Ovulation is the phase in your menstrual cycle when a mature egg is released from the ovary. Ovulation is a complex process that lasts up to 24 hours.
What is ovulation?
Quite simply, about once a month a follicle matures and releases an egg. Ovulation is a process in the female body in which an egg is released from the ovary and travels into the fallopian tube, where it can potentially be fertilised by sperm. This normally happens once a month, around the middle of a woman's menstrual cycle. Hormones in the body solve release of the egg and prepare the uterus for a possible pregnancy. If the egg is not fertilised, it disintegrates and is excreted from the body during menstruation. Ovulation usually takes place around the 14th day of the menstrual cycle, assuming a 28-day cycle. However, it is very important to remember that this is an "average". Every woman is an individual with her own cycle length, and this cycle length can also vary from month to month depending on lifestyle, illness, stress, travelling, etc.
Ovulation begins with the release of follicle stimulating hormone (FSH), which causes several follicles, each containing a single immature egg, to rise to the surface of the ovary. An increase in luteinising hormone causes the follicle to rupture and release a mature egg from the ovary. Many eggs mature in each cycle - but only one (occasionally a second) reaches the point where it is released from the ovary. All the others die and are absorbed by the body. A woman can expect to ovulate around 500 times in her lifetime until all the eggs are used up and she reaches the menopause.
After release, the egg travels down the fallopian tube to the uterus. Ovulation is the only time in your cycle when you can become pregnant. If the egg is not fertilised and pregnancy does not occur, the egg is absorbed by the body. After the follicle has released its egg, it turns into the corpus luteum. This structure releases hormones, mainly progesterone and some oestrogen. The progesterone causes a tiny rise in basal body temperature that lasts until the next period. It is this tiny rise in temperature that femSense can measure and which confirms ovulation. The rise in temperature is a direct result of ovulation - the follicle transforms into the corpus luteum, which in turn causes a rise in basal body temperature - and is therefore a reliable confirmation that ovulation has taken place. After ovulation, oestrogen levels fall and progesterone levels rise. If an egg has been fertilised, the progesterone level continues to rise; if fertilisation has not taken place, the progesterone level falls and the uterine lining sheds and leaves the body with the period.
The time shortly before and immediately after ovulation is a woman's most fertile period. This fertile window is shorter than most people think - it only lasts a few days. Just before and during ovulation, the environment in the uterus is very sperm-friendly, allowing sperm to survive for up to four days while waiting for an egg to arrive. The egg itself is capable of fertilisation for about 24 hours after ovulation, after which it dies. This means that you have about 5 days per cycle when you are at your most fertile and pregnancy is likely.
Symptoms of ovulation
What does ovulation feel like? There are some common physical signs of ovulation Ovulation, which you can observe if you want to know if and when you are ovulating. The hormonal changes that trigger ovulation also cause other symptoms in your body that can be so mild that you may not even notice them. You can learn to pay attention to these symptoms to recognise when you might be ovulating.
- An increase in basal body temperature
- Changes in the cervical mucus
- Middle pain
- LH increase
Fun fact: Did you know that baby girls are born with all their eggs? The developing female foetus has about 7 million eggs weeks before it is born! The body absorbs most of the eggs before birth, but about 2 million eggs are still present when a baby girl is born, and about 500,000 when she reaches puberty and starts menstruating. A woman's remaining supply of eggs that can produce a baby is called the "ovarian reserve". This means that a woman's eggs are always a few months older than she is.
Whelan (2023), What Are the Signs and Symptoms of Ovulation?
Showell (2023),9 Signs of Ovulation