the strength of the association between gynecologic surgeries, tubal ligation and hysterectomy, and ovarian cancer.

METHODS

We searched the PubMed, Web of Science, and Embase databases for all English-language articles dated between 1969 through March 2011 using the keywords "ovarian cancer" and "tubal ligation" or "tubal sterilization" or "hysterectomy." We identified 30 studies on tubal ligation and 24 studies on hysterectomy that provided relative risks for ovarian cancer and a p-value or 95% confidence interval (CI) to include in the meta-analysis. Summary RRs and 95% CIs were calculated using a random-effects model.

RESULTS

The summary RR for women with vs. without tubal ligation was 0.70 (95%CI: 0.64, 0.75). Similarly, the summary RR for women with vs. without hysterectomy was 0.74 (95%CI: 0.65, 0.84). Simple hysterectomy and hysterectomy with unilateral oophorectomy were associated with a similar decrease in risk (summery RR = 0.62, 95%CI: 0.49-0.79 and 0.60, 95%CI: 0.47-0.78, respectively). In secondary analyses, the association between tubal ligation and ovarian cancer risk was stronger for endometrioid tumors (summary RR = 0.45, 95%CI: 0.33, 0.61) compared to serous tumors.

CONCLUSION

Observational epidemiologic evidence strongly supports that tubal ligation and hysterectomy are associated with a decrease in the risk of ovarian cancer, by approximately 26-30%. Additional research is needed to determine whether the association between tubal ligation and hysterectomy on ovarian cancer risk differs by individual, surgical, and tumor characteristics.

The fallopian tube: primary site of most pelvic high-grade serous carcinomas

Epithelial ovarian cancer is the most common cause of mortality from gynecologic malignancy, and most of epithelial cancers are of serous type. The site of origin of pelvic high-grade serous carcinoma has been the subject of debate for 60 years. This paper reviews the evidence that pelvic serous carcinoma originates from the fallopian tube mucosa and puts forward a theory that inflammation in the tube, caused by menstrual cytokines or infection, is critical to the genesis of these tumors. Other risk factors for pelvic serous carcinoma will be reviewed, including oral contraceptive use, parity, infertility, and tubal ligation.Studies were identified for this review by searching the English language literature in the MEDLINE database between the years 1995 and 2007 using the following keywords: fallopian tube neoplasia, ovarian serous adenocarcinoma, pregnancy, oral contraceptive, infertility, pelvic inflammatory disease, cytokines, menstruation, and tubal ligation, followed by an extensive review of bibliographies from articles found through the search.The clinical implications of this theory are discussed, and a change in surgical practice is recommended, with salpingectomy at the time of simple hysterectomy. This theory also has implications for the development of new methods of screening for pelvic serous carcinomas, as there are no screening methods that are currently available to find this form of cancer in an early stage. Inflammatory markers could be detected in the vagina from the fallopian tube indicating possible chronic inflammation and a risk factor for mutagenesis leading to serous carcinoma.

Effects of three different sterilization methods on utero-ovarian Doppler blood flow and serum levels of ovarian hormones

OBJECTIVE

The aim of the study was to assess pre-operative and post-operative serum levels of ovarian hormones and changes in utero-ovarian arterial blood flow by Doppler ultrasonography in women in whom one of three different sterilization methods was applied.

STUDY DESIGN

The Pomeroy method of tubal ligation, fimbriectomy, or laparoscopic bipolar coagulation were applied in 42 patients. Serum levels of sex hormones were checked, and utero-ovarian arterial Doppler measurements were performed pre-operatively and post-operatively. The presence or absence of dysmenorrhea was noted before and after the operations.

RESULTS

We detected a significant increase in the average uterine arterial resistivity index (RI) and both ovarian arterial pulsatility index (PI) values in the Pomeroy method group (p<0.05). There was a significant increase in dysmenorrhea complaints in the total number of patients (p<0.05), particularly in the fimbriectomy group.

CONCLUSION

The significant increase in uterine arterial Doppler measurements with the Pomeroy method may be due to the removal of a larger tubal segment. Even though the increase is not statistically significant, fimbriectomy should not be applied in young women, because it may increase dysmenorrhea and the procedure is not reversible.

Effect of tubal ligation on ovarian reserve and the ovarian stromal blood supply

AIM

Our aim was to evaluate possible adverse effects of tubal ligation on ovarian reserve and ovarian stromal vascular support.

METHODS

Ninety-one women who underwent tubal ligation, using a modified Pomeroy technique, were studied. The main outcome measurements were serum follicle stimulating hormone, luteinising hormone and oestradiol levels, ovarian volume, number of antral follicles and Doppler study of ovarian stromal artery on the third day of the menstrual cycle immediately before, 1 month and 12 months after the surgical intervention.

