The second trimester is when sleeping on your side becomes the go-to position, and a few simple adjustments to your setup and habits can make a real difference in sleep quality. Your body is changing fast between weeks 13 and 27, bringing new discomforts like hip pain, heartburn, leg cramps, and frequent bathroom trips. Here’s how to handle all of it.
Why Side Sleeping Matters Now
Left-side sleeping is the most commonly recommended position during pregnancy. As your uterus grows, its weight can compress the large vein that returns blood from your lower body to your heart when you lie flat on your back. This compression can lower your blood pressure and reduce blood flow to the placenta. The effect becomes more significant as pregnancy progresses, but many providers suggest building the side-sleeping habit during the second trimester so it feels natural by the third.
A large case-control study found that women who fell asleep on their backs had a 2.3 times higher risk of late stillbirth (after 28 weeks) compared to those who fell asleep on their left side. That said, a National Institutes of Health-funded study found that sleeping position during early and mid-pregnancy did not significantly affect the risk of complications. The key word is “going-to-sleep position,” meaning the position you intentionally settle into. If you wake up on your back in the middle of the night, simply roll to your side. You don’t need to panic about positions you shift into while asleep.
Right-side sleeping is also fine. While some older studies suggested left was superior, the practical difference between left and right is small. The main goal is to avoid spending prolonged time flat on your back.
Setting Up Your Pillow System
A single pillow between your knees is the most effective small change you can make. It keeps your hips aligned and prevents your top leg from pulling downward, which strains the lower back and pelvis. If you’re waking up with hip pain, this alone often helps.
Beyond the knee pillow, you can add support in two other spots. A small wedge pillow or folded towel tucked under your belly prevents it from pulling you forward and twisting your spine. A pillow behind your lower back keeps you from rolling onto your back during the night and gives you something to lean into, which many people find more comfortable than pure side-lying.
Full-body or U-shaped pregnancy pillows combine all three functions into one piece. They wrap around your body and support your knees, belly, and back simultaneously. They’re bulky and take up bed space, but if you’re tossing and turning trying to keep individual pillows in place, they simplify things. C-shaped pillows work similarly but support only one side, making them better if you tend to stay on one side all night.
Dealing With Nighttime Heartburn
Heartburn often starts or worsens in the second trimester as your growing uterus pushes stomach contents upward and pregnancy hormones relax the valve between your esophagus and stomach. Lying down makes it worse because gravity is no longer helping keep acid where it belongs.
Elevating the head of your bed by about 20 centimeters (roughly 8 inches) reduces reflux symptoms. You can do this by placing wooden blocks or risers under the legs at the head of your bed, or by using a wedge-shaped pillow with an elevation angle of about 20 degrees. Stacking regular pillows under your head doesn’t work as well because it bends your neck without actually angling your torso, and it can create neck pain. The goal is a gentle slope from your waist to your head.
Timing matters too. Eating your last meal or snack at least two to three hours before bed gives your stomach time to empty. Avoiding spicy, acidic, or fatty foods in the evening helps, and eating smaller portions more frequently throughout the day keeps your stomach from overfilling.
Managing Leg Cramps
Sudden, painful calf cramps that wake you from a dead sleep are one of the most common second-trimester sleep disruptors. They tend to get more frequent as pregnancy progresses.
Magnesium supplementation has solid evidence behind it. A randomized controlled trial found that 300 mg per day of oral magnesium bisglycinate chelate (taken as 100 mg three times daily with meals) significantly reduced both the frequency and intensity of pregnancy-related leg cramps over four weeks compared to a placebo. Talk to your provider about whether magnesium supplementation makes sense for you, especially if cramps are a recurring problem.
In the moment, flexing your foot (pulling your toes toward your shin rather than pointing them) helps release an active cramp. Gentle calf stretches before bed, like standing on a step and letting your heels drop, can reduce how often cramps happen. Staying well hydrated during the day also plays a role, since dehydration makes muscles more cramp-prone.
Restless Legs and Iron Levels
Restless leg syndrome, that irresistible urge to move your legs when you’re trying to fall asleep, affects a significant number of pregnant women. It tends to peak in the third trimester but often begins in the second. The exact cause during pregnancy isn’t fully understood, but iron deficiency is one of the most treatable contributing factors.
If your ferritin level (a measure of your iron stores) is below 75 micrograms per liter, oral iron supplementation once or twice daily may improve symptoms. Iron supplementation is generally recommended for pregnant women whose ferritin falls below 30 or whose iron saturation drops below 20%, but for restless legs specifically, the threshold is higher at 75. If you’re dealing with persistent restless legs, it’s worth asking your provider to check your ferritin level rather than just a standard iron panel.
Non-medication strategies include gentle leg massage before bed, moderate exercise earlier in the day, avoiding caffeine, and warm baths in the evening. These work for mild cases and are the first-line approach before adding supplements.
Reducing Nighttime Bathroom Trips
Your kidneys are filtering more blood during pregnancy, and your growing uterus is putting pressure on your bladder. Waking up two or three times to urinate is normal in the second trimester, but you can minimize it. Front-load your fluid intake by drinking most of your water during the morning and early afternoon, then tapering off in the two to three hours before bed. You still need plenty of fluids during pregnancy, so don’t cut back overall. Just shift the timing.
When you do get up, keep the path to the bathroom dimly lit. Bright light suppresses melatonin production and makes it harder to fall back asleep. A small nightlight with a warm (red or orange) tone is ideal.
Building a Sleep-Friendly Routine
Your body temperature rises slightly during pregnancy, and overheating is a common reason for restless sleep. Keeping your bedroom cool, around 65 to 68°F (18 to 20°C), helps. Breathable, moisture-wicking sheets and sleepwear make a noticeable difference, especially if you’re dealing with night sweats.
A consistent wind-down routine signals to your body that sleep is coming. This doesn’t need to be elaborate. Dimming lights 30 to 60 minutes before bed, putting screens away, and doing something low-key like reading or gentle stretching is enough. The consistency matters more than the specific activity.
If you can’t fall asleep within about 20 minutes, get up and do something quiet in another room rather than lying in bed getting frustrated. This prevents your brain from associating the bed with wakefulness, a pattern that can snowball into persistent insomnia if it sets in during the second trimester and continues through the third.
Sleep Aids During Pregnancy
Most sleep medications haven’t been well studied in pregnant women, so options are limited. Diphenhydramine (the active ingredient in many over-the-counter sleep aids) has not been shown in animal studies to increase the risk of birth defects, though some reports have raised questions about first-trimester use. It’s one of the more commonly used options in pregnancy when non-medication approaches aren’t enough, but it can cause next-day grogginess and isn’t meant for nightly use.
Melatonin is widely available but has limited safety data in pregnancy, and dosing isn’t standardized. Many providers are cautious about recommending it. If sleep problems are significantly affecting your daily functioning, the most productive step is a conversation with your provider about what’s specifically keeping you awake. Treating the root cause, whether that’s heartburn, leg cramps, anxiety, or restless legs, is almost always more effective than a general sleep aid.