Increase in plasma leptin and Lep mRNA concentrations by food intake is dependent on insulin

The difference in pregnancy rates following intrauterine insemination (IUI) for 1 vs. 2 days in the periovulatory period has been reported as either inconsequential or favoring the use of two consecutive inseminations, 24 hours apart. Our study compared the monthly fecundity and cumulative probability of pregnancy in a large group of women (n = 123) undergoing controlled ovarian hyperstimulation and 1- or 2-day inseminations with donor sperm prepared from frozen-thawed samples. All patients underwent controlled ovarian hyperstimulation employing either clomiphene citrate in 217 cycles or human menopausal gonadotropin in 185 cycles. The choice of single or double insemination was decided by the day of the week each patient received human chorionic gonadotropin for ovulation induction. Approximately 80% of all the patients underwent both single and double insemination treatments during the 2.5-year study period. Ninety-three patients received single inseminations in 180 cycles, whereas 103 patients received double inseminations in 222 cycles. Nine clinical pregnancies were achieved in the 1-day group (5% per cycle, 9.7% per patient), while 39 pregnancies occurred in the 2-day group (17.9% per cycle, 37.9% per patient). Two and five spontaneous abortions occurred in the 1- and 2-day groups, yielding take-home baby rates of 3.9% per cycle (7.5% per patient) and 15.3% per cycle (33.0% per patient), respectively. The cumulative probability of conception over 15 cycles of treatment was consistently twice as high or higher for the 2-day group. The results of this study support the use of 2-day IUI treatment cycles when using frozen-thawed donor sperm.     

Single versus double insemination: a retrospective audit of pregnancy rates with two treatment protocols in donor insemination

Our objective was to evaluate the effect of a change in treatment protocols, suggested following an inspection visit by the regulatory authority, from single to double inseminations during donor insemination treatment cycles. We therefore conducted a retrospective audit of pregnancy rates in the reproductive medicine clinic of a major teaching hospital. All patients were treated for male factor infertility by donor insemination, without ovulation induction with gonadotrophins between October 1992 and December 1995. The main outcome measures were cumulative conception and live birth rates. During the study period 250 patients underwent treatment and 650 single insemination and 277 double insemination treatment cycles were undertaken. The pregnancy rate per cycle was 0.054 and 0.119 for single and double insemination respectively. After six cycles the cumulative pregnancy rates were 0.28 and 0.47 and the take-home baby rates were 0.25 and 0.37 for single and double inseminations respectively. The change in practice from single to double insemination resulted in a doubling of the pregnancy rate per treatment cycle. Cumulative pregnancy rates after two treatment cycles of double insemination were comparable with those achieved after six cycles of single insemination. These results have significant implications for both patients and purchasers.     

Sex ratio associated with timing of insemination and length of the follicular phase in planned and unplanned pregnancies during use of natural family planning

This was a multicentred, prospective study of pregnancies among women using natural family planning. The women maintained natural family planning charts of the conception cycle, recording acts of intercourse and signs of ovulation (cervical mucus changes, including peak day and basal body temperature). Charts were used to assess the most probable day of insemination relative to the day of ovulation and length of the follicular phase of the cycle. The sex ratio (males per 100 females) for 947 singleton births was 101.5, not significantly different from the expected value of 105. The sex ratio did not vary consistently or significantly with the estimated timing of insemination relative to the day of ovulation, with the estimated length of the follicular phase or with the planned or unplanned status of the pregnancy. Although these findings may be affected by imprecision of the data, the study suggests that manipulation of the timing of insemination during the cycle cannot be used to affect the sex of offspring.     

