BWH Egg Freezing Counseling Tool (EFCT)

BWH Egg Freezing Counseling Tool

Age

years

AMH (Anti-Mullerian Hormone)

ng/mL

AFC (Antral Follicle Count)

follicles

Score:–

–

Predicts likelihood of live birth for elective egg freezing in women.

Why Use

Predicts likelihood of having at least one, two, or three live births using only two data points. Incorporates likelihood that an embryo will have normal number of chromosomes. Helps determine whether undergoing additional egg freezing cycles would result in a meaningful increase in likelihood of having a live birth.

When to Use

Patients seeking fertility preservation with elective egg freezing.

Formula

p(Livebirth) = 1 – [1 – 0.6 × p(Euploid) × p(Blast)] ^ (Number of mature eggs) where p(Blast) = 0.95 × exp(2.8043 – 0.1112 × Age) if Age <36 p(Blast) = 0.85 × exp(2.8043 – 0.1112 × Age) if Age ≥36 and p(Euploid) is from table below Note: number of mature eggs assumes 95% survival of thawed eggs (85% if age is ≥36 years).

Pearls / Pitfalls

Uses a woman’s age at egg retrieval and the number of mature eggs frozen to predict the probability of having at least one, two, or three live births. Since limited data exist regarding live births following elective egg freezing, the BWH Egg Freezing Counseling Tool was developed from a surrogate population of presumably fertile women (egg donor, male-factor, and tubal-factor only infertility). No number of frozen eggs can guarantee a live birth. IVF stimulation cycles produce a variable number of eggs, even among women of similar ages. Older women typically obtain fewer eggs per stimulation cycle. May be less reliable for women ≥39 years old. May overestimate live birth rates for women undergoing non-elective egg freezing for medical reasons, such as cancer. Data are retrospective and from a single academic institution in an insurance-mandated state. Individual IVF clinics with different thaw survival and live birth rates may need to modify and customize this model. Has yet to be prospectively validated.

Management

Decisions about egg freezing should be made by the patient in conjunction with her physician, considering patient-specific characteristics.

More Information

Age (years) p(Euploid) Egg donors (for reference) 0.647 ≤35 0.574 36 0.564 37 0.486 38 0.466 39 0.440 40 0.359 41 0.327 42 0.285 43 0.206 44 0.127 Note: In the study, ages 24–35 were grouped together, as fertility is fairly stable up to age 35 and begins to decrease appreciably after that age.