Hormones are chemical messengers. The ovaries release the female hormones estrogen and progesterone. These hormones cause the lining of the uterus or womb to build up. The built-up lining is ready for a fertilized egg to attach to and start developing.
If there is no fertilized egg, the lining breaks down and bleeds. Then the same process happens all over again. It usually takes about a month for the lining to build up, then break down. That is why most girls and women get their periods around once a month.
Ovulation pronounced: ov-yoo-LAY-shun is the release of an egg from the ovaries. The same hormones that cause the uterus lining to build up also cause an egg to leave one of the ovaries. The egg travels through a thin tube called a fallopian tube to the uterus. If the egg is fertilized by a sperm cell, it attaches to the wall of the uterus, where over time it develops into a baby.
If the egg is not fertilized, the uterus lining breaks down and bleeds, causing a period. For the first few years after a girl starts her period, it may not come regularly. This is normal at first. By about 2—3 years after her first period, a girl's periods should be coming around once every 4—5 weeks. Yes, a girl can get pregnant as soon as her period starts. A girl can even get pregnant right before her very first period.
Humans are obviously different. But does this mean that women have evolved to conceal ovulation? Women are most fertile during the late follicular phase of their menstrual cycle, which starts about a week after their period begins and ends a week later with ovulation. At this time, women experience subtle changes in their psychology, behaviour, and physiology that are akin to the changes we see in non-human primates. Miller asked professional exotic dancers to keep a record of their nightly tip earnings for two months.
The women also reported when their periods began and ended, so Miller could calculate when they were most fertile. This suggests that women are sufficiently more attractive at peak fertility to persuade men to part with their hard-earned cash. Reproductive system - female. Home Reproductive system - female.
Menstrual cycle. Actions for this page Listen Print. Summary Read the full fact sheet. On this page. Hormones and the menstrual cycle Phases of the menstrual cycle Common menstrual problems Where to get help.
Hormones and the menstrual cycle The menstrual cycle is complex and is controlled by many different glands and the hormones that these glands produce. Phases of the menstrual cycle The four main phases of the menstrual cycle are: menstruation the follicular phase ovulation the luteal phase. Menstruation Menstruation is the elimination of the thickened lining of the uterus endometrium from the body through the vagina.
Follicular phase The follicular phase starts on the first day of menstruation and ends with ovulation. Ovulation Ovulation is the release of a mature egg from the surface of the ovary. Luteal phase During ovulation, the egg bursts from its follicle, but the ruptured follicle stays on the surface of the ovary. Common menstrual problems Some of the more common menstrual problems include: premenstrual syndrome PMS — hormonal events before a period can trigger a range of side effects in women at risk, including fluid retention, headaches, fatigue and irritability.
Treatment options include exercise and dietary changes dysmenorrhoea — or painful periods. It is thought that the uterus is prompted by certain hormones to squeeze harder than necessary to dislodge its lining. Treatment options include pain-relieving medication and the oral contraceptive pill heavy menstrual bleeding previously known as menorrhagia — if left untreated, this can cause anaemia. Treatment options include oral contraceptives and a hormonal intrauterine device IUD to regulate the flow amenorrhoea — or absence of menstrual periods.
This is considered abnormal, except during pre-puberty, pregnancy, lactation and postmenopause. Possible causes include low or high body weight and excessive exercise.
Ancestral women who were attracted to these feauture could have produced offspring who were more successful in attracting mates and producing progeny. However, the report reiterates that women look for more in a partner than solely sexual physical attractiveness. The problem is that there is a limited number of potential mates who are high in both. So many women are forced to make trade-offs. Many people experience symptoms, such as cramps, acne, or tender breasts, when a period is on its way.
Learn the signs a period is coming. When a period comes early, it is often no cause for concern. Learn about some potential causes of an early period and when to see a doctor.
Some menstrual problems, such as painful, heavy, or absent periods, are common, but treatments and self-care techniques can help.
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