Dr. Ruth K. Westheimer - Sex For Dummies

Just because a woman is fertile only a few days a month, don’t assume that those are the only days that unprotected sexual intercourse can make her pregnant. A woman’s reproductive organs are much more complicated than that, as I explain in Chapter 3.

Unlike a man, who continually makes sperm (more than 26 trillion a year!), a woman has all her eggs already inside her at birth. These eggs — about 200,000 of them — reside in a woman’s two ovaries (see Figure 1-1). About every 28 days, a fluid-filled sac in the ovary, called a follicle , releases one of the eggs. When a follicle releases an egg, many women feel a dull ache, known as mittelschmerz , in the area around the ovary.

Illustration by Kathryn Born

FIGURE 1-1:The egg begins an incredible journey in search of a sperm to produce a child. No wonder sex has been called “making whoopee”!

Becoming aware of when mittelschmerz occurs is a good point of reference for anyone practicing natural family planning . I talk more about family planning in Chapter 7.

Everyone’s talking about what happened last night at Club Fallopian. Mr. Sperm bumped into Ms. Egg, and now they’re really stuck on each other!

Just as people have to meet each other before they can form a relationship, the process of fertilization can’t begin until a sperm gets up into the fallopian tubes and meets the egg. This introduction takes place as a result of sexual intercourse , which is defined as a man placing his penis in a woman’s vagina. When the man has an orgasm, he releases millions of sperm into the back of the woman’s vagina. These sperm bind to the cervical mucus and swim right up through the entrance to the uterus, called the cervix , through the uterus itself, and then into the fallopian tubes — each sperm hunting for an egg. And if an egg happens to be floating along, the fastest sperm takes the prize.

You should always keep in mind two very important points about sperm:

Sperm can live from two to seven days inside a woman. So although the egg may have only a short time during which it can be fertilized, sperm that a man deposited in the woman up to a week before can still fertilize the egg and cause pregnancy.

Even before a man ejaculates, his penis releases some liquid (the proper name is Cowper’s fluid , because the Cowper’s gland produces it, but it’s popularly referred to as “precum”), which serves as a lubricant to help the sperm go up the shaft of the penis. Any sperm that may not have been ejaculated during the man’s previous orgasms may be picked up by the Cowper’s fluid. Although that number is less than the millions of sperm in the ejaculate, how many sperm does an egg require for fertilization? One fast one.Because of Cowper’s fluid, a man may deposit sperm inside a woman’s vagina before he has an orgasm. That’s why the pullout, or withdrawal, method is not an effective means of preventing pregnancy.

Little finger-like appendages on the end of the fallopian tube called fimbria lead the egg into the tube, through which it makes its way into the uterus . If, during this trip, the egg encounters some sperm swimming along, then the first sperm to reach the egg and penetrate the hard outer shell, called the zona pellucida , will enter the egg and begin the life-creating process called fertilization.

A fertilized egg continues down the fallopian tube on a journey that takes about three days. During the first 30 hours, the chromosomes of the egg and the sperm merge, and the cells begin to divide. This new entity is called an embryo . When the embryo finishes its journey and enters the uterus (see Figure 1-2), it gets nourishment from uterine secretions, and the cells inside it continue to divide, causing the embryo to grow. Approximately six days after fertilization, the egg “hatches,” emerging from its hard shell and then burrowing its way into the uterine wall, or endometrium .

Illustration by Kathryn Born

FIGURE 1-2:The embryo nests in the wall of the uterus after fertilization. Happy landing!

The embryo releases a hormone called hCG. When the hCG reaches the mother’s bloodstream, it signals that she is pregnant and causes the ovaries to continue producing the hormones estrogen and progesterone, which are necessary to maintain the pregnancy.

If the egg is not fertilized, it passes through the uterus. About two weeks later, the uterus sheds its lining, the endometrium, in a process called menstruation . A new lining then begins to grow, ready to receive a fertilized egg the next month.

One more thing about sexual intercourse and its pleasures: As great a feeling as you get when having an orgasm during sexual intercourse, I think that most couples will tell you that they got even more pleasure from the intercourse they had while trying to make a baby. You get an extra kick from knowing that the possible result of this union between two people who love each other is another little human being.

After an embryo burrows its way into the endometrium, it grows until it has a human shape and all its organs — a process that takes about 12 weeks. At this point, the embryo is renamed a fetus . (Also, by this stage of the pregnancy, many couples give the fetus funny names — none of which, hopefully, will land on the final birth certificate.)

During early pregnancy the only sure way is to take a test, which you can buy at your local drug store. But a woman will undergo many physical changes that will at least give an indication of a possible pregnancy, and these often occur before the most obvious sign, a missed period. (Not that all missed periods indicate a pregnancy, but if you had unprotected sex, the odds of a missed period being an indicator of pregnancy grow much stronger.) One of the first possible sign is a tenderness in the woman’s breasts. Another is morning sickness, as many women during the first trimester suffer bouts of nausea, particularly in the morning. Fatigue and more frequent urination are other signs that it’s time to buy a pregnancy test or visit your gynecologist.

The fetus grows inside the uterus until approximately nine months after the egg was first fertilized. Then, in a process called giving birth , a fully formed baby comes out of the uterus and through the vagina into the world (unless doctors have to remove the baby surgically, which is called a cesarean section , or c-section). If you want to know more about the specifics of pregnancy, pick up Pregnancy For Dummies , 4th Edition, by Joanne Stone, M.D., Keith Eddleman, M.D., and Mary Duenwald (Wiley).