Pregnancy brings many temporary and permanent changes. Women start feeling nauseous, experience leg cramps and their heart rate increases. As the foetus grows bigger, the bump causes backache and they find it difficult to lie down comfortably.
“In the first semester, sleeping at night is difficult,” says Dr Rama Shankarnarayan, gynaecologist and IVF specialist in Bengaluru. “Women, especially the younger ones, feel drowsy during the day and tend to fall asleep. Because of this, they can’t sleep at night. It’s the hormonal imbalance – that’s what causes sleeplessness in the first semester.”
The 2007 Women and Sleep Survey by the National Sleep Foundation showed that up to 78% of women reported disturbed sleep during their third trimester of pregnancy.
Pregnant women sleep more than usual in the first trimester, as the body is nurturing the womb and pumping more blood while the placenta is still forming. But though they sleep longer, they don’t sleep well.
A 2015 study found that nearly 46 percent of pregnant women reported poor sleep quality. This may also be the reason why sleepiness increases in the daytime.
“In my first trimester, the nausea prevented me from sleeping well,” says Sowmya, mother to a five-month-old daughter. “Frequent urination woke me up around three to four times at night. In the third trimester, however, I slept a lot. I had over eight hours of sleep at night and napped during the day for around four hours, sometimes right after breakfast.”
Sleep in pregnant women changes not just in duration and quality but also in its pattern. Transformations in the body, which may be anatomical, physiological, hormonal or psychological in nature, affect many aspects of their sleep.
Anatomical
One of the first signs of pregnancy is weight gain. Women gain up to 20 per cent of their earlier weight. At around 12 weeks, the uterus grows to the size of a grapefruit. By the third trimester, it will have grown to the size of a watermelon. The position of the diaphragm, the major muscle of respiration, moves upwards by 5 cm as the uterus balloons, which leads to trouble in breathing. Troubled breathing, in turn, causes sleep disruption.
“There is a compromise in the abdomen in the third trimester,” Dr Shankarnarayan says. “There is not space for the baby to grow so it presses on the diaphragm. They are not comfortable when they lie down, so they get up again. When they eat later in the night and try to sleep, the stomach is full so there’s no space. This discomfort disrupts their sleep.”
Physiological
When the volume of blood in the body increases with pregnancy, it increases the stress on the heart. The blood vessels in the placenta are narrow, pressuring the heart to pump a large volume of blood.
“I couldn’t sit straight because of my huge belly, in the third trimester. I couldn’t breathe well because of the pressure on my chest,” Sowmya says. “It felt like no matter how deep or frequently I inhaled, there was never enough oxygen.”
As the size of the uterus increases, it grows freely and occupies free spaces. Because the abdomen is a closed cavity, the uterus cannot grow there and swells in the direction of the diaphragm. The movement of the diaphragm is restricted, so it cannot contract and expand freely. The pregnant woman, therefore, may need to breathe faster to get enough oxygen.
Sympathetic activity (affected by hormones), which determines the body’s fight or flight response, also increases. All these cause fatigue and exhaustion in the expectant mother.
Other physiological changes related to pregnancy include slower digestion and constipation. Pregnant women wake up several times in the night due to frequent urination. Gastroesophageal reflux, a condition where bile flows into the food pipe and irritates the lining, affects over 75% of pregnant women in some populations.
Psychological
It has been determined that mood and sleep affect each other. Anxiety and stress affect the duration and quality of sleep, while insomnia during pregnancy has been linked to postpartum depression.
In Sowmya’s case, the fluctuations in her mood caused disruptions in her sleep throughout her pregnancy. “In the seventh month, I heard of incidents where women miscarried in their seventh month of pregnancy,” she says. “Despite being someone who has never been easily affected by others’ words, I became so anxious that it used to often wake me up at night. My thoughts ran in a loop endlessly.”
Obstructive sleep apnoea
A more common type of sleep disorder is obstructive sleep apnoea (OSA), where the muscles in the throat relax, narrowing the airway. As a result, people might choke or gasp to get enough oxygen in the body. Sensing that reduced oxygen levels, the brain wakes you up from sleep frequently during the night.
“In pregnancy, the mucus membranes are swollen,” says Dr Shankarnarayan. “There is water retention in our body because of our hormones. That can become more obstructive. So, while sleeping, it becomes difficult to breathe in. Their breathing becomes so shallow that they become apnoeic, not breathing at all — then they suddenly take in a large breath and get up gasping. This can happen in those who have a deviated nasal septum. Apnoea happens in women with pregnancy induced hypertension (PIH), but this is very rare.”
In pregnant women, weight gain and nasal congestion may cause OSA, which is a risk factor for high blood pressure. Moreover, OSA restricts the flow of oxygen to the foetus. Other consequences include preeclampsia, a condition where women at around 34 weeks of pregnancy have high blood pressure, protein in their urine and swelling in their hands and legs. Preeclampsia can cause eclampsia, a serious condition which poses several health risks to the mother and the baby.
Poor sleep during pregnancy may also lead to gestational diabetes, gestational hypertension, preterm births, a longer and more painful labour and caesarean delivery. It is also a known risk factor for postpartum depression.
Restless legs syndrome
This syndrome is characterised by crawling, itching or tickling sensations that cause an irrepressible urge to move the legs. It is known to occur or worsen in the evening or at night. Restless legs syndrome (RLS) affects a third of women in their third trimester. RLS causes difficulty in falling and staying asleep, waking them up frequently throughout the night and interfering in their daytimes naps.
Swedish neurologist Karl-Axel Ekbom, one of the earliest authors to describe this condition, found in a study that RLS was prevalent in 11.3% of 486 pregnant women. Today, the prevalence of gestational RLS in 26-30% of pregnant women has been established.
Sleep problems during pregnancy affect not just the mother but also the newborn. Babies may have low birth weight and more crying during infancy. Sleep and temperament of infants may also be affected by the mother’s sleep patterns before and during pregnancy; a study shows that in the cases where mothers slept for less than six hours before pregnancy, the infant cried more intensely.
Improving sleep quality during pregnancy
Changes in lifestyle go a long way in helping women sleep better during these months. It is important to maintain sleep hygiene, which includes the following:
- Keep a fixed sleep routine, which means waking up and going to sleep at fixed times
- Don’t stay in bed for activities other than sleeping
- Do relaxing activities before bedtime, such as listening to music, meditating or talking to a friend.
- Put away all electronic devices an hour before bedtime — since artificial light is proven to affect the sleep-wake cycle (circadian rhythm)
- Try napping during the day if you aren’t getting enough sleep at night
Diet is another important aspect which affects sleep. Here are some tips:
- Avoid caffeine, tea and soda
- Avoid spicy foods
- Having smaller meals for dinner will prevent gastrointestinal problems, which may disrupt sleep
- Drink plenty of water throughout the day, but not very close to bedtime. Frequent urination at night is another cause of sleep disruption.
Many women find it difficult to sleep in a comfortable position in their third trimester. Lying on the back is not advisable, so it is recommended that they sleep on their left side (or the right) with their legs curled. This position improves the flow of blood to the heart, kidneys and the uterus. It also aids the supply of oxygen and nutrients to the foetus.
Exercising both the body and calming the mind regularly also helps improve sleep. Gentle exercises such as yoga and tai chi helps reduce prenatal depression. Practising mindful meditation and breathing techniques alleviates anxiety and relieves stress.
