Association of serum leptin at 24-28 weeks gestation with initiation and progression of labor in women.

Concentrations of the hormone leptin, which is produced by adipose tissue, increase with increasing BMI, whereas leptin sensitivity often declines with higher BMI. Thus, altered leptin signaling may play a role in reproductive health risks observed with increasing BMI, which include later onset and slow progression of labor. Conflicting evidence from clinical, animal and in vitro studies have suggested that leptin either promotes or inhibits labor.

Associations Between Prenatal Urinary Biomarkers of Phthalate Exposure and Preterm Birth: A Pooled Study of 16 US Cohorts.

Importance: Phthalate exposure is widespread among pregnant women and may be a risk factor for preterm birth.

Objective: To investigate the prospective association between urinary biomarkers of phthalates in pregnancy and preterm birth among individuals living in the US.

Design, Setting, And Participants: Individual-level data were pooled from 16 preconception and pregnancy studies conducted in the US.

Sperm Cohort-Specific Zinc Signature Acquisition and Capacitation-Induced Zinc Flux Regulate Sperm-Oviduct and Sperm-Zona Pellucida Interactions.

Building on our recent discovery of the zinc signature phenomenon present in boar, bull, and human spermatozoa, we have further characterized the role of zinc ions in the spermatozoa's pathway to fertilization. In boar, the zinc signature differed between the three major boar ejaculate fractions, the initial pre-rich, the sperm-rich, and the post-sperm-rich fraction. These differences set in the sperm ejaculatory sequence establish two major sperm cohorts with marked differences in their sperm capacitation progress.

Semen and reproductive hormone parameters in fertile men with and without varicocele.

Although varicoceles are a widely accepted identifiable male factor in infertile couples, the benefit of varicocele repair in improving pregnancy and live birth rates remains uncertain. The Study for Future Families obtained semen and reproductive hormone samples from US men whose partners were currently pregnant. In our analysis cohort of 709 men, a varicocele was detected by clinical examination in 56 (8%) of men.