Ovarian stimulation

Spontaneous ovulation in women is a process that starts early in the menstrual cycle, that is to say with the rule, and that culminates approximately on day 14 of each cycle. During this process, many follicles begin to develop in the ovaries. The follicles are cystic structures where the ovum develops, which start out very small, grow filling with nutrients for the ovule and when they reach a size of about 22 mm, a hole is opened in the wall to allow the exit of the ovum. When, during this growth process, one of the multiple follicles reaches a larger size than the rest, it inhibits the other follicles to prevent several eggs from reaching maturity.

The doctor who specializes in reproductive treatments will decide, based on the results of the previous study of the couple, the best treatment for each case. In about a 20-25% of infertility cases are due to an ovulation problem, and these women usually have irregular or nonexistent periods. If the rest of the tests in the sterility study are correct, then ovulation stimulation is usually recommended in order to achieve optimal maturation of at least one egg1 as the first step in the attempt to achieve pregnancy. The Pregnancy rate with this treatment varies between 15 and 30% of cases. It is usually recommended to do a maximum of between 4 and 6 months of treatment.

Side effects of ovarian stimulation

The most common side effects, of between 10-14% of patients, are hot flashes and ovarian enlargement, followed by abdominal distension and discomfort, nausea and vomiting, and breast tension that occurs in less than 6% of cases. Less than 2% of patients report headache or vaginal bleeding.

Phases of treatment

• Egg maturation: through medical treatment with hormones for the development of one or more mature eggs.
• Ovulation: Hormone treatment is given to trigger ovulation in a controlled way.
• Preparation of the endometrium: the inner layer of the uterus must be well prepared for a correct implantation of the embryo.

Egg maturation

The medications used in the first phase, for the maturation of the ovum, are clomiphene citrate and gonadotropins. clomiphene citrate is the most widely used medication that has been on the market since the 60s. It is administered orally, in tablets, and treatments of 1 to 2 tablets daily are usually made for about 5 days at the beginning of the cycle.

The dose and days of treatment vary from one patient to another according to the characteristics of each one. This medication stimulates the secretion of menstrual cycle hormones (LH3 and FSH4) so that the growth of the follicle in the ovary is stimulated. It is an effective medication to produce ovulation and should not be administered to women who are already ovulating correctly.

The gonadotropins are hormonal preparations to stimulate ovulation that are administered injected since orally they would be destroyed by gastric juices. There are two basic types:

• The obtained synthetically, more expensive but subcutaneous administration and therefore can be administered by the patient herself.
• That of urinary origin, cheaper but intramuscular administration.

Treatment is usually started the first days of the cycle and at appropriate doses for each patient. Are very effective medications to produce ovulation and depending on the case, multiple follicles can mature (especially in in vitro fertilization cycles).

Ovulation induction requires a control by the doctor to assess the number of growing follicles, its size and predict the fertile days with maximum confidence. This control is carried out by means of vaginal ultrasound, which observe the number of follicles and their growth rate, allows modifying the medication regimen if necessary and setting the day of the next control.

When the follicle reaches 18 mm is considered mature to ovulate and the endometrium2 of at least 6 mm suitable for implantation. On some occasions, the determination of an estrogen in the blood, 5 estradiol, is also indicated, since it increases as the ovum matures and therefore allows a more strict control of the response to treatment.

The controls allow to prevent or detect Risks of Ovulation Induction Medication, which are multiple pregnancy (10%) and ovarian hyperstimulation syndrome (1%). Ovarian hyperstimulation consists of an excessive enlargement of the ovaries associated with fluid retention and abdominal distension.

It is usually mild and then the treatment is bed rest and the ingestion of liquids with a high content of solutes, but when it is severe it requires hospital admission. It is more frequent in patients with and in the cycles in which pregnancy is achieved. In some cases it is necessary to cancel the cycle due to the risk of complications it entails.

Ovulation

The second phase of treatment, ovulation, requires a HCG treatment. This is a hormone that stimulates the final maturation of the follicle and the release of the ovum, which occurs between 36 and 40 hours after its administration, and is when sexual intercourse should be scheduled.

Endometrial preparation

Finally, the third phase of the treatment is the preparation of the endometrium for the adequate implantation of the embryo, which can be achieved with two additional doses of HCG or with. Progesterone is a hormone produced by the body that plays an important role in achieving a pregnancy. It is indicated in cases where the woman does not produce it in sufficient quantity and it is generally administered vaginally. Side effects of this medication are nausea, headache, drowsiness, breast tension, joint pain, and depression.

Of interest

Of the patients subjected to these treatments, one Approximately 20% will achieve a pregnancy. In this case, pregnancy has the same risks for both the mother and the fetus as a pregnancy achieved with a natural conception, so they do not require a more exhaustive follow-up or additional tests.

If in a period of between four and six months Ovulation induction treatment has not achieved pregnancy, other assisted reproduction techniques such as artificial insemination or in vitro fertilization are recommended.