Fecundity and sex ratio of offspring in an infertile cohort

Department of Urology, University of California, San Francisco, California, USA.
Fertility and sterility (Impact Factor: 4.59). 08/2011; 96(4):833-6. DOI: 10.1016/j.fertnstert.2011.07.1141
Source: PubMed
To determine whether male and female subfecundity is associated with the gender ratio.
Retrospective cohort study.
Reproductive endocrinology clinics in California.
A cohort of 30,448 women who sought infertility treatment or evaluation in California between 1990 and 1998 was identified. A fertile comparison group was assembled after matching data from vital statistics records.
Not applicable.
Multivariate logistic regression was used to determine the odds of a male birth based on fertility status.
We identified 5,293 infertile women and 6,730 fertile matched women in the live-birth and fetal death records. There were 6,178 children born to women evaluated and/or treated for infertility, compared with 9,131 born to fertile women, for a total of 15,309 births. There was no significant difference in the secondary sex ratio between births in the infertile cohort and the fertile cohort or on the basis of male factor infertility versus female factor infertility. After controlling for confounding factors, there was no difference in sex ratio based on the use of advanced reproductive technologies, duration of infertility treatment, or the type of infertility.
This study found no statistical evidence to support an association between infertility and secondary sex ratio.

Full-text preview

Available from:
  • [Show abstract] [Hide abstract] ABSTRACT: The fertility rate has recently declined in many parts of the World, including Europe. To a large extent, this change can be explained by the socio-economic development. However, increasing fertility problems and widespread occurrence of poor semen quality could in part explain the few births. The objective of this registry based study was to investigate birth cohort related trends in fertility and childlessness among Danish men. The study population comprised all 1 616 677 men in Denmark born from 1945 to 1980 of whom 1 359 975 (84.1%) were native Danes. Data were obtained from Statistics Denmark and contained information from The National Danish Birth Registry and The Danish In Vitro Fertilization (IVF) Registry. For consecutive birth cohorts of native Danish men cumulative fertility rates at age 45 declined from 1.91 children per man in the 1945 birth cohort to 1.71 for men born in 1960. The proportion of childless men at age 45 increased from 14.8% to 21.9% in the same birth cohorts. Assisted reproductive technology (ART) seemed to compensate partly for the lower fertility and to reduce the proportion of childless men. In contrast, recent reports on corresponding birth cohorts of Danish women showed that the proportion remaining childless throughout life has been lower than in men and has not shown a similar increase. In conclusion, using unique Danish registries the study showed a birth cohort related decline in fertility rates and an increase in childlessness among men. In the more recent cohorts more than one in five men remained childless. The causes behind the findings are likely multi-factorial. Hitherto, most attention has been given to socio-economic factors which undoubtedly play a major role. Our findings lend support to the hypothesis that the high prevalence of low sperm counts among young Danish men may be a contributing factor.
    No preview · Article · Apr 2012 · International Journal of Andrology
  • [Show abstract] [Hide abstract] ABSTRACT: In recent years, investigators have noted a trend toward a declining proportion of male births in many industrialized nations. While men bear the sex-determining chromosome, the role of the female partner as it pertains to fertilization or miscarriage may also alter the gender ratio. We attempted to determine a man's secondary sex ratio (F1 generation) by directly examining the sex chromosomes of his sperm. We examined our male infertility clinic database for all men who had undergone a semen fluorescence in situ hybridization (FISH). Patient demographic and semen parameters were recorded. Chi-squared analysis was used to compare gender ratios (Y chromosomes/total chromosomes). Multivariable logistic regression was used to predict the odds of possessing a Y-bearing sperm after accounting for demographic and semen parameters. A total of 185 men underwent sperm FISH. For the entire cohort, the proportion of Y chromosome-bearing sperm was 51.5%. Men with less than five million motile sperm had a significantly lower proportion of Y chromosome-bearing sperm (50.8%) compared to men with higher sperm counts (51.6%; P=0.02). After multivariable adjustment, a higher sperm concentration, total motile sperm count and semen volume significantly increased the odds of having a Y chromosome-bearing sperm (P<0.01). As a man's sperm production declines, so does the proportion of Y chromosome-bearing sperm. Thus, a man's reproductive potential may predict his ability to sire male offspring.
    No preview · Article · Jul 2012 · Asian Journal of Andrology
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: To study the association between salivary stress biomarkers and the secondary sex ratio. Prospective, longitudinal cohort study. Community setting in the United Kingdom. On discontinuation of contraception for purposes of becoming pregnant, 338 women aged 18-40 years with complete data (90%) were followed until pregnant or up to six menstrual cycles. None. Secondary sex ratio. Human chorionic gonadotropin pregnancies were detected in 207 (61%) women of whom 130 (63%) delivered singleton infants with available gender data. The adjusted odds ratio for a male birth was decreased for women in the highest quartile (AOR = 0.26; 95% confidence interval = 0.09, 0.74) of salivary cortisol relative to women in the lowest quartile during cycle 1. An inverse relation was observed between α-amylase and the 2° sex ratio, though not statistically significant. Our findings are consistent with a reversal in the 2° sex ratio with increasing preconception salivary cortisol concentrations. This relation suggests that activation of the hypothalamus-pituitary-adrenal axis may have implications in sex allocation and requires further study.
    Full-text · Article · Aug 2012 · Fertility and sterility
Show more