How to know if I am fertile: Ovarian Reserve and Reproductive Health

The average age a woman in Spain falls pregnant has progressively increased over the years, from an average of 25.06 years old for the birth of the first child in 1980 to 31.56 years old in 2021 (data obtained from the National Statistics Institute: INE). This delay in childbearing comes from different social and economic factors; nowadays having children is no longer a social imposition, but in order to decide whether become a mother or not, it is often sought economic stability, to have achieved an adequate professional development, to have a long-term relationship, etc. Thus, when a woman considers starting a family, she finds a very important obstacle, the decrease in fertility associated with an increased age, resulting in a reduction of ovarian reserve and oocyte quality, which ultimately translates into greater difficulty in achieving pregnancy.

Women start their fertile life with their first menstrual period, the most fertile period has been described around the age of 20, and from the age of 30 onwards, fertility may be affected, with a significant decline in fertility and an increase in the miscarriage rate from the age of 35 onwards. After 40 years of age, women’s fertility suffers a very significant decline due to a greater decrease in ovarian reserve that could lead to a greater probability of miscarriages and genetic alterations in the baby (Down’s syndrome, Turner, Klinefelter, etc). After the age of 43, the chances of getting pregnant drop to less than 3%, and at 45 and with the woman’s own eggs, the chances are less than 1%. In male fertility, age does not seem to be as decisive as in women; there may be a decrease in seminal quality from the age of 40-45 onwards, although there is no age limit for men to be able to seek pregnancy or carry out assisted reproduction techniques.

According to the World Health Organization (WHO), reproduction health is defined as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity, in all matters relating to the reproductive system, its functions and processes. Reproductive health implies that people are able to have a satisfying and safe sex life and that they have the capability to reproduce and the freedom to decide if, when and how often to do so”. Therefore, both men and women have the right to be correctly informed about the possibilities and/or existing methods to know their reproductive function as well as the different existing treatments to achieve pregnancy when their possibilities have been affected.

There are some markers that can help us determine a women’s reproductive function, such as:

Luteinising Hormone (LH) en urine (Ovulation test)

This test is very useful for women who are seeking pregnancy as it determines when she’s having the LH hormone peak. Shortly after, the woman will be ovulating (expulsion of the mature oocyte into the fallopian tubes), which is the maximum fertility period. This type of test has low sensitivity because the LH peak may last for a short time, giving a false negative if the peak has passed, so it is recommended to perform the test at least twice a day. Any alteration in these tests (continued positive or negative results throughout the menstrual cycle) should be consulted by a specialist gynaecologist in order to link these changes to a possible pathology. For instance, polycystic ovarian syndrome, anovulatory cycles, etc.

Menstrual indicators

Some changes during menstrual cycle can give information about women’s reproductive health.

• Cervical mucus: Cervical mucus or vaginal discharge amount, consistency and texture help us determine the most fertile days (Billings method), and it can be tested at home; that is, it can be easily checked at home. In order to do so, it is necessary to observe the previous cycles and determine the changes in the cervical mucus during menstrual periods. These variations suggest ovulation days, as the cervical mucus changes and the previous days leading up to ovulation it is usually clear, stretchy and slippery. This period lasts 4 – 5 days and marks the beginning of the period when you’re more likely to get pregnant.  

• Periodicity, duration and volume: A woman’s menstrual cycle usually lasts 3 to 5 days and occurs every 21 and 35 days (regular periods). Menstrual periods can suffer variations both in time (less than 2 or more than 8 days) and in regularity, shorter or longer cycles (less than 21 days or more than 35 days respectively). When this happens, it is called irregular menstrual cycle and its causes are multiple: high level of stress, intense exercise, changes in eating habits, excessive weight loss; in addition, it could be associated with the intake of certain medications, polycystic ovarian syndrome, thyroid disease, hormonal changes among others. These menstrual cycle variations could result in alterations in ovulation and therefore female infertility, so it is very important to see your doctor to determine the cause these alterations produce in the menstrual cycle.

• Menstrual cramps: Uterine / pelvic pain during menstrual periods (usually precedes 1 to 3 days before bleeding) is called dysmenorrhoea; this pain may or may not be accompanied by other symptoms such as headache, nausea, diarrhoea, lumbago, etc (premenstrual syndrome). There are two types of dysmenorrhoea: Primary or idiopathic dysmenorrhoea, in which there is no gynaecological disease to explain it, and is usually due to the high production of prostaglandins which in turn cause intense uterine contractions and consequent pelvic pain. Secondary dysmenorrhoea is due to a pathology such as endometriosis, adenomyosis or uterine myomatosis. It is very important, once again, to rule out these types of pathologies that could affect a woman’s fertility.

Basal body temperature

This is a method to predict ovulation day and therefore the most fertile days by monitoring the basal body temperature. To that end, we need to stablish a basal temperature pattern for a few months, so we must always measure the temperature in the same part of the body, at the same time (before getting up), at rest, with the same thermometer, and record the temperature every day, starting from the first menstruation day. The basal body temperature will increase between 0.3 – 0.5 ºC a few days after ovulation, so having sexual intercourse in the days before the basal body temperature increases will improve the probability of pregnancy. The best would be to combine this method with another (cervical mucus) so we can have more information about the days of maximum fertility.

Status of the cervix

It can give us information about where we are in our cycle. During menstruation, the cervix is usually in a lower position and harder, and slightly open to facilitate the exit of menstrual bleeding. During ovulation, the cervix is higher and softer to the touch and there is an increase in cervical mucus, after ovulation (second half of the cycle or luteal phase) the cervix lowers again and hardens. This method can be useful when a woman cannot stablish a pattern in the cervical mucus, but it is not a recommended method of first choice as there is a risk of developing an infection.

Therefore, after knowing these markers and identifying their alterations, we should always consult the relevant specialist in order to rule out any disease that could affect a woman’s fertility status, which in some cases can be irreversibly if not identified and treated in time.

Why it is important to know your ovarian reserve

The ovarian reserve is the number of eggs a woman has at any given time. It is very important to bear in mind that it is a prognostic factor related to the ability to achieve a pregnancy either spontaneously or through in vitro fertilisation.

Age is the most important factor able modify this ovarian reserve, since at an older age there is a decrease in the ovarian reserve and a lower quality of the oocytes, which leads to greater difficulty in having children. There are also other factors that can cause a decrease or even disappearance of the ovarian reserve, which in some cases can cause a woman to become sterile, such as: ovarian endometriosis, early ovarian failure, medical treatments, surgery, radiotherapy, chemotherapy, among others. There are two ways of measuring the ovarian reserve, by blood analysis through the antimullerian hormone (AMH) and by ultrasound with the antral follicle count. We speak of a normal ovarian reserve when the AMH values are between 0.7 and 2.9 ng/ml. It is very important to know the ovarian reserve and also that it can be assessed and interpreted together with a specialist in order to be properly informed about the causes and possible treatments if necessary. If a woman has a low ovarian reserve and does not yet wish to have children, there are oocyte preservation techniques that in these cases would be the treatment of choice. If there is a desire to become a mother, artificial insemination or in vitro fertilisation could be necessary to achieve this; furthermore, if a woman has a very low ovarian reserve or is over 42 years of age, there are techniques such as receiving donated oocytes that can help these couples to achieve their desire to start a family.

Dr Carlos Alvarado (MD Associated no. 303311276), gynaecologist in Instituto Bernabeu