As you creep closer and closer to your mid-thirties, that once-quiet biological clock begins ticking exponentially louder. After all, everyone’s heard that once you hit 35—boom!—your chance of pregnancy plummets! AND if you do manage to conceive—hold onto your rocker, Grandma—your risk of complications skyrocket! (Or so they say.)

But wait…how much does your “advanced maternal age” really impact your fertility, your pregnancy, and your baby's health? Does a “geriatric pregnancy” mean you’re destined for troubles?

Here’s the truth: Research does show that certain risks do increase with age. At the same time, 35 isn’t the scary cliff that it’s sometimes made out to be. A healthy 38-year-old could very easily have a smoother pregnancy than a 22-year-old who’s dealing with some medical issues. That’s because there’s way more than age that factors into a healthy pregnancy! In fact, a 2021 study in JAMA Health Forum found that women over 35 had better pregnancy outcomes than those slightly younger, likely due to better prenatal care those of an “advanced maternal age” receive.

If you are pregnant or planning to conceive over 35, it’s a good idea to understand the complications associated with being of an “advanced maternal age”—as well as the specialized prenatal care and testing you’re eligible for. Here, we break down what a so-called “geriatric pregnancy” means for you and your baby-to-be.

What is advanced maternal age?

According to The American College of Obstetricians and Gynecologists (ACOG), you’re at an advanced maternal age if you’re 35 years old or older at the time you deliver your baby. Advanced maternal age may also be dubbed a “geriatric pregnancy” or “elderly pregnancy” (!!), but those terms are rarely used nowadays because, well, they’re offensive and misleading.

How did 35 become “advanced maternal age?”

It’s important to know that 35 became the go-to age to stoke worry way back in 1978 when, 1) having a baby at 35 was still rare, and 2) amniocentesis was brand-new technology. At the time, the National Institutes of Health announced that all pregnant women aged 35 and older should be offered an amniocentesis, a prenatal genetic diagnostic test in which amniotic fluid is removed from the uterus and tested for abnormalities, such as trisomy 21, aka Down syndrome. But according to reports, 35 was “arbitrarily decided by logistical consequences and is not the sudden biological difference between women above and below any given age.” According to a report in the journal PLoS One, there’s actually a limited consensus as to the precise maternal age at which the risk of adverse pregnancy outcome becomes clinically important. In short, the Mayo Clinic notes that 35 is simply an age at which pregnancy “risks become more discussion worthy.”

What happens to fertility at age 35?

Surprise! Once you turn 35, there is no switch that gets flipped that instantly grinds your fertility to a halt. What happens is a little more subtle than that. Starting at around 32, a woman’s fertility begins to gradually decrease, with a more rapid decline beginning after age 37, notes ACOG. But a slow decline in no way means that pregnancy is now a long shot! Research shows that a 35-year-old woman has a 66% chance of conceiving within one year of trying—and that bumps to 84% probability within four years. (Come 40, those numbers shift to a 44% chance of having a baby after a year of trying, and a 64% shot of having a little one after four years of trying.) Here’s why fertility changes around 35 years old:

Decrease in Egg Quantity

You’re born with about 2 million eggs…and that’s the most you'll ever have. About 11,000 eggs will die every month prior to puberty. And by your late 30s, you’ll typically have around 27,000 eggs left. Where do all these eggs go?

  • Your ovaries release one mature egg every month and—if unfertilized—it leaves your body as part of your period.

  • Many eggs that aren’t released with your period simply reabsorb into your body, thanks to a process called follicular atresia.

Decrease in Egg Quality 

Right before you ovulate, your eggs go through cell division called meiosis. Unfortunately, older eggs are more susceptible to errors during this delicate process, which can result in abnormal DNA, like eggs having too few—or too many—chromosomes.

  • Most eggs with abnormal DNA don’t fertilize at all.

  • Many embryos with too many or too few chromosomes result in miscarriage.

  • Embryos containing an extra chromosome (trisomy), or a missing chromosome (monosomy) can result in genetic birth defects.

What are the advanced maternal age risks to babies?

Studies have repeatedly shown that there’s a significant association between chromosomal abnormalities and congenital issues in babies born to moms aged 35+. However, this connection appears to be a progressive age-related risk. That means, the risk for babies born to moms between the ages 35 to 39, for instance, is not the same as those born to moms aged 40 to 44 years old, and so on. With that, here are some risks associated with having a baby over 35: 

  • Chromosomal abnormalities: The overall risk of having a baby with chromosome abnormalities is very small, according to ACOG. But with age, the chance of having a baby with an extra chromosome (trisomy), missing chromosome (monosomy), or damaged chromosomes increases. For example, at 35, the chance that your pregnancy will be affected by Down syndrome (trisomy 21) is 0.28%. At 40, you’ve got a 1.176% chance. And at 45, 1 in 35 pregnancies (that’s 2.86%) is impacted by Down syndrome.

