Menstrual cycles are regulated by a group of hormones, the increase/decrease in the levels of which induces bleeding/ovulation/maintenance of pregnancy. Luteinizing hormone (LH) is one such hormone which promotes the release of eggs into the fallopian tube, once the Follicle Stimulating Hormone (FSH) has completed nurturing the maturation of egg. Thus, the levels of LH can be used to determine if ovulation is about to happen or has occurred.
Ovulation will usually occur 12-36 hours after LH surge (increased levels) and the surge likely remains for 12-24 hours. Thus, a detection of these levels would help predict ovulation and schedule the intercourse to achieve conception. However, this method should not be used as a means of contraception. It is also a matter of fact that small amount of LH is always present in the blood/urine sample but during surge it is 5 folds that of the normal levels. Below is the representation of LH surge:
The test should be begun from 11th day of the cycle for a normal 28 days cycle. If the cycles are not of 28 days the surge has to be tested according to this. Once the surge is detected one can stop taking the test. The levels of LH are monitored in two ways:
1. Blood test
– A sample of blood is withdrawn from the woman’s body in a clinic or a laboratory. This sample is tested for the levels of LH. Since this method is slightly painful due to puncturing by the needle, followed by mild bruises, it is not as common as the urine test done for the same purpose. Since needles are involved chances of infection also prevail. Moreover, as surge cannot be detected in one shot multiple samples of blood need to be collected adding to the number of punctures. However, some studies suggest this method as more accurate, since the exact level of LH can be detected and the figures could be used to carry out IUI or IVF.
2. Urine test
– The sample of urine can be tested for LH surge by two methods:
• Dip-stick method – Here the test strip shows the level of LH after it is being dipped in the urine sample for 3-5 seconds. The results would appear in less than 5 minutes. The strip has a control line with a particular (red/dark pink) color and the test line will be developed to show the level of surge. If the color exactly matches/ greater than that of the control line, then the surge is triggered. If it is fainter than the control line, the surge would happen in a day or two. Urine sample can be collected between 10 am to 8 pm, preferably in the afternoon. First urine in the morning should be avoided since LH surge usually triggers later in the morning.
• Mid-stream method – Here the test strip (made of plastic) is held in the stream of the urine and the level of LH is determined similar to the above one.