Bronchiolitis obliterans and no radiographic abnormalities in a patient with rheumatoid arthritis

In a case-control study, we evaluated the association of the risk of menstrual disorders with four periconceptional factors: short preceding interpregnancy interval (< 6 months), low (< or = 19 years) or high (> or = 40 years) maternal age at conception, and month of conception. We divided 919 women who had visited a fertility clinic between 1991 and 1995 into three categories: cases (with mean menstrual cycle length > or = 42 or < or = 21 days, or a variation of > or = 14 days between cycles, or amenorrhea, N = 294), controls (with cycles within a range of 25-35 days and variation < or = 7 days, N = 520), and intermediates (N = 105). A self-administrable questionnaire was mailed, asking for information about maternal reproductive history and age, and potential confounders such as smoking, exercise, and level of education. Response (77%) differed little among cases, intermediates, and controls. We found elevated risks for short pregnancy intervals [adjusted odds ratio (OR) = 2.04; 95% confidence interval (CI) = 1.04-4.02] and advanced maternal age (OR = 3.24; 95% CI = 1.27-8.30) but not for low maternal age (OR = 0.58; 95% CI = 0.11-3.14) (cases vs controls). We found similar effects for intermediates vs controls. The distribution of month of conception did not differ much from controls for both cases and intermediates. The results indicate that conception after short pregnancy intervals or at advanced maternal age increases the risk of menstrual disorders in daughters. The precise etiology is unclear, but it may lie in the quality of the oocyte at conception.     

Strategies in frozen donor semen procreation

Data were analysed from 710 couples who had been assessed to determine the effectiveness and the drawbacks of three different methods of insemination using frozen donor semen. Intracervical insemination (ICI) was the first method used when the women had no tubal disorder: 255 pregnancies were achieved in a total of 2558 cycles (10%). Intrauterine insemination (IUI) associated with ovarian stimulation resulted in 152 pregnancies over 966 cycles (16%). In-vitro fertilization (IVF) was proposed after approximately 12 insemination failures using either of the other methods or when the initial gynaecological examination had revealed abnormalities such as tubal occlusions; 48 pregnancies were obtained in 262 cycles (18.3%). The pregnancy rate using ICI was significantly higher when two inseminations were performed per cycle, compared with one insemination per cycle (12.3 versus 7%, P < 0.001). The number of motile spermatozoa per straw was correlated with the pregnancy rate when using ICI, rising from 9% with < 4 x 10(6) motile spermatozoa to 13.8% with 4-8 x 10(6) and 17.2% with > 8 x 10(6). No relationship was found between the number of motile spermatozoa and the pregnancy rate using IUI and IVF. The incidence of primary ovulatory disorder was higher among women whose husbands were oligozoospermic than among those whose husbands were azoospermic (19 versus 9%, P < 0.01), but ovarian stimulation improved the fecundity of subfertile women. The outcome of pregnancies was also analysed for the three methods. From these data, strategic plans have been proposed to maximize the pregnancy rate for women undergoing therapeutic donor insemination with frozen semen.     

Automatic image analysis of argentophil protein granule quantitative measurement on nucleolus area of limbus epithelial neoplasms

The present study was carried out to examine whether a relationship between bovine major histocompatibility complex (BoLA) class I alleles and carcass traits or reproductive performance exists in Braunvieh and Fleckvieh AI (artificial insemination) bulls. The influence of BoLA class I (BoLA-A) alleles on deregressed breeding values for net growth rate, carcass index and thigh volume was assessed in Braunvieh crosses and Fleckvieh bulls with a gene substitution model. The reproductive traits: non-return rate and interval between first and last insemination of daughters (female fertility), as well as non-return rate of inseminated cows (male fertility), were only investigated in Fleckvieh animals. No influence of the BoLA-A region on the traits evaluated could be demonstrated. An improper, i.e. less restrictive analysis would have led to spurious results.     

The effect of monoclonal or ion-exchange purified factor VIII concentrate on HIV disease progression: a prospective cohort comparison

OBJECTIVE: To examine the effects of alcohol and caffeine on conception. DESIGN: Prospective observational study. SETTING: Healthy volunteers in two manufacturing facilities. PATIENT(S): One hundred twenty-four women who provided daily urine samples for measurement of steroid hormones and hCG, and prospective information about alcohol and caffeine consumption. MAIN OUTCOME MEASURE(S): Probability of conception per 100 menstrual cycles. RESULT(S): There was >50% reduction in the probability of conception during a menstrual cycle during which participants consumed alcohol. Caffeine consumption did not independently affect the probability of conception but may enhance alcohol's negative effect. Women who abstained from alcohol and consumed less than one cup of coffee or its equivalent per day conceived 26.9 pregnancies per 100 menstrual cycles compared with 10.5 per 100 menstrual cycles among those who consumed any alcohol and more than one cup of coffee per day. CONCLUSIONS: This study revealed an independent dose-related negative effect of alcohol consumption on the ability to conceive. Our results suggest that women who are attempting to conceive should abstain from consuming alcohol.     

