Fertility and conception

Article to inform the reader on optimising their chances of a natural conception by understanding the physiology. The menstrual cycle, oogenesis, male fertility, spermatogenesis and timing of intercourse.

Fertility and conception

Maximising your chance of conception.

Unfortunately many couples today find it takes longer to conceive than they expect, and many have trouble conceiving for a variety of reasons. The aim of this article is to educate you about how the menstrual cycle and conception work so you can optimise your chances of conceiving naturally.

It may seem obvious to you how to get pregnant and have a baby, but there are a number of common misconceptions that I encounter regularly in clinic, which may hinder a couples chance of conceiving. These misconceptions are often reinforced by health professionals simply through ignorance and by marketing of devices like pregnancy tests.

Physiology of the menstrual cycle

The hypothalmus, an organ in the brain, emits a pulse of GnRH (Gonadotrophin releasing hormone) which stimulates the pituitary gland, also in the brain, to release follicle stimulating hormone (FSH)- the 'gonadotrophin'. FSH then builds in the body stimulating the development of follicles in the ovaries, and the production and secretion of oestrdiol- the second and most important form of oestrogen for fertility, also know as e2.

Oestrdiol stimulates the growth of the lining of the uterus (endometrium), and when it reaches sufficient levels changes the cervical mucus to a receptive fertile, egg-white consistency, softens and opens and raises the cervix. All these things prepare the female body to receive sperm and allow it towards the soon to be released ova.  

Toddler girl looking at mothers pregnant tummy, both wearing pinkIn the properly functioning system a number of follicles will develop on each ovary. When FSH reaches a certain level, a feedback reaction stimulates the release of luteinising hormone (LH) from the pituitary, and this triggers ovulation.

After ovulation the old follicle is called the corpus luteum and secretes progesterone which helps sustain the endometrium. When the corpus luteum runs out and progesterone stops you have your period. What happens in pregnancy is that the foetus secretes a hormone called Human Chorionic Gonadotrophin (hCG) which tells the corpus luteum to keep producing progesterone until the placenta is developed enough to take over. This happens around twelve weeks into a pregnancy, which is why twelve weeks is often treated as a landmark in the progress of a pregnancy. hCG is also the hormone measured in the over the counter pregnancy tests, they pick up levels secreted by the developing embryo when they are high enough and can show either before the period would be due or shortly after. I usually advise waiting until the cycle is late as there is a tendency to build up expectations, get upset and increase your stress if you check too frequently, and when the result may be inaccurate in any case. 

Life of sperm

Average sperm can live for around five days in the vagina and uterus, and even poor quality sperm can survive for up to three days and some evidence suggests that really high quality sperm can survive for up to seven days. The process of sperm development goes on constantly and millions are produced daily in the testes, unless there is a male factor fertility problem. I shall write more on this in another article. However the semen which the sperm are in, which feeds them and protects them from the females immune system for a time, takes over 24 hrs to replenish. Since a smaller amount of semen necessarily contains fewer sperm, it is optimal (for fertility purposes) to have intercourse every other day. That said, there is also recent evidence to suggest that intercourse more than once in succession on those days can increase the chances of conception. 

Conception- Timing and frequency of sexual intercourse

Research into the timing of sex and pregnancy rates shows a curve starting with a tiny amount seven days beforehand, peaking two days before ovulation and then declining again until the day after ovulation. One thing to learn from this is that, although the testing kits you can buy are useful, you shouldn't wait for them to be positive before having sex. The LH surge mentioned above is what the tests detect, and ovulation may occur on the day of, or up to two days after the LH surge, on the outside. Therefore if you wait until the test is positive, you have missed four or five days of possibly fertile procreation time.

On the whole when calculating optimum timing for sexual activity to conceive, it is practical to think of the five or six days before ovulation, the day of ovulation itself and then the day after. And trying every other day, what you want is for the sperm to be there in the fallopian tube prior to the ovulation in order to maximise your chances. The issue then is predicting when you are going to ovulate beforehand.

Predicting Ovulation

If you have a regular cycle this is quite straight forward, you can assume the luteal phase (after ovulation) is about 14 days long, so subtract 14 from your cycle length and you are probably ovulating within a day either side of that. If you have a less regular or erratic cycle it can be a lot more difficult and one of the ways we can work with that is to regulate the cycle with acupuncture and Chinese herbal medicine.

BBT chartingbabys foot held in an adults hand

Using a basal body temperature (BBT) chart can give you lot more information about when you are ovulating, and can also be useful diagnostically. If that extra information reveals that you ovulate at less than regular intervals, it essentially means your potential fertile window is longer, so all the days in your cycle when you might ovulate, based on the last three or so months of BBT charting, plus 5 days before and 2 days after becomes your active fertile period. So have sex every two days within that time of your menstrual cycle to maximise your chances of conception.

Cervical Mucus

Another way, possibly the most reliable way, is the observation of cervical mucus. In some people a cervical mucus defect is the only thing in their way of conceiving naturally. This people therefore respond very well to IVF, but we can also treat this using herbs if you want to conceive naturally.

As mentioned above, rising oestrodiol changes the cervical mucus, in effect the strands of protein in the fluid line up to form channels ushering the sperm into the uterus with ease. It also forms a protective layer against the immunologically hostile environment of the vagina. 

You can monitor it, by being in touch with your cervix, and noticing when the consistency changes to a clear fluid that can be stretched a way between two fingers, this is a very reliable way of knowing you will be ovulating soon, within a day or two, and therefore an optimum time to conceive. This may or may not match up exactly with what the urine tests show, but has the benefit that it happens before you ovulate so is predictive.

If you are having any problems conceiving and want to get some help using acupuncture and/ or Chinese herbal medicine please do get in touch to ask any questions you may have or book an appointment.