Women who are skinny during their teenage years and into their mid 30s are at higher risk of having early menopause, according to new research.

The study, published in the journal Human Reproduction, found that underweight women who lost nine kilograms or more at least three times between age 18 and 30 doubled the chances of their reproductive life ending prematurely.

Menopause occurs when a woman’s ovaries stop producing eggs and the hormone oestrogen, with one strong indicator being when a woman does not have her period over a 12-month period.

However, early menopause is defined as a woman naturally ceasing to have periods by age 45.

Lead scientist Dr Kathleen Szegda, from the University of Massachusetts, said up to 10 per cent of women experience early menopause which has been found to be associated with a higher risk of cardiovascular disease.

It is also linked to other health problems such as cognitive decline, osteoporosis and premature death, she said.

“Underweight women may want to consider discussing the potential implications of these findings with their doctors,” Dr Szegda said.

The study examined data from more than 78,700 pre-menopausal American women aged 25 to 42 who joined the Nurses’ Health Study II in 1989.

It is part of a series of major investigations into the causes of chronic disease in women.

What you may not know about menopause

The menopause process usually corresponds with a flux in hormones.

Dr Stephanie Simonds, a National Health and Medical Research Council research fellow, said many commonly reported symptoms include mood changes such as frustration, anger and hate, as well as feeling lethargic.

She said symptoms were not the same for every woman.

“Oestrogen is at a fairly constant level in young women, but when a woman reaches menopause, there is a drop in oestrogen levels and this sets off a drop in other hormones as well,” she told The New Daily.

“It does have an effect on quite a number of physiological functions.”

Dr Simonds said one example is temperature control, with some women describing “hot flushes”. Another is control of fluids and nutrient salts which would lead to skin drying out.

Post-menopausal women also often find they put on weight, she said. This can lead to increased blood pressure and heart rate.

Any perceived change to libido was likely a result of the hormone imbalance.

Dr Simonds said, surprisingly, it is often men who recognise menopausal symptoms before women identify it themselves.

“All women go through this. There are going to be changes,” she said.

“The best thing men can do is start a conversation about menopause with the women in their lives and support them through any GP visits.”

Dr Simonds said one health tip for women entering menopause would be to change their exercise regime to focus from cardio to weight training, to compensate for loss of muscle mass and bone density changes during menopause.

“It’s important to remember that the health implications we’re talking about are chronic diseases. You’re not going to die overnight,” she said.

“The best treatment is maintaining a healthy body-fat level and to keep track of your heart rate during exercise.”

– with AAP