Successful fertility treatment in a female Western Lowland Gorilla
Successful fertility treatment in a female Western Lowland Gorilla from Bristol Zoo Gardens
Successful pregnancy and birth in a sub-fertile Lowland Gorilla
Salome, a 28 year old Western Lowland gorilla (Gorilla gorilla gorilla) was investigated for failure to reproduce. Her previous history was a stillborn infant in 1986 then a surviving infant born 1987.
Since then she has appeared to cycle and had been repeatedly mated by two proven fertile males yet failed to produce any offspring.
Hormone tests from blood samples obtained under general anaesthesia showed an elevated follicular stimulating hormone level and depressed oestrogen levels. Hormone analysis of the monthly reproductive cycle using blood tests was not pursued due to the difficulties and negative welfare implications of anaesthetising the animal every day or two for a month.Therefore urinary hormones were analysed using techniques no longer used in human medicine revealing that the female was not ovulating, despite showing behavioural oestrus and allowing mating.
The diagnosis was of diminished ovarian reserve (Note; NOT technically menopause, this can happen at any age). Fertility treatment using clomiphene was initiated. 14 days after oestrus the urine was tested using a human pregnancy kit. If this was negative, she was started on clomiphene tablets for 5 days of various doses each month until daily urine samples indicated ovulation.
The eventual effective dose was 150mg clomiphene daily for 5 days. Clomiphene treatment as described was started in April 2004. A conception occurred in October 2004 but the pregnancy was lost in the first trimester.
The next pregnancy in November 2004 was maintained but resulted in miscarriage July 2005 at almost full term. Treatment was delayed to allow the reproductive system to recover.
Further treatment resulted in a conception in March 2007. The baby was born on 15 December 2007 by natural birth.
Developed by: Bristol Zoo Gardens