MENSTRUATION: OVULATION

Ovulation, release of the egg from the ovary, typically occurs at about the fourteenth cycle day in most twenty-eight-day cycles. However, we have studied cycles in which ovulation ranged from the ninth day to the nineteenth day of a cycle of this length, and in some menstrual cycles, ovulation does not occur at all. Ovulation usually follows the LH peak by twelve to twenty-four hours. The ovulatory phase is the shortest phase of the menstrual cycle.

The third portion of the menstrual cycle is the luteal phase, which encompasses the time from immediately after ovulation until the start of the next cycle. This phase is named for the corpus luteum, the mass of cells left in the ovary after the follicle ruptures during ovulation. The corpus luteum produces large amounts of progesterone and estrogen, leading to increased levels of these hormones in this portion of the menstrual cycle. The progesterone causes the small blood vessels in the thickened endometrium to develop and produces coiling in the endometrial glands, changes that prepare the uterus to receive a fertilized egg if pregnancy occurs. The progesterone also registers in the hypothalamus, where it shuts off output of GnRH, resulting in a rapid decline in LH and FSH from the pituitary. Unless the egg is fertilized, the corpus luteum degenerates ten to twelve days after ovulation and its hormone production drops drastically. The next menstrual flow occurs as the lining of the uterus sheds in preparation for regrowth in the next cycle. Menstruation is thus the result of abrupt withdrawal of hormone stimulation the time of ovulation, when pregnancy can occur. In most animal species, the female follows this pattern of behavior rather exclusively, avoiding sexual contact at all other times. Some studies document a pattern of increased sexual activity around the presumed time of ovulation and do not find such a "peak" in women using birth control pills, which block ovulation, but these findings appear to have been a result of imprecise determination of when ovulation occurred. Other reports find no evidence of heightened female sexual interest during ovulation.

A recent well-designed study by Schreiner-Engel and co-workers (1981) found objective laboratory evidence of higher levels of vaginal vasocongestion during the follicular and luteal phases of the menstrual cycle. Subjective reports of sexual arousal were also higher at these times than during the ovulatory phase, providing further confirmation that an ovulatory peak in female sexual responsivity is unlikely. Another recent study confirmed that female sexual activity and sexual interest peak in the follicular phase well before ovulation. Nevertheless, individuals differ in unique ways, so that some women may well find themselves feeling sexier at mid-cycle while others are most interested in sex earlier or later in their cycles.

Taboos about sexual intercourse during menstruation are still a part of everyday life for many people. In some cases, avoiding sexual contact is a matter of religious practice. For example, Orthodox Jews are supposed to abstain from sex for seven days after the end of menstrual flow, and sex is resumed only after the woman has immersed herself in a ritual bath, called the mikvah. In other cases, abstinence seems to stem from cultural and psychological sources, as Delaney, Lupton, and Toth note: "A man is as likely to be sexually aroused by a woman when she is menstruating as he is at any other time. But the blood of the menstruating woman is somehow dangerous, magical, and apparently not something he wants to get on his penis." The following comments illustrate the broad range of feelings people have about sexual activity during menstruation:

I often find that I feel sexiest when I'm having my period, so making love is particularly enjoyable then.

I somehow feel like it's not right to have sex when my girlfriend is menstruating. I don't know why, but I just feel funny about it.

Jill and I love to have sex during her periods. It's a particularly passionate time because we don't need to use any birth control then.

In a word, I'm embarrassed about it. I feel like I'm not completely clean when I'm flowing, and tampons make me dry inside, so I really prefer waiting until my period is done.

The notion that sexual activity, including intercourse, is "dangerous" to either partner during menstruation has no basis in fact. Yet some people feel that intercourse is messy during

menstruation and restrict their sexual experiences to noncoital options. It appears as though attitudes toward sex during menstruation are beginning to change however, since younger people seem to be less affected by the negative attitudes concerning such activity than their parents' generation was.

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