As a GP, I frequently deal with fertility concerns and menstrual disorders. We can all too often become focused on what may be wrong and in turn, we overlook what may be normal. So reviewing the basics is an important place to start!
It can be helpful when thinking about trying to conceive that you have some understanding of your menstrual cycle. Most people spend a significant proportion of their lives trying not to get pregnant and when the time actually arrives when you start thinking about trying to conceive, it can be a surprise for many to know it’s not as easy as you may think! Figures vary on monthly pregnancy rates but it is felt to be in the region of 15-25% chance in any one month. Around 84% of couples who are trying to conceive will fall pregnant within a year of regular intercourse. If you haven’t already, check out the Nua ovulation calculator to estimate when your ‘fertile window’ may be.
So let’s talk about ovulation!
Ovulation involves the monthly release of an egg from the ovary. The menstrual cycle allows for ovulation to occur. Ovulation is essential for egg release and requires hence fertilization by sperm to result in pregnancy. It is regulated by hormones released from the pituitary gland (about the size of a pea at the base of the brain) to relay signals to the ovaries telling them when to release an egg.
The menstrual cycle has four phases: Menstrual, Follicular, Ovulatory, And Luteal.
The brain releases Follicle Stimulating Hormone (FSH). This causes several follicles in the ovary to mature. Usually only one dominant follicle is able to survive and continue to grow. This maturing follicle produces a form of oestrogen. This stimulates the brain to increase production of Luteinizing hormone (LH). The peak of LH leads to rupture of the ripe follicle. This is ovulation. The egg is released into the fallopian tube. An egg survives on average 12-24 hours. It needs to be fertilized by sperm within this timeframe for pregnancy to occur. This occurs in the fallopian tube. The egg then moves into the uterus. When it has reached the uterus a fertilized egg implants into the uterine wall. If pregnancy doesn’t occur the egg is passed out during menstruation. Declining levels of oestrogen and progesterone result in the lining of the womb coming away and a period occurs.
The duration of the menstrual cycle can be regular for many people but for some this process can occur on a more irregular basis. The average duration is around 28 days but can vary from 21 to 40 days.
How can I tell when I’m ovulating?
Ovulation tends to occur 10-16 days before your period starts. Changes to cervical mucus can be seen. It becomes thinner and clearer, this is to allow sperm to swim more easily to reach the egg in the fallopian tube.
There are various investigations which can be carried out to detect ovulation. The standard test would be Day 21 progesterone which is a simple blood test that can be carried out by your GP. Other methods include ultrasound follicular tracking, temperature charts, and LH based urine predictor kits.
A combination of methods is felt to give a more accurate indication.
Sperm can live up to 7 days in woman’s body so if you have had sex in the days leading up to ovulation the sperm will be waiting to fertilise the egg. Having sex every 2-3 days in the month is felt to enhance the chances of pregnancy
What can affect ovulation?
Some problems with fertility stop ovulation occurring while others impact on egg release in some cycles but not others. Below is a list of some conditions which can result in issues with ovulation.
- PCOS – Polycystic ovarian syndrome (Here at Nua fertility we love all things gut health and there is emerging evidence of the role of gut health in the management of PCOS!)
- Thyroid problems – both hypothyroidism and hyperthyroidism
- Premature ovarian insufficiency – the loss of normal ovarian function before the age of 40
- Hyperprolactinaemia – abnormally high levels of prolactin hormone.
If you are experiencing problems with your periods or are having difficulties trying to conceive, talking with your GP is a good place to start to review your history, carryout initial blood tests and make a plan for the next steps in your fertility journey.