Ovulation Induction

If ovulation is not occurring regularly it may be necessary to give hormone tablets/injections to stimulate the ovaries. However, before these treatments are used it is important to find out why regular ovulation is not occurring, as more specialised treatment may be necessary for some women.

Ovulation induction treatment is the same as for cycle tracking or ovulation tracking with the addition of medication to induce ovulation.  After taking the medication, the patient has blood tests and ultrasounds to predict the time of ovulation (see Treatments>Cycle Tracking for detailed information on this).  The patient is informed of the optimal time for intercourse in order to conceive.

Risk of a multiple pregnancy

The aim of ovulation induction is to stimulate the ovary to produce one follicle and for a result of one oocyte to be fertilised.  Occasionally, the dose of medication may induce two or more follicles to develop and this may cause more than one oocyte to be released, which could result in a multiple pregnancy.  If this is indicated on the ultrasound tests then the patient will be informed of this possibility and advised to abstain from unprotected intercourse in order to prevent this.  The dose of the medication used can be reduced in subsequent cycles to reduce the likelihood of multiple ovulation.

Medications for Ovulation Induction

The most common treatments used include clomiphene citrate (trade name Clomid/ Serophene), or follicle stimulating hormone (FSH).

Clomiphene acts by interrupting the chain reaction of stimuli to the pituitary gland and allows more FSH and LH to be released. These hormones in turn stimulate the ovaries. Clomiphene tablets are usually given for five days commencing a couple of days after the start of a monthly cycle.  Ovulation is expected to occur between five and ten days later. Some women notice they have less vaginal mucous while taking clomiphene and may not be able to use this method to detect ovulation. The chance of multiple pregnancy after using clomiphene depends on the dose and the specialist should discuss this with patients.

FSH and human chorionic gonadotropin (hCG) are hormones that are given by injection. HCG is used to trigger ovulation when a mature oocyte has developed. It is used when it is thought that the rise in the LH has been insufficient. HCG injections are nearly always used when FSH is used. FSH stimulates the oocyte-maturing process and the development of the follicles on the ovaries, and is given each day from day 2 of the cycle. When the oestrogen level reaches its peak an ultrasound will be done and the hCG injection will be given as appropriate. When using FSH it is very important to monitor its effect by regular blood and ultrasound tests as this treatment is more likely to cause a multiple pregnancy. Usually FSH is given as either Gonal-F or Puregon and hCG is either Pregnyl or Oridrel.