There is surprising variability in how much height girls gain after they have their first menstrual period. Half of the girls either grow more or less than the typical 6-8 centimeters that is commonly expected. This was highlighted in research conducted at the University of Gothenburg.
The study, featured in the journal Frontiers in Pediatrics, aimed to explore the connection between the timing of the first period and the following height growth in girls, along with the underlying factors involved.
The research focused on 793 healthy women from the Gothenburg and Halland regions in southwest Sweden. These participants were monitored from birth, through their childhood, puberty, and into adult life. Information was gathered through participant surveys, interview questions, and registry data, including details on parental height.
Girls had their first period at an average age of 13.0 years, with some starting as early as 8.2 years and others as late as 17.2 years. On average, after their first period, the girls experienced a height increase of 8.0 centimeters, with a median increase of 7.0 centimeters, which falls within the expected range.
One in two outside the chart
However, the variations were remarkably wide, ranging from an increase of 0.2 centimeters to 31.1 centimeters. Only half of the participants grew the typically expected 6-8 centimeters after their first period.
The findings support the notion that an earlier onset of menstruation correlates with greater height increase, while a later onset results in less growth. Girls who began menstruating before the age of 12 grew a median of almost 13 centimeters, whereas those who started after 14 years of age grew only about 3 centimeters.
“The differences in growth following menstruation and final height are considerably larger than what has been reported in previous studies. The timing of when they get their periods greatly influences these variations. There is a significant gap between those who start their periods early versus those who start later,” explains Jenni GÃ¥rdstedt Berghog, a doctor at Halland Hospital’s women’s healthcare clinic and one of the study’s lead authors.
The study also indicates that body mass index (BMI) during childhood plays a critical role. Both a low BMI in childhood and having tall parents are linked to later onset of menstruation. On the other hand, a high childhood BMI, which contributes to height growth in children, is associated with earlier menstruation and ultimately shorter final height. These observations are noted at the group level, highlighting that individual variations are quite significant.
Unexpectedly large variations
The principal investigator, Anton Holmgren, a Pediatric Researcher at Sahlgrenska Academy and a Pediatrician at Halland Hospital in Halmstad, emphasized the findings.
“Many believe that all girls grow 6-8 centimeters after their first period, a fact often taught even to medical students,” he states. “Our study demonstrates a remarkable variation, showing that those who enter puberty and menstruate early tend to grow much more than previously recognized, while those who start menstruating later see less growth.”
“Enhancing understanding in this area is valuable, even when it’s not related to any health issues. A person’s growth pattern, the timing of puberty, and whether they end up being tall or short are relatable topics for everyone,” concludes Anton Holmgren.
