Last week, the Jaipur bench of the Rajasthan High Court overturned the sentence of a woman convicted of murdering a child after she pleaded insanity due to severe premenstrual stress syndrome, reports Scroll. In their ruling, the two male justices cited Section 84, which designates “unsoundness of mind” as a pardonable mitigating factor: “the offence that she committed was an involuntary act on her part, inasmuch owing to this fact, she was labouring under the defect of reason or was suffering from psychological disorder or unsoundness of mind.”

Let’s be clear: premenstrual syndrome, or colloquially PMS, does not cause insanity. PMS is characterized by a lot of different symptoms, some physical, but many emotional, like anxiety or depression. Some women experience all symptoms, some none; most women experience at least a few symptoms regularly. Severe PMS symptoms that affect women’s mental wellness, emotions and self-esteem, are known as premenstrual dysphoric disorder. But no PMS symptom, however severe, is recognized as a legitimate excuse for murder.

Menstrual psychosis, on the other hand, is a very rare phenomenon that can occur between three days prior to three days after a period. During this time, an acute onset of impaired thought and emotion, to the point connection with reality is lost, is followed by a full recovery to normalcy. An episode of menstrual psychosis is characterized by symptoms of psychosis generally: confusion, stupor and mutism, delusions, hallucinations, or a manic syndrome. So few women suffer from the disorder that most evidence is anecdotal. In fact, there is some dispute whether it is it’s own disorder at all; some argue menstrual psychosis is schizophrenia exacerbated by the hormonal fluctuations associated with menses.

The truth is, we don’t really know. For much of modern science, researchers have eschewed studying women of reproductive age; they have been excluded from experiments and trials precisely because their hormones fluctuate on a monthly basis. Fluctuating hormones mean more variables to control for and more complex and less pure results, the argument goes.

This scientific bias means cold hard facts are difficult to come by, allowing outdated gender stereotypes to run riot. It doesn’t help anyone that much of the literature around menstrual psychosis dates from the 19th and early 20th century — a time when “hysteria” was still a legitimate medical diagnosis for women and used to deny women agency.

In this case, specifically, it doesn’t help that the woman’s lawyer, the ‘expert’ witnesses brought by the defense, and the dated research cited by the judges are questionable at best. All men, they argued that at the time of the murder she was “suffering from the mental disease known as premenstrual stress syndrome”; they spoke of the potential for PMS to make some women violent or suicidal; they wrote of menstruation’s link to ‘crimes’ like alcoholism and prostitution.

They were wrong. But they also might have been right — had the defense argued menstrual psychosis. One doctor testified he had treated the woman on three occasions for a “‘psycho-neurotic disease’ that caused her to become ‘violent to the extent of reaching madness,'” Scroll reported.

While it doesn’t make the court’s judgment legally sound, an optimistic reading that assumes everyone involved in the case — like much of the general, scientific, and medical worlds — has only a superficial understanding of women’s menstrual and mental health suggests that, perhaps, a very sick woman received mercy. And that we should spend more time studying women’s physiology, and less time judging them.