  • Multiples: Hormonal changes associated with age can cause the release of more than one egg at the same time...resulting in twins! Your chance of having twins between 30 and 39 years old are double that of folks under 20 years…and the rate of twinning is triple for those 40+.

  • Premature birth: Research shows being 40 years and over is associated with an increased risk of preterm birth (babies born before 37 weeks), even after adjusting for factors, like placenta previa and gestational diabetes.

  • Low birth weight: A study in the American Journal of Epidemiology found that mothers aged 40+ had the highest prevalence of babies born at a low birth weight, which is less than 5 pounds, 8 ounces. However, their analysis indicates this is due to factors other than age.

  • Miscarriage: At age 35, you have about a 20% chance that your pregnancy will end in miscarriage and that moves to 40% at age 40. (This is likely due to preexisting conditions or chromosomal abnormalities.) For context, the rate of miscarriage is 9 to 17% for those between 20 and 30 years.

  • Stillbirth: While overall risk for stillbirth is still very low, the rates do go up with age. For example, there’s a 0.27% chance of stillbirth among 25- to 29-year-olds, but that risk bumps to 0.40% for those between 35 and 39 and 0.53% for those 40+.

What are the advanced maternal age risks to parents?

The number of folks getting pregnant between age 35 and 39 rose about 67% from 1990 to 2019. But despite all of these “older moms”—and the worry that surrounds them—recent research out of Northwestern University found that young moms-to-be are actually experiencing more problematic pregnancies than those at a so-called advanced maternal age. That means, while those 35+ may experience complications in pregnancy, their age is not the only driving factor. That said, here are some known issues that are associated with advanced maternal age.

  • Gestational diabetes. According to the Centers for Disease Control and Prevention (CDC), if you’re older than 25 years old, you’re already at an elevated risk for gestational diabetes. But research shows that your chances seem to steadily increase with age—and that’s regardless of pre-pregnancy weight.

  • High blood pressure: If you are younger than 20 or older than 40, your risk of gestational high blood pressure (aka hypertension) increases. Carrying multiples also ups your chances.

  • Preeclampsia: Being 40+ (or under 20) also puts you at an elevated risk for preeclampsia, marked by high blood pressure, swelling, and kidneys and liver issues. While most pregnant folks with preeclampsia have healthy babies, if preeclampsia is left untreated, it can cause serious problems.

  • Cesarean section: ACOG attests that “advanced” age alone is not an indication for cesarean delivery. However, research shows that moms-to-be who are 35 and older have progressively higher cesarean rates—both elective and otherwise—as compared with their younger cohorts. This could, at least partially, be because one’s chances of carrying multiples goes up with age…as does the chance that baby-to-be will not head-down at go-time.

Are there special prenatal tests or precautions if you’re 35 and older?

Yes. Because of the increased chance that your baby will have a birth defect, it’s recommended that all pregnant folks 35 and older consider certain prenatal tests to see if your baby is at risk. Here’s what ACOG recommends:

  • Possible daily low-dose aspirin: If you’re 35+ and have at least one other risk factor for preeclampsia, such as having a 10-year gap between pregnancies, taking a daily low-dose aspirin can reduce your preeclampsia chances. (Ideally, a low-dose aspirin regimen should begin before 16 weeks.)

  • Maternal serum screening: ACOG recommends the second trimester maternal serum screening test, aka the “triple screen” or “quad screen,” for those 35 and older (or cell-free DNA screening). That recco holds strong whether you’ve had nuchal translucency screening between 10 weeks and 13 weeks or not. This blood test usually takes place between 15 and 18 weeks. This prenatal test evaluates your chance of carrying a baby who has Down syndrome (trisomy 21), spina bifida, trisomy 18 (a chromosomal disorder that causes severe delays and abnormalities), and abdominal wall defects where the baby’s abdominal organs protrude through their belly button.

  • Cell-free DNA screening: Again, those expecting at 35+ years should consider the quad screen or cell-free DNA screening (aka non-invasive prenatal testing or NIPT). The latter prenatal blood test can be conducted at 10 weeks and can detect more than 99% of Down syndrome cases, 97% of trisomy 18 pregnancies and about 87% of trisomy 13 pregnancies. As a bonus, this test can also tell you your baby’s gender.

  • Detailed fetal anatomic ultrasound: This prenatal test is often simply called an anatomy scan or the 20-week scan—though it can be given between 18 and 22 weeks. The scan can often determine if you’re having a boy or a girl and it can help detect certain congenital disorders and anatomical abnormalities, including cleft palate, spina bifida, Down syndrome, and skeletal dysplasia.

  • Diagnostic testing. Often offered after a screening test that reveals elevated risk, chorionic villus sampling (CVS) or amniocentesis provide more definitive results on genetic abnormalities. You can discuss these options with your doctor regardless of age and risk.

  • Third trimester growth scan: If you’ll be 40 or older at your delivery date, it’s suggested that you get a growth assessment sonogram during your third trimester to help determine if your baby is too large or too small for their gestational age…which occurs more frequently as your age increases.

