More than half of U.S. babies born in 2023 had birth mothers in their 30s and older, according to provisional CDC data.

Why it matters: In the last few years, age 35 has gone from the start of "geriatric pregnancy" to potentially a maternal-age sweet spot.

The intrigue: 35-year-olds received more prenatal monitoring and had a small decrease in prenatal mortality compared to those even a few months younger, according to a 2021 JAMA Health Forum study.

• And some research suggests that being 35+ and pregnant could lead to better brainpower after menopause and a smaller gender wage gap.

Between the lines: Although non-invasive prenatal tests (NIPT) are offered to patients of any age, some insurance plans only cover them for women age 35 and older at time of delivery.

Catch up quick: 35 became the start of "advanced maternal age" decades ago, largely thanks to studies on the then-new invasive genetic test called an amniocentesis.

• Researchers determined that for a woman 35+, the chances of carrying a baby with a genetic condition were greater than the risk of pregnancy loss as a result of getting an amniocentesis to test for that condition, Tiffany Pham, OB-GYN and Flo Health medical adviser, tells Axios.

But that's a "dated paradigm" and "there's nothing really particularly magic" about age 35, says Alison Cahill, professor and associate dean of translation research at the Department of Women's Health at Dell Medical School, University of Texas at Austin.

• We have since learned that the amniocentesis risk is much lower than previously thought.
• And there are now less-invasive and lower-risk procedures for prenatal genetic screening.

Reality check: Pregnancy risks do increase with age. But the effects are much more pronounced after age 40, compared to 35.

• New ACOG guidelines emphasize that pregnancy risks should be considered among patients in five-year age groups — ages 35-39, 40-44, etc. — instead of in one big advanced maternal age group.

Yes, but: Women considering having kids by their mid-30s should be acquainted with their own physiology and possible fertility challenges "much earlier than 35," says Jane van Dis, OB-GYN and assistant professor at the University of Rochester.

The big picture: Insensitive wording has long added to the stigma about later-in-life pregnancy — but there's been some progress when it comes to maternal health terminology.

• In a poll conducted last month with users, women's social app Peanut found that 40% of women in their mid-30s and above reported a positive shift in language from their health care providers, moving away from terms like "geriatric pregnancy" to their recommended "35+ pregnancy."

Carly's thought bubble: I'm a healthy 35-year-old pregnant person, and in my first prenatal appointment, I pointed out to my OB-GYN that I was of "advanced maternal age."

• I asked her if that made me a high-risk patient.
• Her response: laughter. After a pause, she said: "You're one of my younger patients."
• We haven't talked about my age since.

Go deeper: Please don't call my cervix incompetent