Structurally the breasts resemble sweat glands. At the center is a nipple containing 15 to 20 depressions, into which ducts from the lobes of the gland empty. During pregnancy hormones secreted by the ovaries cause the glandular tissue to grow in preparation for lactation. After childbirth hormones secreted  by the anterior lobe of the pituitary gland stimulate production for 6 to 9 months.

The graafian follicles are microscopic pockets in the ovaries. Once a month, under hormonal influence, a follicle matures, ruptures, and expels its ovum into the uterus. Each ovary normally releases an ovum every 56 days, the right and left ovary alternately discharging an ovum every 28 days. The menstrual cycle in most women is therefore 28 days in length.

The uterus averages 7 cm in length and 5 cm in width. It has three opening: the openings of the fallopian tubes laterally and the opening into the vagina. The parts of the uterus are the body, which is the large upper portion, and the cervix, which is the smaller portion that projects into the upper part of the vagina. The cervical opening into the vagina is called the external os. The walls of the uterus are highly flexible and are composed of three layers that are continuous with the respective layers of the fallopian tubes.

In addition to being the focal point of the endometrial (menstrual) cycle, the uterus is the site of implantation, growth and development of the fertilized ovum. The muscular walls of the uterus produce powerful rhythmic contractions that are important in the expulsion of the fetus at birth.

As previously mentioned, each ovary produces a mature ovum every 56 days. They expel their ova on an alternating basis, approximately one every 28 days. The length of this cycle may vary markedly from individual to individual and between cycles of the same individual. ON the first days of menstruation, several ova within the graafian follicles begin to mature, an normally one will be expelled 14 days before the next menstrual flow. This is the ovarian cycle.

The endometrial cycle centers around the periodic development and breakdown of the endometrial lining of the uterus. The first phase of the cycle is the menses, or menstruation. It begins when the endometrial lining starts to slough off from the walls of the uterus, and it is characterized by bleeding from the vagina. This is day 1 of the cycle, and this phase usually lasts through day 5. The time between the last day of the menses and ovulation is known as the postmenstrual phase. It lasts from day 6 through day 13 or 14 and is characterized b y proliferation of endometrial cells in the uterus, which develop under the influence of the hormone estrogen. Ovulation is the rupture of a graafian follicle with the release of a mature ovum into the fallopian tubes. It usually occurs on day 14 or 15 of the cycle. The postovulatory (premenstrual) phase is the time between ovulation and the onset of menses and normally lasts 14 days. During this phase the ovum travels through the fallopian tubes to the uterus. If the ovum becomes fertilized during this passage, it will become implanted in and nurtured by the newly developed endometrial lining. However, if fertilization does not take place, the lining deteriorates and eventually sloughs off, marking day 1 of the next cycle.

2. American Academy of Orthopaedic Surgeons: Emergency Care and Transportation of the Sick and Injured, ed 3.

When the corpsman is faced with an imminent childbirth, the first determination to be made is whether there will be time to transport the expectant mother to the hospital. To help make this determination, the corpsman should try to find out whether or not this will be the woman's first delivery (first deliveries usually take much longer than subsequent deliveries); how far apart the contractions are (if less than 3 minutes, delivery is approaching); whether or not a mother senses that she has to move her bowels (if so then the baby's head is well advanced down the birth canal); whether or not there is crowning (bulging) of the orifice (crowning indicates that the baby is ready to present itself); and how long it will take to get to the hospital. The corpsman must weigh the answers to these questions to decide if it will be safe to transport the patient to the hospital.

Prior to childbirth a corpsman must quickly "set the stage" to aid the event. the mother must not be allowed to go to the bathroom since the straining may precipitate the delivery in the worst possible location. Do not try to inhibit the natural process of childbirth by having the mother cross her legs. The mother should be lying back on a a sturdy table, bed, or stretch. A folded sheet or blanket should be place under her buttocks for absorption and comfort. Remove all clothing below the waist, bend the knees and move the thighs apart, and drape the woman with clean towels or sheets. The corpsman should then don sterile gloves or, if these are not available, rewash his or her hands.

In a normal delivery, your calm professional manner and sincere reassurance to the mother will go a long way towards alleviating her anxiety and making the delivery easier for everyone. Help the woman rest and relax as much as possible between contractions. During contraction, deep, open mouth breathing will relieve some pain and straining. As the child's head reaches the area of the rectum, its pressure will cause the mother to feel an urgent need to defecate. Reassurance that this is a natural feeling and a sign that the baby will soon be born will alleviate her apprehension.

Watch for the presentation of the top of the head. Once it appears, take up your station at the foot of the bed and gently push against the head to keep it from popping out in a rush. Allow it to come out slowly. As more of the head appears, check to be sure that the umbilical cord is not wrapped around the neck. If it is, gently try to untangle it, or move one section over the baby's shoulder. If this is impossible, clamp in two places, 2 inches apart, and cut it. Once the chin emerges, use the bulb syringe from the pack to suction the nostrils and mouth while you support the head with one hand. Compress the bulb prior to placing it in the mouth or nose; otherwise, there will be a forceful aspiration into the lungs. The baby will now start a natural rotation to the left or right, away from the face down position. As this is occurring, keep the head in a a natural relationship with the back. The shoulders appear next, usually one at a time. From this point on, it is essential to remember that the baby is VERY slippery, and great care must be taken so that you do not drop it. The surface beneath the mother should extend at least 2 feet out from the buttocks to that the baby would not be hurt if it did slip out of your hands, and use the other to support its emerging body.

One the baby has been born, suction the nose and mouth again if breathing has not started. Wipe the face, nose and mouth clean with sterile gauze. Your reward will be the baby's hearty greeting to the world.

Clamp the umbilical cord as the pulsations cease. Use two clamps from the prepackages sterile delivery pack, 2 inches apart, with the first clamp 6 to 8 inches from the navel. Cut between the clamps. For safety, use gauze tape to tie the cord 1 inch from the clamp toward the navel. Secure the tie with a square knot. Wrap the child in a warm, sterile blanket and log the time of the child's arrival.

The placenta (afterbirth) will deliver itself in 10 to 20 minutes. This can be aided by massaging the mother lower abdomen. Do not pull on the placenta. Log the time of its delivery, and wrap it up for hospital analysis.

Place a small strip of tape (1/2 inch wide), folded and inscribed with the date, time of delivery, and mother's name, around the baby's wrist.

Because of the increasing frequency with which hospital corpsmen are required to attend to persons of either sex, the following guidelines are presented to assist you in developing some decision-making judgments.

To ensure the protection of health care personnel from unjustified accusations, a witness should be present when a member of the opposite sex is being examined or treated. Whether this witness is a member of the same sex as the patient may be dictated by the availability of personnel. When you are caring for a patient, sensitivity to both verbal and nonverbal communication is paramount. A grin, a frown, or an expression of surprise may all be misinterpreted by the patient. Explanations and reassurances will go far in preventing misunderstanding of actions or intentions. Knowledge, empathy and mature judgement should guide the care provided to any patient; this is especially crucial when the care involves touching. As a member of the health care team, you are responsible for providing complete, quality care to all who need and seek your service. This care must  be provided in a manner compatible with your individual legal and technical limitations.