Dec. 27 (UPI) — More than one in five women experience menstrual cycle irregularity, potentially impacting their ability to accurately recognize a potential pregnancy early on, a study published Monday by the Proceedings of the National Academy of Sciences found.
Among nearly 270,000 women in the United States ages 18 to 39 years, 22% reported menstrual cycle irregularity, defined as consecutive cycles differing by an average of seven or more days, the data showed.
Women ages 18 to 24 had twice the risk for menstrual cycle irregularity compared to women ages 35 to 39, the researchers said.
In addition, those with polycystic ovary syndrome, Type 2 diabetes, obesity, hormone irregularity and thyroid problems were up to nearly twice as likely to have irregular menstrual cycles.
Hispanic women were more than 40% more likely than Black women to experience irregular menstrual cycles, while Asian women were about 25% more likely, according to the researchers.
The findings suggest that menstrual cycle irregularity may affect abortion access under so-called “six-week” limits to access the procedure before the fetus develops a heartbeat, which typically occurs within six weeks of the last menstrual cycle, they said.
“Menstrual irregularity is common, especially among young people,” study co-author Jenna E. Nobles told UPI in an email.
“Legislation that limits abortion access to the days before fetal cardiac activity may make abortion unequally accessible,” said Nobles, a sociologist at the University of Wisconsin in Madison.
By their design, “heartbeat bills” restricting abortion may unintentionally but disproportionately limit access to the procedure “for young people, Hispanic people and people with common medical conditions because of differences in menstrual regularity,” she said.
Several states across the country, including Texas, have proposed laws that prohibit abortions after embryonic electrical activity, or a fetal heartbeat, is detectable, according to Planned Parenthood.
This typically occurs six weeks following the beginning of the last menstrual period, Nobles and her colleagues said.
A missed period often is the earliest symptom of pregnancy, but irregular menstrual cycles can delay pregnancy detection past this six-week period, they said.
For this study, Nobles and her colleagues analyzed data from a commercial mobile device app for roughly 1.6 million menstrual cycles reported by 267,209 women in the United States between 2014 and 2016.
“It is important for policymakers to know that there may be no time between when a person discovers they are pregnant through a missed period and fetal cardiac activity,” Nobles said.
“This is particularly true for people with unpredictable cycles, [so] legislation that restricts abortion to the days before fetal cardiac activity will make abortion less available to certain groups of people for reasons entirely outside their control,” she said.