Natural conception

How does it happen?

Fertility amination

Natural conception requires regular unprotected intercourse, regular monthly ovulation (egg release), normal sperm production and normal Fallopian tubes to allow the passage of the sperms. Every month around midcycle, an egg is released from the ovary by a process called ovulation. The finger-like projections of he Fallopian tube collect the released egg and pass it inside the tube. When intercourse takes place around the time of ovulation (midcycle) a large number of sperms travel through the neck of the womb, into the womb, then through the Fallopian tube to reach the egg, near the end of the tube. Only one of the several thousand sperms that reach the egg will fertilise it to form the zygote (the very early embryo). The zygote will start to develop and grow within the tube. It will also slowly travel through the tube in a journey that takes around 5 days before reaching the cavity of the womb where it will finally settle. In the womb, the egg gradually digs itself in the wall of the womb in a very sophisticated process called implantation where it will continue to grow and develop until term.

What is the chance of natural conception?

Couples trying to achieve a pregnancy in their first year have a 20% chance of pregnancy in each cycle. If they continue to try for a year, they will have an 85% by the end of the year. The chances of pregnancy are reduced in the second year to 10% per cycle and 50% by the end of the year. These figures are further reduced in the third year to 5% and 15% respectively.

How can this chance be maximised?

This can be achieved by adhering to the following:

  1. Starting under the age of 35 as the chances of conception decline significantly after that age.
  2. Timing of intercourse around ovulation (between day 10 and 17 in women with 28-day cycles)
  3. Avoiding too frequent or too infrequent intercourse (2 - 3 times a week is preferred) and
  4. Living a healthy lifestyle with good stress management.

What is infertility and how common is it?

Infertility is defined as inability to conceive after 1 year of regular unprotected intercourse. In other words, couples with no obvious problems are encouraged to continue to try regularly for of at least one year before seeking medical help. This one-year rule applies to young (female age under 37) couples with no known reproductive problems such as abnormal menstrual pattern, disease of the tubes or coital problems.

What causes infertility?

There are three main disorders that cause infertility including lack of ovulation (found in about 25%), disease of the Fallopian tube (about 30%) and sperm abnormalities (about 25%). Other less frequent causes include coital problems, disorders of the cervix (neck of the womb), abnormalities of the womb or immunological disorders (production of antibodies against the sperm or the egg). In about 10-15% of cases no apparent cause could be found and these will be diagnosed as unexplained infertility.

How can fertility be tested?

Routine investigations include a blood test on day 21 of a 28-cycle to check to ovulation, x-ray with dye test or laparoscopy to check for the condition of the Fallopian tubes and a sperm test for the male partner. Further tests may be required depending of the findings of the initial tests e.g. women with lack of ovulation will need to be tested for thyroid function, prolactin level and evidence of polycystic ovary syndrome.

Management options

Treatment of infertility depends on the cause, the age of the couple and the duration of infertility. The following are some examples:

  1. Lack of ovulation: clomiphene citrate is the usual first line to induce ovulation. It is the most widely used medicine in fertility treatment, although it is not suitable for every one. It is given for 5 days in the beginning of the cycle.
  2. Disease of the Fallopian tube: Depending on the nature and extent of the disease, the options of treatment include surgical correction of the tube or IVF (test tube baby).
  3. Sperm abnormality: depending on the severity, the treatment will be either intra-uterine insemination (IUI) or ICSI (IVF with injection of the sperm into the egg under the microscope).
Saad Amer

Saad Amer MSc., FRCOG, MD
Consultant Gynaecologist

Private sec: 01332 785693
NHS Sec: 01332 786773
Private appointment: 01332 540104