Sleep and Fertility: How Much Rest You Need When Trying to Have a Baby

Sleep Deprivation and Infertility:
Is There Overlap?

I speak from personal experience when I say that infertility is one of the most lonely and painful seasons. I probably took hundreds of pregnancy tests during the time I was struggling to get pregnant, and each time I saw the “negative” result it felt like a dagger in my heart. 

I lost a lot of sleep during that time thanks to stress and anxiety, and if you’re struggling to conceive too, I’m sure you can relate. In some ways, it becomes a chicken and egg scenario. Maybe you were sleeping fine before you started this journey, but now that could be the very thing holding you back.

Research on sleep and infertility is still very new. Over 72 million women face infertility worldwide, and in many cases the exact cause is unknown. Unfortunately, the relationship between sleep and fertility is complicated because there are so many factors that come into play.

Given the fact that sleep is so crucial to overall health and emotional well-being, it’s not surprising that it plays a role in our ability to conceive too. Let’s start by taking a look at why sleep is so important for our bodies and minds.

Humans spend approximately one-third of our lives sleeping, but have you ever wondered what’s happening in your body while you’re off in dreamland? There are four stages of sleep that we cycle in and out of throughout the night. Three are NREM (non-rapid eye movement) and one is REM (rapid eye movement).

Each stage is important and anything that reduces overall sleep or the time spent in one of these stages can impact health. Just like there isn’t one single cause of infertility, there isn’t one single function of sleep. Instead, sleep plays a crucial role in nearly every system of the body.

During lighter stages, the brain is working hard to consolidate information into short and long-term memories. Missing out on these stages could impact learning, memory, information processing, and so much more.

Deep sleep is when scientists believe the body works on tissue repair and new cell growth. Daily life can put a lot of stress on the body, so this stage is when the body works hard to catch up on repairs and maintenance that it can’t do during the day. Deep sleep is kind of like getting your car serviced – oils are topped up, loose threads and bolts are tightened, and all the clutter and debris are cleared away.

Some of the other functions of sleep include:

As you can see, when the body is deprived of sleep, the effects are ubiquitous. But how does that factor into the ability to conceive? Let’s take a deeper look at some of the known causes of infertility.

What Causes Infertility?

What Causes Infertility?

The American Society for Reproductive Medicine defines infertility as “the failure to achieve a successful pregnancy after 12 months or more of appropriate, timed unprotected intercourse or therapeutic donor insemination.” In some cases, medical history or certain physical findings may warrant earlier evaluation and treatment. In women over age 35, treatment is started after 6 months instead of 12.

If you’ve been trying to conceive for some time, you’ve likely already received a referral to a physician that specializes in fertility.  I remember the first appointment my husband and I went to and how overwhelming it was to hear about all of the different factors that could be causing our issues. 

In most cases, it takes a lot of detective work to pinpoint the exact cause. Even if they do discover something such as a failure to ovulate, they may never be able to tell you why it started happening in the first place. 

According to research, infertility may be organic – the result of something physical such as blocked tubes or problems with ovulation, iatrogenic – the adverse effect of another medical condition or treatment, or lifestyle-related – poor nutrition, weight, drugs, and alcohol. 

The World Health Organization task force on the Diagnosis and Treatment of Infertility classifies the prevalence rates of infertility into the following categories:

Source: “Sleep, Sleep Disturbance and Fertility in Women” – National Center for Biotechnology Information ^[1]

Now that we know some of the major causes, we can move on to looking more closely at the process of conception.

Conception: It’s More Complicated
Than We Think

It all starts with a little innocent flirting, a bottle of wine, and then eventually the egg and sperm meet. Seems simple, right? Wrong. The process of getting pregnant is  a lot more complicated than it sounds.

Not only does it take two people to conceive, but both people have to be healthy and have properly functioning reproductive systems for the process to go smoothly. Then, there’s timing.

