Most women are alien to the fact that there is a certain time period that comes with their best chance of getting pregnant. This time period is known as the ‘fertile window’ which lasts only three days in the life of an average couple. In simple words ‘fertile window’ is the days in which the woman is ovulating and is her body is ready to get pregnant.
Ovulation is the process in which a matured egg is released from ovary and moves to the fallopian tube. The egg will be sitting in the fallopian tube for the next 12-24 hours, available for the sperm to fertilise it. It will be disintegrated after 24 hours and the chances of becoming pregnant is lost until next ovulation.
However, fertile window is not limited to these 24 hours because unlike ovum/ egg, sperms can survive inside the female body for up to 72 hours (3 days). So the sperm that has entered the fallopian tube two days before ovulation can fertilise the egg that is released on the third day, thus creating the fertile window of three to five days in one ovulation cycle.
What Is Your Ovulation Cycle?
Knowing your ovulation cycle will help you predicting your best chance of getting pregnant. An average woman ovulate after approximately 14 days from the first day of her period. In other words, the three to five days that happens to be in the middle of your last period and next expected period is when you ovulate.
It is not correct to assume that everyone will have the same cycle. So your best chance is to look at your menstrual cycle and figure out your fertile window. If you have a menstrual cycle of 28 days, then you will be ovulating on day 14 and your fertile window is on days 12 to 16. If you have a longer cycle that has approximately 35 days, you are most likely to ovulate on day 21 and that makes days 19 to 25 most fertile days. In case of shorter cycles of 21 days, one can expect ovulation on day 7 and the fertile window will be on days 5 to 10.
Another essential factor apart from these statistics is regular sexual life (at least every 2-3 days). It will be helpful irrespective of the regularity of your menstrual cycle. Timed sexual intercourse is not only the best way to fight stress but it improves the quality of semen as well, both of which are key factors to your reproductive health.
While your body is preparing for ovulation, it gives you signs such as temperature variation and cervical mucus. Maintaining a basal body temperature chart (BBT) will be helpful in predicting the pattern of your cycle. Temperature should be measured before getting out of bed in the morning because physical activities will increase body temperature and give inaccurate results. BBT can be measured with a thermometer on body parts such as mouth, vagina and anal area.
Cervical mucus is secreted by glandular cells in the cervix which acts as barrier to foreign bodies most of the time. However, it acts as a carrier for sperms during ovulation. You can assess cervical mucus and figure out if you are ovulating at the moment. During your fertile window, it looks like raw egg white with a transparent appearance and is stretchable up to 10 inches. It cannot be wiped off with a toilet paper and will stay as a lump. Some of the other signs found on the days leading up to ovulation are light spotting, cramps or slight pain on pelvic area, breast tenderness and abdominal bloating.
Even with keen observation of one’s cycle and signs, it can be hard to predict the day of ovulation. Luckily we have something called ovulation tests/ ovulation predictor kits (OPKs) which tells you if you are about to ovulate or not.
These tests are designed to detect the amount of luteinizing hormone (LH) in urine. A woman’s body will have a dramatic increase in LH level before 12 to 36 hours from ovulation. There are two types of ovulation tests available in the market, test strips and midstream tests. For both the tests, you should collect your urine sample in a clean container. If you are using stripes then dip them in the sample for 3-5 seconds. In case of using midstream test, you can drop few drops of urine to the instructed spot and wait for the results. Typically a positive result will be indicated with a darker line and the lighter line indicates the normal amount of LH which is present in urine all the time. However, you can interpret the results by following the instructions on the package to find out the correct result.
It is recommended to start taking ovulation test after one and a half weeks from the first day of period. Taking the test at the same time every day increases chances of accuracy. And afternoon or evening is the appropriate time to take ovulation tests. They are a good method to know the pattern of your ovulation cycle which will help you predict your fertile window and increase your chances of pregnancy.
If you find yourself not getting pregnant after knowing your cycle and having intercourse during your fertile window, you should know that it is time to consult a good gynecologist and discuss your situation.
About the Author
Dr. Parasuram Gopinath is the Senior Consultant & Scientific Director at CIMAR Fertility Center with branches in several parts of Kerala. Tamil Nadu & Dubai. After Dr Parasuram completed his post-graduation in Obstetrics and Gynecology, his work has been mainly focused on infertility and embryology. He had undergone further training in Advanced Reproductive Techniques like Oocyte Cryopreservation, IMSI, IVM etc. from several centers in Singapore, Germany & Canada. He has personally done over 3000 ICSI procedures and was instrumental in introducing the technique of IMSI in South India. He is an Invited speaker at Several National conferences on Infertility and do also have several publications to his credit.
Dr. Parasuram Gopinath, MBBS. MS(OBG)