RESULTS

Statistically significant elevation of follicle stimulating hormone levels was observed at 1 and 12 months after tubal ligation (P < 0.05).

CONCLUSION

Doppler flow studies of the ovarian stromal arteries showed that there were no significant differences before and after tubal ligation.

Hormonal and ovarian stromal blood supply changes after laparoscopic tubal sterilization: a prospective controlled study

OBJECTIVES

The purpose of this study is to determine if the effects of tubal sterilization (TS) by laparoscopy have any risk of a subsequent significant decrease in ovarian reserve and vascular support within the ovary by means of stromal artery Doppler study, and to compare the results with matched paired controls.

DESIGN

Between February 2002 and January 2005, 148 healthy volunteers were enrolled sequentially, 74 undergoing laparoscopic TS (study group) and 74 age-, parity-, body mass index-matched women were recruited as a control group. The main outcome measurements were blood levels of follicle-stimulating hormone (FSH), luteinizing hormone and E2, ovarian volume, number of antral follicles and Doppler study of ovarian stromal artery pulsatile index (PI) and maximum velocity (Vmax) on the third day of the cycle immediately before, and 1 and 12 months after the surgical intervention.

RESULTS

There were significant elevations in both serum FSH levels and PI values observed 1 month after TS, compared to the preoperative levels (p < .05), and also when compared to controls. However, there were no significant elevations at 12 months postoperation in both study and control groups. The other outcome measurements did not show any significant differences between the two groups.

CONCLUSIONS

Tubal sterilization by laparoscopic electrocoagulation does not cause any decrease in ovarian reserve or ovarian stromal blood supply, except an early postoperative increase in FSH and PI.

Histopathological changes in ovary and endometrium after tubal ligation: a rat model

BACKGROUND

To evaluate the histopathological effects of tubal ligation on ovary and endometrium in a rat model.

METHODS

Twenty-four female Wistar albino rats weighing 220-260 g were used. The rats were assigned randomly into tubal ligation and control groups. While tubal ligation was applied to the first group of rats, only a laparotomy was performed in the second group. Six weeks later, a second laparotomy was performed and uterine horns and ovaries of the rats in the two groups were excised for histopathological assessment. A pathologist blinded to the groups made histopathological examination including quantification of endometrial phases, presence of endometrial inflammation and counting the number of tertiary follicles and corpora lutea in each ovary.

RESULTS

We found no significant difference between tubal ligation and control groups related to the number of tertiary follicles and corpora lutea (p > 0.05). However, in the tubal ligation group, endometrial inflammatory infiltration was significantly higher than in the control group (p < 0.05).

CONCLUSION

Tubal ligation does not affect ovarian histology as an indicator of ovarian function. However, endometrial inflammation may occur after tubal ligation and lead to menstrual irregularities as an early complication.

The effect of surgical sterilization on ovarian function: a rat model

OBJECTIVE

To evaluate the effects of various methods of sterilization on ovarian function, in a rat model.

STUDY DESIGN

Forty-eight female Whistar albino rats weighing 200-250g are divided equally into four groups. All rats underwent laparotomy, while no specific intervention was made to the first group. Bilateral tubal ligation by Pomeroy's technique, unipolar and bipolar cautery was done to the second, third and fourth groups, respectively. All rats were then individually caged and fed on demand for 6 months. Afterwards, the rats were sacrificed and underwent bilateral oophorectomy. A pathologist blinded to the groups made histological examination by counting number of healthy tertiary follicles and corpora lutea in each ovary. The results of the groups were statistically compared by one-way ANOVA using post-hoc Bonferroni correction.

RESULTS

Rats in group 1 had significantly higher number of healthy tertiary follicles than every other group. Rats in group 1 also had significantly more corpora lutea than those in group 3.

CONCLUSION

Tubal ligation may affect ovarian function, which in turn may reflect to ovarian histology in rats.

Luteal function declines after laparoscopic sterilization by Hulka or Filshie clips

We evaluated the influence of laparoscopic sterilization by Hulka or Fishie clips on corpus luteum function. Changes in corpus luteum function were evaluated in 46 women, before and after sterilization by Hulka (n = 22) or Filshie clips (n = 24). The mean age of the participants was 37 years (range 31-43 years). All women were healthy with regular menstrual cycles. Serum progesterone (P) was measured in one cycle before, and 3 and 12 months after the sterilization on cycle day 20-24. Endometrial biopsies were performed in the luteal phase before and one year after the procedure. The women measured the basal body temperature daily and kept a menstrual diary. The luteal phase P concentrations declined after the sterilization and the values were at the lowest level 3 months after the procedure (27.9 +/- 14.3 nmol/L vs. 18.7 +/- 13.4 nmol/L, = 0.0016). The values seemed to have recovered by 12 months (23.0 +/- 14.0 nmol/L, = 0.114 vs. baseline). Endometrium tended to be out-of-phase more frequently 1 year after the sterilization than before the surgery (= 0.065). Laparoscopic tubal sterilization is associated with an increased risk of luteal phase deficiency. However, the change may be only temporary in nature.

