Which hormone stimulates ovulation

This is the time of your cycle when you have a period, also known as menses. The first day of your period is a visual marker that you and your healthcare provider use to distinguish both the beginning and end of an Ovulation Cycle. This phase typically lasts 4 to 7 days. When you have a period, your body is shedding the nutrient-rich lining created during the previous cycle from inside your uterus. This occurs when estrogen and progesterone hormone levels decrease and there is no pregnancy.

This phase accounts for the first half of the menstrual cycle; beginning on the first day of your period and continues for 10 to 17 days. At birth, your ovaries contain all the immature eggs you will use during your entire lifespan. Under the control of various hormones following puberty, your brain will send a hormonal signal to the Follicle Stimulating Hormone FSH to your ovaries to recruit several follicles to mature each month.

We can think of this as a race amongst the follicles as to which follicle will result in a mature egg to be released at the time of ovulation. Each follicle recruited during a cycle contains a single egg. The fastest, healthiest follicle and egg also known as the dominate follicle will win the race and release an egg ovum at the time of ovulation.

The other follicles and eggs that were in the race are then reabsorbed, having lost their chance to fully mature or ever be released. As follicles within the ovary race to mature, changes are also occurring within the lining of your uterus. Increasing amounts of estrogen stimulate a thickening of the lining of the uterus, known as the endometrium.

Estrogen is the fertilizer. Other hormones are released near the end of the Follicular phase including testosterone. These hormonal changes are responsible for increased vaginal lubrication and an increase in libido or sexual desire. Everything that took place during the Follicular phase has prepared your body for a spectacular series of hormonal events that lead to ovulation.

The menstrual cycle Menstrual Cycle Menstruation is the shedding of the lining of the uterus endometrium accompanied by bleeding. The menstrual cycle begins with menstrual bleeding menstruation , which marks the first day of the follicular phase.

When the follicular phase begins, levels of estrogen and progesterone are low. As a result, the top layers of the thickened lining of the uterus endometrium break down and are shed, and menstrual bleeding occurs. About this time, the follicle-stimulating hormone level increases slightly, stimulating the development of several follicles in the ovaries.

Each follicle contains an egg. Later in this phase, as the follicle-stimulating hormone level decreases, only one follicle continues to develop. This follicle produces estrogen. The ovulatory phase begins with a surge in luteinizing hormone and follicle-stimulating hormone levels. Luteinizing hormone stimulates egg release ovulation , which usually occurs 32 to 36 hours after the surge begins.

The estrogen level peaks during the surge, and the progesterone level starts to increase. During the luteal phase, luteinizing hormone and follicle-stimulating hormone levels decrease. The ruptured follicle closes after releasing the egg and forms a corpus luteum, which produces progesterone.

During most of this phase, the estrogen level is high. Progesterone and estrogen cause the lining of the uterus to thicken more, to prepare for possible fertilization. If the egg is not fertilized, the corpus luteum degenerates and no longer produces progesterone , the estrogen level decreases, the top layers of the lining break down and are shed, and menstrual bleeding occurs the start of a new menstrual cycle.

Doctors ask women to describe their menstrual periods menstrual history What the doctor does Having no menstrual periods is called amenorrhea. Based on this information, doctors may be able to determine whether women are ovulating.

To determine if or when ovulation is occurring, doctors may ask a woman to take her temperature at rest basal body temperature each day. If possible, she should use a basal body temperature thermometer designed for women who are trying to become pregnant or, if it is unavailable, a mercury thermometer.

Electronic thermometers are the least accurate. Usually, the best time is immediately after awakening and before getting out of bed. A decrease in basal body temperature suggests that ovulation is about to occur. An increase of more than 0. However, this method is inconvenient or stressful for many women and is not reliable or precise.

This kit detects an increase in luteinizing hormone in the urine 24 to 36 hours before ovulation. To provide a more accurate result, some kits also measure by-products of estrogen. Urine is tested on several consecutive days. Measurement of the level of progesterone in the blood or the level of one of its by-products in the urine. A marked increase in levels of progesterone or its by-products indicates that ovulation has occurred.

Doctors may do other tests to check for disorders that can cause ovulation problems. For example, they may measure testosterone levels in the blood to check for polycystic ovary syndrome. A drug, such as clomiphene , letrozole an aromatase inhibitor , or human gonadotropins, can usually stimulate ovulation.

