Lead and Women's Health
How much white lead will fatally poison a woman?
The number one question about Lady Coventry's death is 'how much poison would it have taken to kill her?' However, the answer is complicated. It depends on how lead gets into a person's body.
White lead is known to be fatal if inhaled or eaten. One forensic scientist says that eating 20 g of white lead at once would be a death sentence. It is not clear if we know the minimum fatal amount.
Health effects observed today are from lower level exposure. Lead can come from water, dust or soil. There is no known safe level for lead. However, urban Canadians' blood lead levels are now about 10% of the levels in the late 1970s.
Lead and Women
A partial list of lead health effects that have been studied in women. The consequences of adult lead exposure have been studied extensively, but most studies have been performed on men.
Lead-exposed women have higher blood pressure (also called hypertension). The increase may be bigger after the menopause. However, lead exposure is a risk factor for pregnancy induced hypertension.
Lead's effect on blood pressure persists for a long time. Fiona was an investigator in a study which found that young women who were lead poisoned as children had higher blood pressure 20 years later.
Elevated blood pressure is a serious health issue: it increases the risk of heart attack and stroke, heart failure, memory loss and dementia.
There is mixed evidence that lead-exposed woman suffer from endometriosis. One major US study found no link between lead and endometriosis but did find a link between lead and uterine fibroids. A recent study in Asia found a strong relationship between lead and endometriosis. There is also evidence from non-human primates that supports a link.
Fiona was an investigator in a study where lead-exposed women were found to have more hysterectomies. A question is whether the hysterectomies were perhaps because of higher rates of endometriosis?
Endometriosis can be an extremely painful condition that can badly impact a woman's life. Many women report trouble being diagnosed and their pain being disbelieved.
Studies of the effect of lead on fertility mostly focus on men where the data are clear: lead reduces fertility.
In women, there has been some mixed reporting. On balance, it appears lead exposure reduces a woman's fertility.
Lead has effects on a woman's hormones during child bearing years. It delays menstruation onset in teenagers, causes disrupted menstrual cycles in young women and affects the function of the ovaries.
Reduced fertility is deeply distressing and an often secret pain for many couples.
Women exposed to lead undergo early menopause. The date of early menopause may depend on the level of exposure.
Fiona was an investigator in a study which found that occupationally exposed women (some with very high exposure) experienced menopause on average 7 years early. Studies performed by the Harvard School of Public Health on nurses found menopause shifts of 1 year in environmentally exposed women.
Menopause is when a woman’s period has stopped for 12 months. Menopause takes place at age 51 on average in Canada. Early menopause increases a woman’s risk of heart disease and osteoporosis.
At extremely high levels, lead causes miscarriages. In the late 19th century, women died from lead poisoning because they tried to end a pregnancy with lead compounds. Survivors had permanent blindness and nerve or brain damage.
At lower levels, lead increases the chances of a miscarriage. A Mexican study reported an 80% increased risk for every 5 μg/dl increase in a woman’s blood lead level. Average blood lead levels in urban Canada are now less than 1 μg/dl so the risk is small.
A number of studies have shown an increased number of stillbirths among more highly lead-exposed women. Fiona was an investigator in a 1990s study which found that occupationally exposed women had more stillbirths than unexposed women.