Test for ovulation

introduction

Ovulation occurs roughly in the middle of a woman's cycle, more precisely 10-16 days before the next menstrual period. The timing of ovulation can vary greatly from woman to woman. Ovulation causes the egg to enter the fallopian tube, where it has to be fertilized by sperm within 24 hours. If this does not happen, the egg cell dies.

Ovulation is triggered by the maximum increase in luteinizing hormone (LH peak). This hormone can e.g. be found in the woman's urine. Ovulation can be expected 24-36 hours after the LH peak. For successful family planning, it is important to watch this moment in order to ensure fertilization of the egg.

Read more on the subject at: ovulation

What tests are there to determine ovulation?

A relatively reliable method of detecting the fertile days of women is to determine the luteinizing hormone (LH), or more precisely the LH peak, with so-called ovulation tests. At the beginning of the first half of the cycle, the LH is at a constantly low level until it falls within a few days, between the 10th-16th Day, quickly reached a summit. Ovulation occurs one to two days later. The LH concentration can be determined in the urine. The test is carried out like a pregnancy test. The test becomes positive when the LH peak is reached.

Read more on the subject at: Luteinizing hormone

There is also the cycle computer. It is based either on the determination of the luteinizing hormone and estrogen, or on the detection of body temperature. In addition, symptoms such as the occurrence of middle pain (drawing in the abdomen and breasts at the time of ovulation) or the nature of the cervical mucus can be entered on some computers. After a short learning phase in the first few months, the computer calculates the fertile days and shows them on the display.

You can also determine your body temperature with a normal thermometer and document it in a calendar. An increase in temperature of 0.2-0.6 degrees Celsius indicates ovulation.

Read more on the subject at: Ovulation and temperature - what is the relationship?

What do test strips do?

There are different types of test strips. Simple strips, such as a pregnancy test, which determine the LH concentration in the urine, or complex test strips that are connected to a monitor, which can also determine estrogen in addition to the luteinizing hormone. The test strips should be used according to a fixed schedule, i.e. always at the same time. Furthermore, morning urine should not be used for this.

The hormones during the healthy female cycle always change according to a fixed pattern. At the beginning of the cycle, the luteinizing hormone is consistently low. Shortly before ovulation, it suddenly increases, and ovulation can be expected 24-36 hours afterwards. Estrogen increases slightly in the first half of the cycle. Shortly before the LH peak, there is also an increased increase.

Antibodies to which the corresponding hormones can bind are applied to the commercially available test strips. The hormones are in the urine. If the urine hits the test strip, the hormones react with antibodies. If a certain amount of antibodies is occupied with hormones, the test will be positive.

How safe are the tests?

The ovulation tests detect an LH surge with a very high degree of certainty (up to 99%). Unfortunately, an LH surge is not always a sign of imminent ovulation. Menstrual cycle disorders, a luteinized, uninterrupted folicle, or diseases such as polycystic ovary syndrome also lead to an increase in hormones without ovulation. Furthermore, the basal hormone level can differ from woman to woman. If the basic level is high, some test strips show positive results at the beginning of the cycle. If, on the other hand, you use test strips from a manufacturer that are positive at relatively high values, the test can remain negative despite the impending ovulation.

You should therefore have your individual LH concentration determined by a doctor in advance in order to choose the right test strip. Other tests, such as the temperature measurement method or temperature computer, are generally rather unsafe, as the body temperature is influenced by many factors and is often subject to fluctuations. This method is an option, if at all, for women who have a very regular cycle.

When does the test become positive?

The ovulation test becomes positive at the maximum LH concentration (LH peak). Or depending on the sensitivity of the test strips from a certain threshold value. This is between 10-30mlU / ml. Antibodies are applied to the test strip and form a firm bond with the corresponding hormones (LH or estrogen). If a certain number of antibodies are occupied with hormones, a color change can be seen in the form of a dark line in the display field. Usually ovulation can be expected one to two days after the LH peak.

How long has the test been positive?

The test is positive as long as the hormone level is above a certain threshold. Depending on the manufacturer, these threshold values ​​are different, between 10-30mlU / ml. The LH concentration drops quickly after a peak, so that the test is usually only positive for one day. It is the same with the estrogen concentration; it usually reaches a peak for one day and then drops again immediately.

Can you also use the ovulation test for contraception?

The ovulation test is rather unsuitable as a method of contraception. The test turns positive 24-36 hours before ovulation. The probability of fertilization is highest two days before and one day after ovulation. However, sperm can survive in the female body for two to five days. That means sexual intercourse that takes place five days before ovulation can lead to fertilization. At this point the ovulation test is still negative. External influences, such as illness or stress, can lead to cycle deviations and cycle disorders, and in this case too the ovulation test is not suitable as a method of contraception. Hormonal contraception or the use of condoms is much safer.

Read more on the subject at: Overview of contraception methods