Sleep during pregnancy: what changes, and what is safe?

Almost every pregnant woman sleeps worse than usual at some point. You have to urinate more often, you can't find a comfortable position, your back protests or your legs are restless in the evening. That is largely part of it and usually harmless — but around sleep position and around sleep aids there are indeed important safety points. This article explains why your sleep changes by trimester, what is safe and when to contact your midwife or GP.

Why your sleep changes — by trimester

In the first trimester, the hormone progesterone rises sharply. That often makes you sleepy during the day, but at the same time disrupts your night's rest: you become more sensitive and have to urinate more often at night because the womb presses on the bladder. Nausea can make sleep no easier either.

The second trimester is, for many women, relatively the calmest period: the nausea decreases and the belly is not yet so large that it hampers sleep. A good moment to build up a pleasant sleep rhythm.

In the third trimester, the discomforts pile up. The growing belly makes it hard to find a position, you have to urinate more often again, and back pain, heartburn, shortness of breath and the baby's movements interrupt the night. Restless legs also peak now (see below). So sleeping worse in this phase is the rule rather than the exception ^[1][6].

Restless legs (restless legs syndrome)

A restless, tingling or twitchy feeling in the legs that comes up in the evening and at rest and forces you to move, is restless legs syndrome (RLS). In pregnancy it is strikingly common: the prevalence is two to three times higher than usual, and the symptoms are most severe in the third trimester ^[4]. A common underlying factor is a shortage of iron (and folic acid), substances your body needs to produce dopamine.

Sleeping on your side in the last trimester

This is the most important safety point of this article. The KNOV (the professional association of midwives) advises women, from about 28 weeks, to try to fall asleep on their side and to avoid sleeping on their back as much as possible ^[2]. The reason: in the last trimester, the heavy womb can, when lying on your back, press on a large blood vessel (the inferior vena cava), which can temporarily reduce the blood and oxygen supply to the baby.

Practically: place a pillow between your knees or under your belly for comfort; left or right makes no essential difference. If you wake at night on your back, don't be alarmed — simply roll back onto your side. It's about the position when falling asleep.

Most sleep aids are not recommended

If you sleep poorly, the temptation to reach for a sleep aid is great. In pregnancy that is exactly the point where you need to be careful: most sleep aids are not recommended and you should only use them after consulting your doctor or midwife. The Dutch guideline emphatically advises trying non-medication measures and good sleep hygiene first, before medication is even considered ^[5]. Over-the-counter products and herbal preparations are not automatically safe either: "natural" does not automatically mean harmless to your baby.

What can safely help: a fixed sleep rhythm, enough exercise and daylight during the day, limiting caffeine, and winding down your evening calmly. This approach — the core of cognitive behavioral therapy for sleep — is the first step for persistent insomnia ^[1].

When to make contact?

Contact your midwife or GP if the insomnia seriously affects your daily functioning, with severe or persistent restless legs, or with low mood and anxiety. Always raise the alarm right away with warning signs unrelated to sleep — such as significantly reduced fetal movements, severe headache with blurred vision, or upper abdominal pain. Poor sleep often comes with pregnancy, but you don't have to just put up with it on your own: your midwife can think along with you about position, restless legs and safe steps.