The particular drug is selected based on the specific problem. If the cause of infertility is early menopause, neither clomiphene nor human gonadotropins can stimulate ovulation. If ovulation has not occurred for a long time, clomiphene is usually preferred. A few days after menstrual bleeding begins, the woman takes clomiphene by mouth for 5 days. Before the drug is started, the woman usually needs to be given hormones to induce menstrual bleeding.

Usually, she ovulates 5 to 10 days after clomiphene is stopped, and she has a menstrual period 14 to 16 days after ovulation. Clomiphene is not effective for all causes of ovulation problems. It is most effective when the cause is polycystic ovary syndrome. If a woman does not have a period after treatment with clomiphene , she takes a pregnancy test. If she is not pregnant, the treatment cycle is repeated. A higher dose of clomiphene is used in each cycle until ovulation occurs or the maximum dose is reached.

When the dose that stimulates ovulation is determined, the woman takes that dose for up to four more treatment cycles. Most women who become pregnant do so by the fourth cycle in which ovulation occurs. The number of twin, triplet, and other multiple births has been increasing during the last two decades Side effects of clomiphene include hot flashes, abdominal bloating, breast tenderness, nausea, vision problems, and headaches.

In this syndrome, the ovaries enlarge greatly and a large amount of fluid moves out the bloodstream into the abdomen. This phase ends when the level of luteinizing hormone increases dramatically surges. The surge results in release of the egg ovulation and marks the beginning of the next phase. The ovulatory phase begins when the level of luteinizing hormone surges. Luteinizing hormone stimulates the dominant follicle to bulge from the surface of the ovary and finally rupture, releasing the egg.

The level of follicle-stimulating hormone increases to a lesser degree. The function of the increase in follicle-stimulating hormone is not understood. The ovulatory phase usually lasts 16 to 32 hours. It ends when the egg is released, about 10 to 12 hours after the surge in the level of luteinizing hormone. The egg can be fertilized for only up to about 12 hours after its release. The surge in luteinizing hormone can be detected by measuring the level of this hormone in urine.

This measurement can be used to determine when women are fertile. Fertilization is more likely when sperm are present in the reproductive tract before the egg is released. Most pregnancies occur when intercourse occurs within 3 days before ovulation. Around the time of ovulation, some women feel a dull pain on one side of the lower abdomen. This pain is known as mittelschmerz literally, middle pain. The pain may last for a few minutes to a few hours.

The pain is usually felt on the same side as the ovary that released the egg, but the precise cause of the pain is unknown. The pain may precede or follow the rupture of the follicle and may not occur in all cycles. Egg release does not alternate between the two ovaries and appears to be random. If one ovary is removed, the remaining ovary releases an egg every month. The luteal phase begins after ovulation. It lasts about 14 days unless fertilization occurs and ends just before a menstrual period.

In this phase, the ruptured follicle closes after releasing the egg and forms a structure called a corpus luteum, which produces increasing quantities of progesterone. The progesterone produced by the corpus luteum does the following:. Causes the endometrium to thicken, filling with fluids and nutrients to nourish a potential embryo. Causes the mucus in the cervix to thicken, so that sperm or bacteria are less likely to enter the uterus.

Causes body temperature to increase slightly during the luteal phase and remain elevated until a menstrual period begins this increase in temperature can be used to estimate whether ovulation has occurred Overview of Infertility Infertility is usually defined as the inability of a couple to achieve a pregnancy after repeated intercourse without contraception for 1 year. Frequent intercourse without birth control usually During most of the luteal phase, the estrogen level is high.

Estrogen also stimulates the endometrium to thicken. The increase in estrogen and progesterone levels causes milk ducts in the breasts to widen dilate. As a result, the breasts may swell and become tender.

If the egg is not fertilized or if the fertilized egg does not implant, the corpus luteum degenerates after 14 days, levels of estrogen and progesterone decrease, and a new menstrual cycle begins. If the embryo is implanted, the cells around the developing embryo begin to produce a hormone called human chorionic gonadotropin. This hormone maintains the corpus luteum, which continues to produce progesterone , until the growing fetus can produce its own hormones. Pregnancy tests are based on detecting an increase in the human chorionic gonadotropin level.