Ovarian induction is the process to stimulate ovulation (production and release of eggs from a woman) by medication. This is used for women who have difficulty conceiving as their ovaries do not release eggs. Medications can be used to either cause ovulation in a patient who does not ovulate regularly or to cause multiple eggs to be developed and released. There is approximately 25% of infertile women who have problems with ovulation. By helping these women to ovulate regularly, it increases their chances of pregnancy. These medications are called “fertility drugs” and may also improve the endometrium (lining of the womb or uterus) which is required for pregnancy.
Ovarian induction can help women who have irregular periods as they are likely to have ovulatory dysfunction by helping them to have regular ovulation. Some ovulation problems include: polycystic ovarian syndrome (PCOS) – a hormonal condition which causes the eggs to not be released, ovaries that do not respond to hormones that help the maturation and release of the egg (luteinizing hormone (LH) and follicle stimulating hormone (FSH)), thyroid problems, eating disorders, extreme weight gain and weight loss.
Before fertility drugs are given to patients, doctors often use a hysterosalpingogram (HSG) to make sure that the fallopian tubes (tubes for the fertilized egg to travel into the womb for implantation) are unblocked. Patients who have a blocked tube may have an ectopic pregnancy (pregnancy that occurs outside of the uterus) and can be dangerous. Many women are suitable candidates for ovulation induction. Women who have ovulation issues and those with unexplained infertility can be treated to increase the number of eggs released. A possible complication that may occur is Ovarian Hyperstimulation Syndrome (OHSS).
Some of the commonly used fertility drugs includes:
- Clomiphene Citrate: this medication is commonly used to stimulate the maturation and release of eggs. The standard dose is 50-100 milligrams (mg) every day for 5 consecutive days. Treatment starts usually on the second to fifth day after menstruation begins. Chances of success depends on the age of the patient, health condition and quality of the semen. The chance of twins is 6-10% and chance of triplets is 1% or less.
- Aromatase inhibitors: Used to temporarily decrease estrogen levels in the body which leads to the body producing more follicle stimulating hormone (FSH). FSH is used to help in the production and maturation of eggs. Drugs in this class include letrozole and anastrozole. Studies show that pregnancy rates are similar to Clomiphene Citrate.
- Other drugs that can be used are insulin sensitizing drugs – Metformin, gonadotropins, human chorionic gonadotropin (hCG), bromocriptine or cabergoline, gonadotropin-releasing hormone (GnRH) and GnRH Analogs.
Long term studies have not found any association of increased birth defects with clomiphene citrate and gonadotropins. There is also no evidence associating an increased ovarian risk with clomiphene citrate, gonadotropins or aromatase inhibitors.
- A guide for patients: medications for inducing ovulation, American Society for Reproductive Medicine. 2014. https://www.asrm.org/uploadedFiles/ASRM_Content/Resources/Patient_Resources/Fact_Sheets_and_Info_Booklets/ovulation_drugs.pdf. Accessed 2/3/2017.
- Ovulation Induction. UCSF Medical Center. https://www.ucsfhealth.org/education/ovulation_induction/. Accressed 2/3/2017.