While men can technically get a woman pregnant any day, any time, with women, there’s a very short ‘fertile window’ of opportunity. This ‘fertile window’ refers to the days in a woman’s menstrual cycle when pregnancy is possible. For most women, there is a six-day window which includes the day an egg is released from the ovary (ovulation) and the five days beforehand.

What this means is that there are really only six days out of the entire month that women can become pregnant. It’s a wonder that humankind has been able to reproduce and experience the level of population growth that we have!

Timing isn’t the only factor for fertility. Both men and women have many other variables that must be properly functioning for conception to occur.

Let’s start with men. Males have it slightly easier in this department because they don’t have a monthly cycle to worry about and also aren’t the ones responsible for growing babies. In fact, their role in the entire process comes down to one single job – provide healthy sperm.

People rarely think of fertility issues being caused by men, but in over one-third of couples struggling with infertility, that’s the case. According to Mayo Clinic, “Male infertility is due to low sperm production, abnormal sperm function or blockages that prevent the delivery of sperm. Illnesses, injuries, chronic health problems, lifestyle choices and other factors can play a role in causing male infertility.”

In order to get a woman pregnant, men need to produce healthy sperm (strong and fast swimmers), they need to produce enough sperm (around 40 million or more per ejaculate is ideal), and they need to be able to transport the sperm efficiently (from the testicles to be mixed with semen, then ejaculated out of the penis).

There are many different physical requirements for this whole process to go smoothly as well. Healthy sperm require healthy hormones. The penis and testicles must be healthy enough to produce sperm, maintain an erection, and ejaculate that sperm via semen. 

Once the sperm make it into the vagina, they have to be strong enough to swim up through the cervix and uterus into the fallopian tubes where they can begin looking for an egg. Only the strongest swimmers make it, and they have just six days to find an egg before they die. Talk about survival of the fittest!

There’s a lot more at stake when it comes to females and fertility. We already discussed the limited window of opportunity, but there are many other factors before and after sex that can affect conception. 

Around the age of 12, most females begin menstruating and the passage from childhood into womanhood begins. The monthly cycle involves four phases: the follicular phase, the ovulatory phase, the luteal phase, and the menstrual phase. The average length is 28 days, although if you surveyed a room full of women, you’d find that some have cycles that are shorter and others much longer.

The main hormones involved in this process are follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen, and progesterone.

The follicular phase technically begins the first day of your period when the hypothalamus sends a signal to your pituitary gland to release FSH, stimulating your ovaries to produce 5-20 follicles. So while you’re eating chocolate and popping Midol to deal with your horrible cramps, your body is already in baby mode again.

Each of these tiny follicles contains an immature egg, but only the healthiest one will mature and the others will be reabsorbed into your body. As the follicle begins to mature, estrogen levels surge to thicken the lining of the uterus and trigger the release of LH from the pituitary gland.

This starts the ovulatory phase, which is when the ovary releases the mature egg to make its journey down the fallopian tube towards the uterus. This is the only time in the whole cycle when you can get pregnant. Two signs to look for during ovulation are an increase in basal body temperature and thick discharge with the same texture as egg whites.

The egg only has about 24 hours to be fertilized by sperm, or it dies. However, because sperm can survive for up to 5 days, there is that 6-day ‘fertility window’ leading up to ovulation. 

The luteal phase is when the follicle that released the egg becomes the corpus luteum, releasing estrogen and progesterone to thicken the uterus lining further in preparation for implantation of the fertilized egg. If no egg is implanted, the corpus luteum shrinks, hormone levels drop, and the uterus lining is shed – a.k.a. the menstrual phase.

Since this is such an intricate process that requires hormones and multiple organs to be working together, there are many more things that can go wrong. Blocked tubes, irregular cycles, hormone imbalance, ovarian cysts, fibroids, and so much more. You can see why a healthy lifestyle is crucial for this process to run smoothly.

Poor Sleep’s Effect on Women

The Centers for Disease and Control (CDC) estimates that more than one-third of Americans aren’t getting the minimum of 7 hours of sleep at night that we all need. 

