Electronic/World Wide Web>Internet Article:  Sadedin, Suzanne (Nov 7, 2016), Why do women have periods? What is the evolutionary benefit or purpose of having periods? Why can’t women just get pregnant without the menstrual cycle?, Retrieved on 2018-03-20
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  • Folksonomies: human evolution pregnancy menstrual cycle

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    20 MAR 2018

     Human Pregnancy is Adversarial Between Mother and Fetus

    Inside the uterus we have a thick layer of endometrial tissue, which contains only tiny blood vessels. The endometrium seals off our main blood supply from the newly implanted embryo. The growing placenta literally burrows through this layer, rips into arterial walls and re-wires them to channel blood straight to the hungry embryo. It delves deep into the surrounding tissues, razes them and pumps the arteries full of hormones so they expand into the space created. It paralyzes these arteries ...
    Folksonomies: human evolution pregnancy
    Folksonomies: human evolution pregnancy
      1  notes
     
    20 MAR 2018

     Human Females Menstruate to Eliminate Unviable Fetuses

    From a female perspective, pregnancy is always a huge investment. Even more so if her species has a hemochorial placenta. Once that placenta is in place, she not only loses full control of her own hormones, she also risks hemorrhage when it comes out. So it makes sense that females want to screen embryos very, very carefully. Going through pregnancy with a weak, inviable or even sub-par fetus isn't worth it. That's where the endometrium comes in. You've probably read about how the endometriu...
    Folksonomies: human evolution pregnancy
    Folksonomies: human evolution pregnancy
      1  notes