How ovulation normally works
In a normal case of ovulation, an egg is released once per menstrual cycle from one of your ovaries.
This process calls for follicle-stimulating hormones (FSH) to stimulate the growth of many egg-containing follicles until one dominant follicle (usually the largest or most developed) emerges. While all other follicles die off, this dominant follicle will continue to grow and release an egg from the ovary during ovulation. The released egg will then either move into the fallopian tubes to become fertilized or it will disintegrate and the uterine lining will be shed through menstruation.
Hyperovulation explained
In the case of hyperovulation, also referred to as multiple ovulation, more than one egg can be released from one or both of the ovaries within one menstrual cycle. When this occurs, it can result in a woman having multiple babies, such as having twins, triplets, and so on.
For example, in the case of fraternal twins, two separate eggs are released at the same time during ovulation and each egg is fertilized by different sperm. This process leads to fraternal twins with different genetic information. In this scenario, having fraternal twins is a result of hyperovulation.
In contrast, identical twins are not considered to be the result of hyperovulation. With identical twins, only one egg is released during ovulation and fertilized by sperm, after which the resulting zygote (fused egg and sperm) separates into two identical zygotes with the same genetic information. Hence, hyperovulation does not lead to having identical twins because there is only one egg that is fertilized by sperm.
Are you hyperovulating?
Many women report symptoms of increased vaginal discharge as an indication of hyperovulation. The discharge may be whiter and stretchier, and may even be accompanied by severe ovulation pain. However, the only way to know for sure whether you are hyperovulating is by obtaining an ultrasound.
Can you ovulate twice in a month?
Technically, you cannot ovulate twice in a month. That is, you do not release separate eggs at different times within the same cycle.
However, you could potentially ovulate more than one egg at the same time. For example, if you were to ovulate two eggs at the same time, you could potentially give birth to fraternal twins if both eggs were successfully fertilized. So you could say that you released two eggs at once during ovulation but not that you ovulated twice.
The misconception that you can ovulate twice in a month likely came from a 2003 study which found that some women had multiple follicular waves throughout their cycles. Specifically, 68% of women had two waves of follicle development during one interovulatory interval and 32% had three waves. Yet, having multiple follicular waves doesn’t mean that ovulation actually occurred during each wave. In fact, it found that only the final wave of follicle development was ovulatory and the preceding waves were anovulatory (without ovulation).
Although the study did not conclude that you can ovulate twice in a month or even multiple times in a cycle, there are some practical implications of the results. For example, knowing that a woman can have more than one wave of follicular development is beneficial for providing women seeking fertility treatments with better ovarian stimulation options.
Causes of hyperovulation
Research indicates that having higher FSH levels could be one cause of hyperovulation. An example of this in action is the use of hormone-based medications like Clomid which triggers the brain to give out more FSH; the higher FSH levels lead to greater follicular development and potentially the release of more eggs.
Study findings have also shown that FSH being released more frequently may be a cause of hyperovulation, as seen in the case of mothers of fraternal twins releasing FSH more frequently during early-cycle follicle development.
Another potential cause for multiple ovulation points to FSH sensitivity across individuals, although research findings are not as strong for this claim.
Factors contributing to hyperovulation and multiple pregnancies
There are many factors that can increase your odds of ovulating more than once per menstrual cycle, some of which may also raise your chances of having multiple pregnancies (being pregnant with more than one fetus at once, such as with twins, triplets, and so on).
Age
There is strong research evidence to support that age influences the chances of hyperovulation. Specifically, older women may have higher levels of FSH, which translates to increased odds of ovulating more than one egg per cycle. As a result, women of advanced age may be more likely to have multiple pregnancies. However, note that this is not always the case since declining egg quality with age increases the risk that not all eggs will be viable.
Genes
There is also research which supports that some individuals naturally have higher FSH levels or release FSH more frequently than others. These increased FSH levels raise the chances of having more than one dominant follicle, resulting in more than one egg released during ovulation.
Also, if a woman’s family members have experienced multiple pregnancies, she may have higher chances of having multiple babies at once.
Previous pregnancies
Your chances of having multiple pregnancies also increase if you’ve had at least one pregnancy already, especially if it resulted in multiple babies.
Many women have also reported having more success with pregnancy after a miscarriage, with that pregnancy resulting in multiple babies, although there is less research to support this claim.
Body composition
Research also suggests that mothers who are taller (around 5 feet 4 inches or over 163 cm) or have a high body mass index (BMI) of 30 or more have a higher risk of having twins.
Stopping birth control
Some studies have also found that having twins was more frequent in mothers who became pregnant soon after discontinuing oral contraceptives.
Fertility treatments
Fertility medications and treatments that encourage conception by stimulating the release of multiple eggs can also result in multiple pregnancies.
Moreover, assisted reproductive technology (ART) including in vitro fertilization (IVF) can also lead to multiple pregnancies. It is estimated that the chances of having twins via IVF with fresh embryos is 12.1% for women under the age of 35.
What this means if you’re trying to conceive
You may want to take note if you have many of the risk factors above for hyperovulation and multiple pregnancies. Whether you are trying to conceive or avoid pregnancy altogether, it may be beneficial to use ovulation test kits like the Eveline Digital Ovulation Test which provides accurate and personalized ovulation and fertility window predictions specific to your period cycle. Keeping track of your reproductive cycle can empower you to make decisions regarding future family planning, whether that means avoiding pregnancy, having a baby, or even multiple babies.
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This article is for informational purposes only and is not meant to offer medical advice.
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References:
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Cornelis B. Lambalk, Dorret I. Boomsma, Lonneke de Boer, Corry H. de Koning, Erik Schoute, Corry Popp-Snijders, Joop Schoemaker, Increased Levels and Pulsatility of Follicle-Stimulating Hormone in Mothers of Hereditary Dizygotic Twins, The Journal of Clinical Endocrinology & Metabolism, Volume 83, Issue 2, 1 February 1998, Pages 481–486, https://doi.org/10.1210/jcem.83.2.4552
Al-Hendy A, Moshynska O, Saxena A, Feyles V. Association between mutations of the follicle-stimulating-hormone receptor and repeated twinning. Lancet. 2000 Sep 9;356(9233):914. doi: 10.1016/s0140-6736(00)02687-8. PMID: 11036902.
Beemsterboer, S.N. & Homburg, Roy & Gorter, NA & Schats, Roel & Hompes, P & Lambalk, Cornelis B. (2006). The paradox of declining fertility but increasing twinning rates with advance maternal Age. Human reproduction (Oxford, England). 21. 1531-2. 10.1093/humrep/del009.
Chantal Hoekstra, Zhen Zhen Zhao, Cornelius B. Lambalk, Gonneke Willemsen, Nicholas G. Martin, Dorret I. Boomsma, Grant W. Montgomery, Dizygotic twinning, Human Reproduction Update, Volume 14, Issue 1, January/February 2008, Pages 37–47, https://doi.org/10.1093/humupd/dmm036
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https://www.cdc.gov/art/pdf/2014-report/art-2014-national-summary-report.pdf
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Photo Credit: Photo by Vitor Monthay on Unsplash
