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What is the Luteal Phase?
The luteal phase is the second phase of the menstrual cycle, during which the body prepares itself for pregnancy. If a woman does not become pregnant, the luteal phase ends with the shedding of the uterine lining. If a pregnancy occurs, hormones secreted by the developing fetus will prevent the shedding of the lining. Women who are trying to get pregnant are sometimes very interested in tracking their luteal phases, along with the menstrual cycle in general.
This phase starts when ovulation ends, and the ovarian follicle which produced an egg during ovulation begins to develop a structure called the corpus luteum or “yellow body.” This structure produces progesterone, which is used to thicken the endometrium and prepare it for implantation of an embryo. If no embryo implants, the corpeus luteum gradually withers, allowing the lining to thin and slough off in a menstrual period. A woman's basal body temperature also rises during the luteal phase, turning her into a literal incubator.
There is a small window for pregnancy to occur; the egg lasts less than a day after ovulation occurs, and a fertilized embryo must implant before the corpus luteum starts to atrophy. Delays in fertilization and implantation can result in a miscarriage, in which an embryo is shed along with the uterine lining because it did not implant early enough to stop the luteal phase. Women who are trying to avoid pregnancy should be aware that sperm can last up to seven days in the Fallopian tubes while it waits for the emergence of an egg to fertilize.
Classically, the luteal phase lasts between 12 and 16 days, with 14 days being the most common. A luteal phase of at least 10 days is needed for pregnancy to occur, and women who are struggling with fertility issues sometimes find that they can't get pregnant due to a so-called “luteal phase defect” which can be treated by a doctor. Ovulation problems can be diagnosed with the use of ovulation charting to keep track of ovulation, and blood tests which look for levels of specific hormones to indicate the stage of a woman's cycle.
The length of a menstrual period is primarily determined by the time at which ovulation occurs. Ovulation can occur early or late for a variety of reasons, ranging from stress to medical problems. The luteal phase tends to be very regular in length, unless a woman is experiencing a medical issue, which makes it easy for women to determine when their periods will arrive if they are able to pinpoint the time of ovulation.
Discussion Comments
I've seen a lot of articles on how much of a chance women have to get pregnant over the course of a year, but I do wonder how much of a chance women have if they specifically aim at the luteal phase for conception.
I mean, the average woman who is casually trying to get pregnant isn't going to look up these phases and will just try as often as possible. But it sounds like you've got to get the timing just right. So I wonder what the chances are when someone does get it just right.
@KoiwiGal - I think it varies from person to person, but one thing that always stuck with me is that those hormones can affect how attractive you find someone. When you're on the pill, I assume the luteal phase, along with fertility hormones and all the rest are affected. And there have been studies that women are attracted to one particular kind of man during that phase, when it's possible to become pregnant, and to another kind of man when they aren't in that phase. There are also studies showing that women on the pill are attracted to a different kind of guy than when they are off the pill.
Some doctors have even said that women should try going off the pill for a while before they marry someone, just to make sure that it's not the artificial hormones talking.
I think it would be interesting to just see if you fight more with your boyfriend when you are going through the luteal phase. Might shed some light on what your hormones are doing to your choices!
There is some really good, free software and websites online if you are interested in tracking this kind of thing. If you're doing it as a birth control method, or if you're trying to get pregnant, I would definitely consult a doctor rather than just doing your own research, but if you've just got a casual interest you can find out a lot.
It is kind of weird knowing when your luteal phase is happening. Pregnancy isn't exactly on my plans at the moment, but I have noticed that I tend to be a bit cluckier during that phase. I've heard it can affect decisions and everything, just because you've got slightly different hormones going through your body.
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