Tubal ligation and risk of cervical cancer. The World Health Organiztion Collaborative Study of Neoplasia and Steroid Contraceptives

Data from a hospital-based case-control study collected in eight countries were analyzed to determine whether tubal ligation alters risk of invasive squamous-cell cervical cancer. Study subjects included 2339 cases aged 22 to 64 years with newly diagnosed squamous cell cervical cancer in 10 participating medical centers, and 13,506 hospitalized controls matched on age and place of residence to the cases. After adjustment for age, center, caesarian section, number of live births, number of marriages or other sexual relationships, age at first sexual relationship, and frequency of Pap smears, a small decrease in risk was observed during the first 5 postoperative years. Tubal ligation probably provides an opportunity for secondary prevention of cervical cancer.

Tubal sterilization and use of an IUD and risk of cervical cancer

The relationship of tubal sterilization and use of an intrauterine device (IUD) to the risk of invasive squamous cell cervical cancer was evaluated in a case-control study carried out in Shandong, China, from 1989 to 1991. Patients (cases) were 272 women aged 30-77 years with newly diagnosed invasive squamous cell cervical cancer in Shandong Province Tumor Hospital. Controls were 893 randomly selected screened women matched to the cases by age (within 2 years) and county. A decrease in risk was observed in uses of an IUD, especially in long-term users under age 33. A nonsignificant decrease in risk in women under age 33 who had had a tubal ligation was also observed, especially in the first 10 years since the procedure. Tubal ligation and IUD insertion and removal provide opportunities to screen women for cervical cancer and reduce the risk of invasive disease.

Contraceptive status and sexual function of climacteric Chinese women

The objective of the present survey was to assess the contraceptive status and sexual function of climacteric Chinese women. One cross-sectional study randomly recruited 742 premenopausal, perimenopausal, and naturally menopausal women aged 45-55 years from Beijing. Contraceptive methods were used by 75.6% of premenopausal and 54.2% of perimenopausal women. The primary methods were the IUD and barrier method. The women's choices of methods were related to parity and frequency of sexual activities. Sexual activity was related to the satisfaction of contraceptive methods. Perimenopausal and postmenopausal women were about half as likely to enjoy sexual activity and to experience orgasms than premenopausal women. Women of higher socioeconomic status had a lower risk for decreased sexual functioning. The IUD was the most popular and the most appropriate contraceptive method for perimenopausal women. Sexual function was associated with the women's satisfaction with the contraceptive method used, their menopausal status, and their socioeconomic class.

Is there any evidence for a post-tubal sterilization syndrome?

OBJECTIVE

To review the literature on menstrual and hormonal changes in women who under go tubal sterilization.

DESIGN

A systematic review through MEDLINE and a literature search identified more than 200 articles in the English literature from which the most relevant were selected for this review.

RESULT(S)

Many authors have investigated the sequelae of female sterilization. Increased premenstrual distress, heavier and more prolonged menstrual bleeding, and increased dysmenorrhea have been reported. However, failure to control for age, parity, obesity, previous contraceptive use, interval since sterilization, or type of sterilization may have affected study results. Most studies that have controlled for these important variables have not reported significant changes, except in women who undergo sterilization between 20 and 29 years of age.

CONCLUSION(S)

Tubal sterilization is not associated with an increased risk of menstrual dysfunction, dysmenorrhea, or increased premenstrual distress in women who undergo the procedure after age 30 years. There may be some increased risk for younger women, although they do not appear to undergo significant hormonal changes.

Tubal sterilisation, hysterectomy and decreased risk of ovarian cancer. Survey of Women's Health Study Group

