Thatcher’s Thoughts on Aspirin, Endometrium and Paternal Aging

1. Aspirin and infertility

2. Uterine responsiveness and reproductive aging

3. Paternal age

Aspirin and infertility
Title: Low-dose aspirin for infertile women with thick endometrium receiving intrauterine insemination: A prospective, randomized study
Author: Y. Hsieh
Address: Taichung, Taiwan
Source: Journal of Assisted reproduction and Genetics 17:174-178 (March) 2000
Summary: To evaluate the effect of aspirin on infertile women with thin endometrium, 114 women were placed into an aspirin group and 122 women into a nonaspirin group. These subjects had an endometrium £ 8mm and intrauterine insemination. Endometrial pattern and thickness, the pulsatility index and resistance index of the uterine artery, spiral artery, and ovarian dominant follicles, and pregnancy rates of both groups were measured. Significantly higher percentages of trilaminar endometrium (46.5% vs. 26.2%) and pregnancy rate (18.4% vs. 9.0%) after aspirin therapy were noted. Researchers concluded that higher pregnancy rates and better endometrial pattern were achieved in patients with thin endometrium after aspirin administration. However, aspirin therapy could not significantly add to the endometrial thickness and the resistance of uterine and ovarian flow.
Comment: Use of aspirin to improve implantation or prevent miscarriage has been bantered about for a number of years. Theoretically, aspirin could improve circulation by its action on prostacyclin/thromboxane pathways, but its anti-inflammatory action could equally blunt the prerequisite inflammatory response necessary for implantation. The mere fact that most do not use it can be taken as an indication of its lack of effectiveness. I wish someone would perform a definitive well-designed and controlled study to put this issue to rest. 

Uterine responsiveness and reproductive aging
Title: Pregnancy after embolization of uterine myoma: report of 12 cases
Author: J. H. Check, et al.
Address: Camden, New Jersey
Source: Human Reproduction 15: 1679-1684 (August) 2000
Summary: The purpose of this study was to determine if uterine vascular impedance escalates with aging in women experiencing ovarian stimulation for IVF. Women (n=162) who had undergone standard IVF and embryo transfer were divided into three subgroups according to age: 30-34 years (n=49), 35-39 years (n=79), and 40-44 years (n=34). Pulsatility index (PI) and resistance index (RI) of the right and left uterine arteries were measured at baseline, the day of oocyte retrieval, and at mid-luteal phase. The luteal phase values of PI and RI were lower than those observed earlier in the cycle for all groups. Ovarian response, as measured by mean number of oocytes retrieved, declined significantly with age. Researchers concluded that reduced pregnancy rates in older women undergoing ovarian stimulation are more likely to occur because of oocyte quality and quantity rather than uterine senescence. 
Comment: More support for the issue of fertility rests more with egg and therefore, embryo quality than that of the uterus. 

Paternal Age
Title: Increasing paternal age is associated with delayed conception in a large population of fertile couples: Evidence of declining fecundity in older men
Author: W. C. Ford, et al. 
Address: Bristol, UK
Source: Human Reproduction 15:1703-1708 (August) 2000
Summary: Because controversy continues to surround the issue of aging and male fertility, researchers conducted this study to determine the effect of male age on the length of time it takes to conceive. This study is based on pregnancies that resulted in the birth of a baby. Both the male and female partners completed questionnaires at 18 weeks gestation. The questions were related to such topics as parity, paternity, cohabitation, oral contraception, education, smoking and obesity. Out of 8515 planned pregnancies, 74% were conceived in £6 months, 14% in the second 6 months and 12% after more than a year. After adjustment for 9 different variables, including the age of the woman, the likelihood of conception within 6 or 12 months was lower in older men. Compared to men less than 25 years old, the adjusted odds ratios for conception £12 months were 0.62 in men aged 30-34, 0.50 in men 35-39, and 0.51 in men >40 years of age. 
Comment: Still not too bad for the old men. 

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