Application of gonadotropin releasing hormone in dairy herds with fertility disturbances with regard to milk yield data and metabolic parameters]

The presented study was made to determine the factors influencing the fertility supporting effect of GnRH application at the time of insemination in a dairy herd with fertility problems. The metabolic parameters considered influencing conception results were milk yield, milk protein and milk fat and for blood parameters Urea, GOT and Bilirubin. The total effect of GnRH consisted in an improved pregnancy rate by 18.8% compared to the non treated control group. The improvement of pregnancy rate was observed mainly in groups with an adequate supply of energy at the time of insemination. Therefore the use of GnRH at insemination time is more successful, when milking test data and blood parameters are taken into account and indicate an equilibrated supply in energy. To explain these effects endocrinological regulation models are discussed.     

Factors that affect outcome of in-vitro fertilisation treatment

BACKGROUND: The effectiveness of in-vitro fertilisation (IVF) treatment depends both on the overall success rate in the treating clinic and on the characteristics of the couple seeking treatment. Since 1991, the Human Fertilisation and Embryology Authority (HFEA) has been collecting information on all IVF cycles carried out in the UK. This database has been analysed to identify the factors that affect the outcome of treatment. METHODS: All IVF treatment cycles and outcomes registered between August, 1991, and April, 1994, were identified (52507). Cycles that involved gamete or embryo donation, frozen embryo transfer, or micromanipulation and unstimulated cycles were excluded. Thus, 36961 cycles (70% of those registered) were included in the analysis. The main outcome measure was liverbirth rate per cycle started. The relation between age and outcome was investigated by fitting of different fractional polynomials of age with logistic regression models. All other factors were analysed by logistic regression with age included in the model. FINDINGS: The overall livebirth rate per cycle of treatment was 13.9%. The highest livebirth rates were in the age-group 25-30 years; younger women had lower rates and there was a sharp decline in older women. At all ages over 30, use of donor eggs was associated with a significantly higher livebirth rate than use of the woman's own eggs, but there was also a downward trend in success rate with age (p = 0.04). After adjustment for age, there was a significant decrease in livebirth rate with increasing duration of infertility from 1 to 12 years (p < 0.001). The medical indication for treatment had no significant effect on the outcome. Previous pregnancy and livebirth significantly increased treatment success. The possibility of success decreased with each IVF treatment cycle. INTERPRETATION: We were able to identify by logistic regression the factors that significantly affect the outcome of IVF treatment, and to measure the magnitude of that effect. These factors should be taken into account in assessment of IVF results. After allowance for background clinic success rates, these factors can be used to predict outcome in individual cases.     

Reproductive performance of dairy herds infected with Leptospira interrogans serovar hardjo relative to the year of diagnosis

To assess the impact of Leptospira interrogans serovar hardjo infection on the reproductive performance of nine dairy herds with evidence of infection, forty years' fertility data were analysed relative to the year of first diagnosis. Fifty per cent of various fertility variables had their lowest values only in the year of diagnosis. Culling rates were highest during the year of diagnosis in five of the herds, and were above 22 per cent in five of nine (55-6 per cent) of the diagnosis years considered compared with seven (22-6 per cent) of the 31 non-diagnosis years. An assessment of the fertility status of the herds by means of a formula with incorporated the first service conception rate, the number of services per conception for cows conceiving, the calving to conception interval and the culling rate, revealed low reproductive performance during the year of diagnosis in six of the nine herds. Abortion rates were highest in four of the herds during the year of diagnosis, and these included the herds in which the fertility status was not lowest. It was concluded that L. interrogans serovar hardjo affected reproductive adversely by causing both abortions and low fertility, but that the effect was temporary.     

