In a typical menstrual cycle, one egg is usually released from one of the ovaries. This is known as ovulation. However, in some cycles, two or more eggs can be released in a phenomenon called double ovulation. So how often does double ovulation occur? Let’s take a closer look.
What is double ovulation?
Double ovulation, also known as hyperovulation, is when two oocytes (immature egg cells) are released from the ovaries during one menstrual cycle instead of the normal single oocyte. This results in two eggs being available for fertilization by sperm. If both eggs are fertilized, it can lead to dizygotic (fraternal) twins.
Ovulation occurs roughly halfway through the menstrual cycle, when a mature egg is released from a follicle within one of the ovaries. The egg then travels down the fallopian tube where it may be fertilized. In double ovulation, this process occurs twice within the same cycle, releasing two eggs.
What causes double ovulation?
The exact causes of double ovulation are not entirely clear, but several factors may influence it:
- Genetics – Some women may be predisposed to releasing multiple eggs.
- Age – Double ovulation seems to occur more frequently in younger women.
- Long or irregular cycles – Cycles longer than 35 days or very irregular cycles may be associated with double ovulation.
- High FSH levels – Elevated follicle stimulating hormone (FSH) may stimulate the ovaries to mature and release more than one egg.
- Medications – Some fertility medications like clomiphene citrate may induce double ovulation.
- Previous pregnancy – Having previously been pregnant may increase chances of multiple eggs being ovulated.
Oftentimes, no specific cause can be identified. Double ovulation seems to occur randomly in some women who are otherwise ovulating normally.
How common is double ovulation?
It’s difficult to pin down exactly how often double ovulation occurs, but estimates generally range from 5% to 20% of menstrual cycles:
- One study found hyperovulation in 8.6% of natural cycles in women trying to conceive.
- Another study showed double ovulation in 5-15% of cycles among regularly menstruating women.
- Up to 20% of conception cycles may involve double ovulation based on some estimates.
In women taking clomiphene citrate, double ovulation may occur in 15-30% of cycles. So while not extremely common, double ovulation is certainly not rare either.
Does double ovulation increase the chances of twins?
Yes, double ovulation can increase the odds of having fraternal (dizygotic) twins. Fraternal twins occur when two eggs are fertilized by two different sperm. As double ovulation releases two eggs, it provides the opportunity for twin conception if both eggs are fertilized.
Normally, the chance of natural twin conception is about 1 in 250 pregnancies. But with double ovulation, estimates suggest the twin conception rate may increase to between 1 in 17 to 1 in 25. So double ovulation approximately doubles the odds of twins.
Signs and symptoms of double ovulation
Double ovulation doesn’t usually cause any specific symptoms. But some possible signs include:
- Mittelschmerz (ovulation pain) occurring twice in one cycle
- Changes in cervical mucus suggestive of two surges of estrogen
- Detection of two corpus luteum cysts on the ovaries
- Elevated basal body temperature indicating two distinct shifts
Many women do not experience any noticeable symptoms. Testing hormone levels or using ultrasound monitoring would be needed to confirm double ovulation.
Risks associated with double ovulation
For the most part, double ovulation is not considered risky or problematic. However, there are a few potential concerns:
- Higher chance of multiples – As mentioned, double ovulation increases the odds of conceiving twins or triplets. Higher order multiples carry greater health risks.
- Hormonal fluctuations – The extra ovulation could potentially lead to more hormonal changes in the cycle.
- Ovarian cysts – Each ovulation releases a corpus luteum cyst, so double ovulation means two cysts that could become large or ruptured.
These risks are still relatively low. But those with concerns may wish to track ovulation patterns or use protection around suspected double ovulation.
Double ovulation and getting pregnant
For couples trying to conceive, double ovulation can increase the chances of getting pregnant in that cycle. Each released egg has the potential to be fertilized. However, it does also then increase the probability of twins.
Those using fertility treatments like clomiphene have higher double ovulation rates. This is sometimes intentionally induced to improve pregnancy success. But it can result in twins more often than desired, so monitoring is needed.
For those not wanting to conceive, the possibility of double ovulation means using protection for the entire menstrual cycle. Natural family planning methods may be less reliable if relying on detecting a single ovulation day.
When to see a doctor
Occasional double ovulation is usually not a major concern. But see a doctor if:
- Double ovulation occurs frequently or every cycle
- Significant pain or bleeding occurs around ovulation
- Other symptoms appear related to hormone fluctuations
- Trying to or avoiding conceive and need to track ovulation patterns
Testing and tracking by a doctor can help determine if high double ovulation rates are normal or require intervention. Monitoring is also recommended when using fertility treatments to reduce higher order multiple risks.
Diagnosing double ovulation
To confirm if double ovulation is occurring, a doctor may use:
- Blood tests – Measuring reproductive hormone levels can detect more than one estrogen and LH surge.
- Ultrasound – Visualizing the ovaries can show two developing follicles about to ovulate.
- Progesterone test – Checking consecutive progesterone level increases can reveal two distinct ovulations.
Ovulation predictor kit urine tests may also show two LH surges in one cycle. Tracking basal body temperature can similarly indicate two ovulation dips and spikes.
Treatment depends on the specific goals and symptoms:
- Fertility medications may be adjusted if double ovulation occurs too frequently.
- Ovulation suppression can be used to prevent frequent double ovulations.
- Pain medication helps relieve difficult mittelschmerz or cyst discomfort.
- Preventing fertilization through birth control or condoms avoids potential complications.
If double ovulation frequencies are within normal ranges and not highly symptomatic, no treatment may be necessary beyond monitoring.
In summary, double ovulation resulting in two egg releases per cycle occurs in a substantial minority of women – estimates range from 5-20% of cycles. It can increase the chances of fraternal twins if fertilization occurs. While not inherently problematic, multiple ovulations per cycle can impact fertility planning and treatment. Monitoring ovulation patterns and being aware of the possibility of double ovulation can help guide family planning choices.