Girls who start their periods before turning 14 are 51% more likely to have underage sex (and get pregnant and married younger)

• Over half of girls who had periods before 14 have sex before the age of 16
• This compares to just 4% of those who menstruated at 16 or over, study reveals
• Few girls engage in intercourse before they began menstruation, it was found
• For each year menstruation was delayed, age at marriage rose by 9 months
• 'Significant' link found between age of first period and age of first pregnancy
• Girls menstruating before 14 were up to 31% more likely to get herpes

The earlier a girl gets her first period, the younger she will have her first sexual experience, get pregnant and marry.
 

Over half of girls (55 percent) who had periods before the age of 14 – when most girls have hit puberty – had sex before the age of 16, a study reveals.

This compares to just 4 percent of those who menstruated at 16 or over – considered latefor the start of puberty. 

Eleven is the average age for girls to start their periods, but experts have previously suggested puberty is starting younger, and that the trend is linked to obesity.

Another study suggested that for each year menstruation was delayed, the age when a girl got married increased by nine months, according to researchers from Columbia University Mailman School of Public Health in New York

Menstruating at an earlier age is also linked to having an increased risk of getting sexually transmitted infections (STIs), research suggests. 

'Menstruation marks the beginning of a girl's reproductive life and is an important indicator of girls' physical, nutritional, and reproductive health, yet it is often overlooked in public health,' said senior study author Dr Marni Sommer, who is associate professor at the school. 

Two of the studies were conducted in Malawi; the others were conducted in South Africa, Nepal, Jamaica, Nigeria, Zimbabwe, India, and Bangladesh.

Overall, an earlier age at menstruation was associated with earlier first sexual encounter, age at pregnancy, and first child.

A sample of Jamaican women who menstruated early were found to be 28 percent more likely to have intercourse before the age of 16.

In rural Malawi, 55 percent of those who had their first period before age 14 had sex before the age of 16.

This compares to 27 percent of those at age 14 to 15, and only four percent of girls who menstruated at 16 or over.

Few girls engaged in sexual intercourse before they began menstruation.

Girls who got periods earlier were also more likely to get married at a young age.

In India, for example, one study suggested that for each year a girl did not get her first period, the age she got marriage increased by nine months.  

And when it came to age at first pregnancy, a study among South African adolescents found a 'significant' link between the age of first menstruation.

In a survey from Malawi, earlier menstruation was associated with an increased likelihood of infection with Herpes simplex type-2 virus (HSV-2). 

Girls with periods before 14 were were 11 to 31 percent likely to test positive for HSV-2 than those who had them before age 14.

EARLY PUBERTY RAISES CANCER RISK

A recent study has revealed an early puberty raises the person's risk of several cancers in later life.

An 11-year-old girl going through puberty has a six per cent higher risk of getting breast cancer in later life than a girl aged 12.

The danger of endometrial cancer rises by 28 per cent every year, while boys see their risk of prostate cancer go up by nine per cent, found researchers from the University of Cambridge.

The risk most applies to types of the disease that are associated with sex hormones, such as breast, ovary and endometrial in women, and prostate cancer in men.

This is thought to be due to gene variants that influence puberty's onset also playing a role in our cancer risk. 

What the experts say  

Studies from several high-income countries have shown that early menstruation is also linked with increased delinquency, substance use and depression – all of which have sexual and reproductive health implications, the report notes.

'Although our analysis did not examine these patterns, there is a critical need to assess if similar associations exist in low-and middle-income countries,' said Dr Sommer. 

The researchers said the findings highlight the need for more to be done to tackle child marriage in low-income countries.

'This finding could be particularly relevant to ongoing global efforts to curb child marriage,' the report noted.

'Early marriage may increase girls' vulnerability to the negative health effects of early pregnancy and childbirth, since girls are often expected to bear children soon after marriage.

'In addition, girls who get married early are often unable to effectively negotiate safer sex, increasing their vulnerability to STIs such as HIV.'

The study was published online in the journal PLOS ONE.