We have examined the effect of tubal sterilisation and hysterectomy on risk of ovarian cancer in a large case-control study in eastern Australia involving 824 women aged 18-79 years, diagnosed with epithelial ovarian cancer between 1990 and 1993, and 855 controls randomly selected from the electoral roll. Relative risks for ovarian cancer were estimated using multiple categorical regression to adjust for age, parity, oral contraceptive use and other risk factors. Tubal sterilisation was associated with a 39% reduction in risk of ovarian cancer (RR 0.61, 95% CI 0.46-0.85) and hysterectomy with a 36% reduction (RR 0.64, 95% CI 0.48-0.85). Risk remained low 25 years after surgery and was reduced irrespective of sterilisation technique, and estimates were similar among various types of epithelial ovarian cancer. The greatest reduction (74%) was observed among women with primary peritoneal tumours. Pelvic infection and use of vaginal sprays or contraceptive foams were not related to ovarian cancer, while use of talc in the perineal region slightly but significantly increased risk among women with patent fallopian tubes. Reportedly heavy or painful menses, perhaps associated with retrograde flow, were associated with ovarian cancer, and reduction in risk of disease after hysterectomy was greatest among women who had heavy periods. Our findings support the theory that contaminants from the vagina, such as talc, and from the uterus, such as endometrium, gain access to the peritoneal cavity through patent fallopian tubes and may enhance the malignant transformation of ovarian surface epithelium. Surgical tubal occlusion may reduce the risk of ovarian cancer by preventing the access of such agents.

Effects of age and non-hormonal contraception on menstrual cycle characteristics

The objective of this study was to investigate the effects of age and non-hormonal contraceptive method on menstrual cycle parameters. The menstrual cycle data were collected prospectively, and the study was cross-sectional with regard to age. The subjects were 142 women, including 14 asymptomatic volunteers and 128 women who presented to a premenstrual tension (PMT) clinic. The age range was 20-45 years. Contraceptive methods used were intrauterine device (IUD) (n = 12), tubal ligation (n = 61) and non-intensive methods (n = 69). Daily menstrual cycle diaries were used to calculate cycle length and number of days of menstruation. Daily 24-h urine collections were used to calculate the day of the preovulatory estrogen peak. Pearson correlations found significant relationships between age and preovulatory estrogen peak day (p < 0.001) and length of cycle (p < 0.002), but not between age and length of menstruation or luteal phase. Analysis of variance was highly significant for age and contraceptive method, for both cycle length and preovulatory estrogen peak day. Non-intrusive contraception users aged 30 years and younger had significantly longer follicular phases than did women with tubal ligation (p < 0.05). It was concluded that cycle length decreases with age due to shortening of the follicular phase. Further research on whether tubal ligation affects ovulation and follicular phase length in young women is needed.

Sterilization

Sterilization is accepted as a permanent method of contraception by many couples in the world. Female sterilization is more widely used than male sterilization, but the latter is used by many couples in developed countries. The most widely used methods for female sterilization are simple tubal ligation, electrocautery of the fallopian tubes, and occlusion of the tubes by Hulka or Filshie clips or Falope rings. These procedures may be carried out either by minilaparotomy or by laparoscopy, under local anaesthesia. Sterilization may be performed immediately following pregnancy, or as an interval operation. The effectiveness of female sterilization is high, with failure rates of about 1-2 per 1000 procedures. Immediate complications are few and minor, while there appear to be no serious, long-term adverse effects. It is possible that there is a protective effect against ovarian cancer. Potential new technologies for female sterilization include the use of chemicals, such as quinacrine, for transcervical tubal occlusion, and hysteroscopic methods. Male sterilization is more simple and can readily be performed under local anaesthesia. A new technique originating in China, the no-scalpel technique, has made the procedure even more simple and produces fewer complications such as haematoma. It is possible that the direct injection of plug-forming material into the vas may render the procedure more reversible. Concerns about possible adverse effects of vasectomy on cardiovascular diseases and testicular cancer largely have been dispelled, but a possible weak association between vasectomy and prostatic cancer continues to be studied.

Tubal sterilization and the risk of endometrial cancer

Several animal and human studies suggest that tubal occlusion may curtail ovarian function, altering the production and balance of endogenous estrogens and progesterone, 2 hormones closely related to endometrial carcinogenesis. Despite this, and the increasing world-wide popularity of this method of contraception, little is known about its relationship with the risk of developing endometrial cancer. To assess whether tubal sterilization influences a woman's risk of developing epithelial endometrial carcinoma, data from a large multicenter population-based case-control study of endometrial cancer were analyzed. Cases were 437 women aged 20 to 54 years with histologically confirmed epithelial endometrial cancer ascertained through 6 population-based cancer registries in the United States. Controls were 3200 women selected at random from the populations of the areas from which the cases were detected. As compared with women who had never had tubal sterilization, women who had had this surgery had a crude odds ratio of 0.58 [95% confidence interval (CI), 0.43-0.78]. However, after adjusting for the combined confounding effects of age and parity, the magnitude of the protective association decreased to 0.87 (95% CI, 0.63-1.20). The magnitude of the protective effect did not significantly change with years since surgery or age at surgery. Although a modest, non-significant protective effect is suggested, these findings indicate that tubal sterilization does not substantially alter the risk of developing epithelial endometrial cancer in women 20 to 54 years of age. If there is an increase in risk, these data indicate that it is unlikely to be any greater than 20%.