Getting pregnant at age 37 is a common reality today. The medical term “Advanced Maternal Age” (AMA) describes pregnancy occurring at age 35 or older, a classification established decades ago. This designation means certain considerations become more prominent for both the mother and the baby. While 37 is far from “too old,” it marks a point where biological changes accelerate, necessitating informed planning and proactive medical support.
Conception Rates and Egg Health After 35
The ability to conceive is closely tied to the health and quantity of the available eggs, known as ovarian reserve. Fertility begins a gradual decline around age 32, but the rate of decline accelerates notably after age 37. This acceleration is the primary reason why it may take longer for a 37-year-old to conceive compared to someone in their early thirties.
For a healthy couple with a 37-year-old woman, the probability of achieving a pregnancy within a single menstrual cycle is significantly reduced. Data suggests that women aged 37 to 39 have a 67% chance of achieving a live birth within one year of trying to conceive, compared to much higher rates for younger age groups. This extended time to conception is largely due to a phenomenon called diminished ovarian reserve (DOR) and a decline in egg quality.
A woman is born with all the eggs she will ever have. By age 37, the estimated number of remaining eggs is around 25,000. More significantly, the proportion of eggs with a normal set of chromosomes decreases substantially. Estimates suggest that at age 37, approximately 42% of eggs may be chromosomally abnormal, which can prevent fertilization, implantation, or lead to early pregnancy loss.
Potential Maternal Health Complications
Pregnancy at age 37 introduces a modest but definite increase in the risk for certain health conditions affecting the expectant mother. These risks are not certainties, but they require closer monitoring during prenatal care. One of the more common concerns is the increased likelihood of developing gestational diabetes, a type of diabetes that occurs during pregnancy.
The risk of hypertensive disorders, such as gestational hypertension and preeclampsia, is also elevated for mothers in this age group. Preeclampsia, characterized by high blood pressure and organ damage, necessitates careful management to prevent serious complications. Older mothers also face a slightly higher incidence of certain placental issues, including placenta previa, where the placenta covers the cervix.
This age group also experiences a statistically higher rate of medical interventions during delivery. The likelihood of a delivery via Cesarean section, whether elective or emergency, is increased compared to younger mothers. The heightened risk of conditions like gestational diabetes or preeclampsia can necessitate a planned or emergency C-section to ensure the safety of both the mother and the baby.
Fetal and Chromosomal Considerations
The most pronounced biological change associated with pregnancy at age 37 relates to the increased potential for fetal chromosomal abnormalities, or aneuploidies. This is directly linked to the aging of the eggs, which have been suspended in a stage of cell division called meiosis since before the mother’s birth. With time, the cellular machinery responsible for accurate chromosome separation can malfunction, leading to an incorrect number of chromosomes in the egg.
The most commonly discussed aneuploidy is Down Syndrome (Trisomy 21), where an extra copy of chromosome 21 is present. While the risk of having a baby with Down Syndrome is about 1 in 365 at age 35, it rises considerably by age 40 to about 1 in 100. The risk at age 37 falls within this accelerating range, making genetic screening a routine part of care.
The increased rate of chromosomal errors also contributes to a higher incidence of pregnancy loss. The risk of miscarriage increases with maternal age, primarily because many early miscarriages are the result of a non-viable chromosomal combination. Additionally, mothers in their late thirties have a slightly increased risk of other adverse outcomes, including preterm birth and stillbirth.
Proactive Medical Strategies and Screening
A proactive approach to preconception and prenatal care can help mitigate the considerations associated with an older age pregnancy. Optimizing maternal health before attempting conception is strongly recommended, including managing pre-existing conditions and adopting a healthy lifestyle. Preconception counseling offers an opportunity to discuss individual risks and create a tailored plan.
During pregnancy, several screening and diagnostic options are available to provide information about the baby’s genetic health. Non-Invasive Prenatal Testing (NIPT) offers highly accurate screening for common aneuploidies like Trisomy 21. For a definitive diagnosis, invasive procedures like Chorionic Villus Sampling (CVS) or amniocentesis can be performed. Assisted Reproductive Technology (ART), such as In Vitro Fertilization (IVF) coupled with Preimplantation Genetic Testing (PGT), provides options for those who experience difficulty conceiving and allows for the screening of embryos before implantation.