- Perimenopause is the time when the body begins to transition to menopause.
- As hormone levels fluctuate, it's still possible to get pregnant.
Dr. Mary Jane Minkin, a clinical professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine, was at work one day when a patient came in complaining about menopause symptoms. The woman was especially concerned about weight gain, but when Minkin examined the 47-year-old, she realized there was a different cause: pregnancy.
"The crazy thing was that her due date was the same day as her older daughter's scheduled wedding," Minkin, who has delivered babies for three 47-year-old women, said. "So they postponed the wedding, and the new baby came to the wedding in a Moses basket."
Dr. Bruce Dorr, a fellow at the American College of Obstetricians and Gynecologists and Biote Senior Clinical Advisor, was himself a late-in-life baby, born when his mother was 43. But even he was surprised when a 49-year-old nurse came to him for a menopause consult. She had symptoms like nausea and breast tenderness, which aren't usually associated with menopause, so Dorr ordered a pregnancy test.
"I checked a urine pregnancy test — which was positive — and took her back to show her 8-week identical twins on ultrasound," Dorr said.
There's a real risk of pregnancy at 40-plus
While there's a lot of talk about how fertility decreases with age, it's less common to hear about the flip side: the surprise pregnancies that occur when people think they can no longer conceive.
Menopause is when a person hasn't had a period for one year. The lead-up to that, known as perimenopause, is a time of shifting hormones when there's still a pregnancy risk. A 2014 study found 75% of pregnancies in people older than 40 were unplanned.
"In perimenopause, your ovaries are working sporadically — sometimes they are working; sometimes they are not," Minkin said. "And if they are working at all, and a sperm happens to find its way to a released egg, you can get a pregnancy."
Perimenopause often begins in the early 40s, though it can appear in younger or older women. Minkin recommends that all her patients who don't wish to conceive use birth control until they've done an entire year without a period. If your birth control results in no periods, ask your doctor about blood work that can confirm menopause.
If pregnancy occurs, complications are more common
Pregnancy in a person's 40s comes with additional risk, especially if the person is already in perimenopause, Dorr said. Fluctuating hormone levels can contribute to miscarriage, so a pregnant person should talk to their doctor about measuring hormone levels and maybe taking progesterone.
There's also a much higher risk for chromosomal abnormalities at that age.
"The eggs that are released, unfortunately, are indeed older eggs, and there are many more genetic abnormalities possible," Minkin said.
For example, the risk of giving birth to a child with Down syndrome is about one in 2,500 when the mother is 25 years old but rises to one in 100 when the mother is 40.
Perimenopausal pregnancies can bring risk but also joy
Women who get pregnant during perimenopause should work closely with their doctors to navigate their unique risks, Dorr said.
"Pregnancy is a great gift but can also carry life-threatening consequences, so seek guidance from a trained professional," he said.
But his professional and personal experience has shown him that perimenopausal pregnancies can bring great joy.
"I was a complicated, high-risk pregnancy, but my mom always said I kept her young and was worth every tear and worry," he said. "She made me into the caring and understanding physician that I am today."