AMA in pregnancy stands for “advanced maternal age,” a medical term used to describe anyone who is 35 or older at the time of delivery. The label flags a statistically higher risk for certain pregnancy complications, but it’s worth knowing upfront that 35 is an arbitrary cutoff. Many risks don’t meaningfully increase until age 40 or later, and millions of people over 35 have healthy pregnancies every year.
Why 35 Is the Cutoff
The age of 35 has been used in obstetric research for decades, and clinical guidelines have kept it as the threshold largely for consistency with that body of literature. The American College of Obstetricians and Gynecologists (ACOG) acknowledges that it’s an arbitrary line, noting that “some risks associated with older age may not influence outcomes until later ages (ie, 40 years and older).”
To capture risk more accurately, recent studies break things down in five-year increments: 35 to 39, 40 to 44, 45 to 49, and 50 and older. A 36-year-old and a 44-year-old face very different odds, so grouping them under one label has real limitations. Still, the AMA designation serves as a prompt for providers to discuss additional monitoring and screening options with you.
What Changes Biologically With Age
The core issue is egg quality. Women are born with all the eggs they’ll ever have, and over time, those eggs accumulate changes that make healthy cell division less reliable. Structures called cohesin complexes, which hold chromosomes together during cell division, weaken with age. The internal checkpoints that catch division errors become less effective, and the energy-producing components of the egg (mitochondria) decline. DNA damage and shifts in how genes are regulated also play a role. Together, these changes increase the likelihood that an egg will end up with the wrong number of chromosomes, a condition called aneuploidy.
This is why chromosomal conditions like Down syndrome become more common with maternal age. At 25, the chance of having a baby with Down syndrome is roughly 1 in 1,030. At 35, it’s about 1 in 272. By 40, it rises to 1 in 65, and at 45, it’s approximately 1 in 27. The increase is gradual, not a sudden jump at any single birthday.
How AMA Affects Fertility
Getting pregnant also takes longer as you age. In the early to mid-20s, the chance of conceiving in any given month is about 25 to 30 percent. Fertility begins a slow decline in the early 30s, then drops more steeply after 35. By 40, the monthly chance of natural conception falls to around 5 percent. This doesn’t mean pregnancy is impossible, but it often takes more cycles, and the likelihood of needing fertility treatment increases.
Pregnancy Complications That Become More Common
Gestational diabetes is one of the clearest examples of age-related risk. CDC data shows the rate climbs steadily with maternal age. In 2021, 15.6 percent of mothers aged 40 and older were diagnosed with gestational diabetes during pregnancy, nearly six times the rate among mothers under 20 (2.7 percent). That same year, the overall rate across all ages was 8.3 percent, up from 6.0 percent in 2016.
Other complications linked to AMA include preeclampsia (a dangerous spike in blood pressure during pregnancy), placenta previa (where the placenta covers the cervix), and a higher rate of cesarean delivery. The risk of miscarriage also increases with age, driven largely by the same chromosomal errors described above. Stillbirth risk rises as well, particularly after age 40, which is one reason providers may recommend earlier delivery timing or closer monitoring in late pregnancy.
Extra Screening and Monitoring
If you’re 35 or older, you’ll likely hear about genetic screening options early in pregnancy. ACOG recommends that all pregnant people, regardless of age, be offered both screening tests and diagnostic tests for chromosomal abnormalities. But the conversation tends to be more detailed for AMA pregnancies because the baseline risk is higher.
Screening tests include blood draws combined with an ultrasound measurement of the baby’s neck (nuchal translucency), typically done in the first trimester. Cell-free DNA screening, sometimes called NIPT, is the most sensitive screening test for common chromosomal conditions. It analyzes fragments of fetal DNA circulating in your blood and can be done as early as 10 weeks. It’s important to understand that screening tests estimate probability. They don’t give a definitive answer.
For a definitive diagnosis, two options exist: chorionic villus sampling (CVS), performed around 10 to 13 weeks, and amniocentesis, typically done between 15 and 20 weeks. Both involve collecting a small sample of cells from around the pregnancy for direct chromosome analysis. These carry a small risk of miscarriage, which is why many people start with screening and only pursue diagnostic testing if results suggest a higher risk. A second-trimester ultrasound to check for structural differences is recommended for all pregnancies.
What Late Pregnancy Looks Like With AMA
Because stillbirth risk is slightly elevated in AMA pregnancies, your provider may suggest antenatal fetal surveillance in the third trimester. This typically means periodic non-stress tests, where sensors on your abdomen track the baby’s heart rate and movement patterns. For most at-risk patients, this monitoring begins at 32 weeks or later, though the exact timing depends on your overall risk profile. If you have multiple high-risk factors, surveillance may start earlier.
Your provider may also discuss delivery timing. For some AMA pregnancies, induction around 39 weeks is recommended to reduce the small but real risk of late stillbirth. This doesn’t apply universally, and the decision depends on your individual health, the baby’s status, and any other complications that have developed during the pregnancy.
Putting the Risk in Perspective
Seeing “advanced maternal age” on your chart can feel alarming, but the label is a risk factor, not a diagnosis. Most people in the 35 to 39 range have pregnancies that look a lot like those of younger parents. Risks do increase, and they increase more sharply after 40, but the absolute numbers for most complications remain relatively low. The additional screening and monitoring that come with an AMA designation exist to catch problems early, when they’re most manageable. Being informed about what the label means, and what it doesn’t, puts you in a stronger position to make decisions about your care.