Effects of caffeine consumption on delayed conception

The authors examined the effects of caffeine consumption on waiting time to conception in the Reproductive Health Study, a retrospective study of 1,430 non-contracepting, parous women interviewed between July 1989 and June 1990 at Fishkill, New York, and Burlington, Vermont. Information was obtained on 2,501 pregnancies since 1980. Women's reported consumption of caffeinated beverages during the first month of pregnancy was used to estimate daily caffeine intake, which was categorized as none, 1-150, 151-300, and > or = 301 mg. Information on delayed conception was analyzed as a dichotomous variable (< or = 12 months delay vs. > 12 months delay), and the per cycle probability of conception (fecundability) was estimated using waiting time to conception as a continuous variable. Odds ratios of delayed conception and fecundability ratios adjusted for age, parity, smoking, last contraceptive used, infertility history, and race, were estimated by logistic regression and Cox proportional hazard models, respectively. Women who did not smoke and who consumed no caffeine were used as a reference group. The adjusted odds ratio of delayed conception for more than one year was not increased among women who consumed < or = 300 mg of caffeine daily. However, the odds ratio (OR) was 2.65 (95% confidence interval (CI) 1.38-5.07) among nonsmokers who consumed > or = 301 mg of caffeine daily. Although smoking per se was associated with a significant increased risk of delayed conception (OR = 1.77, 95% CI 1.33-2.37), no effect of high caffeine consumption was observed among women who smoked. Fecundability was reduced among nonsmokers who consumed more than 300 mg caffeine daily (fecundability ratio = 0.74, 95% CI 0.59-0.92). Smoking reduced the fecundability ratio, but the authors observed no effect of caffeine consumption on fecundability among women who smoked. Other studies provide biologic plausibility for these findings. The authors conclude that high levels of caffeine consumption may result in delayed conception among women who do not smoke cigarettes.     

Using the hospital emergency department as a regular source of care

OBJECTIVE: To assess pregnancies and conceptus after artificial insemination (AID) or IVF with frozen semen donor (IVF-D) on sufficiently large study population in order to distinguished minor variations. STUDY DESIGN: From 1987 to 1994, all pregnancies obtained after AID or IVF-D were registered prospectively in the French CECOS Federation data base. Different factors were recorded for this study: first menarche age of the recipient women, cycle length, insemination date in the conception cycle, maternal age at delivery, hormonal treatments, donor age, sperm conservation length and follow up of the pregnancy: miscarriage, tubal pregnancy, time at delivery, sex of the foetus, weight, malformation. RESULTS: 21,597 pregnancies obtained after AID and 3381 after IVF-D were registered. 2% were lost to follow up. Foetal loss rate is 18% after AID and 21.5% after IVF-D (p < 0.001). The tubal pregnancy rate is 0.9% after AID and 1.7% after IVF-D (p < 0.0001). 18,128 children were born after AID and 3313 after IVF-D. After AID, the twin pregnancy rate is 6.9% and the multiple pregnancy (> or = 3 foetus) rate is 0.7%. After IVF-D, these rates are 24.8% and 4.2% respectively (p < 0.0001). After AID the mean weight at delivery, sex ratio, premature rate, intra uterine growth retardation rate are not different from national rates published in 1995. The foetus malformation rate (including medical abortions) is 1.9% after AID and 2.7% after IVF-D (p < 0.009). After AID the trisomy 21 rate increases with the mother age but also with the donors age if the maternal age is equal. The birth defects rate is not different from those registered in Paris, Strasbourg and Marseille. The birth defects rate observed after IVF-D is not different from the rate observed after IVF with husband semen. (2.74% versus 2.99%; p = 0.16). CONCLUSION: After AID the miscarriage and tubal pregnancy rate, the children's weight, the premature rate is not different from that of the general French population. Sex ratio is normal as is the global malformation rate. The multiple pregnancy rate (x 7 for twin and by 10 for multiple pregnancies more than 3 foetus) is high, showing the influence of ovulation induction treatment. The birth chromosomal abnormalities rate is normal and correlated not only to the mother's age but also to the donor's age. This result without clear biological explanation will require further verification in a greater population. Practically speaking, these observations encourages lowering the age limit for semen donors less than 45 years. IVF-D practice instead of AID doubles the tubal pregnancy rate (0.9% versus 1.7% and increases the twin pregnancy rate by 2.5% and the multiple pregnancy (> or = 3 fetus) rate by 3. It is necessary to promote good practice for AID for which the pregnancy rate is very different from one centre to another within the centres with AID low results a too high rate of IVF-D. Finally we can say that pregnancies from IVF-D or IVF with husband semen are not significantly different. In other words pregnancy outcome is not changed after sperm cryopreservation.     

