Conception date

[Butterflycolors123]

Hi, I am a little confused on how to calculate my conception date.
The first day of my last period was October 20th (actual bleeding not spotting). I usually ovulate on the 15 or 16 day counting from the first day of the last period and my cycles last about 26 to 27 days. Anyone can help me with what would have been my conception date?
Thank you

[AnnieBrooke]

Besides trying to assess your conception date from your ovulation date, you could also make a pretty accurate guess if you had an early ultrasound that gave you a due date.  Did you get an ultrasound before your tenth week, and did the doc give you an estimated due date from it?

[Butterflycolors123]

I just know it is on days 15-16 because I had been tracking my ovulation with fertility sticks, the ones from the pharmacy like the pregnancy tests. We had been trying to get pregnant for a while.

[hkjen]

Ok, the OPKs show your body is preparing to ovulate, but don't necessarily mean that you do.  However, in most women they are accurate and given that you did get pregnant it's likely you ovulated when they predicted.  In which case, you would have actually conceived (sperm met egg) around day 16/17.  Sperm lives for around 3/4 days, so the sex that led to the baby would have occurred between day 12 and day 16.

[AnnieBrooke]

Hi, butterfly, if your cycles are 26 or 27 days long, you would ovulate on about day 12 or 13 of your cycle.  Ovulation is the lead event, and the period is the following event, and the period comes 14 or 15 days after ovulation no matter how long or short that makes things at the part of the cycle before ovulation.  What makes you think you ovulate so late in your cycle?  Has an ob-gyn followed you with ultrasounds and watched when the follicle develops and then is empty?

[hkjen]

Actually that's not true.  Although women *on average* have a 14 day luteal phase (time between ovulation and period), not all women are the same. Personally my luteal phase is 10 days, and I normally have a 29 cycle, so I would normally ovulate on day 19.  Some women have a luteal phase of only 7 days. That is why it is so important for women to track their own cycles and not really on averages. We are all different.

[Butterflycolors123]

I understand that's the general rule, but we had been trying to get pregnant for a while, so I was seen by a fertility doctor who told me to start checking every month when my fertile days would be, so I bought the sticks from the pharmacy, just like the pregnancy tests and every month it would be around the 15-16 day. Not everybody can go by the general rule.

[hkjen]

But what day did you ovulate this cycle?

[Butterflycolors123]

I know I actually ovulate on the 15-16 day of my cycle.

[hkjen]

Do you know that's when you ovulate or are you just guessing?  Your conception date is basically your ovulation date to all intents and purposes.  Though you would have actually had sex between 1-4 days earlier.