Menstrual cycle follicular phase

The female menstrual cycle is divided into four functional phases follicular, ovulatory, luteal, and menstrual.6 The follicular phase starts the cycle, and ovulation generally occurs on day 14. The luteal phase then begins and continues until menstruation occurs.6 The menstrual cycle is regulated by a negative-feedback hormone loop between the hypothalamus, anterior pituitary gland, and ovaries6 (Fig. 45-1). 

The median length of the menstrual cycle is 28 days (range 21 to 40). The first day of menses is day 1 of the follicular phase. Ovulation usually occurs on day 14 of the menstrual cycle. After ovulation, the luteal phase lasts until the beginning of the next cycle. 

The results 68% of the women treated with extracts from the follicular phase of the menstrual cycle shortened their own current cycle by an average of 1.7 days. A different 68% of the women treated with extracts from the ovarian phase of the menstrual cycle lengthened their own current cycle by an average of 1.4 days. Finally, underarm extracts taken following ovulation, in the luteal phase, had no effect on the... 

Figure 19.6 A 28-day menstrual cycle. The approximate number of days for menstruation, ovulation and the follicular and luteal phases are shown.

Figure 19.12 Representation of changes in hormone levels during the menstrual cycle. Note that LH peaks about one day before ovulation. Oestrogen has two peaks one in the Luteal phase prior to LH surge and a smaller one in the follicular phase. Progesterone peaks in the follicular phase to stimulate development of endometrium.

In a later experiment, two pheromones from axillary odor of young women influenced the estrus cycle of other women (Stern and McClintock, 1998). Armpit secretion that appears odorless to humans was applied daily between the upper lip and nose of healthy young women and had two opposite effects depending on the menstrual phase of the odor donors. Secretion from nine donor women, collected on pads in their armpits during the follicular phase of their cycles... 

During the follicular phase of the menstrual cycle, one or more follicles are prepared for ovulation. FSH and estrogens are the most important hormones for this developmental process. Complete follicular maturation cannot occur in the absence of LH. Rupture of a mature follicle follows the midcycle peak of LH and FSH by about 24 hours. In humans, usually one mature ovum is released per cycle. During the luteal phase of the menstrual cycle and under the influence of LH, the ovarian granulosa cells of the corpus luteum become vacuolated and accumulate a yellow pigment called lutein. 

Furthermore, these symptoms have a significant impact on a woman s interpersonal relations and general lifestyle and usually require the help of a mental health professional. Typically, at least five symptoms have been present in most menstrual cycles within the previous year, usually during the last week of the luteal phase, begin to remit within a few days after the onset of the follicular phase, and are absent during the week after menses ( 20). 

In normal women, estradiol is produced at a rate that varies during the menstrual cycle, resulting in plasma levels as low as 50 pg/mL in the early follicular phase to as high as 350-850 pg/mL at the time of the preovulatory peak (Figure 40-1). 

A loss of primary oocytes will irreversibly affect a woman s fecundity, but this is difficult to measure directly. Reproductive dysfunction can be studied by the evaluation of irregularities of menstrual cycles and onset of menarche and menopause. However, menstrual cyclicity and onset of menopause and menarche are affected by many parameters, such as age, genetics, nutritional status, stress, exercise, certain drugs and the use of contraceptives that alter endocrine feedback. The length of the menstrual cycle, particularly the follicular phase (before ovulation), can vary between individuals and may make it difficult to measure significant effects in groups of women (Burch et al., 1967 Treloar et al., 1967). 

Melatonin affects reproduction in seasonally breeding animals. In humans, findings of increased endogenous melatonin in hypogonadism and low concentrations in precocious puberty imply an interaction between melatonin and gonadotropins however, data on the effects of exogenous melatonin are limited (1). In a randomized study in 16 women, melatonin enhanced LH and FSH responses to submaximal GnRH stimuli in the follicular but not the luteal phase of the menstrual cycle (24). 

The relation between antipsychotic drug-induced hyperprolactinemia and hypoestrogenism has been studied in 75 women with schizophrenia (762). Serum estradiol concentrations were generally reduced during the entire menstrual cycle compared with reference values. There was hypoestrogenism, defined as serum estradiol concentrations below 30 pg/ml in the follicular phase and below 100 pg/ml in the periovulatory phase, in about 60%. 

Vaginal immunization experiments with a cholera vaccine containing killed vibrios and CTB have been conducted in both the follicular (V-FPimm) and luteal (V-LPimm) menstrual cycle phase. With both producing comparable cervical CTB-specific IgA responses, however, only the V-FPimm induced cervical IgA2-restricted Ab to the bacterial lipopolysaccharide (LPS) vaccine component and induced CTB-specific IgA in rectal secretions. 

The vagina demonstrates a relatively high permeability to many drags, particularly during the late luteal and early follicular phases of the menstrual cycle. 

According to the changes in the ovary and the endometrium, the menstrual cycle is divided into (i) the follicular phase and (ii) the luteal phase. 

Q3 At the start of the cycle (which is the first day of the menstrual flow) a number of primary follicles begin to develop in the ovary, and initially oestrogen and progesterone levels are low. In the follicular phase, as the follicles develop, oestrogen levels rise considerably and ovulation occurs after 14 days when the follicle ruptures. 

The subjective and behavioral effects of triazolam were investigated in 20 healthy women, who took oral triazolam 0.25 mg or placebo at the follicular, periovulatory, and luteal phases of their menstrual cycle in a within-subject design (12). After triazolam most of them reported the expected increases in fatigue and decreases in arousal and psychomotor performance. Neither plasma concentrations of triazolam nor mood and performance differed across the three phases. This study shows that the effects of triazolam are highly stable across the menstrual cycle. 

---