Inhibin B has been used as a marker of ovarian reserve.
Every female is born with a specific number of follicles
containing oocytes, a number that steadily and naturally
declines with age. The number of follicles remaining in the
ovary at any time is called the ovarian reserve. As ovarian
reserve diminishes, it is increasingly more difficult for
the hormones used for in vitro fertilization (IVF) to
stimulate follicle development and, thus, the likelihood of
successful oocyte retrieval, fertilization, and embryo
transfer decreases, all leading to a lower chance of
conceiving. As part of an infertility evaluation, attempts
are made to estimate a woman’s ovarian reserve. Tests to
assess ovarian reserve include: day 3 FSH, day 3 inhibin B,
and antimullerian hormone levels. The amount of inhibin B
measured in serum during the early follicular phase of the
menstrual cycle (day 3) directly reflects the number of
follicles in the ovary.
Inhibin B concentrations are
elevated in patients with granulosa cell tumours, over 80%
of those with mucinous cystadenocarcinoma and in about 20%
of those with other ovarian tumours. They can also be
elevated in ovarian benign pathology.