Plasma levels of high-energy compounds compared with severity of illness in critically ill patients in the intensive care unit

OBJECTIVE: To compare the prevalence of type 2 diabetes mellitus (DM) and coronary artery disease (CAD) and hypertension in DM in the rural and urban populations of north India. DESIGN AND METHODS: Two populations of the same ethnic background were randomly selected for this cross sectional survey. There were 1769 rural (894 men, 875 women) and 1806 urban subjects (904 men, 902 women) between 25-64 years of age. The survey methods included fasting and 2 h blood glucose and electro-cardiogram and blood pressure measurement of all subjects. RESULTS: Using the criteria of World Health Organization, the prevalence of diabetes mellitus (6.0 vs 2.8%) hypertension (24.0 vs 17.0%) and CAD (9.0 vs 3.2%) was significantly (P<0.001) higher in urban compared to rural subjects. Hypertension and CAD were significantly more frequent among subjects with diabetes compared to nondiabetes. The association of CAD and hypertension with diabetes was greater in urban than rural subjects. Excess body weight and obesity, central obesity, sedentary lifestyle, higher visible fat intake (>25 g/day), and social class 1-3 (higher and middle) were significantly associated with diabetes. Multivariate logistic regression analysis showed that after adjustment of age and sex, body mass index, central obesity, sedentary lifestyle and higher visible fat intake and alcohol intake in men were significant risk factors of diabetes among all the sub-groups. CONCLUSIONS: The study showed a high prevalence of diabetes in urban north Indian population compared to rural subjects in the same ethnic group. CAD and hypertension were significantly associated with diabetes more in urban than rural subjects. The findings suggest that higher body mass index, waist-hip ratio and visible fat intake and sedentary lifestyle were risk factors of diabetes.     

Inbreeding effects on fertility in humans: evidence for reproductive compensation

The effects of inbreeding on prereproductive mortality have been demonstrated in many natural populations, including humans. However, little is known about the effects in inbred individuals who survive to adulthood. We have investigated the effects of inbreeding on fertility among inbred adult Hutterites and demonstrate significantly reduced fecundity among the most inbred Hutterite women, as evidenced by longer interbirth intervals (P=.024) and longer intervals to a recognized pregnancy (P=.010) but not by increased rates of fetal loss (P>.50). These data suggest the presence of recessive alleles that adversely affect fecundity among the population. In contrast, completed family sizes do not differ among the more and the less-inbred Hutterite women who were born after 1920, suggesting that reproductive compensation is occurring among the more-inbred and less-fecund women. This recent reproductive strategy would facilitate the maintenance of recessive alleles and contribute to an overall decline in fertility in the population.     

