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Meaghan Bowling, MD

Fertility tracking apps are everywhere.  Here, Dr. Bowling reviews some of the common misconceptions about tracking your ovulation, and when to seek help from a fertility specialist.

What exactly is my cycle length?  One of my top questions for patients when I see them for a new patient visit is ‘how many days are there between your periods?’  This means, how many days from the start of one period (or ‘cycle day 1’) to the next cycle day 1?’  The typical cycle length should be around 28-31 days in length.  Cycle day 1 is defined as the first day of bright red, full flow.  Spotting does not count.  Many women have a few days of spotting before the true start of their period, so I let them know that spotting doesn’t count as your cycle day 1.

How are fertility apps helpful?  Fertility apps are great for helping a woman understand her cycle length, but are not the final word on knowing when she ovulates.  For most women with regular periods, the apps correctly predict the fertile window.  The fertile window is the 5 days leading up to and including the day of ovulation.  These apps use a mathematical prediction to determine that the day of ovulation is the half-way mark of the overall cycle length.  So, for a 28 day cycle, the day of ovulation is cycle day 14.  For a 30 day cycle length, the day of ovulation should be cycle day 15.

How should I time intercourse?  Studies have shown that having sex every other day in the fertile window is just as likely to result in pregnancy as having sex every day.  So I like to reassure my patients that daily sex is not going to improve your chances of success.  Often time couples struggling with infertility may be adding more stress to their lives by feeling the need to schedule daily sex.  Studies have also shown that, of all the days in the menstrual cycle, the day of the month that offers the best chance of pregnancy is having sex THE DAY BEFORE ovulation.  So, if you have a 28 day cycle, you should ovulate on day 14, and then best time to have sex is day 13.  That being said, it’s always important to have ‘back up sperm’ in the vagina, as sperm can survive for 3-5 days after ejaculation.  So, in this scenario, the couple should have sex on day 9, 11, and 13, with sex on day 14 being potentially helpful.  I recommend that patients not “save up” for the critical moment of ovulation, as they may miss ovulation this way.

How can fertility apps backfire?  Fertility apps are not a replacement for ovulation predictor kits (OPKs), which are tests that detect ovulation by checking for a hormone called LH in the woman’s urine.   I would encourage all women to use OPKs for at least 1 month at the beginning of their attempt to conceive.  OPKs should turn positive the day before ovulation, and therefore the day that you get a ‘positive’ OPK is the best day to have sex.  If your OPKs don’t turn positive or if they are turning positive much later than what your fertility app is suggesting, then there is a high likelihood that you have an ovulatory disorder leading to lack of conception.  In this case, I am more likely to believe what the OPKs are saying rather than what the app is predicting.  Women who are getting their positive OPKs around cycle day 16 and later are unlikely to get pregnant, because an ovulation which occurs later in the cycle is unlikely to result in a pregnancy.  This is because, even though the egg is released and may be fertilized by a sperm, the subsequent embryo that develops is unlikely to implant because at that point, the lining of the uterus is already beginning to break down in preparation for the next period.

When should a woman seek help for an ovulation disorder?  Women should seek help sooner than the 6- or 12-month mark if they have any of the following: 1) irregular periods (meaning cycle lengths shorter than 27 days and longer than 32 days, 2) Ovulation predictor kits that do not turn positive or turn positive before day 11 or later than day 16.  Treatment to correct ovulation issues is often very simple and requires minimal intervention.  Often women are scared about the potential need for aggressive treatments such as hormone injections or even IVF, when something as simple as a pill (clomid or letrozole) can correct the underlying ovulation dysfunction.  I encourage women to be proactive about seeking help sooner rather than later!