What is ovulation - Find out your most fertile days

Ovulation is the part of the menstrual cycle when an ovary releases a mature egg. The egg is typically captured by the fallopian tube, where fertilization can occur if sperm are present. For many, understanding ovulation is helpful because it can aid in planning pregnancy or gaining a better overview of their cycle. The most important thing to know is that timing can vary from person to person and from cycle to cycle.

Ovulation often occurs approximately 14 days before the next menstruation, but it depends on your cycle length. For example, if you have a 28-day cycle, ovulation will often be around day 14, counting from the first day of bleeding. With a 30-day cycle, it can typically be around day 16.

A simple method is to take the length of your cycle and subtract about 14 days to get an estimate. It is an estimate, not a guarantee, because stress, illness, travel, weight changes, and other factors can affect the timing.

You are most fertile in the days leading up to ovulation itself and on the day of ovulation. This is because sperm can sometimes survive for several days in the female reproductive tract, while the egg itself can typically only be fertilized for a short period after ovulation.

If you are trying to conceive, it can be relevant to have intercourse every 2-3 days during the period when you expect ovulation, so that timing does not become a stress factor. If you wish to avoid pregnancy, it is important to know that calendar methods alone can be unreliable, especially with irregular cycles.

Some experience clear signs, while others notice almost nothing. Possible signs can be changes in discharge (often clearer and more elastic), mild pain on one side of the lower abdomen (mittelschmerz), or increased libido.

Contact a doctor if pain is severe, lasts a long time, or if you have a fever, heavy bleeding, or other symptoms that concern you. There may be other explanations than ovulation.

There are several practical ways to predict or confirm ovulation:

You can keep a cycle calendar in an app or on paper and use your cycle length to make an informed guess about when ovulation will occur. This method is most useful for relatively stable cycles.

Ovulation tests measure the increase in LH hormone in urine, which often occurs shortly before ovulation. The test can be helpful if you want more precise timing, but it does not definitively confirm whether ovulation actually occurs.

Measuring temperature in the morning can show a small temperature increase after ovulation. This method is mostly used to confirm that ovulation has likely occurred and requires regularity to be useful.

Ovulation is controlled by an interplay of hormones. FSH stimulates the maturation of eggs in the ovaries. When estrogen rises, it can contribute to an LH surge, which triggers ovulation itself. After ovulation, the body produces progesterone, which prepares the uterine lining for a possible pregnancy.

Irregular cycles can make it more difficult to predict ovulation. If you often do not bleed, have very long cycles, or have difficulty getting pregnant, it may be relevant to talk to a doctor about possible causes and next steps.

If you are trying to conceive, it can be helpful to know where to start if the test comes back positive. Many quickly find that comfort around the breasts and body means a lot as the body changes. One option is a pregnancy and nursing bra without metal underwire, for example, the Gel-Support Maternity & Nursing Bra. If you want to gather relevant items in one place, a ready-made package can also be practical, such as the Mum to be Essentials Box.

• Sundhed.dk, patienthåndbogen (about fertilization and cycle)
• Med24 (professional review of ovulation and hormones)
• Matas (symptoms and methods for tracking ovulation)