Features

• According to the fertility website Shared Journey, estradiol is a type of estrogen naturally produced by the ovaries and is secreted in the follicles that grow in the ovaries. The amount of estradiol in a woman's blood changes from day to day as her monthly menstruation cycle progresses.
  
  

Diagnostic Tests

• A blood test is used to measure the estradiol or E2 level. The result gives fertility doctors a baseline to track how well a woman is responding to follicle-stimulating hormone injections, such as Menopur or Follistim, both of which are used to stimulate multiple follicle growth during IVF.
  
  

Considerations

• Along with the blood test, an ultrasound is used to measure the follicles. With these results, a doctor will know when a woman is ready for egg retrieval in the IVF process.
  
  

Significance

• Typically, a follicle is mature once it measures 14 to 20 mm in diameter and the E2 level reaches 200 pg/mL. The E2 level will be higher depending upon the number of follicles present. According to Advanced Fertility Center of Chicago, peak estradiol levels in IVF are usually between 1,000 and 4,000 pg/mL.
  
  

Facts

• Age can be a factor when it comes to estradiol levels. Typically, the older a woman is, the less ovarian reserve--which means fewer eggs are stimulated--during IVF cycles.
  
  

Warning

• As with any medical procedure, IVF and increased follicle stimulation comes at a risk. An elevated estradiol level can cause ovarian hyperstimulation syndrome (OHSS). According to MayoClinic.com, symptoms of OHSS begin three to 10 days after a woman begins injections. Symptoms of OHSS include abdominal bloating and rapid weight gain