Development, pharmacology and clinical experience with clomiphene citrate

This review describes the development and pharmacology of clomiphene and those specific characteristics of both drug and patients which determine its clinical efficacy. The studies reviewed describe clinical observation of patient characteristics (age, additional infertility diagnosis, semen quality), vaginal ultrasound observations of ovaries (number and size of pre-ovulatory follicles) and endometrial lining (thickness, pattern) in 2841 clomiphene cycles in patients who required intrauterine insemination (IUI) because of poor sperm quality or an unsatisfactory postcoital test. They show that (i) conception in clomiphene cycles is related to the number and size of pre-ovulatory follicles, endometrial thickness, patient age, pelvic adhesions, type of anovulatory disorder and semen quality; (ii) pregnancy rates per clomiphene-IUI cycle are constant through at least six cycles; (iii) multiple births cannot be prevented by withholding human chorionic gonadotrophin or advising against coitus when multiple pre-ovulation follicles are present unless all follicles down to 10-12 mm diameter are counted. We also reviewed pregnancy outcome (number of gestational sacs, babies, preclinical and clinical abortion, ectopic pregnancy and birth sex) in 1744 clomiphene pregnancies from our clinic. We found that (i) preclinical and clinical abortions are increased only slightly by clomiphene use, compared to spontaneous pregnancy; (ii) clinical abortions are decreased in patients with polycystic ovaries and luteal insufficiency who use clomiphene; (iii) conception and preclinical abortions are related to endometrial thickness prior to ovulation; (iv) ectopic pregnancies are not increased by clomiphene and (v) the ratio of male births is not altered by clomiphene, except possibly in timed insemination cycles. These studies repudiate many misconceptions regarding clomiphene. They also show that clinical outcome may be improved by pre-ovulation ultrasound monitoring of ovarian and endometrial response.     

Thalamic NMDA transmission in a genetic model of absence epilepsy in rats

OBJECTIVES: Whether menopause per se influences fat distribution independently of the effect of aging remains controversial. The lack of consistency in the menopause related changes in body fat distribution may be the result of differences in the methods for measuring fat distribution or in the characteristics of the women studied. The aim of this cross sectional study in obese women was to compare total body composition and regional fat and lean distribution, in premenopausal, perimenopausal and postmenopausal women. METHODS: Body composition was assessed by dual energy X-ray absorptiometry (DEXA) in premenopausal (n = 26), perimenopausal (n = 24) and postmenopausal (n = 73) obese women with no intercurrent diseases. RESULTS: It was shown that postmenopausal obese (n = 73) women had a higher proportion of total fat mass in the trunk and a lower proportion of total fat and lean mass in the femoral and leg regions than premenopausal women after adjustment for age and total fat mass. In the same analysis, perimenopausal women had a lower proportion of total fat in the leg and femoral regions and of total lean in the femoral region than premenopausal women; they had a regional body composition similar to that of postmenopausal women. CONCLUSION: The present data indicate that in obese women, post menopause and perimenopause are associated with differences in fat and lean distribution, independently of age and total fat.     

Cognitive deficits precede motor deficits in a slowly progressing model of parkinsonism in the monkey

In a population survey of 162 rural and 152 urban subjects aged 26-65 years at Moradabad, the findings are compared with existing data on Indian immigrants to Britain and United States. In comparison with rural subjects, urban subjects had a higher prevalence of coronary artery disease (8.6 vs. 3.0%) and diabetes (7.9 vs 2.5%), higher blood pressures, total and low density lipoprotein cholesterol, triglycerides and postprandial 2-h blood glucose and plasma insulin similar to observations made in UK in immigrants compared to Europeans. Fasting plasma insulin and high density lipoprotein cholesterol levels in urban subjects were comparable with rural subjects. Mean body weights were significantly higher in urban women, but not in men, than in rural subjects. However the body mass index (22.9 +/- 4.2 vs. 21.6 +/- 2.4 kg/m2) and waist-hip girth ratio (0.89 +/- 0.10 vs. 0.86 +/- 0.07) were significantly higher in urban men compared to rural men without such differences in women. Underlying these differences in risk factors, urban subjects had three times better socioeconomic status than rural subjects and were eating higher total and saturated fat, cholesterol and refined carbohydrates and lower total and complex carbohydrates compared to rural men and women. Energy expenditure during routine and spare time physical activity was significantly higher in rural compared to urban subjects. Those patients who had risk factors, showed lesser physical activity and had greater adverse factors in the diet compared to subjects without risk factors. Body mass index and waist-hip girth ratio in patients with risk factors were significantly higher than in subjects without risk factors. The findings suggest that decreased consumption of total and saturated fat and increased physical activity may be useful for prevention of coronary artery disease among urbans as well as in immigrants.     

