Your cycle is a pattern that repeats itself, in it differences in length may occur also the ovulation day may vary from cycle to cycle. A healthy adult woman's menstrual cycle lasts between 21 and 35 days and consists of three main phases:
The follicular phase (duration: 7 to 21 days): this phase starts with your period. Under the influence of Follicle Stimulating Hormone (FSH), several follicles (vesicles in which eggs mature) start to grow.
Ovulation: ovulation (duration: 1 day)
The luteal phase (duration: 10 to 16 days): if fertilisation has occurred, during this phase the egg cell moves to your uterus to implant. If fertilisation has not occurred, the build-up of the uterine wall stops and it is shed: you get your period and your cycle starts again.
So the follicular phase starts with your period, during which you lose blood and mucus from your uterine wall. Therefore, implanting a fertilised egg during bleeding is not possible even if there is no build-up of endometrial mucus on the inside of the uterus yet.
You can only become pregnant if a sperm fertilises the egg immediately after the moment of ovulation (within 18 hours of ovulation). The fertilised egg then moves from the ovary through the fallopian tube to your uterus, which takes 5 to 7 days. Arriving in the uterus, the egg nests to grow further into a foetus. Then you make the pregnancy hormone HCG which shows with a urine pregnancy test that you are pregnant. Your next period stays off, you are ‘overdue’ because the corpus luteum (yellow body/follicle) continues to produce the hormone progesterone.
Ovulation occurs roughly in the middle of your cycle between one period and your next. Your body needs the weeks before and after ovulation to provide the uterine wall with a layer of mucus for the fertilised egg to survive.
My midwife says I have been pregnant since my last period
For convenience, if you are pregnant, from the first day of your last period is used as the first week of pregnancy. In reality, it is not, but it is the easiest way to calculate how many weeks you are pregnant because most women remember when their last period started. If your doctor or midwife were to ask ‘when was your last ovulation’? Then that is not easy to answer for many ladies because feeling a pain sensation in the lower abdomen is not always the time of ovulation. As the follicle containing the egg matures, surrounding tissue can be stimulated which can also definitely give a pain sensation. To pinpoint the exact moment of ovulation is difficult. Fortunately, your BBT (basal body temperatures) do indicate when ovulation was.
So you get about 2 weeks of pregnancy in time as a gift. If you are 40 weeks pregnant, the baby was really formed about 38 weeks ago.
Getting pregnant with a short menstrual cycle
A menstrual cycle should last at least 21 days. If the cycle is shorter, then you have a cycle without ovulation, a short follicular phase or short luteal phase. In all these cases, the buildup of the endometrium is not optimal and the production of progesterone lags far behind, making it impossible to conceive. Read all about the hormone progesterone for a smooth cycle and chances of pregnancy.
Suppose you have a short cycle of 21 days, then the first chance of ovulation is on day 12, according to science. Suppose you menstruate for 7 days, then there are 5 more days between day 7 and 12. These are the days Daysy indicates red (fertile days) because sperm can survive a maximum of 5 days.
In the above calculation example, we see that getting pregnant during menstruation is not possible: if you include the last day of menstruation (day 7) and add 6 days to that is ovulation (day 12). These are 6 days but sperm can survive a maximum of 5 days. Getting pregnant during a short cycle while menstruating is out of the question.
But my doctor says it is possible!
Perhaps the doctor is referring to a study done on 40 women in which ovulation could not be determined in 10% (4 women). In which the researchers found a cycle length variation between 22 and 37 days with an average of 27 days. Ovulation day varied according to ultrasound study between day 8 to day 26 with an average of day 15. The luteal phase length was 12.3 +/- 2.5 days. (1)
You get the idea that if you do research on 40 women (very few for a serious study) of whom 10% lose weight and you find a luteal phase length of say 10 days. Did in the most short cycle that of 22 days ovulation occurred on day 12 and not on day 8. To clarity; the luteal phase is from ovulation day to the first day of menstruation of your next cycle.
If you assume both extremes, the earliest ovulation on day 8 and the shortest luteal phase of 10 days, then you are talking about a total cycle length of 18 days and they did not find this in the study (1). The question is whether your body then has enough time to produce progesterone after ovulation to hold a fertilised egg which must be nestled in the uterine wall.
Capturing ovulation is not easy with an ultrasound
Wasn't it discussed before that if you really want to capture ovulation you have to monitor women for more days in a row 24 hours a day through an internal ultrasound? Something we are really not waiting for!
Oestrogen and LH hormone peaks in urine and serum showed a range of signalling characteristics before and after ovulation in the study group. The increase in oestrogen and LH always occurred before ovulation; the increase in progesterone from baseline always occurred after ovulation.
That's nice, clear but surely we know that before ovulation actually occurs there can be more times when oestrogen and LH spike? Which still does not necessarily mean that ovulation actually occurs. Women who sail on ovulation tests (an LH test) in childbearing know that this test can be positive before that while ovulation is not yet coming.
This is a big frustration we hear a lot here at Daysy.nl while BBT temperatures then still do not confirm ovulation. Another shortcoming of this study, in my personal opinion, is that FSH (follicle stimulating hormone) and testosterone were not tested because those hormones are also definitely active in the ovulation phase.
It is said (in the study), the most early ovulation in these 36 women was seen on day 8. Most women menstruate for 3 - 4 days. So how is it possible to get pregnant during menstruation? Surely you need an egg for that! People have, to my knowledge, never studied whether sperm survive in the vagina and uterus during menstruation. Let's not complicate things
Suppose your periods last 7 or 8 days then you definitely already have red fertile days if you measure with the Daysy or LadyComp (see 2nd image in this blog). Your device takes into account ovulation and the maximum survival time of sperm internally.
I hope you have gained more knowledge with this explanation so worry about getting pregnant during menstrual days.
Sources
(1) Factsaboutfertility biomarkers of ovulation and the fertile window a research summary
Monitoring the menstrual cycle: Comparison of urinary and serum reproductive hormones referenced to true ovulation
Medical news today. Can you get pregnant on your period? Articles/324829
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