Low Ovarian Reserve
F was devastated when her doctor told her that her chance of conception was less than 5%. F, 36,had been married for 5 years and was infertile. She lived in a neighbouring country and had failed IVF twice over the past one year. She was told by the local fertility specialist that her ovarian reserve was low.
“Doc, I have always assumed that I should have no problem with fertility and should be able to conceive whenever I want”, she said.
During her first 2 years of marriage, her husband was not ready. So she waited. She only consulted the doctor after she tried unsuccessfully for about a year. Her fertility workout was normal. She ovulated regularly and her womb and tubes were normal. Her husband’s semen analysis was normal. The couple then tried IVF on the advice of the specialist. But it ended in failure.
“I don’t want to attempt IVF again”, she confided, with tears in her eyes. "It was so traumatic emotionally and physically. I just want to know how low my ovarian reserve is. Is there any other way for me to conceive?” she asked.
After blood tests and an ultrasound examination, I confirmed that her ovarian reserve was in the low normal range. I suggested intrauterine insemination(IUI) with superovulation(SO) as an alternative. On the third attempt, she was overjoyed when her urine pregnancy test was positive 3 weeks after the procedure. Her face was beaming with smiles when she saw her baby wriggling in the womb on the ultrasound examination. She finally delivered a healthy boy by Caesarean section.
She sent me a thank you card in which she wrote “Doc, please tell your infertile patients not to give up hope. They are not numbers. They don't need a stockpile of eggs to have a successful pregnancy”.
What is Low Ovarian Reserve?
Ovarian reserve refers to the pool of eggs present in the ovaries at any given time. Low ovarian reserve is when the number of eggs is so depleted that there is an insufficient number to ensure a reasonable chance of pregnancy.
Physiology of egg development
A female foetus is born with a finite number of egg cells. In the first 3 months of pregnancy, the egg cells rapidly multiply. By the 5th month of pregnancy, the foetus has a peak of six to seven million eggs. After that, the eggs start to disintegrate and the number declines to one to two million eggs at birth, falling further to 250,000 to 500,000 eggs at puberty. At 37 years of age, a woman will only have about 25,000 eggs and at menopause the number is almost zero.
There are three types of eggs in the ovary: immature eggs, eggs that are selected to mature and atrophic or dead eggs. These eggs are encased in sacs called follicles that support and nourish them until they mature. Every month, about 1000 immature eggs are selected for growth. One of these eggs will develop, mature and ovulate and the rest will degenerate, die and are reabsorbed into the ovary.
Causes of Low Ovarian Reserve
· Aging: Ovarian reserve is part of the female biological clock. The clock can vary from person to person. Some women continue to be fertile in their 40s, while others begin to lose their fertility in their 20s. But the reserve declines with age.
· Genetic: low ovarian reserve can be due to chromosomal anomalies such as Turner Syndrome, where the woman does not have two X chromosomes, or gene abnormalities such as Fragile X syndrome.
· Infection: Infection from STDs, TB or a ruptured appendix can deplete the egg numbers
· Surgery: removal of part or all of the ovary due to ovarian cysts or cancer
· Cigarette: Smoking can bring forth menopause earlier by 2 years
· Destruction of ovarian tissue from radiotherapy, chemotherapy
· Unknown cause.
Diagnosis of low ovarian reserve
Majority of women with low ovarian reserve have no symptoms though some may experience a change from normal to shortened menstrual cycle, e.g. from 30 days to 25 days. The diagnosis is usually made during investigations of infertility. Tests include transvaginal ultrasound and hormone evaluations for follicle stimulating hormone (FSH), oestrogen and the anti-Müllerian hormone (AMH).
The levels of FSH and oestrogen are good indicators of fertility and AMH usually correlates well with fertility potential by reflecting the number of eggs left in the body.
These tests can detect low ovarian reserve fairly accurately.
Treatment of low ovarian reserve
No treatment can slow down ovarian aging or prevent a low ovarian reserve. Pregnancy is usually achieved through assisted reproductive techniques, as in F's case. It is important that the couple should be counselled and be realistic about the chances of success so that they can make the appropriate decision. Other options include using donor eggs or adoption.