Ovulation as a male mating prime: Subtle signs of women's fertility influence men's mating cognition and behavior.

Women's reproductive fertility peaks for a few days in the middle of their cycle around ovulation. Because conception is most likely to occur inside this brief fertile window, evolutionary theories suggest that men possess adaptations designed to maximize their reproductive success by mating with women during their peak period of fertility. In this article, we provide evidence from 3 studies that subtle cues of fertility prime mating motivation in men, thus facilitating psychological and behavioral processes associated with the pursuit of a sexual partner. In Study 1, men exposed to the scent of a woman near peak levels of fertility displayed increased accessibility to sexual concepts. Study 2 demonstrated that, among men who reported being sensitive to odors, scent cues of fertility triggered heightened perceptions of women's sexual arousal. Study 3 revealed that, in a face-to-face interaction, high levels of female fertility were associated with a greater tendency for men to make risky decisions and to behaviorally mimic a female partner. Hence, subtle cues of fertility led to a cascade of mating-related processes—from lower order cognition to overt behavior—that reflected heightened mating motivation. Implications for theories of goal pursuit, romantic attraction, and evolutionary psychology are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relation between semen quality and fertility: a population-based study of 430 first-pregnancy planners

BACKGROUND: Semen analysis is part of the routine assessment of infertile couples. WHO defines a sperm concentration above 20x10(6) per mL seminal fluid as normal. We studied the association between semen quality and the probability of conception in a single menstrual cycle in Danish couples with no previous reproductive experience. METHODS: In 1992-94, we invited 52,255 trades-union members aged 20-35 years, who lived with a partner and had no children to take part in the study; 430 couples agreed. The couples discontinued use of contraception, and were followed up for six menstrual cycles or until a pregnancy was verified within this period. Each man was asked to provide a semen sample at enrolment (which was analysed without freezing). Women kept a daily record of vaginal bleeding and sexual activity. The association between semen quality and likelihood of pregnancy was assessed by logistic regression, adjusted for sexual activity and female factors associated with low fertility. RESULTS: There were 256 (59.5%) pregnancies among the 430 couples: 165 (65.0%) among those with a sperm concentration of 40x10(6)/mL or more and 84 (51.2%) among those with lower sperm concentrations. The probability of conception increased with increasing sperm concentration up to 40x10(6)/mL, but any higher sperm density was not associated with additional likelihood of pregnancy. The proportion of sperm with normal morphology was strongly related to likelihood of pregnancy independently of sperm concentration. Semen volume and motility were of limited value in pregnancy prediction. INTERPRETATION: Our study suggests that the current WHO guidelines for normal semen quality should be used with caution. Some men with sperm counts above the lower limit of the normal range defined by WHO may in fact be subfertile.     

Leptin in human reproduction: serum leptin levels in pregnant and lactating women

Experiments in ob/ob female mice demonstrated that leptin injections not only reduced weight and fat mass, but also restored fertility and partial lactation. To explore factors regulating ob gene expression in reproductive women, we measured serum leptin, body fat, energy expenditure, and milk production in 65 women at 36 weeks of gestation, and at 3 and 6 months postpartum. Serum leptin was measured by solid-phase sandwich enzyme immunoassay, and serum insulin and PRL by solid-phase 125I RIA. Total body water by deuterium dilution, body volume by hydrodensitometry, and bone density by dual-energy x-ray absorptiometry were used to estimate body fat. Serum leptin per unit fat mass was significantly higher at 36 weeks of pregnancy than at 3 and 6 months postpartum (1.25 vs. 0.75, 0.73 ng.mL-1.kg-1). Postpartum normalization of leptin was associated with changes not only in weight and fat mass, but also serum insulin. Leptin was not different between lactating and nonlactating women. Leptin may have affected milk production indirectly through its negative effect on serum PRL. Adjusted for fat-free mass and fat mass, rates of energy expenditure were not significantly correlated with leptin. Our results provide evidence that factors other than fat mass alone modulate serum leptin in reproductive women.