Does Birth Control Cause Infertility? The Facts You Need To Know

After a few months of trying to conceive, you notice that your period is late. Worried about what might have caused this change in your cycles and wanting to get pregnant as soon as possible, you talk with your doctor about starting Clomid—a drug known for its ability stimulate ovulation. It has been noted that this drug may negatively impact your chances of conceiving by changing the cervical mucus. After several more months of unsuccessful treatments, you are finally able to get an appointment at a fertility clinic.

The doctor discusses the pros and cons of two treatment options with you.

Intrauterine Insemination (IUI), where sperm are washed, concentrated and injected directly into a woman’s uterus in hopes of achieving pregnancy; or In-Vitro Fertilization (IVF), which is similar to IUI except an embryo created in a lab is then implanted into the woman’s uterus

But could all the worrying, doctor visits and interventions be for nothing?

When you are trying to get pregnant after discontinuing the use of birth control but still haven’t been successful.

Many women see their cycles return to normal once a contraceptive device like the IUD, ring, patch or implant is removed. Although most women will see their cycles return fairly quickly after stopping the use of birth control pills, in some cases it can take up to a year for your fertility levels to reach normal again—once you are cycling regularly once more. A woman may not be able to get pregnant for up to 18 months after using the birth control shot Depo-Provera.

Although the pill or other forms of birth control do not cause permanent changes in your cycle after you stop taking them, they may still delay your ability to become pregnant. One possible explanation for the delay in fertility post-birth control is that cervical fluid production may decrease as a result of taking the pill. The possibility that long-term use of certain types of contraceptives may lead to a thinner endometrium (uterine lining) has also been suggested.

Because the endometrium must be thickened in order for an embryo to implant, a thinner lining can make it difficult—though not impossible—to become pregnant. No matter what causes the delay, women are starting families later in life than they used to.

The role of cervical mucus in fertility

We are all taught in high school biology or sex-ed that it takes a sperm and an egg to make pregnancy happen. But another important factor is often left out of this equation: cervical fluid (also called cervical mucus).

Sperm needs fertile cervical mucus to survive longer than a few hours in the vagina, and then have the energy reserves necessary to travel through the uterus all the way up into fallopian tubes—waiting for an egg that might never come. Cervical mucus also helps filter out “bad” sperm—those with poor morphology (shape) or motility (movement)—to increase your chances of getting pregnant. Cervical mucus is secreted by the cervix and changes in appearance before ovulation, to help nourish sperm and ensure that it reaches an egg.

The consistency of cervical mucus changes throughout the month. During and after ovulation, it is thick enough to block sperm from reaching the uterus. Cervical mucus becomes thinner and more liquidy during ovulation, allowing the “good” sperm to swim easily through it toward the uterus. Sperm can remain viable in the female reproductive tract for up to 5 days if conditions are right. Without good, healthy mucus in the uterus, a baby cannot grow.

How birth control prevents pregnancy

The available scientific literature suggests that hormonal contraceptives generally work by preventing ovulation in addition to another mechanism, such as thickening the cervical mucus. Another way in which contraception prevents pregnancy is by changing the consistency of cervical mucus. Hormonal birth control can also increase the thickness of cervical mucus, creating an additional layer to prevent pregnancy even if ovulation does occur. If a woman’s hormones are not being artificially suppressed by birth control, she experiences normal cyclical changes in hormone levels. But when a woman is on hormonal birth control, the synthetic hormones in the pill (or patch or ring, etc.) override her natural ones and change how her cervix produces mucus—so it constantly secretes this non-fertile type. How does it do that?

Conclusion

There are many misunderstandings about how to get pregnant and what causes ovulation. In school, students are generally taught how to avoid unwanted pregnancy and sexually transmitted infections (STIs), rather than the importance of protecting against infertility. How could you have known differently? If you believed some of the things that are said about ovulation, chances are they’re not true. If you have any questions about your fertility, talk to your primary care physician or gynecologist. They want to help you make informed decisions about your overall health and wellness.