Biomedical subjects

Melissa Hays

Publications and source records attributed to Melissa Hays.

5 recordsLinked to original sources

PubMed2006

Frequency and patterns of early recanalization after vasectomy.

BACKGROUND: Our understanding of early post-vasectomy recanalization is limited to histopathological studies. The objective of this study was to estimate the frequency and to describe semen analysis patterns of early recanalization after vasectomy. METHODS: Charts displaying serial post-vasectomy semen analyses were created using the semen analysis results from 826 and 389 men participating in a randomized trial of fascial interposition (FI) and an observational study of cautery, respectively. In the FI trial, participants were randomly allocated to vas occlusion by ligation and excision with or without FI. In the cautery study, sites used their usual cautery occlusion technique, two with and two without FI. Presumed early recanalization was based on the assessment of individual semen analysis charts by three independent reviewers. Discrepancies were resolved by consensus. RESULTS: Presumed early recanalization was characterized by a very low sperm concentration within two weeks after vasectomy followed by return to large numbers of sperm over the next few weeks. The overall proportion of men with presumed early recanalization was 13% (95% CI 12%-15%). The risk was highest with ligation and excision without FI (25%) and lowest for thermal cautery with FI (0%). The highest proportion of presumed early recanalization was observed among men classified as vasectomy failures. CONCLUSION: Early recanalization, occurring within the first weeks after vasectomy, is more common than generally recognized. Its frequency depends on the occlusion technique performed.

Follow-Up Studies↗

PubMed2005

Bleeding patterns after use of levonorgestrel emergency contraceptive pills.

OBJECTIVE: The objective of this study was to describe bleeding after use of an emergency contraceptive pill (ECP) regimen consisting of 1.5 mg of levonorgestrel in a single dose. METHODS: We asked 120 women who had been treated with the regimen to keep daily bleeding diaries for 9 weeks. We compared bleeding patterns observed after treatment with usual patterns reported by the participants and with patterns observed in a prior study on women who had not taken ECPs. RESULTS: Treatment in the first 3 weeks of the menstrual cycle significantly shortened that cycle as compared both with the usual cycle length and with the cycle duration in a comparison group. The magnitude of this effect was greater the earlier the pills were taken. In contrast, the duration of the first menstrual period after treatment increased significantly with cycle week of treatment and was longer in women who used the treatment than in those who did not. Intermenstrual bleeding occurred in only 5% of women in the first cycle after treatment. CONCLUSIONS: The effect of the single-dose levonorgestrel ECP regimen on the timing and duration of the next menstrual period depends on when during the cycle the pills are taken. Intermenstrual bleeding following treatment is uncommon.

Adult↗

PubMed2004

Vasectomy by ligation and excision, with or without fascial interposition: a randomized controlled trial [ISRCTN77781689].

BACKGROUND: Randomized controlled trials comparing different vasectomy occlusion techniques are lacking. Thus, this multicenter randomized trial was conducted to compare the probability of the success of ligation and excision vasectomy with, versus without, fascial interposition (i.e. placing a layer of the vas sheath between two cut ends of the vas). METHODS: The trial was conducted between December 1999 and June 2002 with a single planned interim analysis. Men requesting vasectomies at eight outpatient clinics in seven countries in North America, Latin America, and Asia were included in the study. The men were randomized to receive vasectomy with versus without fascial interposition. All surgeons performed the vasectomies using the no-scalpel approach to the vas. Participants had a semen analysis two weeks after vasectomy and then every four weeks up to 34 weeks. The primary outcome measure was time to azoospermia. Additional outcome measures were time to severe oligozoospermia (<100 000 sperm/mL) and vasectomy failure based on semen analyses. RESULTS: We halted recruitment after the planned interim analysis, when 841 men had been enrolled. Fascial interposition decreased time to azoospermia (hazard ratio [HR], 1.35; P < 0.0001) and time to severe oligozoospermia (HR, 1.32; P < 0.0001) and reduced failures based on semen analysis by about half, from 12.7% (95% confidence interval [CI], 9.7 to 16.3) to 5.9% (95% CI, 3.8 to 8.6) (P < 0.0001). Older men benefited less from fascial interposition than younger men in terms of the speed of achieving azoospermia. However, the number of vasectomy failures was reduced to a similar degree in all age groups. Slightly more adverse events occurred in the fascial interposition group, but the difference was not significant. These failure rates may appear high to practitioners in countries such as the USA, but they are similar to results from other careful studies of ligation and excision techniques. CONCLUSION: Fascial interposition significantly improves vasectomy success when ligation and excision is the method of vas occlusion. A limitation of this study is that the correlation between postvasectomy sperm concentrations and risk of pregnancy is not well quantified.

Adult↗

PubMed2003

Vasectomy effectiveness in Nepal: a retrospective study.

The main purpose of this retrospective, cross-sectional study was to evaluate the effectiveness of vasectomy in an ongoing public sector program in Nepal. We evaluated semen samples from men who had previously had a vasectomy, and asked about the occurrence of pregnancies in the men's partners. In addition, the surgeons who performed the vasectomies completed a questionnaire about their techniques. A two-stage stratified sampling procedure was used to select 1263 men from among over 30,000 men, who had previously undergone a no-scalpel vasectomy, mostly by ligation and excision, in 32 districts between July 1996 and June 1999. Semen samples were preserved and analyzed at a central laboratory. A US andrology laboratory validated the lab results. Twenty-three men (2.3%, 95% confidence interval [CI] 1.1-3.6) had >/=500,000 sperm/mL in their semen. Fifteen of those men reported pregnancies conceived after their vasectomy. In addition, six men with azoospermia reported pregnancies for which conception occurred within 3 months after vasectomy. Eleven men with azoospermia reported pregnancies for which conception occurred more than 3 months after vasectomy. Reported pregnancy was more likely in younger partners. The life table pregnancy rates for all men interviewed were 0.7 (95% CI 0.2-1.1), 1.7 (95% CI 1.4-2.1) and 4.2% (95% CI 3.2-5.2) at 3, 12 and 36 months, respectively. In low-resource, programmatic settings, vasectomy failure rates may be higher than commonly cited rates, especially in younger populations. Additional research is needed to determine if other occlusion techniques could reduce failure rates. Counseling on vasectomy should always convey the possibility of failure and partner pregnancy.

Adult↗

PubMed2003

Termination of a randomized controlled trial of two vasectomy techniques.

Family Health International (FHI) and EngenderHealth conducted a multicenter, randomized controlled trial to evaluate a fascial interposition (FI) component of a vas occlusion procedure for male sterilization. A data monitoring committee (DMC) was established to provide independent review of the interim report. The DMC met to review the interim report after enrollment of 552 men. As planned, an estimate of the hazard ratio (HR) for successful vasectomy for the FI group versus the no-FI group controlling for age of the participant and level of experience of the surgeon was obtained for the interim report using Cox's proportional hazards regression. The main analysis comparing time to vasectomy success, defined as two consecutive azoospermic semen samples, was highly significant and met the prespecified level for stopping enrollment (HR=1.54, p<0.01). However, a troublesome age by vasectomy technique interaction became apparent in the analysis. FI was clearly beneficial for younger males. However, the trend for older men was not as clear. The DMC recommended continuing the trial to better study this interaction and obtain more data to clarify the effect of FI for older men. After consulting further with the DMC, the study statisticians presented the interim report to senior management at FHI. A meeting between FHI senior management and the DMC followed. After much deliberation, trial enrollment was terminated. Follow-up of participants already enrolled in the study continued as planned. This paper presents the issues involved in the decision to terminate the study.

Age Factors↗