How Being Over 35 Can Affect Fertility

We've talked about how women are waiting longer than ever before to tie the knot, and for many women, this means waiting for pregnancy, too. Unfortunately, people are quick to remind a woman that her fertility rapidly declines as she gets older, which causes anxiety and worry among many women wanting to be moms (at some point).

To get to the bottom of the age/fertility connection, we spoke with Dr. Nigel Pereira, MD, FACOG, ALS/ELS (AAB),  Assistant Professor of Obstetrics and Gynecology and Assistant Professor of Reproductive Medicine at the Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine.

How does age impact a woman's fertility?

You may or may not know that every woman is born with a finite amount of eggs that are available throughout their reproductive lifespan.  In fact, that number peaks at about 20 weeks of fetal life (aka right when you are born!), and declines from there. Dr. Pereira explains, "In fact, the number of eggs at birth is about 1-2 million, which further reduces to 300,000 at puberty. The number of eggs available decreases precipitously until the onset of menopause. Most women ovulate approximately 400-500 in their entire life."

In addition to the number of eggs available, age can also affect egg quality as well. He explains that there is, "an inverse relationship between age and egg quality, i.e., older women have poorer egg quality. This is predominantly due to the genetic and chromosomal instability of older eggs. These eggs are less likely to fertilize." If they do in fact fertilize, they are then less likely to implant. Additionally, these embryos are often at higher risk for "miscarriage, birth defects or chromosomal abnormalities like Down’s or Turner’s syndrome."

So, it is true that a woman's chances of conceiving do decrease with each passing year, and Dr. Pereira describes, "these chances decrease precipitously between the ages of 35-40."

Advanced Maternal Age

The terms used to describe pregnancy over 35 are typically less than kind, and include "geriatric pregnancy," as well as being of "advanced maternal age."  However, Dr. Pereira explains that there is concerted effort to gravitate away from this nomenclature.

The good news? Times have changed a bit. "Historically, only women  over 35 years were offered invasive testing such as CVS [chorionic villus sampling] or amniocentesis during pregnancy. This was based on the following data about the risk of having a child with chromosomal abnormalities: 1 in 525 at age 20 years; 1 in 385 at age 30 years; 1 in 200 at age 35 years; and 1 in 65 at age 40 years," he explains. However, in 2007, the American College of OBGYN recommended that CVS or amniocentesis should be offered to all women, regardless of age.

The Risks

There are, however, some documented risks involved in being over 35 and pregnant. Dr. Pereira explains that immediate concerns are those of miscarriage or multiple pregnancy, especially when fertility treatments were utilized.  Additionally he says that, "When compared to younger counterparts, women  over 35 years can have pregnancies complicated by gestational diabetes, pre-eclampsia, pre-term labor, pre-term birth, fetal growth issues, or stillbirth. Some data also suggest that women over 35 years may have a higher likelihood of undergoing cesarean delivery."


Chances are you've heard some myths and generalizations surrounding pregnancy, but don't believe everything you hear. First things first, being over 35 does not mean you need IVF.  "I frequently see patients who are told that they need IVF after the age of 35 years," explains Dr. Pereira. "This is far from the truth. Although IVF may be indicated in some situations, most women over 35 years who face some difficulty in conceiving usually require only minimal treatments such ovulation-inducing medications or inseminations." He adds that while women who fail those treatments may ultimately require it, age 35 is not a "fertility cliff," although women over 42 should be considered separately.

Additionally, it's not true that "most pregnancies over 35 result in miscarriage." Dr. Pereira explains, "While the risk of miscarriage is much higher in women  over 42 years due to egg quality issues, most abnormal eggs do not even fertilize or implant." He says that not conceiving is more common than having a miscarriage.

Your age alone does not determine your status as a "high risk" patient, either. In fact, Dr. Pereira explains that most women between ages 35-42 can be managed by a general OB in the absence of any pregnancy complications.  It also does not mean that you'll need CVS or amniocentesis, which are invasive prenatal tests. Thankfully, "with the advent of non-invasive fetal screening using maternal blood, many women do not have to routinely undergo CVS or amniocentesis."

Best Advice

Preparation is important in all pregnancies, and this is no different. Dr. Pereira advises that, "Women/couples should ideally prepare themselves mentally and physically at least 4-6 months before attempting to conceive. A healthy diet, prenatal vitamins/folic acid and regular exercise is recommended. Smoking cessation is imperative. Alcohol consumption should be none-to-minimal." You might also want to consider seeing a fertility specialist for a pre-conceptional consultation, which can optimize your medical and reproductive health prior to trying to conceive.   Additionally, he advises that, "Women who are 35 year or above who are not trying to conceive imminently or those who are single, may also choose to consult with a fertility specialist to discuss future options."

Additionally, women or couples over 35 years old who have not conceived within 6 months of actively trying should consider seeking out a fertility specialist.