Very interesting:
FAR from being a passive container, the human uterus seems to be highly selective about which embryos it accepts. Women with less "fussy" uteruses may be at higher risk of miscarriage.

Miscarriage is the most common complication of pregnancy, with around 1 in 3 embryos lost before 6 weeks of pregnancy and a further 10 per cent before 12 weeks. For years, faulty embryos or problems such as abnormal clotting or immune responses have been blamed.

Jan Brosens at Imperial College London wondered if another process was at work. He had noted that many women who had repeated miscarriages claimed to have conceived incredibly quickly. "Each one of their pregnancies was conceived within one or two months of trying," he says. What's more, some studies have hinted that embryos implanting outside the normal window of uterine receptivity were more likely to miscarry.

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