Comparing women’s preferences for different men’s body odour before and after they began taking the oral contraceptive pill.
MedWire News: Oral contraception may mask women’s natural ability to sense a compatible partner and consequently impair their fertility, research suggests.
Humans choose partners partly through their body odour, which can draw them to someone with a dissimilar genetic make-up, helping to maintain genetic diversity in their children. But oral contraception can affect our odour preferences, report Craig Roberts (University of Liverpool, UK) and colleagues.
Overriding women’s instinctive attraction to genetically different men could make it harder for them to conceive and raise their risk for miscarriage, the researchers explain.
Also, passing on a more homogeneous pool of genes may weaken their children’s immune system.
For the study, the team asked 100 women about their preferences for six male odour samples drawn from a sample of 97 volunteers, before and after they started using oral contraception.
“The results showed that the preferences of women who began using the contraceptive pill shifted towards men with genetically similar odours,” said Roberts.
He added: “Not only could major histocompatibility complex-similarity in couples lead to fertility problems but it could ultimately lead to the breakdown of relationships when women stop using the contraceptive pill, as odour perception plays a significant role in maintaining attraction to partners.”
ORGYN.com
Determining the effect of controlled ovarian hyperstimulation with excess gonadotrophin use in IVF on cycle cancellations and pregnancy outcomes.
Despite reducing IVF cycle cancellations, increased gonadotrophin use during controlled ovarian hyperstimulation (COH) may also reduce live births, conclude US researchers.
Lubna Pal, from Albert Einstein College of Medicine in Bronx, New York, and colleagues investigated whether attempts to maximize oocyte yield improve the outcome of IVF cycles.
They studied 806 fresh non-donor cycles, examining rates of cycle cancellation, clinical pregnancy, and spontaneous miscarriage after IVF.
The average age of the women was 36.21 years, and the average dose of gonadotrophin was 3584.33 IU. Clinical pregnancy and live birth rates were 28 percent and 24 percent, respectively, per cycle started, 35 percent and 30 percent, respectively, per egg retrieval, and 37 percent and 32 percent, respectively, per embryo transfer.
For all outcomes, increasing age, regardless of ovarian reserve status, was associated with a worse prognosis.
Higher gonadotrophin use was linked to reduced cycle cancellations, at an adjusted odds ratio of 0.98 per 100 unit increase, but was also associated with a significantly reduced likelihood of clinical pregnancy and live birth, at odds ratios of 0.98 for both, and a trend towards spontaneous miscarriage.
“These associations suggest detrimental influences of excessive gonadotrophins that merit further evaluation; in the interim, based on these data, we advise moderation and caution regarding aggressive attempts at COH,” the team says.
ORGYN.com