What are the Side Effects of Gonadotropins?

Gonadotropins are fertility medications given by injection. These injections contain follicle stimulating hormone (FSH) and it may be combined with luteinizing hormone (LH). FSH and LH are naturally produced in the pituitary gland in the brain to naturally stimulate the ovaries to produce a single egg each month. When FSH (with or without LH) is given as an injection, it works directly on the ovaries to make multiple follicles (cysts containing eggs). 

Injections of gonadotropins are started early in the menstrual cycle to stimulate multiple follicles to grow to a mature size. Human chorionic gonadotropin (HCG), another injectable medication, is then used to trigger the release the eggs when they are mature. This requires close monitoring of the patient’s blood work and ultrasound to minimize any side effects or risk. 

Potential Side Effects of Gonadotropins 



  • Ectopic pregnancy- Ectopic pregnancies occur in 1%-2% of naturally occurring pregnancies. With gonadotropin use, the rate is slightly increased. Ectopic pregnancies can be life-threatening and require treatment with medication or surgery.
  • Multiple pregnancy- Up to 30% of pregnancies of multiple implantations are associated with gonadotropin use. The increase of multiples is associated with the increased number of eggs produced in the female. With multiples, there is a high risk of miscarriage, preterm delivery, infant abnormalities, pregnancy induced hypertension, bleeding and other maternal complications.
  • Ovarian Hyperstimulation (OHSS)- OHSS is a condition in which the ovaries become enlarged and fluid accumulates in the abdomen after the stimulation of gonadotropins and occurrence of ovulation. A mild form of OHSS occurs in 10-20% of cycles and results in some discomfort. In these cases, it usually resolves on its own without complication. A more severe form occurs 1% of the time. The chance of OHSS in increased in women who become pregnant during the cycle in which gonadotropins are given, as well as in women with polycystic ovary syndrome.
  • Adnexal torsion (twisting of the ovary)- In a stimulated cycle, the ovary can twist on itself since it is heavy with follicles. The twisting can cut off blood supply. Surgery is often required to untwist the ovary or in severe cases, to remove the ovary.
  • Localized or generalized reaction- Some women can have irritation at the injection sites. It is extremely rare to have an actual allergy to the medication.
  • Gonadotropins and cancer- Early studies suggested a link to ovarian cancer. Current studies do not show an increase of cancer with the use of fertility medications.