Fertile Days: How to Determine the Best Time for Conception?

Do you want to have a baby, but cannot get pregnant? Perhaps the reason is that you do not know enough about fertility, and because of this, do not use all available methods of conceiving a child. Fertile days – what does it mean for women and men? How to calculate the favorable days for conception? When does ovulation occur? All these and we’ve tried to cover in the article.

What is Fertility?

The term “fertility” has a Latin origin, “fertilize” – “prolific, fruitful.” This concept, the opposite of infertility, refers to the body’s ability to reproduce offspring.

In relation to a man, fertility indicates his ability to fertilize a woman. To a woman – the ability to conceive a healthy child. In both cases, we are talking about people of reproductive age who have borders. Female fertility occurs with the establishment of regular menstruation and ends in menopause. Male – from the moment of production of live and active sperm, which are able to fertilize an egg.

In the Fertile Age of a Woman, 4 Conditional Stages are Distinguished

  • Early Reproductive: from the beginning of menstruation to 20 years. Characteristic features: the formation of the cycle, rare ovulation, balancing of the hormonal level. In the case of active sex without contraception, the probability of pregnancy is high.
  • Average Reproductive: from 20 to 40 years. A regular cycle, a stable hormonal background, the absence (usually) of health problems. The most favorable period for the birth of children. Late reproductive: from 40 to 45 years. The hormonal background is unstable. The cycle and ovulation are stable. The beginning of age-related changes in the body. Pregnancy is possible naturally, but gestation may require active medical attention.
  • Decaying Fertility Stage: from 46 to 60 years. The period of menopause is coming. Reduced hormonal background, irregular cycle, or its completion. Natural pregnancy is impossible (with very rare exceptions). A course of hormonal drugs will be required for gestation.

The recommended period for pregnancy from a medical and biological point of view is the age from 20 to 40 years. At the same time, conception and gestation are possible much earlier or later.

Therefore, in general, the fertility period of women is within 15–49 years. As for men, they are able to maintain reproductive functions until the end of life, if external factors do not adversely affect fertility.

Ways of Determining Fertile Days

There are several ways to determine fertile days.

• Calendar method
• By the character of the discharge
• Measurement of basal temperature

Calendar Method

The method is based on the following principles:

The cycle begins on the first day of menstruation. The cycle can last approximately 26-32 days. If you want to create a cycle calendar to determine fertile days, you need to have a regular cycle.


How is ovulation calculated? The date of ovulation can be calculated by subtracting 14 days between ovulation and the first day of menstruation from the menstrual cycle as a whole. This means that if the cycle lasts 28 days, ovulation occurs on the 14th day, whereas if the cycle lasts 33 days, ovulation occurs on the 19th day. If a woman’s cycle is irregular, this calculation is less reliable.

For example, if the cycle lasts 27-30 days, ovulation will occur between 13 and 16 days. In the 28-day cycle, the fertile phase begins from 10-11th day to the 15th day or 3-4 days before and one day after ovulation.

You also need to keep in mind that:

  • Ovulation occurs 14-16 days before the start of the next menstruation (provided there are no gynecological diseases, stress, or other adverse effects)
  • Egg viability after ovulation is only 24-48 hours
  • Sperm viability in a woman’s body is around 3-5 days

Fertilization can occur when the sperm gets into the vagina three days before ovulation and 2 days after it. The egg can be fertilized no earlier than 24 hours after leaving the ovary, and the sperm can remain in the vagina for about 3-5 days. Therefore, the probability of conception is highest 3-4 days before ovulation and during the next 4 days.

The Method of Determining Fertile Days By the Character of the Discharge

From the last day of menstruation, you should observe the consistency of cervical mucus (discharge). Immediately after menstruation, there is little mucus. Some dryness is noted in the vagina during this period. After a few days, the nature of the mucus is different. It becomes more viscous and resembles glue. Further, the mucus continues to liquefy. This state of mucus facilitates the progress of sperm. A sensation of moisture appears in the vagina. Also, women note the appearance of discharge on the underwear.


During ovulation, cervical mucus is more watery, transparent, egg-white, and viscous. This type of mucus is most favorable for sperm activity and its movement and corresponds to the period of greatest fertility.

After ovulation, the amount of mucus is much reduced.

Temperature Method

The basal temperature should be measured in the rectum or orally (in the mouth) daily, after waking up, without getting out of bed.

The temperature should be measured at the same time after sleep.


For measurement, it is better to take a mercury thermometer. Keep in mind that, an infectious disease in a woman, accompanied by an increase in the general temperature, inflammatory diseases of the genitourinary system, a decrease in the duration of night sleep, and stress can affect the measurement results. If there are any of these reasons, you need to mark them on the chart.

The measurement results are written in a special table, a graph is built according to the temperature values. Due to the fact that about a day before ovulation, the temperature drops slightly, and during ovulation, it rises by 0.3 – 0.6 degrees and stays at this level until the end of the cycle.

Based on the obtained graph, you can clearly judge the date of ovulation.

In addition, a complete picture of the temperature changes in the body, recorded in a graph, also helps to determine the absence of ovulation and identify the cause of infertility.

There is also a test to determine ovulation, almost the same as a pregnancy test.

Thus, it is necessary to say that every woman, knowing what the concept of fertile days means and how to calculate them, can easily plan a pregnancy or prevent its onset, avoiding sexual intercourse during this period of the cycle.

What Does Female Fertility Depend On?

Female fertility is determined by physiology. For a woman to become pregnant, regular menstruation and ovulation should occur, which indicate cyclical changes in the uterus and ovaries, maturation, and release of the egg. Throughout life, the fertility rate is constantly changing. In many ways, it depends on the health of the reproductive system, the condition of the endometrium and fallopian tubes. Inflammatory processes in the pelvic area, infection, endometriosis lead to problems with conception and gestation. If a woman has bad habits, it also has a negative effect on fertility. Other factors are the following:

  • Excess weight, which can cause hormonal imbalance
  • Stress
  • Adhesions in the pelvis
  • Tissue adhesions inside the uterine cavity (synechia)
  • Hyper- or hypofunction of the thyroid gland, diabetes mellitus, provoking improper production of hormones
  • Intrauterine interventions (abortion, surgery)
  • Disorders of the immune system that contribute to sperm rejection, etc

Fertility problems are associated with the general condition of the body. In order to give birth to a healthy child, it is not enough to eliminate one negative factor – you should reconsider the lifestyle as a whole, develop the right attitude from the point of view of medicine on nutrition, rest, physical activity, etc.

Factors Affecting Male Fertility

Male fertility indicates the ability of a man, or rather his sperm, to fertilize a female egg. This ability appears from about 15 years. The peak falls on 20-50 years. Over the years, fertility decreased. The amount of testosterone decreases as well, which negatively affects the composition of sperm, and potency worsens. These processes gradually create difficulties with conception. At the same time, a man can remain fertile for up to 80 years and even longer. This largely depends on the general state of health and lifestyle.

Factors that negatively affect fertility:

  • Excess weight
  • Stress
  • Genital injuries
  • Inflammatory and infectious diseases of the reproductive system
  • Chronic diseases (arterial hypertension, diabetes mellitus, etc.)
  • Fluid deficiency in the body
  • Hyperthermia, or overheating, of the testicles
  • Treatment with certain drug
  • Bad habits, etc

In recent years, doctors began to diagnose male infertility more often. The main reasons are improper lifestyle, non-observance of the regime of work and rest, malnutrition, smoking, alcohol abuse, etc. All this is directly related to impaired fertility.