For some women, regular shut-eye isn’t an option because of life demands like shift work, irregular schedules, travel across time zones, or a sleep disorder. Or, maybe you were one of the few that did manage to prioritize sleep prior to your journey with infertility, but now you find yourself tossing and turning just worrying about the whole process.

The circadian rhythm is the body’s internal clock that relies on exposure to sunlight to regulate the sleep-wake cycle. When this cycle is disrupted, it can significantly alter fertility. Most of the research in this area has been done on shift work since many women have jobs that require them to work odd hours.

According to Megan M. Mahoney, Associate Professor of Psychology and Comparative Sciences at the University of Illinois, “Alterations or disruptions of biological rhythms, as commonly occurs in shift work, jet lag, sleep deprivation, or clock gene knock out models, are linked to significant disruptions in reproductive function. These impairments include altered hormonal secretion patterns, reduced conception rates, increased miscarriage rates and an increased risk of breast cancer.”

Nursing is one profession that is predominantly female and requires shift work, with many schedules alternating between 12-hour day shifts and night shifts. In one study of female nurses, 53% reported changes in their menstrual cycles when working shift work. Many other studies have discovered that shift work disrupts the circadian rhythm, altering melatonin levels, triggering inflammation, and hindering fertility by influencing reproductive hormones.

Another way that circadian rhythm disturbance may impair reproduction is through increased inflammation and inflammatory markers, such as CRP. A study looking at shift workers found that circadian misalignment may increase the risk of diabetes and increase inflammation in the body. Inflammation has also been linked to endometriosis, the painful growth of tissue outside the uterus that has been identified as a factor in infertility.

Circadian rhythm disruptions can also lead to insulin resistance, which is implicated in the development of polycystic ovarian syndrome (PCOS), another common cause of infertility.  There is evidence that insulin resistance also increases the risk of pregnancy complications, diabetes, and cardiovascular disease in those with PCOS.

One thing that is clear throughout all of the research is that too little shut eye can wreak havoc on hormones. Have you ever wondered why you get the munchies at midnight, feel overly emotional when you’re not sleeping, or skip a period when your body isn’t getting the rest it needs? That’s because hormones regulate nearly every process in the body, including appetite, blood sugar, emotions, and reproduction.

The relationship between sleep disturbance and hormone levels is still not completely understood, and greater research is needed in this area. However, we do know that many hormones that are involved in conception and pregnancy operate on a circadian rhythm with increased concentrations at night. When sleep is diminished, these hormones aren’t released at optimal levels and this could be one reason why hormone levels in women struggling with infertility are often out of balance. 

For example, FSH and LH are two female reproductive hormones. Both high and low levels of these hormones have been linked to infertility, and they both are also influenced by sleep. One study found that FSH levels were 20% lower in women who slept less than 8 hours per night compared to those that clocked more than 8 hours, even after controlling for age and BMI.

Sleep disorders can be caused by a number of factors, some psychological, and some physical. Many involve the same hormone disruption and circadian rhythm disturbances that have been implicated in struggles with reproduction. Chronic insomnia has been found to increase stress hormones, including cortisol, and as we talked about earlier – increased stress can make it harder to get pregnant and maintain a healthy pregnancy.

One study in Taiwan looked at data on 16,718 women diagnosed with sleep disorders between 2000 and 2010 and a comparison group of 33,436 similar women without sleep problems. They discovered that after they accounted for age and other health issues, the women with sleep disorders were 3.7 times more likely to experience infertility.

Another disorder that affects 11% of women is obstructive sleep apnea (OSA). This condition causes pauses in breathing that can severely limit oxygen and results in a whole host of health problems, including difficulty with conception. Women with OSA are also more likely to be obese and have PCOS. 

The research on OSA and fertility is still new, but some evidence suggests it may increase the risk of miscarriage and that pregnancy itself may increase the risk of developing OSA or a worsening of symptoms.

If you are having trouble with sleep apnea, take a look at our list of the best CPAP machines and best mattresses for sleep apnea.