Luteinizing Hormone (LH) Surge
LH Levels and Ovulation

Luteinizing hormone (LH) surge, or acute rise, signals the dominant follicle in your ovaries to release it's egg (ovum). This is the point of ovulation.


This surge occurs toward the end of the follicular phase and the beginning of the luteal phase of your ovulation cycle / menstrual cycle.

Leading up to the LH surge, is the rise and subsequent fall in FSH, or follicle stimulating hormone. FSH stimulates your follicles to grow an egg (ovum) to maturity.

Estrogens, more so estradial, are released from your ovaries as the eggs begin to mature.

Once FSH starts to drop and estrodial peaks, the hypothalamus signals the pituitary gland to release a surge of LH hormone.

The luteinizing hormones surge for about 12 to 48 hours.

Though low LH levels are present all the time in your body to help regulate the menstrual cycle, it's the surge or rapid increase that triggers the dominant follicle to release it's mature ovum (egg).

The egg then bursts from the ovary and is swept up by the fimbria and starts to travel down the fallopian tube to await fertilization from sperm.

Luteinising hormone also has influence on the now empty ovarian follicle in it's change to a corpus luteum after ovulation occurs. The corpus luteum then produces progesterone and to a lesser degree estradial. These hormones further prepare your uterus and endometrium, or endometrial lining, for implantation of a fertilized egg. FSH and LH levels begin to fall as these hormones start to rise.

After ovulation occurs then the second part of your ovulation cycle, called the luteal phase, begins.

Luteinizing hormone is also what an ovulation predictor kit (OPK) detects. OPK's are home ovulation testing kits that help you predict ovulation and time intercourse.

Once the LH surge has been detected by the ovulation tests from the kit, then you know that you should ovulate within the next 12 to 48 hours and you should time baby-making sex during this period, as it is the most fertile time of your cycle and the best time to conceive.

Buy OPK Ovulation LH Tests Here (opens in new window)

Related pages

Best Days to Get Pregnant | Fertility Monitor | Getting Pregnant Positions | How Long to Get Pregnant? | When Does Conception Occur? | When Does Ovulation Occur? | Luteal Phase | Luteal Phase Defect | Fertility Monitor | Ovulation Predictor Kits |

› Luteinizing Hormone (LH)

› Luteinizing Hormone (LH)

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