Bacteria
Microcospic, single-celled organisms that can cause infections of the genital tract.

Basal body temperature (BBT)
The temperature taken at its lowest point in the day, usually in the morning before getting out of bed.

Biochemical pregnancy
A pregnancy confirmed by blood and urine test only.

Biopsy
A fragment of tissue removed for study under the microscope.

Blastocyst
The developing multi-cell embryo at approximately 5-7 days after fertilization occurs.

Bromocryptine (Parlodel)
A drug that reduces levels of the pituitary hormone prolactin.