Oral contraception and post-operative thromboembolism: an epidemiological review

Association of Surgical Risk With Exogenous Hormone Use in Transgender Patients: A Systematic Review

Importance

A growing number of transgender patients are receiving gender-affirming hormone treatments. It is unclear whether the evidence supports the current practice of routinely discontinuing these hormones prior to surgery.

Objective

To determine how medications used in cross-sex hormone treatment (CSHT) affect perioperative risk.

Evidence Review

A series of searches were carried out in PubMed and Excerpta Medica Database to identify articles using each of the terms testosterone, estrogen, estradiol, oral contraceptive, spironolactone, cyproterone acetate, finasteride, dutasteride, leuprolide, goserelin, and histrelin, in combination with the terms surgery, perioperative, thrombosis, thromboembolism, and operative. The search was not restricted to perioperative outcomes in transgender populations because many surgeons routinely discontinue hormone use prior to surgery in this population, which makes it impossible to study how hormones affect outcomes. Additional sources were also identified from the texts of reviewed articles. Articles were excluded if they were animal studies or case reports, did not explicitly discuss surgical outcomes, or were restricted to removal of hormonally sensitive tissues.

Findings

Eighteen articles addressing perioperative outcomes were identified by this systematic review, including 1 on CSHT, 12 on estrogens and progesterones, 1 on testosterone, and 4 on spironolactone and antiandrogens. Data were limited, but use of exogenous testosterone was not found to be associated with an increased risk of venous thromboembolism or other complications during surgery. Moderate evidence suggests that spironolactone is not associated with negative surgical outcomes. The data linking estrogen use and thrombosis is inconsistent in the perioperative period and does not address the types of estrogens most often used for CSHT.

Conclusions and Relevance

Current evidence does not support routine discontinuation of all CSHT prior to surgery, particularly given the lack of information on risks associated with resuming these medications after they have been stopped. Evidence suggests there is no need to discontinue either testosterone or spironolactone, although their association with perioperative outcome quality has not been studied in depth. Most of the evidence that supports discontinuation of estrogen prior to surgery is based on oral estrogen regimens that are not typically used in transgender patients, and even with those formulations, there are conflicting reports on perioperative risk. Further research is needed to determine the safety of continuing hormone treatment and elucidate risks of short-term discontinuation.

Venous Thromboembolism After Uterine Fibroid Embolization

Thromboembolic complications after uterine fibroid embolization (UFE) are infrequent. The incidence and predisposing factors of thromboembolism after UFE are unknown. We present eight cases of nonfatal thromboembolic complications after UFE and estimate the frequency of such events as 0.4%.

Evidence-based risk factors for postoperative deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a common postoperative complication that is associated with significant morbidity and mortality. Thromboprophylaxis has been shown to be underused. In the absence of prophylaxis, rates as high as 50% have been reported following orthopaedic surgery, and 25% following general surgery. Many risk factors have been suggested but there is often little evidence to support these claims.

METHODS

A systematic review was performed to determine the evidence base behind each suggested risk factor, and, where sufficient data were available, a random-effects meta-analysis was performed.

RESULTS

There is evidence to support a significant association between increased age, obesity, a past history of thromboembolism, varicose veins, the oral contraceptive pill, malignancy, Factor V Leiden gene mutation, general anaesthesia and orthopaedic surgery, with higher rates of postoperative DVT, although there remain some variables within the study designs that may lead to overestimation of effect. There is no evidence to support the suggested risk factors of hormone replacement therapy, gender, ethnicity or race, chemotherapy, other thrombophilias, cardiovascular factors, smoking and blood type.

CONCLUSIONS

An accurate knowledge of evidence-based risk factors is important in predicting and preventing postoperative DVT, and can be incorporated into a decision support system for appropriate thromboprophylaxis use.

A survey of recommendations by gynecologists in Canada regarding oral contraceptive use in the perioperative period

OBJECTIVE

This survey was conducted to determine the practice patterns of gynecologists in Canada regarding the discontinuation of oral contraceptives before gynecologic surgical procedures.

STUDY DESIGN

In May and June of 1997, surveys were sent to all obstetricians and gynecologists on the mailing list of the Society of Obstetricians and Gynaecologists of Canada.

RESULTS

Of the 1472 surveys that were sent, 702 of the surveys were completed and returned, for a response rate of 48%. More than 90% of the gynecologists who were surveyed would advise their patients to continue using oral contraceptives before relatively minor surgical procedures and <1% of them would use low-dose heparin before these procedures. Rates of oral contraceptive discontinuation increased as the extent of the surgical intervention increased: Prolonged laparoscopy (39.8%), vaginal repairs and hysterectomy (54.7%), and abdominal hysterectomy or adnexectomy (56.1%). Just over one half of the gynecologists (56.1%) indicated that they would advise discontinuation > or =4 weeks before the surgical procedure, which is the minimum time required for the prothrombotic changes that are associated with oral contraceptive use to return to baseline. Less than 10% of the surgeons indicated that they would use low-dose heparin even when the patient was advised to continue taking oral contraceptives before major surgical procedures.

CONCLUSION

The controversy over whether young healthy women should discontinue oral contraceptive use before major surgical procedures that are associated with immobility is reflected by a lack of consensus among gynecologists in Canada.

Contraceptive choices in women with coagulation disorders

When compared with older reports on the thromboembolic effects of high-dose oral contraceptives, new studies with low-dose oral contraceptives have a significantly reduced risk of thromboembolism. In the absence of risk factors such as smoking or inherited disorders predisposing to thrombosis, the modern low-dose oral contraceptive (< 50 micrograms of estrogen) is a safe and effective choice for contraception in women without symptoms who have family histories of sporadic thromboembolism. An intrauterine device or some form of barrier method is recommended for women who have a personal history of venous thrombus disease. The low-dose oral contraceptive may be a good choice in women taking oral anticoagulants because of the risk of teratogenic effects of anticoagulants and the risks of intraperitoneal bleeding associated with ovulation. In addition, oral contraceptives help diminish the excessive menstrual bleeding often seen in these women.

Risk of and prophylaxis for venous thromboembolism in hospital patients. Thromboembolic Risk Factors (THRIFT) Consensus Group

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Prevention of venous thromboembolism after surgery: a review of enoxaparin

This review discusses the problem of deep vein thrombosis (DVT) after operation and identifies three levels of risk of DVT: low (less than 10 per cent), moderate (10-40 per cent) and high (40-80 per cent). Special emphasis is placed on the most recent prophylactic treatment, low molecular weight heparins (LMWHs), particularly enoxaparin. Several LMWHs are now available, but they differ slightly and each must be evaluated on its own merits. In general, however, LMWHs are both effective and safe in those patients at moderate or high risk of DVT. Thromboprophylaxis is cost effective when analysed using health-economic methodology.