Pregnancy Changes the Pitch of Your Voice—This Is How Long It Lasts

You’re as prepared as you can be for the bodily changes that come along with pregnancy. But did you know your voice can change too? A new study took a closer look at how pregnancy changes the pitch of a woman’s voice. And that change may last a little longer than you think.

The pitch of a woman’s voice has long been known to change based on hormones; it increases around ovulation and decreases significantly after menopause. But there’s been a lack of evidence about whether or not pregnancy affects your voice; research has largely been limited to one-off individual reports. So Katarzyna Pisanski and her colleagues at University of Sussex’s Voice Lab gathered ten years’ worth of voice recordings from 20 mothers before, during and after their first pregnancies and 20 recordings from a control group around the same age.

Using an acoustic analysis program called Praat, researchers were able to nail down the exact changes in pitch. Women’s voices typically got lower during pregnancy; on average, they dropped 14 Hz, or 1.3 semitones. Not sure what a semitone is? It’s the smallest interval used to describe pitch. If you were looking at a set of piano keys, the difference between a white key and its neighboring black key is equal to a semitone. So pregnant women’s voices aren’t dropping an entire octave; they’re just lowering a little bit. The maximum drop in pitch researchers found after pregnancy was 2.2 semitones.

This may not matter so much to you. But, as Pisanski explains, it matters to someone like Adele.

“This is the first scientific evidence that pregnancy affects women’s voices, though many women claim to have personally experienced it,” Pisanski says. “The singer Adele, after giving birth to her son in 2012, reported that her voice pitch dropped dramatically. Adele says her voice is only now returning to its pre-pregnancy level.”

Normally, though, your voice shouldn’t take years and years to get back to normal. Researchers found the mothers’ voice pitch returned to or near pre-pregnancy levels after a year.

Why is this happening? Pisanski can’t say for sure, but she has a pretty good idea.

“Although our data can’t explain the mechanisms driving these postpartum voice changes, one likely culprit is changes in hormone levels, particularly of testosterone, estrogen and progesterone,” she says. “Ratios in these hormone levels fluctuate throughout the menstrual cycle and have been directly linked to postmenopausal drops in voice pitch. These same hormones rise during pregnancy and drop off sharply after childbirth (contributing to postpartum depression in some women). When it comes to voice pitch, sex hormones can have a direct effect by increasing the effective mass of the vocal folds and slowing their vibratory pattern, thereby lowering pitch.”

Just another thing to blame on the hormones!

H/T The Conversation

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