Ovulation

OVULATION
  • It is the process by which the oocyte-cumulus is released from the follicle. Towards the end of follicular phase the levels of estradiol increases dramatically and exerts a positive feedback at both hypothalamus and anterior pituitary causing LH surge.
  • LH surge last for 48 hours and ovulation occurs approximately 36 to 40 hours after the onset of LH surge.
  • LH peak preceedes ovulation by 10-16 hour.
  • Best predictor of ovulation: Pre-ovulatory rise in LH
  • Ovulation occurs 14 days before the next menstruation.
  • First polar body is released at the time of ovulation
  • Fall of temperature at ovulation is by 0.5 degree fahrenheit.
  • Maximum action of corpus luteum is at 22 day of menstruation (following which it starts regressing - 8 days after ovulation).
  • Fertilization takes place 1-2 days after Ovulation.
  • The fertilised ovum takes 3-4 days to travel through the fallopian tube and reaches the uterine cavity by the 7th day from ovulation.
  • Embryo implantation occurs after 7-9 days of Ovulation.
  • Placental circulation is established 18 -21 days after Ovulation.
  • In non-lactating mothers, ovulation may occur as early as 4 weeks and in lactating mothers about 10 weeks after delivery.
PHYSICAL SIGNS INDICATING OVULATION:
  • Increased body temperature
  • LH surge
  • Increased cervical mucus -cervical mucus is most abundant and becomes clear and slippery and stretches like egg white
  • Change of position and firmness of cervix
  • Abdominal cramps (Mittelschmerz)
  • Increased libido
  • Tender breasts
ClLINICAL CONSEQUENCES OF PERSISTENT ANOVULATION
  • Infertility
  • Menstrual bleeding problems ranging from amenorrhea to irregular, heavy bleeding (DUB). Most common menstrual disorder associated with anovulation is oligomenorrhea. Hirsutism, Alopecia and Acne.
  • Increased risk of Endometrial cancer and perhaps, Breast cancer.
  • Increased risk of Cardiovascular disease.
  • Increased risk of Diabetes mellitus in patients with insulin resistance.
METHODS TO DOCUMENT OVULATION:
  • Luteinizing Hormone Monitoring Documentation of the LH surge represents a remarkably reproducible method of predicting ovulation. Ovulation occurs 34 to 36 hours after the onset of the LH surge and about 10 to 12 hours after the LH peak
  • Basal Body Temperature The least expensive method of confirming ovulation is for the patient to record her temperature each morning on a basal body temperature (BBT) chart.Progesterone is thermogenic & responsible for the rise in basal body temperature at the time of ovulation
  • Midluteal Serum Progesterone
  • Ultrasound Monitoring Ovulation can also be documented by monitoring the development of a dominant follicle by ultrasound until ovulation takes place
  • A ferning pattern is seen when periovulatory cervical mucus is spread and dried on a microscope slide.
  • Endometrial biopsy is the best diagnostic method for finding out ovulation.
  • The finding of secretory endometrium confirms ovulation.
WHO CLASSIFICATION OF DISORDER OF OVULATION
  • Type I - Hypogonadotropic hypogonadism, low FSH and LH, low oestradiol
  • Type II - Normogonadotropic hypogonadism, normal FSH, normal oestradiol
  • Type III - Hypergonadotropic hypogonadism, high FSH and LH, low oestradiol
Exam Question
  • After 7 - 9 days of ovulation embryo implan­tation occurs .
  • In a young female of reproductive age with regular menstrual cycles of 28 days, ovulation occurs around 14th day of periods. First polar body is extruded accompanied by ovulation. In 40 days of menstrual cycle the ovulation occurs at 26th day.
  • Ovulation occurs due to mid cycle FSH and LH surge.
  • Fall of temperature at ovulation is by 0.5 degree Fahrenheit.
  • Post ovulation, the cervical mucus is thick.
  • Maximum function of corpus luteum occurs 9 days after ovulation.
  • LH surge preceedes ovulation by 36 hours.
  • Time of ovulation is detected by urine LH and urine FSH.
  • Best diagnosis of ovulation is by Endometrial biopsy >Ultrasound.
  • Persistent anovulation not treated leads to Hirsutism , Endometrial Carcinoma , Increased risk of CVS disease.
  • Drugs used for ovulation induction are Clomiphene citrate and Tamoxifen.
  • Tests for ovulation :Fern test , Basal body temperature ,LH surge , Ultrasound Monitoring
  • Diagnosis of imminent ovulation is by LH surge.
  • Ovulation can be evaluated by Cervical Mucous.
  • pPacental circulation is established 18-21 days after ovulation .
  • The corpus luteum of menstruation persists after 10 days ovulation. 
  • Hormonal study(Urinary LH surge) for assessment of female fertility during a menstrual cycle can best predict the timing of ovulation.
  • One of your patient who was diagnosed to have hypogonadism was found to have normal FSH and oestradiol levels. This patient belongs to which type II disorders of ovulation as per the WHO classification .
  • Watery nature of the cervical mucus at the time of ovulation may be caused by Oestrogen , Progesterone , Infection.
  • The fertilised ovum takes 3-4 days to travel through the fallopian tube and reaches the uterine cavity by the 7th day from ovulation
  • The mid-cycle shift in the basal body temperature (BBT) after ovulation in women is caused by Progesterone.
  • Separation of first polar body occurs at the time of Ovulation
  • Physical signs indicating Ovulation are Increased body temperature, LH surge, Increased cervical mucus -cervical mucus is most abundant and becomes clear and slippery and stretches like egg white Change of position and firmness of cervix ,Abdominal cramps (Mittelschmerz).
  • Ovulation occurs 14 days prior to next menstruation.
  • Ovulation following delivery, in a non-lactating mother, may occur earliest at 4 weeks.
  • Fertilization takes place after 1-2 days of ovulation
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