  • Fetal surveillance: Fetal movement assessment, nonstress test, contraction stress test, and more are suggested to start between 32 weeks and 36 weeks if you’ll be 40 or older at your due date. This can help reduce the risk of stillbirth.

Tips For a Healthy Pregnancy After 35

Have a preconception visit. Before you try to get pregnant, get a checkup and make sure any medical conditions you may have are well-managed.

Quit smoking. Research shows that the combo of being 35+ and a smoker significantly increased the risks of preterm delivery, preeclampsia, low birth weight, and more.

Go to all your prenatal visits. Go for your first prenatal care visit as soon as you learn you’re expecting. And while you’re there, chat with your OB/GYN or midwife about whether a perinatologist (aka a maternal-fetal medicine specialist) is right for you. A perinatologist is an OB/GYN who specializes in high-risk pregnancy.

Prioritize sleep. Babies born to older moms who slept poorly during pregnancy were more likely to land in the neonatal intensive care unit than their well-rested counterparts, according to a report in the journal Sleep Health. For help getting the ZZZs you need during pregnancy, check out our pregnancy guide to better sleep.

Take prenatal vitamins. And make sure that they contain folic acid. In fact, start taking them before getting pregnant. This can help reduce the risk of some birth defects, like spina bifida.

Get vaccinated. In addition to the COVID-19 vaccine, your annual flu shot, and the Tdap vaccine, make sure you’re up to date on all your vaccinations. They help protect you from certain infections that can harm you and your baby-to-be.

Eat well and exercise. This is important when you’re expecting at any age! For help, check out which nutrients you need when pregnant, our prenatal yoga guide, and these bump-friendly workouts. Of course, talk to your care provider before starting or amping your exercise routine.

 

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REFERENCES

  • The American College of Obstetricians and Gynecologists (ACOG): Pregnancy at Age 35 Years or Older
  • UT Southwestern Medical Center: Pregnancy over age 35: A numbers game
  • Advanced Maternal Age and Adverse Pregnancy Outcome: Evidence from a Large Contemporary Cohort, PLoS One, February 2013
  • Mayo Clinic: Pregnancy after 35: Healthy pregnancies, healthy babies
  • Can assisted reproduction technology compensate for the natural decline in fertility with age? A model assessment, Human Reproduction, July 2004
  • Yale Medicine: Women, How Good Are Your Eggs?
  • Women & Infants: Diminished Ovarian Reserve: What is diminished ovarian reserve?
  • Ovarian ageing and the impact on female fertility, F1000Res, 2018
  • National Human Genome Research Institute: Meiosis
  • The Risk of Advanced Maternal Age: Causes and Overview, Journal of Gynecological Research and Obstetrics, May 2020
  • ACOG: Having a Baby After Age 35: How Aging Affects Fertility and Pregnancy
  • Advanced maternal age and pregnancy outcomes: a multicountry assessment, BJOG, March 2014
  • Effect of maternal age on the risk of preterm birth: A large cohort study, PLoS ONE, January 2018
  • Advanced Maternal Age and the Risk of Low Birth Weight and Preterm Delivery: a Within-Family Analysis Using Finnish Population Registers, American Journal of Epidemiology, December 2017
  • Mayo Clinic: Miscarriage
  • Early Pregnancy Loss, ACOG Practice Bulletin No. 200, August 2018
  • Advanced Maternal Age and Stillbirth Risk in Nulliparous and Parous Women, Obstetrics & Gynecology, August 2015
  • United States Census Bureau: Fertility Rates: Declined for Younger Women, Increased for Older Women
  • Temporal Trends in Adverse Pregnancy Outcomes in Birthing Individuals Aged 15 to 44 Years in the United States, 2007 to 2019, Journal of the American Heart Association, May 2022
  • CDC: Diabetes Risk Factors
  • Incidence and Risk Factors of Gestational Diabetes Mellitus: A Prospective Cohort Study in Qingdao, China, Frontiers in Endocrinology, September 2020
  • Cedars Sinai: Gestational Hypertension
  • Obstetric Complications, Neonatal Morbidity, and Indications for Cesarean Delivery by Maternal Age, Obstetrics & Gynecology, December 2013
  • ACOG: Low-Dose Aspirin Use for the Prevention of Preeclampsia and Related Morbidity and Mortality
  • Mayo Clinic: Quad screen
  • UCSF Health: FAQ: Cell-Free DNA Screening
  • Cleveland Clinic: 20-Week Ultrasound (Anatomy Scan)
  • Association of Prenatal Care Services, Maternal Morbidity, and Perinatal Mortality With the Advanced Maternal Age Cutoff of 35 Years, JAMA Health Forum, December 2021
  • Smoking among older childbearing women - a marker of risky health behaviour a registry-based study in Finland, BMC Public Health, December 2013
  • Antenatal sleep quality associated with perinatal outcomes in women of advanced maternal age, Sleep Health, February 2020
  • Cleveland Clinic: Advanced Maternal Age

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