Peak Reproductive Years for Women: When Does Fertility Begin to Decline?
Dr. Angel Rivera
If you are a woman and plan to get pregnant in the future it is important to know when are your peak reproductive years.
However, fertility begins to decline as women age, and this can pose risks for pregnancy later in life.
There are also a variety of tests that can be performed to screen for chromosomal abnormalities and different methods that can help you if you are trying to get pregnant in the future.
Planning ahead for pregnancy is important and we will help provide the information necessary for you and your OB-GYN to make the best decision for you.
What are the peak reproductive years for women?
The peak reproductive years for women are between your late teenage years and your late 20s.
After you hit the age of 30 your fertility begins to decline.
The decline is gradual at first but models of fertility decline become steeper after the age of 35 until most women are not able to conceive by the age of 45.
According to the American College of Obstetricians and Gynecologists (ACOG), if you are a healthy woman your ability to get pregnant from your late teens to early 30s has an approximately one in four success rate during your menstrual cycle.
Conversely, as you age your ability to get pregnant when you are 40 is around one in 10 per menstrual cycle which highlights the rate of fertility decline.
Your partner's sperm also plays a role and will decline in fertility as they age although in a much less routine manner.
Why does fertility begin to decline as women age?
The primary reason that your fertility begins to decline as you age is because of the decrease in the number and quality of eggs.
When you are born you already have all the eggs you will ever have in your lifetime which is approximately one million, and as you age the number of eggs decreases.
In addition, the older you get the more likely it is that your eggs will have chromosomal abnormalities which can lead to a miscarriage or a baby with genetic disorders.
You also risk having other disorders as you age such as fibroids and endometriosis.
Fibroids are noncancerous growths in the uterus that can interfere with implantation, and endometriosis is when tissue from the lining of your uterus grows outside of it which can damage your fallopian tubes.
What are the risks of a pregnancy at a later age?
There are several pregnancy complications that increase in risk if you are at a later maternal age.
There is an increased risk of having a miscarriage above the age of 35 and, if you are able to get pregnant, you are more likely to have a baby with a genetic disorder such as Down syndrome (trisomy 21) due to chromosomal abnormalities.
Furthermore, you also have an increased risk of stillbirth and multiple pregnancy which is when you have more than one child, for example, twins or triplets, and increases as you age due to your ovaries releasing more than one egg per month.
Preterm births are also a higher risk when you have a multiple pregnancy.
You are at an increased risk for developing gestational diabetes, high blood pressure, preeclampsia, and placental abruption as all of these risks increase as you age.
What are the tests that can be performed for chromosomal abnormalities?
There are several tests that can be performed to check for chromosomal abnormalities.
These are prenatal screening tests and they all occur during the first trimester or second trimester of pregnancy.
The first type of test is a prenatal screening test that assesses the risk of the fetus having certain conditions such as birth defects or genetic disorders.
The other most common type of test is a prenatal diagnostic test which is often used if you are over the age of 35, have had a prenatal screening test come back abnormal, have had previous pregnancies with birth defects, or if you have a chronic medical condition.
These tests are not requirements for your pregnancy but are offered to all women and the decision to have them is up to you and your obstetrician-gynecologist.
What is the best way to plan for pregnancy?
A reproductive life plan is when you decide when you want to have children and family size which can be done with or without the help of a fertility specialist or your OB-GYN.
Your family planning does not have to be detailed at first and can become more detailed as you age although you and your doctors need to be aware of your life goals and if you do not want to become pregnant right now and are engaging in sexual activity then it would be appropriate to discuss birth control options.
If you do plan on becoming pregnant soon then you need to discuss with your doctor the best ways to stay healthy such as avoiding alcohol and tobacco and taking prenatal vitamins which contain folic acid.
What are the best ways to preserve embryos or eggs for later use?
There are two main modern methods to preserve embryos or eggs which are freezing them or using in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI).
IVF is when the egg and sperm are combined in a laboratory dish and then the embryo is transferred to the woman's uterus and ICSI is when a single sperm is injected into the egg in the laboratory during IVF.
The best way to preserve embryos or eggs is to have them cryopreserved (oocyte cryopreservation) which means they are frozen and can be thawed and used at a later date when you are ready to become pregnant.
How viable these eggs are at a later date is fully dependent upon your health and age at the time and your age when the eggs were preserved.
Oocyte cryopreservation is also an option if you are going through cancer treatments that may affect your levels of fertility.
It needs to also be noted that both IVF and cryopreservation can be costly and may not be covered by your insurance.
When is the best time to take a fertility test?
The best time to take a fertility test is when you are having difficulty conceiving after one year of unprotected intercourse or if you are over the age of 35 and have been trying to conceive for six months with no success.
If you are 40 or older it is recommended that you get a fertility test before you start trying to get pregnant.
The best time to have children is when you are in your 20s or early 30s as this is when fertility rates are at their highest.
However, there are many factors that can affect a woman's fertility such as age, health, lifestyle choices, and medications.
There are several tests that can be done to check for chromosomal abnormalities and ensure a healthy baby and your doctor can help you decide which is best for you.
If you are not ready to have children yet but are sexually active, then it is important to discuss birth control options with your doctor.
If you are over the age of 35 and having difficulty conceiving then you need to speak to your OB-GYN about fertility testing and if you are over 40 you should have a fertility test before you try to conceive.
If you have any more questions about conceiving or when to conceive, please talk to your OB-GYN or health care provider.
References, Studies and Sources:
The American College of Obstetricians and Gynecologists
- Having a Baby After Age 35: How Aging Affects Fertility and Pregnancy
- Female Age-Related Fertility Decline
British Fertility Society